Method for isomerizing wax to lube base oils using a sized isomerization catalyst

The present invention is directed to a process for the catalytic isomerization of waxes to liquid products, particularly to the production of high yields of liquid products boiling in the 370.degree. C..sup.+ range suitable for use as lube oil base stocks or blending stocks, said process employing as the catalyst a material made by depositing a hydrogenation metal component on a refractory metal oxide base, preferably alumina, fluoriding said metal loaded base using aqueous HF and subsequently crushing the fluorided metal loaded base to produce a sized material of 1/32 inch and less its largest cross-sectional dimension. Alternately the catalyst can be made by depositing a hydrogenation metal component on a refractory metal oxide base of 1/32 inch and less across its largest cross-sectional dimension and subsequently fluoriding said sized material using aqueous HF. In either case the catalyst is activated before being used by heating in a hydrogen atmosphere to from 350.degree. C. to 500.degree. C. for from 1 to 48 hours or more.

FIELD OF THE INVENTION 
The present invention is directed to a process for the catalytic 
isomerization of waxes to liquid products, particularly to the production 
of high yields of liquid products boiling in the 370.degree. C.+ range 
suitable for use as lube oil base stocks or blending stocks, said process 
employing as the catalyst a material made by depositing a hydrogenation 
metal component on a refractory metal oxide base, preferably alumina, 
fluoriding said metal loaded base using HF and subsequently crushing the 
fluorided metal loaded base to produce a sized material of 1/32 inch and 
less across its largest cross-sectional dimension. Alternately the 
catalyst can be made by depositing a hydrogenation metal component on a 
refractory metal oxide base of 1/32 inch and less across its largest 
cross-sectional dimension and subsequently fluoriding said sized material 
using HF. In either case the catalyst is activated before being used by 
heating in a hydrogen atmosphere to from 350.degree. C. to 500.degree. C. 
for from 1 to 48 hours or more. 
DESCRIPTION OF THE INVENTION 
A process is disclosed of the production of high yields of non-conventional 
lube oil base stocks or blending stocks by the isomerization of waxes over 
isomerization catalysts containing a hydrogenating metal component 
typically one from Group VIII or mixtures thereof, preferably Group VIII, 
more preferably noble Group VIII, most preferably platinum on a 
halogenated refractory metal oxide support. The catalyst typically 
contains from 0.1 to 5.0 weight percent metal, preferably 0.1 0.1 to 1.0 
weight percent metal, most preferably 0.2 to 0.6 weight percent metal. The 
refractory metal oxide support is typically an alumina and the halogen is 
fluorine. The catalyst has a halogen content in the range of 2 to 10 
weight percent halogen, preferably 2 to 8 weight percent halogen. The 
catalyst employed in the present process which results in the production 
of high yields of isomerate is taught in copending application U.S. Ser. 
No. 283,658, filed even date herewith, which is a continuation-in-part of 
U.S. Ser. No. 134,698, filed Dec. 18, 1987, and now abandoned, in the 
names of Cody, Hamner, Sawyer and Schorfheide and consists of a 
hydrogenating metal on halogenated refractory metal oxide support made by 
depositing the hydrogenation metal on the refractory metal oxide support 
and fluoriding said metal-loaded support using acidic fluorine sources 
such as HF by any convenient technique such as spraying, soaking, 
incipient wetness, etc. to deposit between 2 to 10 percent, preferably 2 
to 8 percent. Following fluorination, the catalyst is dried typically at 
120.degree. C. and then crushed to expose inner surfaces, the crushed 
catalyst hereinafter called "sized" catalyst. This sized catalyst will 
typically be 1/32 inch and less across its longest cross-sectional 
dimension and will preferably range from 1/64 inch to 1/32 inch across its 
largest cross-sectional dimension. Alternatively the catalyst is made by 
depositing the hydrogenation metal on the refractory metal oxide base, 
having particle sizes of 1/32 inch and less across its largest 
cross-sectional dimension and preferably in the range between 1/64 to 1/32 
inch across its largest cross-sectional dimension and subsequently 
fluoriding said sized metal loaded base using a low pH fluorine source 
such as aqueous HF. 
The particle or extrudate is sized to expose inner surfaces of the particle 
or extrudate. The starting particle or extrudate may be of any physical 
configuration. Thus, particles such as trilobes or quadrilobes may be 
used. Extrudates of any diameter may be utilized, and can be anywhere from 
1/32 of an inch to many inches in length, the length dimension being set 
solely by handling considerations. It is preferred that following sizing 
the particle be smaller than the initial size of the starting extrudate. 
Following deposition of the hydrogenation metal and the halogenation of the 
particle of extrudate, the particle or extrudate is sized or fractured to 
expose inner surfaces. Alternatively, the hydrogenation metal can be 
loaded into a particle which is already 1/32 inch or less across its 
largest cross-sectional dimension (in which case additional crushing and 
sizing is not necessary) followed by fluoriding or a larger particle can 
be loaded with the hydrogenated metal, then crushed and sized to a size 
about 1/32 inch or less across its largest cross-sectional dimension, 
followed by fluoriding. 
The sizing is conducted to an extent appropriate to the particle or 
extrudate with which one is starting. Thus, an extrudate of 1/16 inch 
across its largest cross-sectional dimension would be sized into pieces 
which range between about 1/64 to 1/32 inch across its largest 
cross-sectional dimension. If the extrudate is only 1/16 inch to begin 
with it will be enough simply to fracture it to produce a crushed material 
less than about 1/32 inch. 
Following sizing, the uncalcined sized catalyst is activated by heating in 
a hydrogen atmosphere at a temperature of 350.degree. C. to 500.degree. C. 
for from 1 to 48 hours or more. The atmosphere may be pure hydrogen or 
plant hydrogen (60 to 70 vol % hydrogen). 
A typical activation profile shows a period of 2 hours to go from room 
temperature to 100.degree. C. with the catalyst being helf at 100.degree. 
C. from 0 to 2 hours, then the temperature is raised from 100.degree. to 
about 350.degree. C. over a period of 1 to 3 hours with a hold at the 
final temperature of from 1 to 4 hours. Alternatively, the catalyst can be 
activated by heating from room temperature to the final temperature of 
350.degree. to 450.degree. C. over a period of 2 to 7 hours with a hold at 
the final temperature of 0 to 4 hours. Similarly, activation can be 
accomplished by going from room temperature to the final temperature of 
350.degree. to 450.degree. C. in 1 hour. 
In small pilot units, sizing down of particles is practiced to improve 
catalyst-liquid feed contacting and minimize back mixing of partially 
converted product and feed. Particle sizing can lead to improved catalyst 
performance because of improved hydrodynamics especially if the system is 
A.fwdarw.B.fwdarw.C where B (in this case oil) is the desired product. 
However, in this case we have found that the improvement caused by sizing 
the particles exceeds the benefits normally associated simply from better 
contacting. We have the benefit of high mass velocity operation (2,000 
lb/ft.sup.2 /h) data to establish performance at plant scale (i.e. no 
hydrodynamic limitations) using unsized particles. Small scale operation 
(approximately 100 lb/ft.sup.2 /h) using sized particles gives higher 
yields than is achieved at plant scale mass velocities using unsized 
extrudates. 
This sized catalyst is unexpectedly superior for wax isomerization as 
compared to the uncrushed particle or extrudate starting material. It has 
also been discovered that 370.degree. C.+ oil products made using the 
sized catalyst starting with wax possessing about 5 to 10 percent oil 
exhibit higher VI's than do 370.degree. C.+ oil products made starting 
with wax possessing either 0 percent oil or 20 percent oil. Therefore, to 
produce products having the highest VI one would isomerize wax having from 
5 to 15 percent oil, preferably 7 to 10 percent oil. 
The wax which is isomerized may come from any of a number of sources such 
as waxes recovered from the solvent or autorefrigeration dewaxing of 
conventional hydrocarbon oils, as well as mixtures of these waxes. Waxes 
from dewaxing conventional hydrocarbon oils are commonly called slack 
waxes and usually contain an appreciable amount of oil. The oil content of 
these slack waxes can range any where from 0 to 45 percent or more, 
usually 1 to 30 percent oil. For the purposes of this application, the 
waxes are divided into two categories: (1) light paraffinic waxes boiling 
in the range about 300.degree. to 580.degree. C.; and (2) heavy microwaves 
having a substantial fraction (.gtoreq.50 percent) boiling above 
600.degree. C. 
As one would expect, isomerization catalysts are extremely susceptible to 
deactivation by the presence of heteroatom compounds (i.e., N or S 
compounds) in the wax feed, so care must be exercised to remove such 
heteroatom materials from the wax feed charges. Waxes obtained from 
natural petroleum sources contain quantities of oil which contain 
heteroatom compounds. In such instances, the slack waxes should be 
hydrotreated to reduce the level of heteroatoms compounds to levels 
commonly accepted in the industry as tolerable for feeds to be exposed to 
isomerization catalysts. Such levels will typically be a nitrogen content 
of 1 to 5 ppm and a sulfur content of 1 to 20 ppm, preferably 2 ppm or 
less nitrogen, and 5 ppm or less sulfur. Similarly, such slack waxes 
should be deoiled prior to hydrotreating to an oil content in the range of 
1 to 35 percent oil, preferably 1 to 25 percent oil, more preferably 5 to 
15 percent oil, most preferably 7 to 10 percent oil. The hydrotreating 
step will employ typical hydrotreating catalyst such as Co/Mo or Ni/Mo on 
alumina under standard, commercially accepted conditions, e.g. temperature 
of 280.degree. to 400.degree. C., space velocity of 0.1 to 2.0 V/V/hr, 
pressure of from 500 to 3,000 psig H.sub.2 and hydrogen gas rates of from 
500 to 5,000 SCF/B. 
Isomerization is conducted under conditions of temperatures between about 
270.degree. to 400.degree. C., preferably 300.degree. to 360.degree. C., 
pressures of 500 to 3,000 psi H.sub.2, preferably 1,000 to 1,500 psi 
H.sub.2, hydrogen gas rates of 1,000 to 10,000 SCF/bbl, and a space 
velocity in the range of 0.1 to 10 V/V/hr, preferably 1 to 2 V/V/hr. 
As is taught in copending application U.S. Ser. No. 283,664, filed even 
date herewith, which is a continuation-in-part of U.S. Ser. No. 135,150, 
filed Dec. 18, 1987, and now abandoned, in the names of Cody, Bell, West, 
Wachter and Achia, it is preferred that the isomerization reaction be 
conducted to a level of conversion such that about 40 percent and less, 
preferably 15 to 35 percent, most preferably 20 to 30 percent, unconverted 
wax remains in the fraction of the isomerate boiling in the lubes boiling 
range sent to the dewaxing unit. The fraction of unconverted wax is 
calculated as unconverted wax/(unconverted wax+ dewaxed oil) X100. The 
amount of unconverted wax in the 370.degree. C.+ oil fraction is taken to 
be the amount of wax removed or recovered from said oil fraction upon 
dewaxing. The total product from the isomerization unit is fractionated 
into a lube oil fraction boiling in the 330.degree. C.+ range, preferably 
in the 370.degree. C.+ range or even higher. This lube oil fraction is 
solvent dewaxed, preferably using 20/80 v/v mixture of MEK/MIBK, and 
unconverted wax is recycled for further isomerization by being fed either 
to the fresh feed reservoir or directly to the isomerization unit. 
In principle a wax extinction process for maximizing lube yields would 
involve operation at a very low severity i.e. where conversion to fuels is 
at a minimum. Under these circumstances the amount of unconverted wax 
recycled to the isomerization reactor would be large and differences in 
catalyst selectivity would be less important. 
In practice, however, it is not practical to operate in a low conversion 
mode. Instead, the operating severity is governed by the need to make a 
low pour (.ltoreq.-21.degree. C. pour point) oil. It has been discovered 
that low pours cannot be achieved from isomerates made at low conversion. 
As is taught in copending application U.S. Ser. No. 283,664, this is 
unexpected since with natural oils the amount of wax present did not 
effect the ability to dewax the oil to low target pour point. A critical 
determinant in reaching low pours is that the amount of wax remaining in 
the 370.degree. C.+ fraction obtained from isomerization should not exceed 
40% and for lower pour points may have to be as little as 15-20%. To 
maximize yield in this situation the choice of catalyst becomes important. 
Following isomerization the isomerate is fractionated into a lubes cut and 
fuels cut, the lubes cut being identified as that fraction boiling in the 
330.degree. C.+ range, preferably the 370.degree. C.+ range or even 
higher. This lubes fraction is then dewaxed. Dewaxing is accomplished by 
techniques which permit the recovery of unconverted wax, since in the 
process of the present invention this unconverted wax is recycled for 
further isomerization. It is preferred that this recycled wax be sent to 
the feed wax reservoir and passed through the hydrotreating unit to remove 
any quantities of entrained dewaxing solvent, which solvent could be 
detrimental to the isomerization catalyst. Alternatively, a separate 
stripper can be used to remove entrained dewaxing solvent or other 
contaminants. Since the unconverted wax is to be recycled, dewaxing 
procedures which destroy the wax such as catalytic dewaxing are not 
recommended. Solvent dewaxing is utilized and employs typical dewaxing 
solvents. Solvent dewaxing utilizes typical dewaxing solvents such as 
C.sub.3 to C.sub.6 ketones (e.g. methyl ethyl ketone, methyl isobutyl 
ketone and mixtures thereof), aromatic hydrocarbons (e.g. toluene), 
mixtures of ketones and aromatics (e.g. MEK/toluene), autorefrigerative 
solvents such as liquified, normally gaseous C.sub.2 to C.sub.4 
hydrocarbons such as propane, butane and mixtures thereof, etc. at filter 
temperature of -25 to -30.degree. C. 
As is also taught in copending application U.S. Ser. No. 283,664, the 
preferred solvent to dewax the isomerate under miscible conditions and 
thereby produce the highest yield of dewaxed oil at a high filter rate is 
a mixture of MEK/MIBK (20/80) used at a temperature in the range 
-25.degree. to -30.degree. C. Pour points lower than -21.degree. C. can be 
achieved using lower filter temperatures and other ratios of said solvent, 
but a penalty is paid due to operation under immiscible conditions, the 
penalty being lower filter rates. Further, when dewaxing isomerate made 
from a microwax, e.g. Bright Stock slack wax, it has been found to be 
preferred that the fraction of the isomerate which is dewaxed is the 
"broad heart cut" identified as the fraction boiling between about 
330.degree. to 600.degree. C., preferably about 370.degree. to 580.degree. 
C. The heavy bottoms fraction contains appreciable wax and can be recycled 
for further isomerization by being sent to the isomerization unit 
directly, or if any hydrotreating or deoiling is deemed necessary or 
desirable then the fractionation bottoms may be sent to the fresh feed 
reservoirs and combined with the wax therein. 
One desiring to maximize the production of lube oil having a viscosity in 
the 5.6 to 5.9 cSt/100.degree. C. range should practice the isomerization 
process under low hydrogen treat gas rate conditions, treat gas rates on 
the order of 500 to 5,000 SCFH.sub.2 /bbl, preferably 2,000 to 4,000 
SCFH.sub.2 /bbl, most preferably about 2,000 to 3,000 SCFH.sub.2 /bbl, as 
is taught in copending application U.S. Ser. No. 283,684, filed even date 
herewith, which is a continuation-in-part of U.S. Ser. No. 134,998, filed 
Dec. 18, 1987, and now abandoned, in the name of H. A. Boucher. 
It has also been found that prior to fractionation of the isomerate into 
various cuts and dewaxing said cuts the total liquid product (TLP) from 
the isomerization unit can be advantageously treated in a second stage at 
mild conditions using the isomerization catalyst or simply noble Group 
VIII on refractory metal oxide catalyst to reduce PNA and other 
contaminants in the isomerate and thus yield an oil of improved daylight 
stability. This aspect is covered in copending application U.S. Ser. No. 
283,659, filed even date herewith, which is a continuation-in-part of U.S. 
Ser. No. 135,149, filed Dec. 18, 1987, and now abandoned, in the names of 
Cody, MacDonald, Eadie and Hamner. 
In that embodiment the total isomerate is passed over a charge of the 
isomerization catalyst or over just noble Group VIII on transition 
alumina. Mild conditions are used, e.g. a temperature in the range of 
about 170.degree. to 270.degree. C., preferably about 180.degree. to 
220.degree. C., at pressures of about 300 to 1,500 psi H.sub.2, preferably 
500 to 1,000 psi H.sub.2, a hydrogen gas rate of about 500 to 10,000 
SCF/bbl, preferably 1,000 to 5,000 SCF/bbl and a flow velocity of about 
0.25 to 10 V/V/hr, preferably about 1 to 4 V/V/hr. Higher temperatures 
than those recited may be employed if pressures in excess of 1,500 psi are 
used, but such high pressures may not be practical. 
The total isomerate can be treated under these mild conditions in a 
separate, dedicated unit or the TLP from the isomerization reactor can be 
stored in tankage and subsequently passed through the aforementioned 
isomerization reactor under said mild conditions. It has been found to be 
unnecessary to fractionate the first stage product prior to this mild 
second stage treatment. Subjecting the whole product to this mild second 
stage treatment produces an oil product which upon subsequent 
fractionation and dewaxing yields a base oil exhibiting a high level of 
daylight stability and oxidation stability. These base oils can be 
subjected to subsequent hydrofinishing using conventional catalysts such 
as KF-840 or HDN-30 (e.g. Co/Mo or Ni/Mo on alumina) under conventional 
conditions to remove undesirable process impurities. 
This invention will be better understood by reference to the following 
examples which either demonstrate the invention or are offered for 
comparison purposes.

EXAMPLE 1 
Catalyst 1 (Catalyst of the Invention) 
Catalyst 1 was a 14/35 meshed platinum on fluorided alumina catalyst made 
by fluoriding a commercially available 1/16 inch alumina extrudate which 
contained 0.6 wt. % platinum and 1 wt. % chlorine as received from the 
manufacturer. Fluoriding was accomplished using an 11.6 wt % aqueous 
solution HF (by soaking), after which the fluorided metal loaded extrudate 
was washed with 10-fold excess water and dried at 150.degree. C. in vacuum 
oven. It was then crushed to produce particles of about 1/30 inch (14/35 
mesh). This sized material, catalyst 1 was activated by heating to 
450.degree. C. in 50 psi flowing H.sub.2 in the following manner: room 
temperature to 100.degree. C. in 2 hours, hold at 100.degree. C. for 1 
hour; heat from 100.degree. C. to 450.degree. C. in 3 hours; hold at 
450.degree. C. for 1 hour. The catalyst had a fluoride content of 8.3 wt. 
%. This catalyst was used to isomerize a slack wax derived from 600N oil 
to three levels of conversion. 
The slack wax feed was first hydrotreated over HDN-30 catalyst (a 
conventional Ni/Mo on alumina catalyst) at 350.degree. C., 1.0 V/V/hr, 
1,500 SCF/bbl, H.sub.2, 1,000 psi (H.sub.2). The catalyst had been on 
stream for 1,447 to 1,577 hours. The hydrotreated slack wax had sulfur and 
nitrogen contents of less than 1 ppm and contained about 23% oil. 
TABLE 1 
______________________________________ 
Isom Conditions 
Pressure, psi H.sub.2 
1,000 1,000 1,000 
Space Velocity (V/V/hr) 
0.9 0.9 0.9 
Gas Treat Rate 5,000 5,000 5,000 
(SCF/bbl, H.sub.2) 
Temperature, .degree.C. 
318 324 327 
Catalyst Time on 
2,257-2,559 
2,045-2,243 
1,801-2,041 
Stream (hrs) 
Conversion Level, 
11.8 20 25.8 
% 370.degree. C.- 
Feed to Dewaxing Cloud, 
60 54 49 
.degree.C. 
Constant Dewaxing Conditions (Batch Conditions) 
Solvent 100% MIBK 
Dilution Solvent/ 
6.1 3.5 3.4 
Feed/V/V 
Filter Temperature, .degree.C. 
-25 -25 -25 
Viscosity, CST @ 100.degree. C. 
5.96 5.08 4.79 
Dewaxed Oil Properties 
Pour Point, .degree.C. 
-14 -19 -23 
Pour-Filter DT .degree.C. 
11 6 2 
Viscosity, CST @ 40.degree. C. 
27.6 22.8 20.7 
Viscosity, CST @ 100.degree. C. 
5.63 5.03 4.61 
Viscosity Index 
149 147 144 
Wt % Wax Recovered 
56 39 30 
from 370.degree. C.+ 
Oil Fraction 
______________________________________ 
From this it is seen that even for isomerates obtained by isomerizing waxes 
from a natural petroleum source, the ability to dewax the isomerate to the 
desired low pour point of at least about -21.degree. C. is dependent upon 
the level of conversion. Low conversion levels produce isomerate which 
cannot be dewaxed to a low target pour using conventional dewaxing 
solvents under typical dewaxing filter temperature conditions. 
EXAMPLE 2 
In the following runs the isomerate was made from slack wax obtained by 
solvent dewaxing a 600N oil. The slack wax was hydrotreated over HDN-30 
catalyst at 350.degree. C., 1.0 V/V/hr. 1,500 SCF/bbl, H.sub.2, 1,000 psi 
H.sub.2 over KF-840 at 340.degree. C., 0.5 V/V/hr, 1,000 psi, 1,500 
SCF/bbl , H.sub.2. These hydrotreated waxes had oil contents ranging from 
21 to 23 percent sulfur ranging from 3 to 10 ppm and nitrogen .ltoreq.1 
ppm. 
This wax feed was contacted with platinum on fluorided alumina catalysts 
produced in the following ways. 
CATALYST 2 
One sixteenth inch .gamma. alumina extrudates impregnated with platinum 
were obtained from the commercial supplier containing 0.6 weight percent 
platinum and 1 percent chlorine on the extrudate. The metal-loaded 
extrudate was then fluorided using a 10-fold excess of 11.6 wt % aqueous 
HF by immersion for 16 hours at ambient temperature. The resulting 
catalyst was washed with H.sub.2 O and dried at 150.degree. C. in vacuum 
for 16 hours. The fluoride content was 8.0 weight percent. The sample of 
catalyst 2 as charged to the 200 cc unit was activated in 300 psi H.sub.2 
as follows: heating from room temperature to 100.degree. C. at 35.degree. 
C./hr; hold at 100.degree. C. for 6 hours; heat from 100.degree. C. to 
250.degree. C. at 10.degree. C./hr; hold at 250.degree. C. for 12 hrs; 
heat to 400.degree. C. at 10.degree. C./hr, hold at 400.degree. C. for 3 
hrs. The sample of Catalyst 2 as charged to the 3600 cc unit was activated 
as follows: at 300 psi H.sub.2 at 11 SCFH.sub.2 /-hr. per pound of 
catalyst, heat from room temperature to 100.degree. C. at 10.degree. 
C./hr; hold at 100.degree. C. for 24 hrs; heat from 100.degree. C. to 
250.degree. C. at 10.degree. C. per hour; hold at 250.degree. C. for 15 
hours; then at 22 SCF H.sub.2 /hour per pound of catalyst, heat from 
250.degree. C. to 400.degree. C. in 31 hours; hold at 400.degree. C. for 3 
hours. 
Table 2 presents comparisons of Catalysts 1 and 2 on slack wax from 600N 
oil. Conditions are recited under which the catalysts were run. 
Dewaxed oil yields were determined by using the test method ASTM D-3235 on 
the 370.degree. C.+ fraction. 
TABLE 2 
______________________________________ 
Catalyst 2 1 
______________________________________ 
Unit* (a) (a) (a) (b) 
Run 1 2 3 4 
Cat Charge cc 3,600 200 200 
80 
Flow Down Up Up Down 
Isom Conditions 
Temperature .degree.C. 
323 318 347 
320 
Pressure (psi H.sub.2) 
1,000 1,000 1,000 
1,000 
LHSV (v/v/hr) 1.0 1.0 0.9 
0.9 
Gas Rate 5,000 5,000 5,000 
5,000 
(SCFH.sub.2 /bbl) 
Max 370.degree. C..sup.+ Oil 
51.0 45.0 56.0 
52.0 
Yield, wt % 
(370.degree. C.-). wt % 
29.0 29.0 29.0 
22.0 
______________________________________ 
*(a) continuous pilot unit. 
(b) small lab unit. 
This example demonstrates that the catalyst of the invention (the sized 
catalyst, catalyst 1) is unexpectedly superior to the extrudate form of 
the catalyst (catalyst 2) even when the extrudate is run at high mass 
velocity (run 1), where feed and catalyst contacting are excellent and 
back mixing is minimized. Therefore the unexpectedly better performance of 
Catalyst 1 is not simply due to hydrodynamics. 
EXAMPLE 3 
The presence of oil in the wax has been found to produce an enhanced 
viscosity index (VI) product as compared to oil-free wax when 
isomerization is performed utilizing the preferred "sized" catalyst, 
Catalyst 1 of Example 2. The amount of oil in the wax, must fall within a 
particular range previously described if this enhanced VI phenomenon is to 
be obtained. 
Catalyst 1 was used to isomerize a slack wax obtained from 600N oil. The 
wax samples had oil contents of &lt;1 percent, about 7 percent and about 23 
percent. The wax containing less than about 1 percent oil was made by 
recrystallizing a 600N slack wax by warm-up deoiling, followed by 
hydrotreating. This 1 percent oil wax has 99 percent saturates, 0.8 
percent aromatics and 0.2 percent polar compounds (as determined by silica 
gel separation). It had an initial boiling point of 382.degree. C. and a 
99 percent off boiling point of 588.degree. C., as determined by GCD. 
Isomerized products were dewaxed to between -18.degree. to -21.degree. 
pour. Fractionation of the products showed that at the higher viscosity 
range the isomerate made from wax possessing about 7 percent oil exhibited 
an unexpected VI enhancement as compared to the other wax samples having 
&lt;1 percent and 23 percent oil. This is to be compared with the results 
obtained using an extrudate Pt/F-Al.sub.2 O.sub.3 catalyst made as 
follows. 
CATALYST 3 
One sixteenth inch .gamma. alumina extrudates impregnated with platinum 
were obtained from a commercial supplier containing 0.6 weight percent 
platinum and 1 percent chlorine. The metal-loaded extrudate was fluorided 
using a solution of NH.sub.4 F/HF at pH about 4 by soaking. The soaked 
material was washed, then dried and calcined for 2 hours at 400.degree. C. 
in air (according to the procedure of copending application USSN 283,709 
filed even date herewith which is a continuation-in-part of USSN 134,795 
filed Dec. 18, 1987, and now abandoned, in the names of Cody, Sawyer, 
Hamner and Davis). Fluorine content was found to be 6.9 wt %. Catalyst was 
activated by heating in 50 pounds flowing H.sub.2 as follows: room 
temperature to 100.degree. C. in 2 hours, hold for 1 hour, 100.degree. C. 
to 350.degree. C. in 2 hours, hold for 1 hour. 
Catalyst 3 was used to isomerize 600N slack waxes containing &lt;1, 10.9 and 
22 percent oil under conditions selected to achieve the levels of 
conversion indicated in Table 3. Comparing the result obtained using 
Catalyst 1 with those obtained using Catalyst 3, one sees that 
isomerization utilizing the meshed catalyst (Catalyst 1) exhibits an 
unexpected VI enhancement when the wax feed employed contains 7 percent 
oil. 
TABLE 3 
______________________________________ 
Example of Enhancement of VI Employing Waxes Having 
0% Oil Using The Sized Catalyst, Catalyst 1 
Oil 
Content Conversion Viscosity 
Catalyst of Wax to 370.degree. C.- 
@ 100.degree. C. 
VI 
______________________________________ 
1 &lt;1 13 4.8 148 
7 24 4.8 150 
23 12.8 4.8 135 
25.8 4.8 137 
3 &lt;1 19.3 4.8 147 
35.0 4.6 142 
10.9 26.8 4.9 143 
22 28.8 5.0 139 
48.6 4.6 136 
______________________________________ 
EXAMPLE 4 
Slack wax from Bright Stock containing 15 percent oil was treated over 
Cyanamid's HDN-30 catalyst at 399.degree. C., 0.5 V/V/hr, 1,000 psi 
H.sub.2 and 1,500 SCF/B, H.sub.2, yielding a hydrotreated slack wax with 
the following properties: 
______________________________________ 
370.degree. C..sup.+ oil content 22.8 wt % 
S = 3 ppm 
N = &lt;1 ppm 
GCD % off at .degree.C. ibp, 255 
80%, 656 
______________________________________ 
The hydrotreated slack wax was then isomerized over the sized catalyst 
(Catalyst 1) described in Example 1 to produce the following isomerate 
products: 
______________________________________ 
Product A B 
______________________________________ 
Isomerization Conditions: 
Temperature, .degree.C. 
332 332 
Pressure, psi H.sub.2 
1,000 1,000 
Gas Rate, SCF/B, H.sub.2 
5,000 5,000 
LHSV Velocity, V/V/hr 
0.9 0.9 
Max 370.degree. C.+ Oil Yield, 
(wt % on feed) 54.6 54.9 
(by ASTM D3235 method) 
370.degree. C.- wt % 
28.4 27.6 
______________________________________ 
The isomerate products A and B made from the Bright Stock slack wax were 
fractionated into a broad heart cut (from product A) and a narrow cut 
(from product B) and dewaxed using MEK/MIBK under conventional dilution 
chilling dewaxing conditions. This was a DILCHILL dewaxing operation run 
at 150 cm/sec. agitation top speed (2 inch agitator) at an outlet 
temperature of -13.degree. C. Indirect chilling was then employed to get 
down to the filter temperature. Only when dealing with the broad heart cut 
fraction could low pour point, high yields and good filter rates be 
simultaneously achieved. From review of the data presented in Tables 4 and 
4A, it is apparent that fractionating the isomerate into a heart cut 
boiling between 370.degree. and 582.degree. C. not only facilitated 
dewaxing the oil to the target pour point but permitted the dewaxing to be 
more efficient (i.e. higher filter rates) than with the narrow fraction. 
Higher yields of oil were obtained at good dewaxed oil filter rates on the 
broad heart cut as compared to narrow cut dewaxed under the same 
conditions. (Compare runs 1 and 2 with A and B.) This shows the advantage 
of dewaxing the broad heart cut when dealing with isomerate obtained from 
very heavy, high boiling wax fractions since operating on the heart cut 
permits dewaxing to be conducted under miscible conditions. 
TABLE 4 
__________________________________________________________________________ 
Comparison of Narrow versus Broad Heart Cut Dilution 
Chilling Dewaxing Performance for Bright Stock Isomerates 
Broad Heart Cut 
Boiling Range, .degree.C.: 
370-582 
Run 1 2 3 4 5 6 
__________________________________________________________________________ 
Process Conditions 
Solvent Type MEK/MIBK 
MEK/MIBK 
MEK/MIBK 
MEK/MIBK 
MEK/MIBK 
MEK/MIBK 
Comp., V/V 10/90 20/80 30/70 20/80 30/70 0/100 
Dilution, Solv/Feed, 
4.3 4.1 4.1 4.3 -- 
V/V 
Filter Temperature, .degree.C. 
-25 -25 -30 -35 -35 -25 
Miscibility Miscible 
Miscible 
Borderline 
Immiscible 
Immiscible 
Miscible 
Wax Content, wt % 
-- 21 23 25 25 21 
Theoretical DWO Yield 
-- 79 77 75 75 79 
(100-WC), wt % 
Feed Filter Rate, 
3.8 3.8 4.2 3.7 4.8 3.4 
M3/M2 Day 
Wax Cake Liquids/ 
7.7 9.4 8.4 10.5 10.5 8.3 
Solids, W/W 
Wash/Feed, W/W 
-- 1.0 1.1 1.0 0.88 -- 
% Oil in Wax 22 42 37 56 66 33 
Dewaxed Oil Yield, wt % 
73.1 63.8 63.5 43.2 26.5 68.7 
Dewaxed Oil Filter 
2.8 2.6 2.6 1.6 1.3 2.3 
Rate, M3/M2 Day 
Dewaxed Oil Inspections 
Viscosity, CST 
@ 40.degree. C. 
25.5 25.3 25.75 24.49 22.67 25.7 
@ 100.degree. C. 
5.31 5.28 5.34 5.15 4.87 5.34 
Viscosity Index 
147 147 147 143 143 147 
Pour, .degree.C. 
-20 -20 -26 -32 -32 -20 
Cloud, .degree.C. 
-17 -17 -22 -31 -31 -16 
__________________________________________________________________________ 
TABLE 4A 
__________________________________________________________________________ 
Comparison of Narrow versus Broad Heart Cut Dilution 
Chilling Dewaxing Performance for Bright Stock Isomerates 
Narrow Cut Topped 
Boiling Range, .degree.C.: 
495-582 370.degree. C.+ 
Run A B C D E I 
__________________________________________________________________________ 
Process Conditions 
Solvent Type MEK/MIBK 
MEK/MIBK 
MEK/MIBK 
MEK/MIBK 
MEK/MIBK 
MEK/MIBK 
Comp., V/V 10/90 20/80 30/70 0/100 5/95 10/90 
Dilution, Solv/Feed, 
4.3 4.5 3.9 4.2 
V/V 
Filter Temperature, .degree.C. 
-25 -25 -25 -25 -25 -25 
Miscibility Miscible/ 
Immiscible 
Immiscible 
Miscible 
Borderline 
Miscible/ 
Borderline Borderline 
Wax Content, wt % 
29 29 30 -- -- 28 
Theoretical DWO Yield 
71 71 70 -- -- 72 
(100-WC), wt % 
Feed Filter Rate, M3/M2 
3.2 3.8 6.6 3.1 3.0 2.9 
Day 
Wax Cake Liquids/Solids, 
5.1 6.9 6.8 6.1 5.6 5.9 
W/W 
Wash/Feed, W/W 
1.19 1.08 0.87 -- -- -- 
% Oil in Wax 18 52 62 -- -- 24 
Dewaxed Oil Yield, wt % 
64.6 39.6 21.1 65.3 65.8 63.2 
Dewaxed Oil Filter Rate, 
2.1 1.5 1.4 2.0 2.0 1.8 
M3/M2 Day 
Dewaxed Oil Inspections 
Viscosity, CST 
@ 40.degree. C. 
56.1 51.3 49.6 48.7 53.6 34.9 
@ 100.degree. C. 
9.18 8.83 8.63 8.37 9.13 6.63 
Viscosity Index 
145 152 152.5 148 152 148 
Pour, .degree.C. 
-20 -21 -22 -15 -15 -20 
Cloud, .degree.C. 
-15 -14 -17 -- -- -18 
__________________________________________________________________________