DEPARTMENT OF THE INTERIOR 

UNITED STATES GEOLOGICAL SURVEY

GEORGE OTIS SMITH, DIRECTOR

BULLETIN 475

THE

DIFFUSION OF CRUDE PETROLEUM 

THROUGH FULLER'S EARTH

WITH

NOTES ON ITS GEOLOGIC SIGNIFICANCE

BY

J. ELLIOTT GILPIN

AND

OSCAR E. BRANSKY

WASHINGTON

GOVEKNMENT PRINTING OFFICE 

1911

CONTENTS.

Page.

Introduction .........^...........i....................................... 5

Object of this investigation................................................. 12

Preliminary experiments ................................ . ................ 12

Relative amounts of oil lost in heated and unheated fuller's earth....... 12

The diffusion of benzene in solution through fuller's earth.............. 15

Fractionation of petroleum................................................ 28

First f ractionation crude petroleum................................... n 28

Specific gravity................................................... 34

Color............................................................ 34

Odor ......'...................................................... 34

Volume of oil retained by the fuller's earth ........................ 34

Second fractionation.................................................. 35

Specific gravity................................................... . 38

Color.......................................'..................... 38

Odor ...............I...................... i.... .;'................. 38

Volume of oil retained by the fuller's earth ........................ 38

Third fractionation ................................................... 38

 Specific gravity ................................................... 41

Color.............................................................. 41

Odor ............................................................. 41

Prolonged diffusion............................................... 41.

Volume of oil retained by the fuller's earth ........................ . 41

Fourth fractionation............................ ...................... 42

Specific gravity.................................................... 43

Color............................................................ 43

Odor ............................................................ .43

Volume of oil retained............................................ 43

Deposition of paraffin............................................. 43

Chemical examination of fractionated oils..........'...'..................... 44

Unsaturated hydrocarbons............................................ 44

Action of concentrated sulphuric acid.......:...........'........... 44

Action of bromine......^......................................... 44

Sulphur compounds ................................:....... .......... 46

Selective action of fuller's earth ........................................ ... 47

Chemical examination of the oils extracted by ether........................ 48

Unsaturated hydrocarbons............................................ 48

Action of concentrated sulphuric acid.............................. 48

Action of bromine................................................ 49

Sulphur compounds ...... .....................^...^.................... 49

Summary---------------------------------------------------.--.-..-.--._. 50

3
ILLUSTRATIONS.

Page. 

FIGURE 1. Arrangement of diffusion tubes.................................. 13

2. Curves bowing results of diffusion of benzene and paraffin oil

through fuller's earth, series 2 ................................ 22

3. Curves showing results of diffusion of benzene and paraffin oil

through fuller's earth, series 3 and 4.......................... 23

4. Curves showing results of diffusion of benzene and paraffin oil

through fuller's earth, series 5 and 6 .'......................... 24

5. Curves showing results of diffusion of benzene and paraffin oil

through fuller's earth, series 7and 8............................ 25

6. Curves showing results of diffusion of benzene, and paraffin oil

.through fuller's earth, series 9and 10.......................... 26

7. Curves showing results of diffusion of benzene and paraffin oil

through fuller's earth ........................................ 27

4
THE DIFFUSION OF CRUDE PETROLEUM THROUGH 

FULLER'S EARTH.

By J. ELLIOTT GILPIN and OSCAR E. BRANSKY.l

INTRODUCTION.

It is well established that the petroleum obtained from the sandstones of the Upper Devonian and Mississippian epo.chs, generally 

known as Pennsylvania oil, differs markedly from the natural oil 

found in the Trenton limestone, usually designated Ohio oil and 

Trenton limestone oil. Both of these oils, in turn, are distinctly 

different from the petroleum occurring in the loose sands and soft 

shales of California. The unconsolidated Tertiary clays, sands, and 

gravels in the southern United States, particularly in Texas, yield still 

another variety of petroleum, characterized by properties more or less 

different from those of any of the other oils.

Not only do these differences exist in.oils found in separate regions, 

but there are extreme variations in color and specific gravity, as well 

as in chemical composition, in many oils occurring in neighboring 

localities. On the other hand, close resemblances are often found 

between petroleums of widely separated regions. Some of the South 

American and many of the European oils, for instance, have been 

found to possess properties very similar to those of the oils of the 

southern United States, while the oil from the "Corniferous" limestone of Canada closely resembles.the Ohio petroleum.

These variations in the oils of the United States and other countries 

have been carefully studied by many investigators. Warren, Storer, 

Mabery, Pelouze, Cahou^s, Schorlemmer, Beilstein, Markownikoff, 

Engler, and Kurbatoff have devoted their lives to the subject. The 

questions that naturally arise in connection with the variations are, 

Are these differences fundamental? Is the Pennsylvania petroleum 

as distinctly different from the Ohio oil as one chemical compound is 

from another ? In 'answer to these questions, the following extract

1 Dissertation submitted to the Johns Hopkins University by Oscar E. Bransky for the degree of doctor 

of philosophy. This research was aided by a grant received from the C. M. Warren committee of the 

American Acadeiny of Arts and Sciences.

5
6

from a paper read by Mabery 1 in 1903 before the American Philosophical Society is of considerable importance:

Now, after years of arduous labor, I have reached the conclusion that petroleum from 

whatever source is one and the same substance, capable of a simple definition a 

mixture in variable proportions of a few series of hydrocarbons, the product of any 

particular field differing from that of any other only in the proportion of the series 

and the members of the series.

The evidence supporting this declaration has been and is accumulating constantly, and at the present time the view is generally 

accepted.

If petroleum, then, is everywhere, one and the same substance, how 

can the extreme variations between the American oils be explained ? 

Were the causes operating in the formation of the Pennsylvania oil, 

which is almost barren of sulphur and nitrogenous bodies, different 

from those acting in the production of the sulphur-bearing oils of Ohio 

or the heavy sulphur and nitrogenous oils of California ?

To account for the formation of crude petroleum, two theories, the 

Organic and inorganic, have been advanced. The Pennsylvania oil, 

according to these theories, may have been formed from either organic 

or inorganic substances, or from both. It'is as yet impossible, however, to state conclusively from which of these sources the oil was 

derived. It is apparent, therefore, that the differences between the 

Pennsylvania and the Ohio, Texas, and California oils can not be 

explained on the assumption that the former was derived from organic 

remains and the latter from inorganic matter, or vice versa. If, however, the oils under discussion are organic in origin, they may have 

been formed either from vegetable or from animal remains. The 

following discussion is based on the assumption that these oils were 

derived from an organic source.

It has been suggested that the differences between these oils may 

be accounted for by assigning a vegetable origin to the Pennsylvania 

oil and an animal origin to the others. Mabery 1 states that 

 It would seem that the small proportion of these bodies [sulphur, nitrogen, and 

oxygen compounds] in the Pennsylvania oil, as compared with the larger proportions 

in the limestone oils and California oil, should be strong evidence in favor of a different 

origin, that the Pennsylvania oil came from organic vegetable remains, which should 

permit of the small amounts of sulphur and nitrogen compounds from this class of oils.

Newberry, Peckham, Orton, and other geologists also favor the 

view that the Pennsylvania oil is of vegetable origin and is derived 

from the organic matter of the bituminous shales of the Devonian 

period.

The association of this oil with a vegetable source has been compelled, it seems, first, by the fact that the oil is of a different character 

from the limestone oils of Ohio and those of Texas and California;

i Proc. Am. Philos. Soc., 1903.
THROUGH FULLER'S EARTH.

second, by the fact that the Pennsylvania petroleum is found in strata 

that bear but few fossils; third, by the belief that the Chemung and 

immediately overlying formations are barren in animal organic 

remains; and fourth, by the existence of large quantities of microscopic fossils,, whose origin many believe is vegetable, in the black 

shales of the Lower and Middle Devonian formations to which many 

investigators are inclined .to refer the origin of the Pennsylvania oil.

Pennsylvania oil differs markedly from the Ohio, Texas, and 

California oils. Investigation has shown that it contains a much 

larger proportion of the paraffin hydrocarbons and a much smaller 

percentage of benzene, unsaturated hydrocarbons, sulphur, and 

nitrogenous bodies. It is further generally admitted that the Pennsylvania oil was not formed in place. These two facts aided strongly 

in assigning a vegetable origin to this oil. .

To what strata should the source of the oil be referred? The 

great coal formations of Pennsylvania, lying above the Chemung, 

seem at first glance to offer a solution. It is a notable fact, however, 

that these formations have not, up to the present time, been connected, either chemically or geologically, with the Pennsylvania oil. 

The possibility exists that it may have been formed from vegetable 

remains in the Carboniferous formations above and. reached its 

present position in the Chemung by downward diffusion. This 

view rests on the physical fact that a liquid diffuses by the force of 

capillarity in all directions, downward as well as upward. Little 

attention has been given to this possibility, but it seems to deserve 

a careful study. Owing, however, to the universal association of 

water under hydrostatic pressure with natural oil and gas, the migration of the latter is generally upward. This fact is attested by the 

accumulation of oil in anticlinal folds when water is present and by 

the existence of the remarkable gushing oil wells. That the Pennsylvania oil, if not formed in place, ascended to its present location 

seems, therefore, more probable.

In what strata below the Chemung, then, was the oil originally 

produced ? It has been previously mentioned that a number of investigators refer the' source of the oil to the black shales of the Lower 

and Middle Devonian. The organic matter of these shales is composed largely of microscopic sporangites, which suggest the existence, 

according to Orton, of masses of floating vegetation, or sargasso seas, 

According to this view the Pennsylvania oil is of vegetable origin 

and its primitive abode was in the shales of Devonian age lying below 

the Chemung formation, to which it ascended under the influence of 

natural agencies. A second view, which assigns an animal origin to 

the oil, is that it was formed in the fossil-bearing strata of Chemung 

age and diffused to the sandstone reservoirs in which'it is now found, 

a*nd that during such a diffusion its original character was changed.
8 DIFFUSION OF CRUDE PETROLEUM

Prof. C. K.°Swartz, of Johns Hopkins University, who has made a 

critical study of the Chemung strata in Maryland, states that fossil 

remains exist in considerable abundance in the strata of this age in 

Maryland and adjoining areas. In Pennsylvania the corresponding 

strata have been found to bear many fossils. It is possible, therefore, that the oil may have formed in these strata and then diffused 

to strata barren of fossil remains, where it now exists.

The evidence accumulated in this investigation seems to show that 

it is not necessary to assign a vegetable origin to the Pennsylvania 

oil to explain the differences between it and the oils of Ohio and California. It is clear from the results of this and other investigations 

that when such oils as those of Ohio, California, and Texas, which 

seem to be animal in origin, are allowed to diffuse through such 

porous media as fuller's earth, they yield oils very similar to those 

of Pennsylvania. By.assuming, therefore, that the Pennsylvania oil 

migrated from some primitive source, in which it may have been formed 

from animal remains, through shales, limestones, and sandstones, its 

peculiar character can be understood.

Wherever the original home of the oil may have been, it seems 

probable that it migrated to its present location from below. It is 

with the changes occurring in crude petroleum as a result of such a 

migration through porous strata that the present investigation is 

primarily concerned.

In 1897 David T. Day,1 on his own observations and those of 

John N. MacGonigle, proposed the view that the Pennsylvania oil, 

at some past time, possessed properties very similar to those of the 

Ohio oil, but that in its migration to its present abode from strata 

below its character was changed. Guided by this view, Day conducted, in the laboratories of the United States Geological Survey, 

an investigation into the changes occurring in crude petroleum when 

allowed to diffuse through porous media, such as fuller's earth. He 

demonstrated clearly that an oil resembling the light Pennsylvania 

oil could be readily produced in the laboratory from the heavier 

crude Ohio oil. Glass tubes were packed firmly with the dry earth, 

through which the crude oil diffused by its own force of capillarity. 

From the earth of the upper sections of the tubes very light, even 

colorless, oils were liberated by treatment with water; from the 

earth of the lower sections of the tubes much darker and heavier oils 

were obtained.

The fractionation, it will be observed, is effected entirely by capillarity; oils with different surface tensions rise with different velocities through the capillary openings, such as the fine interstices and 

minute pores of the fuller's earth. A separation of the .various

constituents making up the complex of any one oil is thus brought

__._______________________________________ _

i Proc. Am. Philos. Soc., 1897.
THROUGH FULLER S EARTH. 9

about. The view once held that this phenomenon is chemical was 

clearly disproved by Engler and Albrecht 1 in 1901, and later by other 

investigators.

Any medium, therefore, sufficiently fine grained and porous to 

afford capillary spaces, causes a separation of the constituents of any 

mixture, provided they possess different surface tensions. The compact sandstones, shales, and limestones that recur in many cycles 

throughout the earth's crust present an excellent medium for the separation of the constituents of so complex a mixture as petroleum. 

The force of capillarity, assisted by the hydrostatic pressure of the 

water occurring in the interior of. the earth, acting over vast periods 

of time, is, it seems safe to state, sufficiently powerful to transport 

the oil from the lower strata to those above. That the conditions, 

therefore, to cause such a migration, with the consequent fractionation of the original oil, are abundantly present appears extremely 

probable.

The members composing the natural oil may be grouped under the 

following general heads: Paraffin; aromatic, unsaturated hydrocarbons; and sulphur, nitrogen, and oxygen compounds. The behavior 

of the paraffin and unsaturated hydrocarbons when subjected to 

fractionation will be considered first.

Day early observed that the unsaturated hydrocarbons are less 

diffusible than the paraffin hydrocarbons. Later, Gilpin and Cram 2 

demonstrated that when petroleum is allowed to diffuse through tubes 

packed with fuller's earth, the unsaturated 'hydrocarbons collect in 

the earth of lower sections of the tubes, while the paraffins tend to 

accumulate in the lightest fraction at the top of the tube. In the 

present investigation these results have been fully confirmed. On 

pages 44-45 are given the bromine absorption values and the percentages by volume absorbed by concentrated sulphuric acid of the 

various oils obtained from definite sections of a tube. These figures 

indicate conclusively that the amount of unsaturated hydrocarbons 

is much greater in the oils from the lower sections of the tube than in 

the lightest fractions at the top of the tube. Furthermore, the bromine absorption values for the oils of similar fractions of the first, 

secondj and third fractionation, given on page 46, show that in the 

progress of the fractionation more and more of the unsaturated 

hydrocarbons are removed. Herr, 3 in Russia, has likewise observed 

that these hydrocarbons are less diffusible than the paraffins.

. An interesting confirmation of these experiments in nature has been 

recently presented by Clifford Richardson and K. G. MacKenzie.4 

They found that a colorless natural naphtha from the Province of

1 Zeitschr. angew. Chemie, 1901, p. 889. 3 Petroleum, August, 1909.

2 Bull. U. S. Geol. Survey No. 365,1908. « Am. Jour. Sci., May, 1910.
10

Santa Clara, Cuba, contained practically no unsaturated hydrocarbons but was almost entirely a mixture of naphthenes and paraffins. 

Concentrated sulphuric acid absorbed but 0.76 per cent by volume, 

while fuming sulphuric acid absorbed only 1.8 per cent. With the 

naphtha were obtained water and an emulsion of water,.oil, and clay. 

These investigators are of the opinion that the naphtha was "undoubtedly formed by the upward filtration of heavy petroleum through the 

clay stratum, similar to the fuller's earth filtrations of Gilpin and 

Cram, and the light naphtha in the upper part of the stratum was 

afterwards partly liberated by saline waters, the oil remaining in the 

clay forming, with water, the emulsion."

A'comparison of the proportions of the unsaturated hydrocarbons 

in the Ohio and Pennsylvania oils shows that the latter contain a much 

smaller percentage of these hydrocarbons. By assuming that the 

Pennsylvania oil diffused upward through such porous media as shales 

and limestones to its present location in the sandstones, it is possible 

to account for. the smaller amounts of the olefines in it on the basis of 

the experimental work described above. In its passage through the 

capillary interstices of the clays, limestones, and sandstones, a fractionation, resulting in the removal of the unsaturated hydrocarbons, 

probably occurred. It is reasonable to conclude, therefore, that the 

variation in the content* of unsaturated hydrocarbons between the 

Ohio, Texas, and California oils, on the one hand, and the Pennsylvania oil, on the other, can probably be accounted for by assuming, 

that the Pennsylvania oil was subjected to capillary diffusion at some 

time in its career. That the light-colored naphthas occurring in 

different parts of the world were originally darker and heavier oils, 

 and that their primitive character was changed by diffusion through 

media possessing the power of fractionation seems very probable.

The behavior of the aromatic hydrocarbons, in particular benzene, 

in passing through fuller's earth constitutes one of the subjects of 

this investigation. The results of this study, given in detail on pages 

15-28, indicate clearly that benzene, like the olefines, tends to collect 

in the lower sections of a tube.of fuller's earth.through which the 

benzene, in solution, is allowed to diffuse. ; That the aromatic 

hydrocarbons in the natural oil behave in a.similar manner has not 

yet been decided. The proportion of these hydrocarbons in the Illinois oil investigated was too small to enable us to determine accurately their amounts in the fractions obtained by the capillary diffusion of the crude oil. The ordinary methods, such as nitration with 

the mixture of nitric and sulphuric acids, and sulphonation, employed 

for the quantitative determination of the aromatic hydrocarbons, 

could not be used in this work, owing to the fact that these reagents 

readily affect the unsaturated hydrocarbons as well." A study of 

the conduct of the aromatic hydrocarbons in the natural oil contain-
THEOUGH FULLER's EARTH. 11

ing large amounts of them will be undertaken in the near future. 

It is probable, however, that the benzene and homologous compounds 

in crude petroleum behave like the unsaturated hydrocarbons.

The presence of larger amounts of aromatic hydrocarbons in the 

Ohio than in the Pennsylvania petroleum, and of still larger amounts 

in the California and Texas oils, seems to afford further evidence in 

favor of the view that the Pennsylvania oil has undergone much 

greater diffusion, and consequently greater fractionation, than any 

of the other oils.

The conduct of the sulphur compounds in petroleum in the process 

of diffusion is similar to that of the unsaturated hydrocarbons. On 

page 46 the percentages of sulphur present in the oils from different 

parts of the.tube and different stages of fractionation are tabulated. 

One series of figures will be given here to show the behavior of the 

sulphur compounds.

Behavior of sulphur compounds in fractionation.

Percent 

First fractionation (lot 6): of sulphur.

Fraction A................................................. 0.04

Fraction B...........:..................................... .05

Fraction D.................................................. .09

Fraction E............:......... ........................... .16

Second fractionation: Fraction A................................ .04

Third fractionation: Fraction A.................................. . 003

It is clear from these figures that the sulphur compounds, like the 

unsaturated hydrocarbons, tend to collect in the lower sections of a 

layer of fuller's earth through which petroleum is allowed to diffuse.

In 1902 Clifford Richardson and E. C. Wallace, 1 in an investigation 

on the occurrence of free sulphur in Beaumont petroleum, passed 

the oil upward through a fuller's earth filter similar to one described 

by Day at the petroleum congress in Paris in 1900, and obtained 

distinct fractionation. The percentages of sulphur in the crude oil 

and in the oils obtained by this fractionation were determined. The 

results are given in the following table:

Percentages of sulphur in crude oil and after fractionalion.

Third fraction. .....................................................................

Specific 

gravity 25° 

25°

0. 9140

.8775

.8986

.9038

Per cent of sulphur.

1.75

.80

.91

1.04

1 Jour. Soc. Chem. Ind., March, 1902.
12 DIFFUSION OF CRUDE PETROLEUM

It seems reasonable to assume from these results that the variations in the sulphur content between the Pennsylvania and Ohio 

oils may be satisfactorily explained by the view that the former oil, 

as previously stated, diffused from other strata to its present location, 

and in its migration a large part of its original content of sulphur 

was removed. Further work on this point will be undertaken in the 

Johns Hopkins University laboratory.

No careful study of the behavior of the nitrogen and oxygen compounds in petroleum diffusing through a porous medium has yet 

been undertaken, but such an investigation will be pursued in the 

same laboratory later. It is probable that such an investigation 

will show that the nitrogen compounds act like the sulphur and 

unsaturated compounds.

OBJECT OF THIS INVESTIGATION.

The present investigation was undertaken for the immediate purpose of studying the changes occurring in the crude Illinois oil when 

allowed to diffuse through fuller's earth. The more distant but 

more fundamental object was to gain further insight into the causes 

of the variations among the oils of this country.

PRELIMINARY EXPERIMENTS.

RELATIVE AMOUNTS OF OIL LOST IN HEATED AND UNHEATED

FULLER'S EARTH.

Before the actual investigation of the Illinois oil was undertaken, 

experiments were made to determine the relative amounts of oil 

lost in heated and unheated fuller's earth.1 In the work of Gilpin 

and Cram the earth was always heated until geysers ceased to form 

and then allowed to cool for several hours. The purpose of heating 

the earth was to obtain larger yields of oil, but toward the close of 

their investigation it became apparent that the amount of oil lost 

in unheated fuller's earth was not as large as they had supposed it 

to be. As much time and labor is consumed in the process of heating 

and then cooling the earth, it seemed advisable to settle this point 

at the outset.

The apparatus employed for the present investigation was essentially the same as that used by Gilpin and Cram. Figure 1 shows the 

arrangement of the diffusion tubes. A, A, A, A are tin reservoirs 

made to hold-somewhat more than a liter. The tin tubes B, B, B, B, 

5^- feet long and 1| inch in diameter, rest upon narrow tin supports 

placed upon the bottom of the reservoirs, and are connected with the 

branched glass tube F by suction tubing fitted with pinchcocks at

 i The fuller's earth employed in this work was generously supplied by the Atlantic Refining Co., of 

Philadelphia.
TKROUGH FULLER S EARTH. 13

E, E, E, E. The branched, glass tube is connected with the large 

tank C, which serves to maintain fairly constant pressures; C is in 

turn joined by the glass* tube D to a manometer, and the latter is 

connected with the Chapman pump. Any number of tubes may be 

set up in series under the same diminished pressure.

After the tubes are closed at their lower ends, with grooved corks 

covered with muslin to prevent the earth from sifting out, they are 

packed to the desired firmness with the fuller's earth. Each tube is 

then placed in its own reservoir, containing the oil to be fractionated. 

When they are connected to the branched tube F, the pressure in the 

system of tubes is reduced by the suction pump. The oil rises at 

first rapidly; then its diffusion gradually diminishes in power. When 

the reservoirs are almost exhausted, the tubes are disconnected and

_&:

D

To pump

FIGUEE 1. Arrangement of diffusion tubes. See text for explanation.

clamped with the bottom ends up above shorter tubes of the same 

diameter, into which the oil-laden earth is allowed' to slide. These 

shorter tubes are made of two curved pieces, joined at the bottom by 

a cap and held together at the top by a ring. The cylinders are 

opened by slipping off the ring and cap and removing one of the curved 

pieces, and the earth is divided into the desired sections. When 

water is'added in portions to the earth and the two mixed thoroughly, 

the oil is displaced and is drawn off in separate portions.

Six tubes packed with heated fuller's earth were set up alternately 

with six tubes filled with the unheated earth. Each tube was placed 

in its own reservoir containing 950 cubic centimeters of crude oil. 

The oil was allowed to diffuse upward through the tubes under diminished pressure. The oil in the reservoirs was not exhausted until
14

16 hours had elapsed. As the tuhes did not rest directly upon the 

bottoms of the reservoirs, a small amount of oil remained in each; 

the volumes were subtracted from the volumes originally supplied. 

The earth from each tube was shaken into a bucket, and the oil was 

recovered by displacement with water, as described above. The 

results of these experiments are arranged in the following table:

Pennsylvania oil lost on heated and unheated fuller's earth. 

Heated fuller's earth.

.Tube.

1.... ................................................ 3 ........................-.................:.........

5.... ............._...........................-.-....

7....................................................

9....................................................

11 ...................................................

Weight 

of fuller's 

earth 

(grams).

1,005 

1,000 

1,035 

1,070 

1,035 

1,045

O'il a'bsorbed 

by earth 

(cubic centimeters).

850 

792 

850 

8G5 

813 

885

5,055

Oil recovered 

(cubic centimeters).

450 

460 

500 

450 

430 

530

2,830

Oil lost.

Cubic centimeters.

390 

332 

350 

415 

383 

355

2,225

Per cent.

46 

41 

41 

48 

47 

41

44

Unheated fuller's'earth.

2....... ..........................:....,.......... ....

4....................................................

6.......... :....... ....................................

8....................................................

10.....:.....................----.--..........-.-....

12........ ............................................

1,075

1,095

1,065

1,045

1,035

1,055

917

853

840

814

873

850

5,147

585

562

500

435

510

485

3,077

332

291

340

379

363

365

2,070

36

34

42

46

41

40

The petroleum employed in the above-described experiments was 

a dark-green oil from Venango County, Pa., possessing a specific 

gravity of 0.810. As the Illinois oil which was used in the fractionation proper, described later, differs materially from the Pennsylvania 

petroleum, further experiments were undertaken to determine the 

relative amounts of this oil retained by heated and unheated earth.

Ten tubes, of which five were packed as uniformly as possible with 

fuller's earth that had been heated until geysers ceased to form and 

the other five with unheated earth, were placed in reservoirs, ea'ch 

containing 950 cubic centimeters of Illinois oil, having a specific 

gravity of 0.8375. When the oil was entirely absorbed, the tubes 

 were taken down, the oil-laden earth was shaken into two breakable 

cylinders, and divided into six sections A, 10 centimeters in length, 

measured downward from the level to which the oil had ascended; 

B, the next 15 centimeters; C, 20 centimeters; D, 30 centimeters; 

E, 35 centimeters; F, the remainder of the earth to the bottom of 

the tube. Section F was entirely discarded.

The earth was then treated with separate portions of water. The 

oils displaced by the successive additions of water were collected 

separately and are designated in the table below as A1 , A2 , B1 , B2;
THEOUGH FULLER, S EARTH. 15

and so on; A1 is the oil first displaced, A2 the oil next expelled by 

further additions of water. The volumes and specific gravities of 

the recovered oils were determined. The results are expressed in 

the following table:

Fractions of Illinois oil recovered after diffusion through fuller's earth.

Fraction.

A' ......................................... '. . ..........'........

A*.............................-................................

B' .............................................................

B2. ............................................................ ci;.............................................................

C2 . ........................ . . ...................................

DI .............................................................

D2.... .........................................................

E' .............................................................

E2

Heated fuller's 

earth.

Specific 

gravity.

0.8287

.8390 

.8485 

.8441 

.8507 

.8450 

.8490 

.8537 

.8504

Volume 

(cubic 

centimeters).

100

157 

35 

280 

 67 

393 

132 

339 

174

1,701

Unheated fuller's 

 earth.

Specific 

gravity.

0.8320 

. 8352 

.8405 

.8451 

.8443 

.8495 

.8483 

. 8517 

. 8500 

.8509

Volume 

(cubic 

centimeters).

72 

22 

184 124' 

270 

147 

308 

210 

SCO 

185

1,942

In these experiments the percentage of oil lost in the unheated 

earth is less than the percentage of oil lost in the heated earth. 

Gilpin and Cram, employing heated earth, recovered in one test 

5,951 cubic centimeters from 9,070 cubic centimeters, and in another 

5,415 cubic centimeters from 8,915 cubic centimeters, the amount of 

oil lost in the earth in the first test corresponding to 34 per cent and 

in the second to 39 per cent. It is clear, therefore, that there is not 

sufficient compensation, if any, for the time and labor spent in heating the earth. In the investigations that followed the unheated 

fuller's earth was always used.

THE DIFFUSION OF BENZENE IN SOLUTION THROUGH FULLER'S

EARTH.

In order to deal more intelligently with the fractionation of the 

crude Illinois petroleum, it seemed advisable to study the behavior 

of the individual aromatic hydrocarbons, especially benzene, both 

alone and mixed with paraffin hydrocarbons, when allowed to diffuse upward through fuller's earth. Gilpin and Cram established 

the fact that the paraffin hydrocarbons tend to collectin the lightest 

fractions at the top of the tube. Their method consisted in distilling 

by heat six samples of oils of different specific gravities, each 300 

cubic centimeters in volume, and collecting 10 fractions between 

definite intervals. Five of these samples consisted of oil partly 

fractionated by fuller's earth and the other sample consisted of the 

crude oil. The specific gravity and viscosity of each fraction were 

determined; then»to 30 cubic centimeters, or to all there was where
16 . DIFFUSION OF CRUDE PETROLEUM

the amount was less than 30 cubic centimeters, an equal volume of. 

concentrated sulphuric acid (specific gravity 1.84) was added, and 

the two were shaken by a machine for half an hour or longer. The 

volume of the oil unaffected by the acid was measured, and by subtraction the volume of oil absorbed was calculated. This latter 

volume represents only approximately the -percentage of unsaturated hydrocarbons present in the oil, because sulphuric acid of 

this strength readily dissolves benzene when the two are thoroughly 

shaken.

In this investigation various solutions of benzene and a refined 

paraffin oil, boiling between 160° and 240° and only slightly attacked 

by sulphuric acid, were made up and allowed to rise in tubes packed 

with unheated fuller's earth. The pressure in the system was 

reduced very little, because the liquid, under a greatly diminished 

pressure, rose too rapidly. About 24 Jiours elapsed before the oil 

in the reservoirs was exhausted.

The earth in each tube was shaken out and divided into six sections. Beginning at the uppermost point to which the oil had 

ascended grade A consisted of the first 8 centimeters, grade B of 

the next 8 centimeters, grade C of 18 centimeters, grade D of 30 

centimeters, grade E of 35 centimeters, and grade F of the remainder 

of the earth, depending on the height to which the oil had ascended. 

This division is the same as that used by Gilpin and-Cram. The 

oil in the earth was displaced by water and drawn off.

The specific gravity of each fraction was determined by means of 

the Mohr-Westphal balance at exactly 20° C. The fourth decimal 

place is not to be considered as strictly accurate, but gives a closer 

approximation to the truth than if it were entirely discarded.

The viscosity was determined by means of the viscosmeter described 

by Ostwald and Luther and modified by Jones and Veazey. 1 The 

time taken for measured volumes of the oils to drain from the small 

bulb, whose capacity was 4.5 cubic centimeters, was compared with 

the. time required for a similar amount of water to run through. 

These values were substituted in the equation 

TS 

y=yo^-Lo^O

in which 

y0 =coefficient of viscosity of water. For this, 0.01002, the value obtained by

Thorpe and Rodger, 2 was used. 

T =time of flow of liquid under examination.

S =specific gravity, measured at 20° C., of liquid under examination. 

T0 =time of flow of water. 

g0 =specific gravity of water. Since the balance was calibrated for water

20° C., the value for S is unity, 

y =coefficient of viscosity of oil under examination.

i Zeitschr. physikal. Chemie, vol. 61, p. 651. * Philos. Trans., Vol. 185A, 1894, p. 397.
THROUGH FULLER S EARTH. 17

The amount of benzene present in each fraction was determined 

by shaking the oil with an excess of ordinary concentrated sulphuric 

acid (specific gravity 1.84) for periods of time varying from 30 to 

60 minutes, until there was no further diminution in the volume of 

the oil.

The results of the experiments tabulated below demonstrate the 

power of this acid to dissolve benzene, .forming benzene-sulphonic 

acid:

Action of concentrated sulphuric acid (specific gravity 1.84) on benzene when shaken by

machine.

Benzene 

taken 

(cubic centimeters).

25

25

25

Acid 

 taken 

(cubic centimeters).

25

50

75

 Time 

.shaken 

(minutes).

30

30

30

Benzene dissolved.

Cubic centimeters.

7

18

25

Per cent.

28

72

100

The reagents usually employed for removing benzene are a mixture of fuming nitric and concentrated, sulphuric acid. The work of 

Worstall, 1 Francis and Young, 2 and others shows that such a mixture readily attacks the paraffin hydrocarbons, especially at higher 

temperatures, forming nitro-derivatives and also oxidizing them to 

a considerable extent. Furthermore, in working with this mixture 

the oil must be kept at a low temperature to prevent a violent reaction, which results usually in the decomposition of the oil. In this 

work, therefore, in order to avoid the danger of attacking the paraffin 

hydrocarbons and for the sake of convenience concentrated sulphuric 

acid was used.

It seems advisable, at this point, to call attention to the fact that 

the power of ordinary concentrated sulphuric acid to remove benzene 

and homologous hydrocarbons has been generally overlooked. In 

order to determine the percentages of these hydrocarbons it is customary to shake the oils to be analyzed with concentrated sulphuric 

acid and then to nitrate the unaffected oil. It is assumed that the 

acid removes such substances as the unsaturated hydrocarbons' and 

does not attack the aromatic hydrocarbons. Thus, P. Poni,3 in determining the presence and percentage of aromatic hydrocarbons in 

Roumanian petroleum, collected fractions between 35° and 70° C., 

distilled under diminished pressure. These were purified by shaking 

with sulphuric acid, and each was nitrated with a mixture of 1 part

1 Am. Chem. Jour., vol. 20, p. 202; vol. 21. p. 210.

2 Jour. Chem. Soc., 1898, p. 928.

' Annales sci. Univ. Jassy, 1907, pp. 192-202. (Abstracted in Jour. Chem. Soc., voL 82,19Q7.)

89823° Bull. 475 11 2
18 DIFFUSION OF CRUDE PETROLEUM

of nitric acid (specific gravity, 1.52) and 2 parts sulphuric acid (specific 

gravity, 1.8). The recovered oils were assumed to be paraffins and 

naphthenes, while the proportions of benzene and unsaturated hydrocarbons were calculated from the nitro-products obtained. It is 

obvious from the results obtained in the present work that some of 

the benzene was removed in the process of purifying the fractions. 

The amount dissolved depended on the vigor of the shaking and its 

duration, as well as the strength of the sulphuric acid. It is highly 

probable, therefore, that Poni's percentage of benzene is too low.

In the study of the mixture of benzene and paraffin hydrocarbons 

25 cubic centimeters of each fraction, or all there was when the amount 

was less, was shaken vigorously with three times the volume of concentrated sulphuric acid for 30 minutes. The amount unabsorbed 

was measured over the acid in a burette, after sufficient time had been 

allowed for most of the oil mechanically held in suspension to rise. 

The oil was then reshaken with a little more acid for 15 minutes and 

the volume again read. When the benzene was present in small quantities one shaking was sufficient; when larger amounts were present 

shaking was repeated.

The paraffin oil employed (specific gravity, 0.797) was shaken several times with fresh portions of concentrated sulphuric acid until 

the coloration of the acid disappeared, and only a slight diminution 

in volume occurred when a small sample of the oil was thoroughly 

shaken by machine for some time with the acid. The oil was then 

washed with water and sodium hydroxide and dried over calcium 

chloride. The specific gravity decreased to 0.792. 

When this oil was mixed with benzene in various proportions and 

allowed to diffuse upward through fuller's earth the following results, 

arranged in series, were obtained:

Results of diffusion of benzene and paraffin hydrocarbons through fuller's earth.

Series 1, oil alone.

[Specific gravity, 0.792. Level of oil, 28 centimeters.]

Grade.

A ........................................................

B................................ ..........................

C..... ...................................................

D. ........................:.............................

E.. ......................................................

F ........................................................

Volume 

of oil 

(cubic centimeters).

11

17

60

100

150

139

477 

778

Specific 

gravity.

0.789

.792

.7912

. 7915

.7913

.7915

Viscosity.

0.0154

.0140

.0134

.0134

Per cent of 

benzene.

(«)

«:In this series the percentages of'benzene a«e not given, because the paraffin oil alone was used.

b '(The original volumes of solution vary with each series, owing to the fact that more or less always remained 

behind in the reservoir below the level of the tin support. In series 1, ", 3, and 4, 950 cubic centimeters 

was.-supplied t.o .each .reservoir; in .the rast of the series each .reservoir contained originally 1,000 cubic centimeters.
THROUGH FULLER S EARTH. 19

Results of diffusion of benzene and paraffin hydrocarbons through fuller's earth Contd.

. Series 2, 90 per cent oil (0.792), 10 per cent benzene (0.8775). 

[Specific gravity, 0.7983. Level of oiJ, 22 centimeters.]

A.........................................................

B ........................................................

C..... ...................................................

D. .......................................................

E.... '....................................................

F... .....................................................

11 

10 

56 

109 

145 

245

582 

872

0.787 

.7923 

.7935 

.7943 

.7957 

.7955

0. 0131 

.0123 

.0120 

.0116

10.0 

13.3 

11.6 

14.8 

14.4 

14.8

Series 3, 80 per cent oil (0.792), 20 per cent benzene (0.8775).

[Specific gravity, 0.806. Level of oil, 25 centimeters.]

A........................................................

B... :....................................................

C..... ...................................................

D. .......................................................

E.. ......................................................

F... .....................................................

25. 

35 

78 

128 

166 

146

576 

892

0. 7948 

.7981 

.8017 

.8005 

.801 

.798

0. 0147 

.0130 

.0117 

.0105 

.0107 

.0110

15.3 

16 

22.4 

21.6 

22.4 

20.8

Series 4, 75 per cent oil (0.792), 25 per cent benzene (0.8775). 

[Specific gravity, 0.810. Level of oil, 33 centimeters.]

A........................................................

B.......... ..............................................

c.. .......................................................

D. ........................................'......-........

E.. ......................................................

F.... ....................................................

16 

35 

74 

128 

152 

120

525 

655

0.800 

' .803 

.8077 

.805 

.8068 

.8065

(a) ' 

0. 0129 

.0126 

.0114 

.0102 

. 0105

22 

23.3 

24. 

24 

26 

28

Series 6, 75 per cent oil (0.794 &), 25 per cent benzene (0.8775). 

[Specific gravity, 0.8115. Level of oil, 24 centimeters.]

A........................................................

B............................................ ............

c.. .......................................................

D........................................................

E........................................................

F... .....................................................

25 

28 

70 

140 

172 

144

579 

875

 0.7942 

.8048 

.8105 

.8100 

.8100 

.8093

0. 0123 

. 0104 

.0094 

.0094 

.0094 

.0095

14 

21.2 

31.2 

27.6 

32 

27.6

a The viscosities of grades A and B in a few of the tables are not given, because in these series, the first 

made, the decision to determine the viscosities was reached only after the fractions had been treated with 

acid. As A and B were small in amount, all the oil was used in this treatment.

& As the quantity of oil of specific gravity 0.792 was not sufficient for all the series, a second quantity 

with the specific gravity 0.794 was prepared. This oil was used in series 5, 8, 9, and 10.
20 DIFFUSION OF CRUDE PETROLEUM

Results of diffusion of benzene and paraffin hydrocarbons through fuller's earth Contd.

Series 6, 75 per cent oil (0.792), 25 per cent benzene (0.8775). 

[Specific gravity, 0.8083. Level of oil, 27 centimeters.]

Grade.

Volume 

' of oil 

(cubic centimeters).

Specific 

gravity. Viscosity. Per cent of benzene.

22

32

82

155

190

93

0.7995 

.8055 

.8052 

.8085 

 .8085 

.8003

0.0106

.0099

.0100

.0093

.0093

.0096

Original volume.

574

923

Series 7, 59.5 per cent oil (0.792), 40.5 per cent benzene (0.8775). 

[Specific gravity, 0.8223. Level of oil, 9 centimeters.]

Original volume.

96

160

255

583

922

0.8069

.816

.8182

.820

.8185

0.0103

.0086

.0082

.0083

Series 8, 50 per cent oil (0.794), 50 per cent benzene (0.8775). 

[Specific gravity, 0.8295. Level of oil, 17 centimeters.]

A......................................................... 22 0.8122

B...........................-..---.-----..-.-.-.......... 32 .819

C......................................................... 78 .8287 0.0077

D............:........................................... Ill .8275 .0077

E...........................-.....-.--.--.-.-.-.-..--.... 155 .827 .0077

F........................................................ 192 .8256 .0079

590 

Original volume.......................................... 960

Series 9, 50 per cent oil (0.794), 50 per cent benzene (0.8775). 

[Specific gravity, 0.8315. Level of oil, 18 centimeters.]

A..............-..--..-...-......--.........-....-.---.-- 18 0.816 0.0091

B.......................................................... 24 .8210 .0085

C........................................................ 76 .8275 .0078

D........................................................ 136 .8283 .0077

E......................................................... 174 .8293 .0076

F........................................................ 144 .8277 .0078

572 

Original volume.......................................... 923

Series 10, 50 per cent oil (0.794), 50 per cent benzene (0.8775). 

[Specific gravity, 0.8295. Level of oil, 16 centimeters.]

A........................................................ 31 0.8135 0.0097

B........................................................ 45 .8251 .0081

C......................................................... 85 .8290 .0076

D......................................................... 140 .8280 .0077

E........................................................ ' 175 .8285 .0076

F........................................................ 137 .8272 .0076

613 

Original volume.......................................... 972

o In series 7 the volume of grade A recovered was so small that no measurements could be made.
THROUGH FULLER S EARTH. 21

Results of diffusion of benzene and paraffin hydrocarbons through fuller's earth Contd.

Series 11, 75 per cent crude oil (0.810), 25 per cent benzene (0.8775). 

[Specific gravity, 0.8312. Level of oil, 18 centimeters.]

Grade.

A........................................................

B ........................................................

C.. ......................................................

D ........................................................

E. .......................................................

F........................................................

Volume 

of oil 

(cubic centimeters).

12

22

52

70

140

186

488 

son

Specific 

gravity.

0. 8255

.8208

.8280

.8290

.8300

.8320

Viscosity.

0. 0445

.0423

.0300

.0298

.0263

.0270

Per cent of 

benzene.

(«)

Series 12, benzene alone.

[Specific gravity, 0.8775. Level of oil, 33 centimeters.]

A........ ....................^......... ..................

B .........................................................

c.:. ......................................................

D. .......................................................

E ........................................................

F.................. .....................................

10

15

68

128

157

89

473 

888

0.87G5

.877

.878

.8778

.8775

.8771

0. 0006

.0060

.0066

.0000

a The percentages of benzene in series 11, in which crude oil was em'ployed, are not recorded, because, 

owing to the formation of heavy black emulsions, the loss in volume could not be determined with any 

degree of accuracy.

The results tabulated for series 2 to 10 are expressed diagrammatically in the curves shown in figures 2 to 6. The ordinates 

represent the different grades of oil, and the abscissas the percentages' 

of benzene and the specific gravities. The curves in figure 7 represent 

as a whole the results of the experimental work on the diffusion of 

benzene in solution through fuller's earth. The ordinates of these 

curves represent the percentages of benzene, and. the abscissas the 

various mixtures of benzene and oil that were allowed to diffusethrough the earth.

An examination of these shows conclusively that benzene tends to 

collect in the lower portions of the tube. The specific gravities and 

viscosities confirm the results obtained by determining the percentages of benzene present by removing the benzene with concentrated 'sulphuric acid. The specific gravities of grades F to C run 

very close together and are all much greater than those of grades 

A and B. As benzene possesses a high specific gravity in this work 

the specimen had a specific gravity of 0.8775 the larger values for 

the lower grades indicate the presence of larger amounts of benzene. 

The specific gravity of the paraffin oil was only 0.792, showing that 

the higher specific gravities were due to larger percentages of ben-
22 DIFFUSION OF CRUDE PETROLEUM

zene. Moreover, as the viscosity of the benzene used was 0.0066 

and that of the paraffin oil about 0.0150, the viscosities of the fractions containing higher percentages of benzene ought to be much 

smaller than those of the fractions containing less benzene. The 

results show that the viscosities of grades F, to C are much smaller 

than those of A and B.

It will be observed that the maximum in specific gravity is not at 

F, as may be expected in the fractionation of the crude oil, but

I

Series Z

2.0

Per Cent

30 40.

Benzene

.78OO .790O .800O .8IOO .8200

Specific Gravity

FIGURE 2. Curve showing results of diflusion of benzene and paraffin oil through fuller's earth, series 2.

between C and D. Between B and G there is a marked decrease. 

This sudden break is found also in the viscosities and in the percentages of benzene. While the sharp breaks in the curves represent 

the marked change in the proportion of benzene and the height to 

which it rises in the tube, no satisfactory explanation has yet been 

obtained as to why it should occur at these points. This action 

will be studied more carefully later.
THROUGH FULLER-S EAKTH. 23

Series 3

\

Series 4-

O IO 2O 3O 4O .79OO .8OOO .8IOO .820O .8300

Per Cent Benzene . Specific Gravity

FIGURE 3. Curves showing results of diffusion of benzene and parafFm oil through fuller's earth, series

3 and 4.
24 DIFFUSION OF CRUDE PETROLEUM

Series 5

<D XI

<0

u 0 

O

Series 6

t- 0

0

10 2O 30 4O

Per Cent Benzene

.79OO .SOOO .8IOO .820O .830O

Specific Gravity

FIGUBE 4. Curves showing results of difEusion of benzene and paraffin oil through fuller's earth, series

5 and 6.
THKOUGH PULLER S EARTH. 25

Series 7

\

Series 8

TJ. 

10

«- D

ib 20 so AO .7900 .eooo .aioo .BZOO .eaoo 

Per Cent Benzene Specific Gravity

FIGURE 5. Curves showing results of diffusion of benzene and paraffin oil through fuller's earth, series

7 and 8.
26 DIFFUSION OF CRUDE PETROLEUM

Serfes 9

Series 10

\

0) 

TJ

(0 .

1- D 

(D

Q to 2O 30 4O .790O .8OOO .8IQO .820O .83OO

Per Cent Benzene Specific Gravity

FIGURE C. Curves showing results of diffusion of benzene and paraffin oil through fuller's earth, series

' 9 and 10.
THROUGH FULLER S -EARTH. 27

In order to determine the degree of exactness of the percentages 

.of benzene obtained, known amounts of benzene were added to the

0-20

Grade C

10% Benzene 20% Benzene 25% Benzene 50% Benzene 

90% Oil 80% Oil 75% Oil' 50% Oil 

Mixtures Fractionated

FIGURE 7. Curves showing results of diffusion of benzene and paraffin oil through fuller's earth.

oil until the specific gravity corresponded closely to that obtained by 

fractionation.

The amount of benzene thus added and the amount actually 

removed by the acid agree very closely, as the following results show r

Results of tests to determine accuracy of benzene percentages.

Benzene in 25 cubic 

centimeters of mixture.

Cubic centimeters.

7.3 

9.4 

11.1 

11.3 

11.9

Specific 

gravity.

0. 8143 

.8213 

.8274 

.8287 

.8293

Benzene found in series 8.

Cubic centimeters.

Grade A, 7.9 

Grade B, 10. 9 

Grade F, 12. 5 

Grade E, 12. 4 

Grade C, 11. 6

Specific 

gravity.

0. 8135 

.8251 

.8272 

.8287 

.8290
28 DIFFUSION OF CRUDE PETOOLEUM

The variations in the specific gravities of the prepared mixtures 

and those of grades A to F are due to the fact that in the latter some 

fractionation had taken place in the paraffin oils, while in the mix-' 

tures the same paraffin oil was used each time. The paraffins found 

in grades A to F, therefore, exhibited slight gradations not common to 

the unfractionated paraffin oil used in preparing the mixtures.

FRACTIONATION OF PETROLEUM.

FIRST FRACTIONATION CRUDE PETROLEUM.

The petroleum employed for the fractionation was an oil obtained 

by the United States Geological Survey from the E. E. Newlin farm, 

2^ miles west of Eobinson, Crawford County, 111. The specific 

gravity of the oil was 0.8375 at 20° C.; its' color was dark brown.

The fractionation of the oil was effected by upward diffusion 

through tubes packed with fuller's earth. In order to shorten the 

time required for the oil to diffuse by capillarity to the upper parts 

of the tube, the fine interstices and pores of the earth were evacuated 

by applying diminished pressure at the top of the tube. By this 

aid the time required for the oil to reach the top of a tube was reduced 

from several weeks to one or two days.

The apparatus employed is the same as that described on page 12.

The tin tubes, 5^ feet long and 1£ inches in diameter, were packed 

as uniformly as possible by introducing definite amounts of earth 

and ramming solidly with rods tipped with rubber stoppers. The 

degree of compactness depended on the kind of oil to be used. For 

the crude oil about 1£ feet of the tube was filled at a time, and the 

earth packed as firmly as possible; for the lighter oils, 1 foot of the 

tube was filled at a time; for the oils heavier than the crude, between 

2 and 3 feet of the tube was filled at one time.

The tubes were then placed individually in reservoirs containing 

950 cubic centimeters of the crude oil, after which diminished pressure 

was applied at the top of the tubes. The oil rose rapidly at first, 

then diffused more and more slowly as it approached the tops of the 

tubes. When the oil in the reservoirs was completely exhausted the 

tubes were disconnected from the branced glass tube (see fig. 1, 

p. 13), and the oil-laden earth was shaken into two breakable cylinders. The following divisions of the earth were made: Fraction A, 

the first 10 centimeters measured downward from the level to which 

the oil had ascended; fraction B, the next 15 centimeters; C, 20 

centimeters; D, 30 centimeters; E, 35 centimeters; and F, the remainder to the bottom of the tube. In the first fractionation up to lot 28, 

fraction F was discarded; from lot 28 to the end of the first fractionation, E and F were collected together.

After the earth was thus divided the several portions were placed 

in separate receptacles and treated with water. After each addition 

of water each portion was thoroughly mixed with it. The earth,
THROUGH FULLER S EARTH. 29

when the oil first appeared, was granular; as more water was added, 

liberating more oil, the earth became muddy, and when as much oil 

as possible had been expelled by the water, the earth had the consistency of glue.

The portions of oil liberated by successive additions of water were 

collected separately. As Gilpin and Cram 1 pointed out, the oil that 

is first expelled, if not very small in volume as compared with the 

succeeding portions, possesses a lower specific gravity than the oil 

liberated by further additions of water; the latter in turn is lighter 

than the next succeeding oil. The oil that is liberated last, therefore, possesses a higher specific gravity than any of the portions preceding it. Sometimes, however, the specific gravity remains constant 

after the second or third extraction. This fractionation by means 

of water was combined with the fractionation effected by the fuller's 

earth. In the tables that follow A1 represents the oil first liberated, 

A2 the oil next liberated, etc. In the lower fractions (C, D, and E), 

three and sometimes four extractions were made before all the oil 

that could possibly be liberated by water was recovered.

The specific gravity of the oils was determined by means of the 

Mohr-Westphal balance. As mentioned before, the fourth decimal is 

not to be considered as rigidly accurate, but it gives a closer approximation to the truth than if it were entirely discarded. The temperature at which the specific gravity was measured was exactly 20° C.

Results of first fractionation.

Number of tubes. ....

Hours required o.....

Fraction.

A'...... ..............

B i .,..............:..

R*. ...................

C'.. .................

C*... ................

C*. ..................

D'...... .............

DS... ................

D3....:... ...........

D'...... .............

EI.. .................

E>. ..................

E>...... .............

1

15

18, 14 tubes; 23, 1 

tube.

Specific 

gravity.

0.8250

.8287

.8307 

.8392

.8413 

. 8400 

.8488

.8470 

.8495 

 . 8514 

.8555

.8527 

.8540 

.8570

Cubic centimeters <>

312 

90

485 

. 250

828 

228 

120

1,014 

375

 200 

172

720 

430 

400

2

5

10

Specific 

gravity.

0. 8285 

.8310

.8370 

.8408

.8440

.8442

. 8430 

.8404 

.8500

.8475 

.8509 

.8540

Cubic 

centimeters.

73 

59

218 

78

272 

130

313 

1.50 

112

285 

135 

118

3

10

17, 8 tubes.

Specific 

gravity.

0. 8223 

.8270

.8372 

. 8400

.8442 

.8455 

.8*80

.8488 

.8500 

.8540

.8537 

.8550 

.8570

Cubic centimeters.

138 

54

258 

200

290 

235 

148

538 

295 

115

380 

245 

170

45, 2 tubes.

Specific 

gravity.

0. 8233

.8405

. 8505 

. 8535

.8540 

. 8019

. 8015

Cubic centimeters.

50

130

120 

05

235 

30

172

a Chapman pump was run day and night. Manomete'r indicated pressures ranging from 30 to 80 millimeters, 

bin lots 1 to 5,1,000 cubic centimeters of crude oil was supplied to each tube.

i Ain. Chem. Jour., vol. 40,1908.
30 DIFFUSION OF CRUDE PETROLEUM 

Results of firs} fractionation Continued.

Number of tubes. ....

Fraction.

A'. ...................

A 2 ...................

BI...................

E*. ..................

GI. ..................

C 2 .. .................

C3. ..................

DI. ..................

D». ..................

DS. ..................

EI. ..:...............

E 2 . ..................

ES. ..................

Number of tubes. ....

Fraction.

A 1 ...................

A 2 ...................

B'. ..................

- B'.-. .................

B3. ..................

GI..... ...............

C2 ..... ...............

C*...... ..............

D». ..................

D 2 . ..................

DS. ..................

EI.. .................

E 2 .. . - . .

ES............ .......

4-

10

16

Specific 

gravity.

0. 8295 

.8315

.8375 

.8413

.8418 

.8442 

.8495

.8449 

.8455 

.8490

.8500 

.8510 

.8567

Cubic centimeters.

170 

100

327 '250

505 

223 

74

495 

328 

260

545 

295 

170

5

8

17, 7 tubes; 24, 1 

tube.

Specific 

gravity.

0.8313 

.8357

.8392 

.8453

.8419 

.8439 

.8465

.8454 

.8500 

.8509

.8495 

.8513 

.8555

Cubic 

centimeters.

130 

56

358 

92

425 

138 

130

640 

167 

195

575 

185 

130

7

9

20, 7 tubes.

Specific 

gravity.

0.8325 

.8350

.8395 

.8418

.8408 

.8408

.8449 

.8487

.8500 

.8524

Cubic centimeters.

66 

30

164 

140

475 

123

500 

270

483 

318

20,. 1 tube; 24, 1 

tube.

Specific 

gravity.

0. 8175

.8333

.8417 

.8500

.8468 

.8498

.8533

Cubic 

centimeters.

45

110

132 

22

110 

106

228

6

10o

17, 1 tube;& 40, 3 

tubes; 96, 1 tube.

Specific 

gravity.

0.8320 

.8352

.8405 

.8451

.8443 

.8495

.8483 

.8517

.8500 

.8569

Cubic 

centimeters.

072 

22

 184 

124

270 

147

368 

210

360 

185

8

10

19, 8 tubes; 22, 2 

tubes.

Specific 

gravity.

0.8364 

.8365

.8400 

.8420

.8445 

.8467 

.8495

.8465 

.8478 

.8500

.8490 

.8495 

.8521

Cubic 

centimeters.

88 

64

215 

240

368 

225 

82

460 

260 

260

450 

354 

233

17, 3 tubes; 40, 1 

tube; 150, 1 tube.

Specific 

gravity.

0. 8287

.8390 

.8485

. .8441 

.8507

.8450 

.8490

.8537 

.8564

Cubic 

centimeters.

<=85

134 

35

218 

67

302 

132

215 

174

9

10 

24, 2 tubes; 40, 8 

tubes.

Specific 

 gravity.

0.8215 

.8234

.8330 

.8350 

.8400

.8415 

.8436 

.8480

.8485 

.8495 

.8545

. .8548 

.8550 

.8580

Cubic 

centimeters.

145 

90

397 

155

87

350 

255 

d!60

507 

' 280 

. 247

313 

275 

375

a Beginning with lot 6, 950 cubic centimeters of crude oil was supplied to each tube.

* The pressure in the tubes was diminished intermittently.

c See page 14. .

d Several cubic centimeters of this fraction were mixed, accidentally, with fraction E'.
THROUGH FULLER S EARTH. 

Results of first fractionation Continued.

31

Number of tubes. . . '. .

Fraction.

A'....................

A".. ..................

B'.. ..................

BS.. ..................

C'....................

G>... .................

/-In

D'. ..................

D». ...................

D'. ..................

E'..... ...............

E»..... ...............

E3.. ..................

Number of tubes.....

Fraction.

A'.. ..................

AS....................

B'.. ..................

BS......... ...........

C'....................

C«............. .......

Cs... .................

D'...................

D*. ...................

DS. ..................

E'..... ...............

E»...... ..............

E'.. .*.................

10

8

17

Specific 

gravity.

0.8273 

.8288

.8395 

.8418

.8423 

.8440 

.8500

.8460 

.8475 

.8500

.8532 

.8535 

.8550

Cubic centimeters.

130

75

220 

160

240 

195 

150

410 

210 

348

320 

282 

215

14

5

24o

Specific 

gravity.

0.8355

. 8470

.8565 

.8560

.8523 

.8550

.8540 

.8532

Cubic centimeters.

132

236

98 

150

170 

205

150 

325

11

10

. 17

Specific 

gravity.

0.8258 

.8318

.8370 

.8480

.8422 

.8450

.8465 

.8490 

.8530

.8510 

.8520 

.8533

Cubic centimeters.

215

70

340 

180

488 

205

565 

310 

187

297 

405 

155

12

9

42

Specific 

gravity.

0.8325 

.8345

.8430 

.8467

.8470 

.8487

.8495 

.8522

.8505 

.8533

Cubic centimeters.

125 

87

235 

120

278 

288

452 

305

475 

490

15

6

20, 3 tubes.

Specific 

gravity.

0.8381

.8487

.8430 

.8480

.8475 

.8517

.8407 

.8502

Cubic centimeters.

60

94

110 

57

212 

104

184 

152

26, 3 tubes.

Specific 

gravity.

0.8305

.8452

.8465 

.8509

.8505 

.8522

.8561 

.8585

Cubic centimeters.

73

143

138 

88

158 

178

192 

140

13

10

24, 8 tubes; 40, 2 

tubes.

Specific 

gravity.

0.8323 

.8352

.8438 

.8470

.8464 

.8505

.8500 

.8492 

. .8518

.8505 

.8489 

.8518

Cubic centimeters.

122 

96

245 

180

317 

235

312 

375 

150

450 

395 

180

16

15

40, 11 tubes; 64, 4 

tubes.

Specific 

gravity.

0.8370 

.8357

.8449 

.8445

.8475 

.8509 

.8562

.8540 

.8530 

.8575

.8538 

.8502 

.8595

Cubic centimeters.

200 

108

490 

226

635 

235 

90

825 

495 

150

775 

620 

205

« When the pressure in the tubes was diminished the oil rose rapidly, and in a short time the reservoirs 

were nearly two-thirds exhausted. The pump was stopped and the remainder of the oil was allowed to 

diffuse during the night under normal pressure.
32 DIFFUSION OF CRUDE PETROLEUM

Results of first fractionation Continued.

Number of tubes.....

Fraction.,

A....................

B. ...................

Ci.... ................

CX...... .............

DI. ..................

D2. ..................

E'.. .................

EZ..... ...............

Number of tubes. . . . .

Hours required b .....

Fraction.

A....................

B. ...................

C>... .................

C*..... ...............

DI. ..................

D2. ..................

El....................

E»......... ...........

17

9

40

Specific 

gravity.

0.8258 

.8432

.8480 

.8488

. .8530 

.8550

.8585 

.8598

Cubic centimeters.

225 

452

450 

168

520 

350

385 

460

21

10

24, 6 tubes; 40, 2 

tub s; 64, 2 tubes.

Specific 

gravity.

0. 8275 

.8410

.8452 

.8488

.8512 

.8535

.8557 

.8625

Cubic centimeters.

s

245 

615

520 

226

533 

415

375

282

18

8

24, 5 tubes; 48, 2 

tubes; 64, 1 tube!

Specific 

gravity.

0.8322 

.8435

.8495 

.8500

.8530 

.8540

.8547 

.8526

Cubic centimeters.

112 

335

250 

250

320 

350

« 90 

640

22 .

10

40, 6 tubes; 64, 4 

tubes.

Specific, 

gravity.

0. 8281 

.8405

.8459 

.8472

'.8505 

.8523

.8615 

.8585

Cubic centimeters.

210 

508

265 

410

435 

450

385 

365

19

10

40, 8 tubes; 64, 2 

tubes.

Specific 

gravity.

0.8320 

.8438

.8480 

.8472

.8509 

.8536

.8492 

.8560

Cubic centimeters.

146 

385

300 

315

422 

' 355

580 

415

23

10

48, 5 tubes; 72, 5 

tubes.

Specific 

gravity.

0. 8241 

,8395

:8448 

.8470

 .-8533

.8541

.8650 

.8624

Cubic centimeters.

330 

615

420 

305

400 

465

305 

350

20

10

20, 6 tubes; 30, 4 

tubes.

Specific 

gravity.

0.8281 

:8413

 ' .8450 

.8495

.8508 

.8538

.8513 

.8540

Cubic 

centi- ' 

meters.

236 

518

350 

300

' 325 

' 460

445 

550

. 24

10

40, 4 tubes; 64, 6 

tubes.

Specific 

gravity.

0. 8250 

.8408

.8463 

.8505

.8540 

.8540

.-8623 

.8645

Cubic 

centir 

meters.

287 

535

475 

186

525 

360

393 

335

a This irregularity that is, the liberation of oil with a specific gravity higher than those of the oils immediately following is observed when an amount of water is added sufficient to replace a very small amount 

of oil for the first fraction.

6 Pressure in the tubes was diminished intermittently. 
THROUGH FULLER S EARTH. 

Results of first fradionation Continued.

33

Number of tubes.....

Hours required a ....

Fraction.

A....................

B....................

C»....................

C». ...................

D'. ..................

D*.. .................

E'............ . .

E«... .................

Number of tubes. ....

Hours required a ....

Fraction.

A....................

B....................

GI ...................

& ...................

T>i ...................

D». ..................

EF1 .................

EF" .................

25

9

48, 8 tubes; 72, 1 

tube.

Specific 

gravity.

0. 8270 

.8425

.8495 

.8492

.8509 

.8510

.8550 

.8570

Cubic 

centimeters.

225 

410

675 

250

320 

480

335 

395

29

10

18, 5 tubes; 40, 5 

tubes.

Specific 

gravity.

0. 8262 

.8395

.8463 

.8488

.8520 

.8543

.8550 

.8559

Cubic 

centimeters.

300 

505

390 

270

510 

290

417 

645

3,327

.26

10

17, 2 tubes; 24, 4 

tubes; 41, 4 tubes.

Specific 

gravity.

0. 8284 

.8422

.8473 

.8508.

.8515 

.8540

.8559 

.8586

Cubic centimeters.

315 

550

520 

178

600 

230

490 

135

30

15

20, 7 tubes; 41, 6 

tubes; 63, 2 tubes.

Specific 

gravity.

0.8348 

.8468

.8490 

.8505

.8485 

.8502

.8520 

.8528

Cubic centimeters.

335 

630

560 

277

750 

540

1,125 

880

5,097

27

10

17, 4 tubes; 29, 6 

tubes.

Specific 

gravity.

0.8312 

.8440

.8460 

.8478

.8482 

.8500

.8520 

.8505

Cubic 

centimeters.

230 

370

400 

232.

435 

420

405 

335

31

10

44, 4 tubes; 89, 6 

tubes.

Specific 

gravity.

0. 8292 

.8439

.8495 

.8523

' .8517 

.8552

.8555 

. 8C10

Cubic 

centimeters.

245 

576

465 

205

670 

210

805 

360

3,536

28

10

24, 7 tubes; 28, 3 

tubes.

Specific 

gravity.

0.8333 

.8440

.8458 

.8500

.8470 

.8498

.8492 

.8505

Cubic centimeters.

240 

410

415 

177

387 

400

«690 

600

32

15

40, 7 tubes; 89, 4 

tubes; 103, 4 tubes.

Specific 

gravity.

0. 8270 

.8423

.8500 

.8500

.8545 

.8543

. 8580 

.8598

Cubic centimeters.

445 

720

730 

220

750 

540

870 

910

5,191

a Pressure in the tubes was diminished intermittently.

& Some oil of this fraction was lost.

c Beginning with lot 28, fractions E and F were collected together.

89823° Bull. 475 11-
34 DIFFUSION OF CRUDE PETROLEUM 

Results of first fractionation Continued.

Fraction.

A.........................................

BI ........................................

B2 ........................................

Ci ........................................

C* .......... ..............................

DI....... .................................

D*.. ........... ...........................

EFi ......................................

EF" .........................:............

33

10

41, 4 tubes; 65, 4 

tubes; 89, 2 tubes.

Specific 

gravity.

0.8330

.8440 

.8462

.8502 

.8540

.8555 

.8562

.8575 

.8585

Cubic 

centimeters.

290

365 

165

500 

160

655 

250

735 

480

3,600

34

10

44, 6 tubes; 68, 4 

. tubes.

Specific 

gravity.

0.8355 

.8475

.8508 

.8543

.8575 

.8585

.8535 

.8555

Cubic 

centimeters.

320 

525

470 

190

530 

325

895 

405

3,660

35

9

48, 6 tubes; 72, 3 

tubes.

Specific 

gravity.

0. 8380 

.8460

.8508 

.8525

.8549 

.8573

.8557 

.8570

Cubic 

centimeters.

235 

452

345 

245

580 

335

645 

492

3,329

a Pressure in the tubes was diminished intermittently.

Specific gravity. The range of the specific gravity extended from 0.8175, the value 

of fraction A1 of lot 7, to 0.8650, the value of fraction E1 of lot 13. The specific gravity 

of the crude oil itself was 0.8375. The range of the specific gravities of the individual 

lots averaged from 0.820 to 0.860. The specific gravity decreases gradually from 

E to B, but in most of the.lots the decrease between B and A is much greater than 

between any two consecutive lower fractions. This marked change was also observed 

in the study of the diffusion of benzene in solution. A detailed investigation of the 

cause will be undertaken in the near future.

Color. The color of the fractions obtained ranged from green to black. The lighter 

oils possessed a beautiful green fluorescent color, which-shaded gradually to brown 

and then to the deep black of the heavier oils.

Odor. The unpleasant odor of the crude petroleum disappeared almost entirely 

in the oils of fractions A and B; but the other fractions still possessed to a greater or 

less extent the odor of the natural oil.

Volume of oil retained by the fuller's earth. The amount of oil retained by the earth 

averaged about 55 per cent of the amount supplied. In the first fractionation of the 

crude Pennsylvania oil, specific gravity 0.810, Gilpin and Cram found that approximately 40 per cent of the oil'was retained by the earth. It is evident, therefore, that 

the amount of oil remaining in the earth depends chiefly on the character of the oil. 

The Pennsylvania petroleum contains a much smaller .percentage of unsaturated 

hydrocarbons, sulphur, and asphaltic substances than the Illinois oil employed in 

this investigation. Inasmuch as the fuller's earth readily removes these substances 

in the process of fractionation, as will be shown later, the large percentage of Illinois 

oil retained by the earth is thus clearly explained. It is safe to conclude that if the 

heavy Texas or California oil was allowed to diffuse through fuller's earth, the amount 

of oil retained would exceed the amounts of either of the above-mentioned oils lost 

in the earth.
THROUGH FULLER S EARTH. 

SECOND FRACTIONATION.

The products obtained from the first fractionation were united 

according to the following arrangement:

Specific gravity of oils united for second fractionation.

Lot.

36

37

38

39

40-43

44-50

Specific 

gravity.

0. 8293

.8390

.8433

.8433

. 8490

.8543

Specific gravity 

of the oils united.

0. 8250-0. 8350

. 8350- . 8400

. 8400- . 8450

. 8400-' . 8450

. 8450- . 8500

. 8500- . 8GOO .

The oils thus combined were subjected to chilling and filtration 

for the purpose of removing as much dissolved paraffin as possible.

The procedure was as follows: The oils were first chilled at temperatures ranging from 0° to 10° C., and then filtered through plaited 

filter papers. When the oil ceased to drip from the funnel, the 

residue upon the filter paper was placed in a larger filter press, and 

the remaining oil was separated by pressure from the paraffin. 

The filter press was simple in construction. A piston, fitted closely 

in an iron cylinder, was gradually forced down upon the oil-laden 

paraffin, which rested upon a membrane of cotton duck, fastened 

between perforated tin supports. The retained oil was forced 

through the membrane and was collected from the outlet below. 

The lighter oils deposited very little paraffin; somewhat more paraffin 

was separated from the heavier ones. Owing to the high viscosity 

of the heavier oils, the filtration proceeded very slowly, and as too 

much time was consumed in this process, the paraffin of some of the 

oils of fraction E was not removed. A slight change in specific 

gravity occurred in the oils from which the paraffin was removed. 

The final specific gravities of the united oils were as follows:

Final specific gravity of oils for second fractionation.

Lot.

36

37

38

39

40-42

43

44-48

49-50

Specific 

gravity.

0.8305

.8415

.8433

.8455

.8515

.8540

.8543

.8557

Para/Tin 

removed.

Yes.

Yes.

No.

Yes.

Yes.

Yes.

No.

Yes.
DIFFUSION OF CRUDE PETROLEUM

When these oils were again allowed to diffuse upward through 

fuller's earth, the following fractionation was obtained:

Results of second fr.actionation.

Number of tubes. ....

Hours required c. . . . .

Fraction.

A.....................

BI.. .................

B*..... ..............

c>. ..................

C". ..................

DI... ................

D»... ................

EFi. ................

EF*. ................

Number of tubes. . . . -

Fraction.

A....................

B 1 .. .................

B»... ................

c». ..................

C 2 . ..................

DI... ................

D«... ................

EFi. ................

EF*. ................

36

0.8305

5

44, 3 tubes; 48, 2 

tubes.

Specific 

gravity.

0. 8272

.8315 

.8331

.8334 

.8355

.8330 

.8339

.8347 

. 8356

Cubic 

 centimeters.

160.

216 

58

350 

85

360 

320

720 

320

2,589

40

0.8515

9

48, 5 tubes; 72, 4 

tubes.

Specific 

gravity.

0.8305

.8438 

.8453

.8518 

.8539

. 8550 

.8560

.8605 

.8620

Cubic 

centimeters.

380

515 

155

600 

170

685 

330

780 

600

4 : 215

37

0.8415

4

51

Specific 

gravity.

0. 8292 

.8421

. 8467

. 8468 

.8485

.8480 

.8489

.

Cubic centimeters.

135 

215

295

340 

152

535 

215

1,887

41

0.8515

5

40

Specific 

gravity.

0.8316

. 8460 

.8480

.8523 

. . 8540

.8558 

.8571

.8620 

. 8622

Cubic centimeters.

235

290 

65

375 

100

470 

110

580 

320

2,545

38

0.8433 a

8 ,

48, 7 tubes; 64, 1 

tube.

Specific 

gravity.

0.8331

.8447 

.8455

. .8490 

.'8505

.8492 

.8509

.8508 

.8518

Cubic 

centimeters.

180

175 

210

305 

175

400 

295

710 

355

3,886

42

0.8515

5

69

Specific 

gravity.

0. 8325

.8487 

.8515

.8540 

' .8567

.8572 

.8582

.8640 

. 8650

Cubic 

centimeters.

210

265 

54

335 

56

420 

175

675 

200

2,420

3s)

0.8455 >>

8

29, 4 tubes; 45, 3 

tubes; 64, 1 tube.

Specific 

gravity.

0. 8290

- .8432 

.8458

.8492 

.8513

.8505

.8A27

. 8546 

.8560

Cubic centimeters.

255

355 

110

455 

180

740 

275

1,166 

350

2,805

43

0.8540

4

10 days, 2 tubes; 17 

days, 2 tubes.

Specific 

gravity.

0.8435 

. 8546

.8575

.8605 

.8040

. 8650 

.8615

Cubic centimeters.

65 

115

200

220 

50

225

78

953

a Paraffin was removed from the oil.

6 Paraffin was not removed from the oil.

c In this series, as well as those following, the pressure in the tubes was diminished intermittently.
THROUGH FULLER S EARTH. 

Results of second fradionation Continued.

37

Specific gravity a. ....

Number of tubes. ....

Fraction.

A.........'............

\ 

BI.. .................

B".. .................

C'. ............I.....

C 2 . ..................

Dl..................

D*... ...............

EFi. ................

El". ................

44

0.8543

3

48, 2 tubes;' 96, 1 

tube.

Specific 

gravity.

0.8330 

.8505

.8582 

. 8605

. 8(505 

.8620

.8672 

. 8080

Cubic 

centimeters.

85 

175

155 

05

195 

120

240 

175

1,210

45

0.8543

5

66

Specific 

gravity.

0. 8362

.8510 

. 8522

. 8562 

. 8585

. 8567 

.8580

.8659 

.8670

Cubic centimeters.

170

210 

80

265 

50

425 

100

015 

150

2,065

46

0.8543

5

93

Specific 

gravity.

0. 8332

.8480 

.8505

.8554 

. 8567

.8600 

.8613

.8666 

.8680

Cubic centimeters.

210

' 260 

50

. 300 

95

370 

]20

010 

130

2,145

47

0.8543

5

13 days.*

Specific 

gravity.

0.8340 

.8500

.8553 

.8576

.8595 

.8618

.8665 

.8670

Cubic centimeters.

145 

275

320 

50

430 

70

330 

215

1,835

Fraction.

A.........................................

B'.. ....... ....... ........................

B".. ......................................

C'. ......... ..............................

C". .......................................

D'........................................

D".... ....................................

EF'......................................

EF ^. ...................... ...............

48

0.8543 a

5

14 days.d

Specific 

gravity.

0.8385 

.8530

. 8568 

.8586

.8610 

.8623

. 8095 

.8700

Cubic centimeters.

. 125 

275

320 

90

325 

115

330 

80

 1,060

49 .

0.&557 c

7

48

Specific 

gravity.

0.8341

.8505 

.8520

.8560 

.8572

. 8620 

.8625

. 8705 

. 8705

Cubic centimeters.

255

395 

95

380 

230

500 

290

500 

580

3,225

50

0.8557 c

5

72, 4 tubes; 89, 1 

tube.

Specific 

gravity.

0.8320

. 8485 

.8500

. . 8505 

.8577

. 8009 

. . 8626

.8085 

.8700

Cubic centimeters.

170

230 

70

300 

100

480 

125

' 640 

235

2,350

« Paraffin was not removed from the oil.

6 Owing to the weakness of the water pressure, the pressure in the tubes was only slightly diminished. 

The tubes were taken down before the reservoirs were completely exhausted. The distances to which 

the oil had risen were 35,25, 30, 20, and 10 centimeters from the tops of the tubes.

c Paraffin was removed.from the oil.

<J Owing to the weakness of the water pressure, the pressure in the tubes was diminished but slightly 

during this time. The tubes were taken down before the reservoirs were completely exhausted. The 

distances to which the oil had risen were 50, 35, 30, 60, and 55 centimeters from the tops of the tubes.
38

Specific gravity. The range of the specific gravities grows smaller as the oils to be 

fractionated become lighter and less complex. Thus, in lot 36, the range of specific 

gravity extends from 0.8272, the value of fraction A, to 0.8356, the value of EF2, the 

difference between them being 0.0084, In lot 38, the mother oil, specific gravity 

0.8433, yielded fractions whose specific gravities ranged from 0.8331 to 0.8518, 

amounting to a difference of 0.0187. This fact appears to be general throughout the 

various lots, and points to the gradual formations of mixtures which will pass through 

the earth unaltered, just as the fractionation by distillation tends to produce compounds with definite boiling points.

Color. The color of the oils in this fractionation shaded from a very light yellow to 

greenish black.

Odor. The odor of the crude petroleum vanished completely from the oils of this 

fractionation. ^ . .

Volume of oil retained by the fuller's earth, The oil retained by the earth in this fractionation amounted to approximately 50 per cent, a smaller percentage, as is naturally 

to be expected, than in the fractionation of the crude petroleum.

THIRD FRACTIONATION.

The following oils obtained from the second fractionation were 

united for the third fractionation. ...

Oils used for third fractionation.

Lot 51.

[Specific gravity, 0.8316.]

Lot.

36..................

39..................

37..................

40..................

36..................

41..................

50..................

42.. ................

36

38..................

46..................

36.................. 

49...................

Fraction.

A.......

A.......

A.......

A.......

BI.......

A.......

A.......

A.......

A.......

B2....... A...:...

A.......

C»....... A....:..

Specific 

gravity.

0. 8272 

.8290 

.8292 

.8305 

.8315 

.8316 

.8320 

.8325 

.8330 

.8331 

.8331 

.8332 

.8334 

.8341

Cubic 

centimeter.

160 

255 

135 

380 

216 

235 

170 

210 

85 

58 

180 

210 

350 

255

2,899

Lot 52.

[Specific gravity, 0.8343.]

36..................

36..................

47..................

36..................

36.................. <Mi

D1 .......

D2......

A.......

EFi.....

EF2.....

C2.......

. 0.8330 

.8339 

.8340 

.8347 

.8356 

.8355

360 

320 

145 

720 

320 

85

1,950

Lot 53.

[Specific gravity, 0.8433.1

Lot.

45...!..............

48..................

37..................

39..................

40..................

38..................

40..................

38..................

39..................

Fraction.

A.......

A.......

BI. ......

BI.......

BI. ......

BI.......

B2.......

B2.......

B2.......

Specific 

gravity.

0.8362 

.8385 

.8421 

.8432 

.8438 

.8447 

.8453 

.8455 

.8458

Cubic centimeter.

170 

125 

215 

355 

515 

175 

' 155 

210 

50

1,970

Lot 54.

[Specific gravity, 0.8473.]

39..................

41..................

37..................

41..................

50..................

42..................

39..................

38..................

B2....... BI.......

Ci.......

B2....... BI....... BI. ......

Ci.......

Ci.......

0.8458 

.8460 

.8467 

.8480 

.8485 

.8487 

.8492 

.8490

60 

290 

295 

65 

230 

265 

455 

305

1,965
THROUGH FULLER S EARTH. 

Oils used for third fractionation Continued.

39'

Lot 65.

[Specific gravity, 0.8485.]

Lot.

37..................

37..................

37..................

37..................

38..................

47..................

Fraction.

DI......

D»......

EFi.....

EF2 .....

DI......

BI.......

- Specific 

gravity.

0. 8468 

.8485 

.8480 

.8489 

.8492 

.8500

Cubic 

centimeter.

340 

152 

535 

215 

400 

275

1,917

Lot 56.

[Specific gravity, 0.8508.]

50. .................

49..................

44..................

46..........:...:...

38..................

AK.

®>... ............... 

42..................

40..................

B2 .......

B1 -......

B1 . ...'...

B 2 -.....

C2 .......

BI

C2.......

B2 .......

C».......

0.8500 

.8505 

.8505 

.8505 

.8505 

.8510 

.8513 

.8515 

.8518

70 

395 

175 

50 

175 

210 

180 

54

600 

1,909

Lot 57.

[Specific gravity, 0.8509.]

39..................

38..................

38..................

38..................

Di......

EFi.....

D2 ......

EF2 .....

0.8505 

.8508 

.8509 

.8518

740 

710 

295 

355

2,100

Lot 58.

[Specific gravity, 0.8558.] .

49..................

41

48.. ................

40..................

42..................

47..................

46. .................

49

45..................

Kft

42..................

48..................

49

43..................

B2 -......

B2 .......

C1 -......

B'.......

C2 .......

C'.......

C2 -......

C1 . ......

C'. ......

C.. ......

C''......

C'. ......

C2 .......

C2 .......

C1 .......

C2 . ......

C':......

0. 8520 

.8522 

.8523 

.8530 

.8539 

.8540 

.8540 

.8553 

.8554 

 .8560 

.8562 

.8565 

.8567 

.8567 

.8568 

.8572 

.8575

95 

80 

375 

275 

170 

335 

100 

320 

300 

380 

265 

300 

56 

95 

320 

230 

200

3,896

^, Lot 59. 

[Specific gravity, 0.8563.]

Lot.

39

40..................

41..................

39..................

40..................

45..................

41..................

42..................

45..................

42.................. 

48..................

47..................

Fraction.

EFi.....

D>.......

DI.......

EF2 ..:..

D2 .......

D'. ......

D2 .......

DI. ...:..

D2.......

D"...... 

C2 . ......

D'......

Specific 

gravity.

0.8546 

.8550 

.8558 

.8560 

.8560 

.8567 

.8571 

.8572 

.8580 

.8582 

.8586 

.8595

Cubic 

centimeter.

1,166 

685 

470 

350 

330 

425 

110 

420 

100 

175 

90 

430

4,750

Lot 60.

[Specific gravity, 0.8615.]

46..................

40

43.................. 

44..................

50..................

4fl

46..................

47..................

40..................

41..................

44..................

49..................

41..................

48..................

49..................

en

42..................

DI......

D'...... 

DI......

D'......

DI......

D2 ......

D2 ......

EF2.....

EF'.....

D2 ......

D'......

D2 ......

D2 ......

D2 ...... El......

0. 8600 

.8605 

. 8005 

.8605 

.8609 

.8610 

.8613 

.8618 

.8620 

.8620 

.8620 

.8620 

.8622 

.8623 

.8625 

.8626 

.8640

370 

780 

220 

195 

480 

325 

120 

70 

600 

580 

120 

500 

320 

115 

290 

125 

675

5,880

Lot 61.

[Specific gravity, 0.8680.]

42..................

43..................

45..................

47..................

46.- .................

47..................

45: .................

44..................

46..................

44..................

50..................

48..................

50..................

49..................

49..................

EF2.....

EFi.....

EFi.....

EFi.....

EF'.....

EF2.....

EF2 .....

EFi.....

EF2.....

EF2.....

EF'.....

EFi.....

EF2 .....

EFi.....

EF2.....

0.8650 

.8650 

.8659 

.8665 

.8666 

.8670 

.8670 

.8672 

.8680 

.8680 

.8685 

.8695 

.8700 

.8705 

.8705

200 

225 

615 

330 

610 

215 

150 

240 

130 

175 

640 

330 

235 

500 

580

4,975
40 DIFFUSION OF CRUDE PETROLEUM

The oils thus united were fractionated by fuller's earth again, 

with the results given below.

Results of third fractionation.

Number of tubes. ....

Fraction.

A....................

B. ...................

Ci. ..................

C*..... ..............

DI. ..................

D«.. .................

EI................'...

&.... ...............

F.. ..................

SoGcific £rr&vitv

Number of tubes. ....

Fraction.

A....................

B. ...................

GI....................

&....................

DI. ..................

DS. ..................

EI.. ................. E3

F. ...................

51

0.8316

3o

60

Specific 

gravity.

0. 8213 

.8303

.8337 

.8345

.8353 

.8356

.8366

.8373

Cubic centimeters.

92 

185

165 

90

210 

170

385

190

1,487

55

0.8485

2

48, 1 tube; 72, 

1 tube.

Specific 

gravity.

0.8283 

.8457 

.8515

.8521 

.8543

.8540

.8566

Cubic 

centimeters:

58 

100 

155

220 

50

270

180

1,033

52

0.8343

2o '

60

Specific 

gravity.

0. 8219 

.8333 

.8375

.8388 

.8393

.8403 

.8411

.8431

Cubic 

centimeters.

65 

143 

190

188 

90

175 

92

88

1,031

56

0.8508

2

%

Specific 

gravity.

0.8313 

.8488 

.8546

.8553 

.8560

.8553 

.8563

.8575

Cubic 

centimeters.

75 

135 

170

150 

92

145 

90

130

987

53

»

0. 8433

2

48

Specific 

gravity.

0. 8266 

.8431 

.8464

.8468 

.8474

.8473

.8488

.8496

Cubic 

centimeters.

.. 73 

115 

175

145 

115

202 

73

170

1,068

57

0. 8509

2

96

Specific 

gravity.

0.8336 

.8491 

.8528

.8551 

.8573

.8568 

.8588

.8611

Cubic centimeters.

55 

130 

180

185 

45

170 

70

170

 1,005

54

0.8473

2

48

Specific 

gravity.

0.8303

.'8488 

.8518

.8523

.8528

.8530 

.8548

.8548

Cubic centimeters.

66 

115 

175

180 

105

245 

60

145

1,091

58

0.8558

4

72, 3 tubes; 90, 

1 tube.

Specific 

gravity.

0.8318 

.8531

.8578 

.8592

.8588 

.8593

.8603 

. 8613

.8628

Cubic 

centimeters.

170 

260

205 

105

205 

340

325 

170

275

2,055

a The tin tubes used in these lots were 1J inches in diameter. 

6 The pressure in the tubes was diminished intermittently.
THROUGH FULLER S EAETH. 

Results of third fractionation Continued.

41

Fraction.

A.........................................

B. ........................................

C1 .. .......................................

ca .. .......................................

D'. .......................................

DS. .......................................

EI.. ......................................

E"........................................

F. ........................................

59

0. 8563

5

72

Specific 

gravity.

0.8328 

.8508

.8578 

.8588

.8608 

.8623

.8628 

.8633

.8073

Cubic 

 centi- 

.meters.

195 

340

325 

112

490 

135

475 

155

330

2,557

60

0. 8615

6

72

Specific 

gravity.

0.8343 

.8540

.8001 

.8618

'.8628 

.8638

.8664 

.8683

.8703

Cubic centimeters.

195 

330

290 

130

440 

85

425 

140

310

2,345

61

0.8680

5

5 days. «

Specific 

gravity.

0.8413 

.8601 

.8683

.8709

.8688

.8691

Cubic centimeters. 6

See below. & The volumes of these oils were not recorded.

Specific gravity. The decrease in the range of specific gravity as the oils supplied 

become lighter was observed in this fractionation as in the preceding ones.

Color. The lightest oils were almost colorless; the heavier oils were dark brown to 

green.

Odor. Most of the oils possessed an agreeable odor.

Prolonged diffusion. In lot 61 the time required for the oils to reach the tops of the 

tubes was five days. No fractionation, as is evident from an examination of the 

specific gravities, occurred in the lower parts of the tubes. The heavier oils of fractions D, E, and F were exceedingly viscous.

Volume of oil retained by the fuller's earth. The volume of oil retained by the earth 

in this fractionation amounted to approximately 45 per cent. The increase in the 

yield of oil indicates, therefore, a process of purification, in which, as will be shown 

later, such compounds as the unsaturated hydrocarbons are removed.
42 DIFFUSION OF CRUDE PETROLEUM 

FOURTH FRACTIONATION.

The following fractions obtained from the third fractionation were 

united for the fourth fractionation:

Oils used for fourth fractionation.

Lot 62.

[Specific gravity, 0.8298.]

Lot.

51.................. 159

53..................

55.......:..........

54

51..................

56..................

58..................

59..................

Fraction.

A.......

A.......

A.......

A.......

A.......

B. ......

A.......

A.......

Specific 

gravity.

0. 8213 

.8219 

.8266 

.8283 

.8303 

.8303 

.8313 

.8318 

.8328

Cubic 

centimeters.

92 

65 

73 

66 

58 

185 

75 

170 

195

979

Lot 63.

[Specific gravity, 0.8343.]

52..................

57..................

51..................

60..................

51..................

51:................. 

51..................

B. ......

A.......

Ci.......

A.......

(X......

DI...... 

D2......

0. 8333 

.8336 

.8337 

.8343 

.8345 

.8353 

.8356

143

55 

185 

195 

90 

210 

170

1,040

Lot 64.

[Specific gravity, 0.8368.]

51..................

51..................

52. .................

52. .................

EI......

F. ......

Ci. ......

DI......

0.8366 

.8372 

.8375 

.8388

388 

190 

190 

188

956

Lot 65.

[Specific gravity, 0.8430.]

52..................

52..................

-52..................

53..................

52..................

55..................

63..................

53..................

D2......

EI......

E2......

BI......

F. ......

BI......

Ci. ......

DI......

0.8393 

.8403 

.8411 

.8431 

.8431 

.8457 

.8464 

.8468

90 

175 

92 

115 88' 

100 

175 

145

' 980

Lot 66.

[Specific gravity, 0.8483.]

Lot.

53..................

53..................

54. .................

56..................

53..................

59..................

Fraction.

EI......

D2......

BI......

BI......

E2...... BI......

Specific 

gravity.

. 0. 8473 

.8474 

' -.8488

.8488 

. . 8488 

.8508

Cubic centimeters.

202 

115 

. 115 

135 

73 

330

970

Lot 67.

[Specific gravity, 0.8513.]

57..................

59..................

55..................

54..................

55........'..........

58..................

BI...... BI......

Ci.......

<X ......

DI......

BI......

0. 8491 

.8508 

.8515 

.8518 

.8521 

.8531

130 

10 

155 

175 

220 

260

950

Lot 68.

[Specific gravity, 0.8533.]

54. .................

54. .................

57..................

54..................

60..................

DI......

D2......

Ci. ......

EI ......

B. ......

0.8523 

.8528 

.8528 

.8530 

.8540

180 

105 

180 

245 

330

1,040

Lot 69.

[Specific gravity, 0.8556.]

55..................

55..................

56..................

54. .................

54..................

57.................:

56..................

56..................

56..................

56..................

55..................

57..................

57..................

56..................

 EI......

D2...... C'. ......

E2......

F. ......

DI......

DI......

EI......

D2......

E2

F. ......

EI......

D2......

F. ......

0. 8540 

.8543 

.8546 

.8548 

.8548 

.8551 

.8553 

.8553 

.8560 

.8563 

.8566 

.8568 

.8573 

.8575

270 

50 

. 170 

60 

145 

185 

150 

145 

92 

90 

180 

170 

45 

130

1,882
- THEOUGH FULLER S EARTH. - 

Oils used for fourth fractionation Continued.

43

Lot 70.

[Specific gravity, 0.8596.]

Lot. '

58..................

59..................

58..................

59..................

57..................

58..................

58..................

60

58..................

59..................

57..................

58..................

60..................

Fraction.

Ci.......

C'.-......

DI......

&.......

E2......

C2.......

D2......

CI

EI......

DI......

F. ......

E2......

C". ......

Specific 

gOavity.

0. 8578 

.8578 

.8588 

.8588 

.8588 

.8592 

.8593 

.8601 

.8603 

.8608 

.8611 

.8613 

.8618

Cubic centimeters.

205 

325 

205 

112 

70 

105 

340 

290 

325 

490 

170 

170 

130

2,937

Lot 71.

[Specific gravity, 0.8638.]

Lot.

59..................

60..................

59..................

58. .................

60..................

59..................

60..................

Fraction.

D2......

DI ......

EI......

F. ......

D2......

E2......

EI ......

Specific 

gravity.

0. 8623 

.8628 

.8628 

.8628 

.8638 

.8633 

.8664

Cubic centimeters.

135 

440 

475 

375 

85 

155 

425

1,990

Results of fourth fractionation.

Number of tubes. . . . .

Fraction.

A....................

B. ...................

C.....................

D... .................

E. ...................

F. ...................

62

0.8298

1 '

72

Specific 

gravity.

0. 8243s 

.8298 

.8323 

.8330 

.8333 

.8341

Cubic centimeters.

 32 

71 

90 

115 

130 

75

1 ' 513

63

0.8343

1

72

Specific 

gravity.

0. 8273 

.8357 

.8378 

.8383 

.8388 

.8393

Cubic 

centimeters.

45 

75 

95 

130 

98 

95

538

64

0.8368

 1

90

Specific 

gravity.

0.8297 

.8378 

.8401 

.8408 

.8413 

.8418

Cubic centimeters.

41. 

57 

81 

115 

135 

70

.499

66

0.8430

1

48

Specific 

gravity.

0.8308 

.8428 

.8463 

.8473 

. 8471 

.8483

Cubic centimeters.

42 

70 

92 

130 

130 

80

544

Specific gravity. As in the preceding fractionations, the decrease in the range of 

specific gravity as the mother oils became lighter was again observed in this fractionation. It was evident, moreover, that there was a constant forward accumulation 

toward definite and constant mixtures. The lighter oils of one lot were found to 

possess specific gravities closely approaching those of the heavier oils of the preceding lot.

Color. The oils of fraction A were almost colorless; the color of the heavier oils 

ranged from green to light brown.

Odor. All the oils of this fractionation possessed agreeable odors.

Volume of oil retained. The volume of oil retained by the earth amounted to approximately 40 per cent.

Deposition of paraffin. In fractions A and B of several of the lots a fine crystalline 

deposit separated out and collected upon the bottom of the bottles containing the oils. 

When the oils were warmed, "this-deposit-dissolved completely, showing it to be 

paraffin.
44 DIFFUSION OF CRUDE PETROLEUM

CHEMICAL EXAMINATION OF FRACTIONATED OILSo

UNSATTJRATED HYDROCARBONS. 

ACTION OF CONCENTRATED SULPHURIC ACID.

The percentage by volume of oil absorbed by concentrated sulphuric 

acid (specific gravity 1.84) was determined according to the following 

procedure. Ten cubic centimeters of the oil to be examined was 

measured into a glass-stoppered bottle, and 30 cubic centimeters of 

concentrated sulphuric acid was added. The mixture was thoroughly 

shaken by a machine for 30 minutes and then poured into a burette. 

After sufficient time had been allowed for any oil that might be 

mechanically absorbed in the acid to rise to the top, the volume of 

unabsorbed oil was read directly over the acid. Owing to the formation of heavy emulsions, no attempt was made to neutralize and 

wash the oil. The results of the analyses are given in the following 

table:

Oil absorbed by concentrated sulphuric acid, lot 51.

Per cent 

by volume. 

Fraction A..................:.................................. 2. 3

B..................................................... 6.1

Cl ................................................... 9.1

C2 ................................................... 10.2

D1 ............ = ....................................... 11.5

D2 ......................................,............: 12. o

E..................................................... 12.5

F.................................................... 14.5

ACTION OF BROMINE.

The following method was employed for determining the amount of 

bromine absorbed by the oils. Between 0.5 and 0.9 gram of the oil to 

be examined was dissolved in 10 to 15 cubic centimeters of carbon 

tetrachloride. Five cubic centimeters of a standard solution of bromine in carbon tetrachloride was then introduced, and the solution 

allowed to remain, with occasional shaking, in a dark place .for 30 

minutes. Ten cubic centimeters of a 10 per cent solution of potassium 

iodide was then added, and the amount of iodine liberated was determined immediately by titrating with. a standard solution of sodium 

thiosulphate. A few drops of a starch solution were introduced to 

mark accurately the end of the titration. The separate amounts of 

bromine absorbed by addition and substitution were not estimated. 

The amounts of bromine absorbed, expressed in the table below, are 

calculated on the basis of 100 grams of oil.
THBOUGH FULLER'S EARTH. 45

Bromine absorbed by oil.

First fractionation.

Per cent.

Lot 32, fraction A................................................5. 02

B............................................... 6.96

C............................................... 7.40

D.............................................. 7.87. .

E..........:.................................... 8.00

Crude oil........................................................ 7. 64

Second fractlonatlon. 

Lot 36, fraction A............................................... 4. 74

B1 ............................................... 5.40

B2 ............................................... 5. 66

C1 ............................................... 5.56 

C2 ............................................... 6.18

D 1 .............................................. 6.81

D2 .............................................. 6. 28

EF1 ............................................ 6. 49

EF2 ............................................ 7.18

Third fractionation. 

Lot 51, fraction A............................................... 3. 27

B............................................... 4.36

C..................:............................ 4. 47

D.............................................. 4.92

E............................................... 4.71

F.............................................. 5. 36

Fourth fractionation. 

Lot 62, fraction A............................................... 2. 86

E............................................... 3. 73

These results demonstrate conclusively that the unsaturated hydrocarbons tend to collect in the lower sections of a layer of fuller's earth 

through which the oil is allowed to diffuse. The figures confirm the 

results obtained by Gilpin and Cram in their work on Pennsylvania 

petroleum. In their investigation distillation by heat was employed 

in order to obtain fractions that could be readily studied. In the 

work here reported the relative amounts of the unsaturated hydrocarbons in the oils were determined directly as they came from the 

earth.

The percentages by volume of oil absorbed by concentrated sulphuric acid represent only approximately the percentages of unsaturated hydrocarbons, for, as was shown previously, any benzene which, 

may have been present in the oils was also removed by the concentrated acid. This fact rendered impossible a quantitative separation 

of the aromatic from the unsaturated hydrocarbons. As no other 

methods besides nitration and sulphonation, neither of which could 

be here employed, were available, no results as to the relative amounts 

of the aromatic hydrocarbons in the various fractions could beobtained.
46 DIFFUSION OF CRUDE PETROLEUM

It is evident from the results of the bromine determinations that 

as the fractionation proceeds the amounts of unsaturated hydrocarbons become smaller and smaller. A comparison of the amounts 

of bromine absorbed by fraction A of the first, second, third, and 

fourth fractionations is given below for the purpose of bringing out 

this point more clearly.

Bromine absorbed by fraction A. 

Per cent. 

First fractionation.............................................. 5.02

Second fractionation................................'............. 4. 74

Third fractionation.............................................. 3. 27

Fourth fractionation............................................ 2. 86

SULPHUR COMPOUNDS.

The amount of sulphur in the oils was determined by the usual 

method of combustion. For these determinations the oils obtained 

from one tube of lot 6 were employed. The results are given in the

following table:

Sulphur in oils of lot 6.

I

B........ .................................................................

C.. ........................................................................

D.........................................................................

E........ .................................................................

Specific 

gravity.

0. 8195

.8362

.8440

.8510

.8600

Per cent 

of 

sulphur.

0.04

.05

.09

.16

The percentage of sulphur in fractions A, C, and E of lot 51 was 

also determined. The results were as follows:

Sulphur in oils of lot 51.

Per cent.

Fraction A..................................................... 0.003

C.................................................... .040

E.................................................... .006

These results show that the sulphur tends to collect in the.oils in 

lower sections of the tube. As the fractionation proceeds the proportion of sulphur becomes smaller. The figures below indicate that 

as the oil is subjected to repeated filtrations the sulphur is gradually 

removed.

Sulphur remaining after first, second, and third fractionations.

C...... .........................................................

B... ............................................................

First.

0.04

. .16

 Second.

0.08

Third.

0.003

.040

.006
THROUGH FULLER S EARTH. 47

SELECTIVE ACTION OF FULLER'S EARTH.

When the earth from which as much oil as possible has been 

extracted by prolonged treatment with water is dried and digested 

with ether, oils of surprisingly high specific gravity and viscosity 

are obtained.

In the experiments undertaken to study the selective action of 

fuller's earth, the following method of procedure was adopted. 

The earth under examination was treated with water until no more 

oil appeared. This muddy earth, of the consistency of thin liquid 

paste, was spread upon porous plates and allowed to dry at room 

temperature. Several weeks usually elapsed before the earth became 

completely dry. It was then pulverized, and after being thoroughly 

soaked and shaken with ether, the mixture was allowed to remain 

undisturbed for 24 hours or more. The mixture was then filtered 

and the dissolved oil recovered by distilling off the ether from the 

filtrate. The residual earth was then digested with'ether for some 

time by means of an electric stove that completely surrounded the 

flask. The oil thus extracted was added to the oil first obtained. In 

several cases the residual earth was treated further with ether in 

the Soxhlet extractor. The results of these extractions are given in

the following table:

Oils extracted by ether.

Lot.

7.............................

8.............................

18 .............................

18..............................

19 .............................

19 .............................

19.............................

25 .............................

25 .............................

Fraction.

A.......

A.......

A'.......

A2......

AI......

A*......

A3. . . . . .

AI......

A». .....

Specific 

gravity 

at 50° C.

0. 8470

.8502

.8419

.8400

 . 8495

.8495

.8000

.8303

.8381

Lot.

25 ............................

25 ............................

51............................

51............................

51............................

51 ...........................

51............................

51............................

Fraction.

A". .....

B .......

A.......

B.......

C.......

D.......

E .......

F.......

Specific 

gravity 

at ^0° C.

0.8391

.8489

.8368

.8473

.8491

.8568

.8518

.8553

The specific gravity of none of the ether-extracted oils of the first 

and second fractionation, except those of lot 19, could be determined 

at 20° C. All were extremely viscous; those of lot 25 were so viscous at this temperature that they would not flow when the bottles 

containing them were inclined. The color of the oils ranged from 

brown to black. The ethereal solutions, however, of many of the 

oils were very light in color.

It is interesting to compare the specific gravities of the etherextracted oils with those of the corresponding water-extracted oils. 

For this purpose, the oils extracted by water and by ether from the 

earth of lot 51 are chosen. In the.folio wing table the specific gravities of these oils at the same temperature (20° C.) are given.
48 DIFFUSION OF CRUDE PETROLEUM 

Comparison of specific gravities.

B...................................... '....... ... .

C............................................................. ...

D................................... . . .

E................................;...................... . .

F.......... ............................ ...............................

Etherextracted 

oils.

0. 8363

.8473

.8491

.8568

.8518

.8553

Waterextracted 

oils.

0. 8213

.8303

.8337

.8353

.8366

. .8373

As the figures indicate, the specific gravities of ether-extracted 

oils are much higher than those of the corresponding water-extracted 

oils. The presence of such heavy and viscous oils in the upper sections of the tube can be explained only by assuming that they were 

carried to these heights in solution with the lighter oils and were then 

removed by the earth. As such viscous oils are totally unable to 

diffuse by capillarity to any appreciable extent, it is not probable 

that their transportation to the upper parts of the tube was effected 

by capillary diffusion.

CHEMICAL EXAMINATION OF THE OILS EXTRACTED

BY ETHER.

TJNSATTJRATED HYDROCARBONS. 

ACTION OF CONCENTRATED SULPHURIC ACID.

The percentage by volume of oil absorbed by concentrated sulphuric acid (specific gravity 1.84) was determined according to the 

following procedure: Ten cubic centimeters of the oil to be examined was measured into a glass-stoppered bottle, and 30 cubic 

centimeters of concentrated sulphuric acid was added. The mixture 

was thoroughly shaken by a machine for 30 minutes and then poured 

into a burette. After sufficient time had been allowed for any 

oil that might be mechanically absorbed in the acid to rise to the 

top, the volume of unabsorbed oil was read directly over the acid. 

Owing to the formation of heavy emulsions, no attempt was made to 

neutralize and wash the oil. The oils selected for examination were 

those extracted by ether from the earth of lots 36 and 51. The 

results of the analyses are expressed in the following table: 

Action of sulphuric acid on oils extracted by ether and by water. 

[Per cent by volume absorbed.]

B...............................................................

B......................................................... .....

C...............................................................

D ...............................................................

E...............................................................

F...............................................................

Etherextracted 

oils.

24

37

7

11.5

17

 16.4

1C. 5

18

Waterextracted 

oils.

3

10.4

2.3

0.1

9.1

11.5

12.5

14.5
THROUGH FULLER S EARTH.

ACTION OF BROMINE.

49

The method employed for determining the amount of bromine 

absorbed by the oils was as follows: Between 0.5 and 0.9 gram of 

the oil to be examined was dissolved in 10 to 15 cubic centimeters 

of carbon tetrachloride. Five cubic centimeters of a standard solution of bromine in carbon tetrachloride was then introduced, and the 

solution allowed to remain, with occasional shaking, in a dark place 

for 30 minutes. Ten cubic centimeters' of a 10 per cent solution of 

potassium iodide was then added, and the amount of iodine liberated was determined immediately by titrating with, a standard solution of sodium thiosulphate. A few drops of a starch solution was 

introduced to mark accurately the end of the titration. The separate amounts of bromine absorbed by addition and substitution

were not estimated.

The amounts of bromine absorbed, expressed in the following 

table, are calculated on the basis of 100 grams of oil. The. values 

for the corresponding water-extracted oils are also given for comparison.

Bromine absorbed by oil extracted by ether and water.

Lot 32,

Lot 30,

:B ..............................................................

fraction A ...............................................................

B ...............................................:...............

c...................... ..........................................

B...............................................................

. C............................................................... D...................................... :........................

E...............................................................

F............................................... ................

Etherextracted 

oils.

Per cent. 

5.30

7.39

5.72

e. 10

0.72

3.27

4.45

0.27

0.09

5.98

5.20

Waterextracted 

oils.

Per cent. 

5.02

0.96

 4.74

5. 40

5.56

3.27

4.36

5.03

4.92

4.71

5.36

As these results clearly demonstrate, one of the properties of 

fuller's earth is to retain the unsaturated hydrocarbons, thus exericsing a selective action.

SULPHUR COMPOUNDS.

The sulphur in the oils obtained by extraction with ether "was 

determined by the usual method of combustion. The results are. 

given in the table below.

Sulphur in oils extracted by ether and water.

0

B...............................................................

C..... ..........................................................

D. ..............................................................

E.. .............................................................

F........................... ....................................

Etherextracted 

oils.

Per cent.. 

0.004

.011

.050

.000

.080

.080

Waterextracted 

oils.

Per cfnt. 

0.003

.040

.006

89823° Bull. 475 11-
50 DIFFUSION OF CRUDE PETROLEUM

The selective action of the earth, in regard to the sulphur compounds, is indicated by these results. This fact was also pointed 

out by Richardson and Wallace. It is very probable that the earth 

also retains largely the nitrogen compounds in the oil, and it may 

also remove to a greater or less extent the benzene hydrocarbons.

These results seem to furnish evidence in favor of the view that 

the Illinois oil at some time in its history diffused through porous 

media, which exercised a selective'action upon it, removing a large 

part of the unsaturated and sulphur compounds and probably the 

benzene and nitrogen compounds.

SUMMARY.

When a solution of benzene and a paraffin oil is allowed to diffuse 

upward through a tube packed with fuller's earth, the benzene 

tends to collect in the lower sections and the paraffin oil in the upper 

sections of the tube.

. When crude petroleum diffuses upward through a tube packed 

with fuller's earth a fractionation of the oil occurs. The oil that is 

displaced by water from the earth from the top of the tube possesses 

a lower specific gravity than the oil obtained from the earth at the 

bottom of the tube.

As the fractionation proceeds the range of specific gravity covered 

in succeeding fractionations becomes smaller, indicating a movement toward the production of mixtures which, will finally pass 

through the earth unaltered.

In the fractionation of petroleum by capillary diffusion through 

fuller's earth the amounts of unsaturated hydrocarbons and sulphur 

compounds in the resulting fractions increase gradually from the 

lightest oils at the top to the heavier oils at the bottom of the tube.

Fuller's earth tends to retain the unsaturated hydrocarbons and 

sulphur compounds in petroleum, thus exercising a selective action 

upon the oil.

o