Process for producing secondary alkyl primary amines from n-paraffin

A process for converting mixtures of C.sub.6 to C.sub.30 n-paraffin and n-paraffin by-products to substantially pure n-paraffin which comprises catalytically hydrogenating the mixture at a temperature of from about 600.degree. to 750.degree. F. in the presence of a Group VIII metal on alumina catalyst where the catalyst contains from about 0.05 to 2.0 weight percent of an alkali metal oxide or alkaline earth metal oxide or thallous oxide. The catalyst can additionally contain a Group VIB or VIIB metal.

This invention relates to a process for converting mixtures containing 
n-paraffins to substantially pure n-paraffins. In particular this 
invention relates to a process for converting mixtures of C.sub.6 to 
C.sub.30 n-paraffins and C.sub.6 to C.sub.30 by-products to substantially 
pure C.sub.6 to C.sub.30 n-paraffins by catalytic hydrogenation. 
Normal paraffin hydrocarbons having from 6 to 30 carbon atoms represent 
valuable feedstock materials which can be converted to highly desirable 
products including amines by nitration and hydrogenation or to oximes by 
photonitrosation or to secondary alcohols by oxidation. In the 
illustrative processes described above, from about 5 to 50 weight percent 
of the normal paraffin undergoes conversion which results in the formation 
of a crude product mixture containing not only the desired material and 
unconverted paraffin but additionally substantial amounts of oxygenated 
paraffin by-products which can in some instances be produced in equal 
quantities with the sought after product. The desired product, for 
example, the amine or oxime or secondary alcohol is separated and 
recovered from the crude reaction product leaving a raffinate composed of 
a mixture of n-paraffin and oxygenated n-paraffin. While the raffinate may 
be recycled for further conversion to the preselected product, the 
presence of the oxygenated compounds present innumerable problems 
including the substantial buildup of undesired by-products and the further 
conversion of the oxygenated hydrocarbons to multifunctional materials. 
The formation and buildup of substantial amounts of by-products in turn 
seriously reduces the attractiveness and selectivity of the process which 
ultimately leads to a highly unsatisfactory and cost prohibitive 
operation. 
Heretofore, the n-paraffins contained in the mixture have been purified 
employing various procedures including the use of molecular sieve 
selective adsorbents to provide streams suitable for recycle substantially 
free of contaminants. However, this procedure is objectionable in that it 
removes substantial amounts of paraffin by-products, which by-products 
must be ultimately disposed of. This operation is particularly costly 
where by-product formation approximates the amount of desired product 
originally formed. Other techniques involved upgrading the mixture by 
hydrogenating crude normal paraffin mixtures containing oxygenated 
paraffins at temperatures of from about 450.degree. to 600.degree. F. in 
the presence of previously disclosed hydrogenation catalysts. However, 
even at this temperature range some hydrocracking to light paraffins and 
hydrogenolysis to methane occurred leading to losses in recoverable 
recycle material. Further, temperatures in excess of 600.degree. F. were 
to be avoided as the same caused excessive undesirable isomerization, 
hydrocracking, hydrogenolysis and coking of the hydrocarbons to, for 
example, isoparaffins and methane. While hydrogenation of the crude 
mixture at 450.degree. to 600.degree. F. is not particularly effective 
inasmuch as some hydrocracking and isomerization occurs which reduces the 
amount of valuable feedstock which can be recycled, the oxygenated 
by-products are only partially hydrogenated such that a considerable 
amount of incompletely converted by-products are recycled. 
It is therefore an object of this invention to provide a process which 
provides substantially pure n-paraffins from mixtures of n-paraffin and 
oxygenated paraffin hydrocarbons in high yields. 
Another object of this invention is to provide a process for converting a 
mixture of n-paraffin and oxygenated paraffin to substantially pure 
n-paraffin. 
Yet another object of this invention is to provide a process wherein 
mixtures of n-paraffins and oxygenated paraffin hydrocarbons are 
continuously converted to pure n-paraffin compositions. 
Other objects and advantages will become apparent from a reading of the 
following detailed description and examples. 
SUMMARY OF THE INVENTION 
Broadly this invention contemplates a process for converting a mixture of 
n-paraffin and n-paraffin by-products, that is, oxygenated paraffin, to 
substantially pure n-paraffin which comprises catalytically hydrogenating 
the mixture at a temperature of from about 600.degree. to 750.degree. F., 
preferably from 610.degree. to 700.degree. F., in the presence of a 
catalyst composed of alumina, a Group VIII metal and from about 0.05 to 
2.0 weight percent of an alkali metal oxide, alkaline earth metal oxide or 
thallous oxide. The catalyst can also contain as a component thereof an 
oxide of a member from Group VIB or a member from Group VIIB. 
The catalyst employed in our process is one which comprises a member of 
Group VIII of the Periodic Table, alumina and an alkali metal oxide or 
alkaline earth metal oxide or thallous oxide. Exemplary of the Group VIII 
metals are platinum, palladium, rhodium and ruthenium. Nickel and cobalt 
are also contemplated preferably in combination with a Group VIB metal 
oxide such as molybdenum oxide or tungsten oxide. A Group VIIB member such 
as rhenium present as the metal can also be used in combination with the 
Group VIII metal. Aluminas in various forms may be used as a component of 
the catalyst and particularly those aluminas having replaceable surface 
hydroxyl groups and surface areas of from 50 to 400 square meters per gram 
using the BET method. Included within our definition of alumina we 
mention, for example, eta-alumina, gamma-alumina, silica stabilized 
aluminas, i.e. aluminas containing up to approximately 5 weight percent 
SiO.sub.2, thoria-alumina, zirconia-alumina, titania-alumina and 
chromia-alumina. The Group VIII metal is present in amounts ranging from 
about 0.1 to 5.0 weight percent, preferably from about 0.1 to 2.0 weight 
percent, for the noble metals and from 1 to 5 percent for nickel and/or 
cobalt, based on the composite catalyst. The Group VIB metal oxide 
component when present ranges from about 5 to 20 weight percent of the 
composite catalyst. The Group VIIB metal can be present in an amount of 
from about 0.1 to 2.0 weight percent. 
The catalyst described above to be selective in converting the mixture of 
n-paraffin and oxygenated paraffin to substantially pure n-paraffin at a 
temperature of from about 600.degree. to 750.degree. F. requires as a 
component thereof from about 0.05 to 2.0 weight percent of an alkali metal 
oxide, alkaline earth metal oxide or thallous oxide or mixtures thereof. 
Illustrative of the alkali metals contemplated we mention lithium, sodium, 
potassium, rubidium and cesium and as the alkaline earth metals calcium, 
strontium and barium. The presence of the additional component moderates 
the activity of the Group VIII metal on alumina catalyst which in the 
absence thereof and at hydrogenation temperatures of from about 
600.degree. to 750.degree. F. otherwise causes substantial isomerization 
and hydrocracking of the mixture to isoparaffins and light paraffins. The 
presence of the minor amount of alkali metal oxide, alkaline earth metal 
oxide or thallous oxide and mixtures or combinations thereof on the 
catalyst deters isomerization and hydrocracking of the mixture including 
the n-paraffin and by-products and thereby selectively converts the 
by-products to valuable n-paraffin recycle feedstock. 
The catalyst described above can be prepared by introducing the Group VIII 
metal, and when desired the Group VIB or VIIB member, to the alumina by 
impregnating with an aqueous solution of a soluble salt of the metal 
followed by drying and calcination at a temperature of from 600.degree. to 
1200.degree. F. for several hours. The alkali metal oxide, alkaline earth 
metal oxide or thallous oxide can likewise be introduced to the alumina by 
impregnating with a soluble salt, such as the nitrate or acetate, either 
simultaneously with or subsequent to the introduction of the Group VIII 
metal followed by drying and calcination at 600.degree. to 1200.degree. F. 
The alumina component of the catalyst complements the hydrogenating 
activity of the Group VIII metal and moderator by promoting the 
dehydration of alcohols or glycols present to the corresponding olefin 
which are in turn hydrogenated to n-paraffin. This property of the 
catalyst is particularly beneficial not only at the operative 
hydrogenation temperature range of from 600.degree. to 750.degree. F., but 
the dual functional aspect of the catalyst is particularly advantageous in 
converting any olefinic material formed at the elevated temperatures and 
partially converted to n-paraffin to be essentially converted to 
n-paraffin by an additional and subsequent hydrogenation undertaken at 
about 450.degree. to 650.degree. F. 
In a further embodiment, the mixture of C.sub.6 to C.sub.30 n-paraffin and 
oxygenated paraffin is initially hydrogenated at a temperature of from 
about 350.degree. to 500.degree. F., preferably from about 400.degree. to 
450.degree. F., and prior to the hydrogenation at 600.degree. to 
750.degree. F. described above. Initial hydrogenation is particularly 
desirable when the mixture contains such oxygenated components as, for 
example, nitrites or nitrates which are thermally unstable at temperatures 
of 600.degree. F. and higher. Such illustrative thermally unstable 
materials when introduced to reactor preheaters operated to raise the 
temperature of the mixture to about 600.degree. to 750.degree. F. prior to 
introduction of the mixture into the hydrogenation reaction, thermally 
decompose and form resinous deposits in the preheater. By initially 
hydrogenating the mixture at 350.degree. to 500.degree. F., the thermally 
unstable materials are converted to more stable forms which can thereafter 
be successfully heated to temperatures of 600.degree. F. and higher in 
reactor preheaters. The initial hydrogenation also serves as a guard 
chamber to protect the catalyst employed at the 600.degree. to 750.degree. 
F. hydrogenation to convert some oxygenates to non-volatile inorganic 
compounds such as when the mixture contains alkyl borate esters described 
below. Conventional hydrogenation catalysts can be employed in the initial 
hydrogenation as, for example, nickel, cobalt, platinum, palladium and 
rhodium. The catalysts can be supported on kieslguhr, silica, carbon or 
alumina as is known in the art. The catalyst described above and employed 
at the hydrogenation conditions of 600.degree. to 750.degree. F. can also 
be used. 
In some instances it may be desirable to pass the recycle mixture through a 
bed of alumina, silica gel or activated carbon to act as guard case for 
the hydrogenation catalyst. Illustratively, a recycle mixture derived from 
the conversion of paraffins to secondary alcohols will contain minor 
amounts of boric acid and borate esters which adversely effect 
hydrogenation catalysts. Such materials can be effectively removed from 
the mixture prior to hydrogenation by, for example, passing the mixture at 
400.degree. to 500.degree. F. through a bed of activated alumina. 
As mentioned above, an additional and subsequent hydrogenation may also be 
desirable as, for example, when the liquid product hydrogenated at 
600.degree. to 750.degree. F. is found to contain minor amounts of C.sub.6 
to C.sub.30 olefins. Such an additional hydrogenation treatment can be 
conducted at from about 450.degree. to 650.degree. F. wherein the olefin 
is converted to n-paraffin employing catalysts of the type described in 
connection with the hydrogenation at 600.degree. to 750.degree. F. 
In general, hydrogenation in each of the above plural temperature ranges is 
undertaken in the presence of hydrogen at pressures ranging from about 100 
to 1500 p.s.i.g. for periods of from 0.2 to 5 hours. In continuous 
processing the mixture can be introduced into the hydrogenation zones at 
space velocities of from 0.2 to 10.0 volumes of liquid feed per volume of 
catalyst per hour (v./v./hr.) 
The mixtures hydrogenated according to the instant invention and composed 
of n-paraffins having from 6 to 30 carbon atoms and n-paraffin 
by-products, that is, oxygenated paraffins having from 6 to 30 carbon 
atoms can be derived from a plurality of sources. Typically, the mixture 
contemplated for hydrogenation in accordance with the instant invention is 
predominantly C.sub.6 to C.sub.30 n-paraffin containing from 0.5 to 30 
weight percent oxygenated paraffins. Representative of the C.sub.6 to 
C.sub.30 oxygenated paraffins are alcohols, ketones and polyoxygenated 
materials such as acids, esters, glycols, lactams, ketoacids, and 
ketoalcohols. The mixture depending upon its source can also contain 
additional materials capable of being converted to normal paraffins in the 
presence of the catalyst described above and under the hydrogenation 
conditions recited. Among such materials are included C.sub.6 to C.sub.30 
nitroparaffins, secondary amines, diamines, nitroalcohols, aminoalcohols, 
aminoketones, nitroketones, nitrates, nitrites, dinitroparaffins, 
alkylchlorides and olefins. 
Illustrative of the sources of the mixtures hydrogenated herein we mention 
the following. In the production of secondary alkyl primary amines from 
n-paraffins having from 6 to 30 carbon atoms, the amines are prepared by 
nitrating from about 5 to 50 weight percent of the paraffin to 
nitroparaffin employing as nitrating agent, for example, nitric acid, 
nitrogen dioxide or dinitrogen tetroxide at a temperature of from about 
250.degree. to 500.degree. F. to form a crude nitrated product containing 
in addition to unconverted n-paraffin and nitroparaffin substantial 
quantities of oxygenated by-products such as C.sub.6 to C.sub.30 ketones, 
alcohols, carboxylic acids, nitrites, nitrates and multifunctional 
materials such as dinitroparaffins, nitroalcohols, nitroketones and 
ketoalcohols. Thereafter the crude nitrated liquid product typically 
comprising from 50 to 94.5 weight percent unreacted n-paraffin, 5 to 35 
weight percent nitroparaffin and 0.5 to 15 weight percent oxygenated 
by-products is introduced to a hydrogenation zone where the nitroparaffin 
is hydrogenated to the amine at average conversion temperatures ranging 
from about 100.degree. to 450.degree. F. in the presence of conventional 
and well known hydrogenation catalysts. A preferred catalyst is palladium 
on carbon. The crude liquid hydrogenated product comprises C.sub.6 to 
C.sub.30 n-paraffin secondary alkyl primary amine and oxygenated 
by-products such as acids, alcohols, ketones, ketoalcohols, aminoalcohols, 
aminoketones, nitrates and nitrites. Other by-products such as unreacted 
nitroparaffin, secondary amines and diamines can also be present. The 
primary amine is separated form the liquid hydrogenated product employing 
conventional recovery procedures such as step-wise fractionation or the 
amine may be converted and recovered as an amine salt by reaction of the 
crude liquid product with an inorganic acid followed by further treatment 
of the amine salt with alkali and thereafter recovering the primary amine 
by distillation. The unreacted nitroparaffin and oxygenated or other 
by-products of the nitration hydrogenation reactions in admixture with the 
paraffin, secondary amines and diamines separated from the primary amine 
represent a typical mixture contemplated by the instant invention which is 
hydrogenated to substantially pure n-paraffin. 
The production of secondary alcohols from C.sub.6 to C.sub.30 n-paraffins 
also provides by-product streams composed of mixtures of n-paraffin and 
oxygenated paraffins which are according to the instant invention 
converted to substantially pure n-paraffin. The production of secondary 
alcohols from C.sub.6 to C.sub.30 paraffins is accomplished by contacting 
the paraffin in the liquid phase with an oxygen containing gas in the 
presence of boric acid at a temperature of from about 300.degree. to 
450.degree. F. to convert from 5 to 50 weight percent of the paraffin to a 
mixture of alkyl borate esters, unreacted paraffin and degradation 
products including olefins and oxygenated products other than the borate 
esters. The mixture is first fractionated to separate an overhead fraction 
comprising unreacted n-paraffins, a portion of the by-products including 
such materials as olefins, ketones, some alcohols and traces of borate 
ester, and a bottoms fraction containing the borate ester and 
polyoxygenated by-products including ketoalcohols, acids, ketoacids and 
glycols. The bottoms are contacted with water at from 100.degree. to 
212.degree. F. to hydrolyze the borate esters to secondary alcohols which 
bottoms separate into two phases comprising a top organic layer containing 
secondary alcohol and substantially all of the polyoxygenated products and 
a bottom layer comprised of aqueous boric acid, which layers are 
separated. The organic layer is fractionated to separate desired secondary 
alcohols as an overhead and a bottoms comprising polyoxygenated materials. 
The overhead recovered by the first fractionation comprised of unreacted 
n-paraffins, olefin and oxygenated products including alcohols and ketones 
represents a typical mixture contemplated for hydrogenation according to 
the instant invention. All or a portion of the final organic bottoms 
containing the polyoxygenated by-products can also be included into the 
mixture contemplated for hydrogenation herein. 
Another process providing mixtures of n-paraffin and oxygenated paraffins, 
which according to the instant invention can be substantially converted to 
pure n-paraffins, involves the production of normal paraffin oximes having 
from 6 to 30 carbon atoms from normal paraffins. The oximes are prepared 
by photochemically reacting and converting from 5 to 50 weight percent of 
a C.sub.6 to C.sub.30 normal paraffin with a gaseous nitrosating agent, 
such as nitrosyl halides, nitrosyl sulfuric acid, nitrogen oxide and 
chlorine or nitrogen peroxide and chlorine at a temperature of from about 
30.degree. to 140.degree. F. under the influence of light to produce 
normal paraffin oximes and up to about 5 weight percent oxygenated 
by-products primarily composed of ketones. Some alkylchlorides are also 
formed. The oxime is thereafter converted to the sulfate and unconverted 
C.sub.6 to C.sub.30 paraffin, ketones and alkylchlorides are extracted 
using a low boiling hydrocarbon such as cyclohexane, n-pentane, isoheptane 
or petroleum ether. Thereafter the low boiling hydrocarbon is separated by 
distillation and the mixture of the n-paraffin, oxygenated paraffin, in 
this instance ketones, along with the alkylchlorides, can be converted to 
substantially pure n-paraffin according to the instant invention. 
It will be appreciated that other known processes providing mixtures of 
n-paraffin and oxygenated paraffin by-products can be improved by 
applicants' catalytic hydrogenation and that the processes mentioned above 
are merely illustrative and are not intended to limit the instantly 
claimed invention. 
In order to illustrate more fully the nature of our invention and manner of 
practicing the same, the following examples are presented. In these 
examples the best mode contemplated by us for carrying out our invention 
is set forth.

EXAMPLE I 
The conversion of n-paraffins to secondary alkyl primary amines is 
undertaken by providing a fresh water-white C.sub.10 to C.sub.14 
n-paraffin hydrocarbon composition having the following carbon chain 
length distribution on a weight percent basis: C.sub.10 11.1, C.sub.11 
28.7, C.sub.12 32.2, C.sub.13 26.9, C.sub.14 1.1. To 10.7 weight percent 
of fresh normal paraffins there is mixed 89.3 weight percent of previously 
processed and upgraded recycle paraffins according to the instant 
invention. 
A paraffin hydrocarbon charge at the rate of 940 pounds per hour is 
nitrated with 60 pounds per hour of nitrogen dioxide wherein nitration 
proceeds at 330.degree. F. under a pressure of 4 p.s.i.g. Off-gases 
comprising paraffin, nitrogen dioxide, nitric oxide, nitrous oxide, 
nitrogen, carbon dioxide, carbon monoxide and water are withdrawn, the 
off-gases partially condensed, and condensed paraffin recycled. Nitric 
oxide in the overhead gas is oxidized to nitrogen dioxide, the oxidized 
gas cooled to condense nitrogen dioxide, and the liquefied nitrating agent 
recycled. Non-condensible gases including nitrogen, nitric oxide, nitrous 
oxide, carbon monoxide and carbon dioxide are vented. 
The crude nitrated paraffin product, 977 pounds, comprising 80 weight 
percent n-paraffin, 14.7 weight percent nitroparaffin and 4.4 weight 
percent by-products including oxidized paraffin and polyfunctionals of 
which 0.6 weight percent are ketones, 1.2 weight percent are nitrites and 
0.5 weight percent are nitrates is continuously caustic washed with about 
70 pounds per hour of 10 percent aqueous sodium hydroxide in a line mixer 
at 200.degree. F. and 50 p.s.i.g. The resulting aqueous layer is separated 
in a settler and removed. The organic layer is washed at 180.degree. F. 
and 50 p.s.i.g. with 27 pounds per hour of water in a conventional 
countercurrent extraction tower. The washed nitrate product contains 129 
pounds of nitrated paraffin and 833 pounds of n-paraffin and other 
materials that include 0.43 weight percent ketones, 0.95 weight percent 
nitrites and 0.41 weight percent nitrates. 
The crude nitrated paraffin composition is introduced at an inlet 
temperature of 200.degree. F. to a hydrogenation reactor containing a 
hydrogenation catalyst composed of one weight percent palladium on carbon 
at a liquid hourly space velocity of 2.0 volumes of liquid per volume of 
catalyst per hour. Hydrogenation is conducted under a hydrogen pressure of 
560 p.s.i.g. and up to a maximum conversion temperature of 410.degree. F. 
Following hydrogenation, substantially all of the nitroparaffin is reduced 
to amine. Hydrogen, ammonia and some water are removed as gases and 
remaining water and ammonia are decanted from the recovered crude 
hydrogenation product at 110.degree. F. 
The crude hydrogenation product at a rate of 950 pounds per hour comprising 
834 pounds of n-paraffins and miscellaneous by-products including 0.49 
weight percent amines (secondary) and 0.52 weight percent ketones, 100 
pounds of secondary alkyl primary amines, about 1 pound of unconverted 
nitroparaffins and 15 pounds of water and ammonia is contacted and 
saturated with 87 pounds per hour of carbon dioxide at 300 p.s.i.g. and 
110.degree. F. thereby forming an amine-carbon dioxide complex. The carbon 
dioxide saturated crude hydrogenation product is counter-currently 
contacted in a tower with 1,500 pounds per hour of a solvent mixture 
comprising 40 percent methanol and 60 percent water, the solvent mixture 
having been previously saturated with 50 pounds per hour of carbon dioxide 
at 300 p.s.i.g. and 110.degree. F. Upon contacting of the carbon dioxide 
saturated crude hydrogenation product with the solvent mixture, the 
primary amine complex transfers from the predominantly paraffin stream to 
the solvent stream. 
The amine depleted paraffin stream is subsequently reduced to atmospheric 
pressure in a flash drum whereupon carbon dioxide therein is removed 
overhead. The amine-enriched solvent stream is heated to a temperature of 
150.degree. F, and introduced to a flash tower maintained at atmospheric 
pressure where carbon dioxide, along with some methanol and water, is 
removed overhead. The amine-rich liquid from the flash tower is passed 
through a fractionator where methanol, residual carbon dioxide and some 
water are removed overhead. The bottom stream containing water and crude 
amines separates as two phases, namely a water phase containing some 
methanol and amines, and a crude amine phase containing some water. 
110 pounds per hour of the crude amine phase are heated to 248.degree. F. 
and flashed at 160 mm. Hg thereby removing as overhead substantially all 
of the residual methanol and water, along with some organic materials. 
After condensation, the organic matter in the overhead is separated from 
the aqueous layer and combined with the flashed amine phase. The flashed 
crude amine phase is thereafter vacuum-distilled at 20 mm. Hg and 
200.degree. F. to remove overhead residual methanol, water, paraffinic 
hydrocarbons and lighter than C.sub.10 amines. Finally, the amine phase is 
vacuum distilled at 10 mm. Hg and 300.degree. F. to produce 100 pounds per 
hour of finished amine containing 98.5 weight percent secondary alkyl 
primary amine. 
The amber colored amine-depleted paraffin stream from the raffinate flash 
drum is combined with the predominantly paraffinic waste streams derived 
from vacuum distilling the crude amines to form a recycle stream 
comprising about 98 weight percent n-paraffin, 0.15 weight percent 
nitroparaffins and about 1.85 weight percent by-products. The mixed 
recycle stream is introduced into an initial hydrogenation zone at the 
rate of 840 pounds per hour and hydrogenated at 400.degree. F. with 17 
pounds per hour of hydrogen at 500 p.s.i.g. at a liquid hourly space 
velocity of 3.0 in the presence of a nickel-molybdenum on alumina 
catalyst. The product of the initial hydrogenation zone is introduced into 
a subsequent hydrogenation zone at the rate of 840 pounds per hour and 
hydrogenated at 660.degree. F. with 16 pounds per hour of hydrogen at 500 
p.s.i.g. at a liquid hourly space velocity of 1.5 in the presence of a 3 
weight percent nickel oxide--12 weight percent molybdenum oxide-- 0.6 
weight percent barium oxide on alumina catalyst. After separating 
hydrogen, ammonia and water, the hydrogenated water-white product is 
essentially free of nitrated and oxygenated by-products and is recycled 
for introduction to the nitration reactor. The system for producing the 
amines continues to operate for long periods of time without interruption. 
EXAMPLE II 
An amine-depleted C.sub.10 to C.sub.14 paraffin stream composed of about 3 
weight percent by-products including nitroparaffins, ketones, secondary 
amines, alcohols, nitrates, nitrites and polyfunctional derivatives of the 
n-paraffin similar to Example I was introduced into a hydrogenation 
reactor containing a nickel on kieselguhr hydrogenation catalyst at the 
rate of 3.3 pounds per hour and hydrogenated at 610.degree. to 615.degree. 
F. with 0.03 pounds per hour of hydrogen at about 600 p.s.i.g. Sampling of 
the off-gas shows it to contain 7 percent methane thereby demonstrating 
that substantial hydrocracking has occurred. 
EXAMPLE III 
A continuous process for converting n-paraffin to secondary alcohols is 
undertaken by introducing a C.sub.10 to C.sub.14 n-paraffin charge 
composed of 12.6 weight percent fresh n-paraffifn and 87.4 weight percent 
recycle n-paraffin hydrogenated according to this invention. 
815 pounds per hour of the paraffin charge is preheated to 350.degree. F. 
and introduced to two continuous stirred tank reactors in series along 
with orthoboric acid, the acid added at the rate of 2.1 weight percent 
basis total paraffin charge to each reactor for a total of 4.2 weight 
percent boric acid basis the total paraffin charge. Air is introduced to 
each reactor in the amount of 1.3 SCF per hour per pound of paraffin 
present in the first reactor and at the rate of 0.7 SCF/hr./lb. in the 
second reactor. The reactors are operated at 10 p.s.i.g. and are each 
equipped with means to separate overhead by-product water. The average 
residence time of the paraffin in the first reactor is 3.1 hours and in 
the second reactor 2.6 hours, thereby providing a total conversion of 
paraffin to 17.1 weight percent borate esters, about 0.55 weight percent 
oxygenates, and about 0.1 weight percent olefins, with the remainder of 
the organic material being unconverted paraffin. The reactor effluent 
stream is first fractionated by vacuum stipping at 365.degree. F. and 5 mm 
pressure to obtain a bottom stream of stripped borate esters and an 
overhead containing predominantly C.sub.10 to C.sub.14 unreacted 
n-paraffin, 0.2 weight percent secondary alcohols, 0.1 weight percent 
olefins, 0.12 weight percent acids, 0.24 weight percent ketones and 0.54 
weight percent borate esters. The bottom stream of stripped borate esters, 
other polyoxygenated by-products and traces of unreacted n-paraffin are 
contacted with water at 180.degree. F. in an in-line mixer at a weight 
ratio of water to borate ester containing stream of 2:1 and a top organic 
layer is separated from a bottom layer composed of aqueous boric acid. 
The top organic layer composed of 85 weight percent secondary alcohols, 0.6 
weight percent unreacted paraffins, 1.2 weight percent boric acid and the 
remainder polyoxygenated paraffins is fractionated at 390.degree. F. and 2 
mm pressure to remove overhead 101 pounds of secondary alcohols of 
approximately 99 percent purity. The bottoms comprising C.sub.10 to 
C.sub.14 polyoxygenated paraffins are steam stripped to form an overhead 
composed of 30 weight percent acids, 12 weight percent ketones, 38 weight 
percent glycols, 17 weight percent esters and 3 weight percent boric acid. 
This overhead is combined with the first fractionated overhead containing 
predominantly C.sub.10 to C.sub.14 unreacted paraffin to form a recycle 
stream comprising 0.1 weight percent olefin, 0.5 weight percent acids, 0.4 
weight percent ketones, 0.5 weight percent glycols, 0.7 weight percent 
borate esters, 0.4 weight percent boric acid and the remainder unreacted 
paraffin. 
The recycle stream is introduced into an initial hydrogenation reactor at 
the rate of about 722 pounds per hour and hydrogenated at 400.degree. F. 
with 25 pounds per hour of hydrogen at 800 p.s.i.g. at a liquid hourly 
space velocity of 2.5 in the presence of a cobalt-molybdenum on alumina 
catalyst. The product of the initial hydrogenation zone is introduced into 
a subsequent hydrogenation reactor at the rate of 719 pounds per hour and 
hydrogenated at 670.degree. F. with 25 pounds per hour of hydrogen at 800 
p.s.i.g. at a liquid hourly space velocity of 2.0 in the presence of a 
0.75 weight percent platinum, 0.4 weight percent potassium oxide on gamma 
alumina catalyst. After separating hydrogen and water, the hydrogenated 
product is essentially free of oxygenated by-products, the n-paraffin 
content is in excess of 99 weight percent and the product is recycled for 
introduction to the stirred tank reactors. Virtually no methane, light 
hydrocarbons and isoparaffins are produced during hydrogenation. For 101 
pounds of 99 percent purity secondary alcohol, there is required 103 
pounds of fresh n-paraffin feed in the continuous process. 
EXAMPLE IV 
A recycle stream similar to that in Example III is hydrogenated at 
550.degree. F. and 800 p.s.i.g. with 3.5 pounds of hydrogen per 100 pounds 
of recycle feed over a nickel on kieselguhr hydrogenation catalyst at a 
liquid hourly space velocity of 2.0. About 12 weight percent of the feed 
is converted to paraffins lighter than C.sub.6. For 101 pounds of 99 
percent purity secondary alcohol, there is required 115 pounds of fresh 
n-paraffin feed in the continuous process employing the catalytic 
hydrogenation described in this example. It will be seen that the claimed 
invention employing the catalyst illustrated in Example III is more 
selective in converting the mixture to n-paraffin than the conventional 
hydrogenation catalyst employed in Example IV. 
EXAMPLE V 
Example III is repeated except that the recycle stream is first introduced 
through a bed of alumina at 400.degree. F. acting as a guard chamber and 
thereafter catalytic hydrogenation of the recycle stream is undertaken at 
670.degree. F. in the presence of a 3.0 weight percent nickel oxide -- 
12.0 weight percent molybdenum oxide -- 0.2 weight percent lithium oxide 
on eta alumina catalyst. The results of hydrogenation and the composition 
of the hydrogenated product are similar to Example III.