Catalytic dewaxing process employing surface acidity deactivated zeolite catalysts

Catalytic dewaxing of a waxy component-containing hydrocarbon feed is accomplished with improved selectivity employing, as catalyst, a zeolite the surface acid catalytic activity of which has been at least partially reduced by chemisorption of a surface-deactivating agent such as a bulky amine thereon. The invention is especially useful for the hydrodewaxing of a waxy lube range product to provide a high viscosity index, low pour point, low cloud point lubricating oil product.

CROSS REFERENCE TO RELATED APPLICATION 
This application relates by subject matter to commonly assigned, 
concurrently filed U.S. Pat. application Ser. No. 07/299,856, filed 23 
Jan. 1989, by Rober J. Anthes and Ross A. Kremer entitled "Catalytic 
Dewaxing of Lubricating Oil Stock Derived From Oligomerized Olefin". 
BACKGROUND OF THE INVENTION 
This invention relates to the catalytic dewaxing of waxy 
component-containing hydrocarbon oils. It is especially directed to the 
preparation of lubricating oils having a high viscosity index, a high 
650.degree. F.+ yield and reduced pour and cloud points. 
Refining suitable petroleum crude oils to obtain a variety of lubricating 
oils which function effectively in diverse environments has become a 
highly developed and complex art. Although the broad principles involved 
in refining are qualitatively understood, the art is encumbered by 
quantitative uncertainties which require a considerable resort to 
empiricism in practical refining. Underlying these quantitative 
uncertainties is the complexity of the molecular constitution of 
lubricating oils. Because lubricating oils for the most part are based on 
petroleum fractions boiling above about 450.degree. F., the molecular 
weights of the hydrocarbon constituents are high and these constituents 
display almost all conceivable structure types. This complexity and its 
consequences are referred to in well-known treatises, such as, for 
example, "Petroleum Refinery Engineering" by W.L. Nelson, McGraw-Hill Book 
Company, Inc., New York, NY 1958 (4th Ed.). 
In general, the basic premise in lubricant refining is that a suitable 
crude oil, as shown by experience or by assay, contains a quantity of 
lubricant stock having a predetermined set of properties, such as, for 
example, appropriate viscosity, oxidation stability and maintenance of 
fluidity at low temperatures. The process of refining to isolate that 
lubricant stock consists of a set of subtractive unit operations which 
removes the unwanted components. The most important of these unit 
operations includes distillation, solvent refining and dewaxing which are 
basically physical separation processes in the sense that if all of the 
separated fractions were to be recombined, the crude oil would be 
reconstituted. 
A refined lubricant stock can be used by itself or it can be blended with 
another refined lubricant stock having different properties. The refined 
lubricant stock prior to use as a lubricant can also be compounded with 
one or more additives which function, for example, as antioxidants, 
extreme pressure additives, V.I. improves, and the like. 
For the preparation of a high grade distillate lubricating oil stock, the 
current practice is to vacuum distill an atmospheric tower residuum from 
an appropriate crude oil as the first step. This step provides one or more 
raw stocks within the boiling range of from about 450.degree. to about 
1050.degree. F. After preparation of a raw stock of suitable boiling 
range, it is extracted with a solvent, e.g., furfural, phenol, sulfolane 
or chlorex, which is selective for aromatic hydrocarbons and which removes 
undesirable components. The raffinate from solvent refining is then 
dewaxed, for example, by admixing with a solvent, e.g., a blend of methyl 
ethyl ketone and toluene. The mixture is chilled to induce crystallization 
of the parafin waxes which are then separated from the raffinate. 
Sufficient quantities of wax are removed to provide the desired pour point 
for the raffinate. 
Other known and conventional processes such as hydrofinishing or clay 
percolation can be used if needed to reduce the nitrogen and sulfur 
content or improve the color of the lubricating oil stock. 
Viscosity index (V.I.) is a quality parameter of considerable importance 
for distillate lubricating oils to be used in automotive engines and 
aircraft engines subject to wide variations in temperature. This index 
indicates the degree of change of viscosity with temperature. A high V.I., 
e.g., one of at least about 85, indicates an oil which resists the 
tendency to become excessively viscous at low temperature or excessively 
thin at high temperatures. Measurement of the Saybolt Universal Viscosity 
of an oil at 100.degree. and 210.degree. F. and referral to correlations 
provides a measure of the V.I. of an oil. For purposes of the present 
invention, whenever V.I. is referred to, the V.I. as noted in the 
Viscosity Index tabulations of ASTM D567 published by ASTM, or equivalent, 
is intended. 
The dewaxing mechanism of catalytic hydrodewaxing is different from that of 
solvent dewaxing resulting in some differences in chemical composition. 
Catalytically dewaxed products produce a haze on standing at 10.degree. F. 
above specification pour point for more than twelve hours--known as 
Overnight Cloud (ONC) formation. The extent of this ONC formation is less 
severe with solvent dewaxed oils. Although such an ONC formation does not 
affect the product quality of catalytically dewaxed oils, it is beneficial 
to reduce the Overnight Cloud (ONC) formation since in some areas of the 
marketplace any increase is considered undesirable. 
In recent years, catalytic techniques have become available for the 
dewaxing of petroleum stocks. A process of that nature developed by 
British Petroleum is described in The Oil and Gas Journal, dated Jan. 6, 
1975, at pages 69-73. See also U.S. Pat. No. 3,668,113. 
U.S. Pat. Reissue No. 29, 398 (of original U.S. Pat. No. 3,700,585) 
describes a process for catalytic dewaxing with a catalyst comprising 
zeolite ZSM-5. Such a process combined with catalytic hydrofinishing is 
described in U.S. Pat. No. 3,894,938. 
U.S. Pat. No. 3,755,138 describes a process for mild solvent dewaxing to 
remove high quality wax from a lube stock which is then catalytically 
dewaxed to specification pour point. 
U.S. Pat. No. 3,956,102 is directed to a process for the hydroewaxing of 
petroleum distillates utilizing a ZSM-5 type zeolite catalyst. 
U.S. Pat. No. 4,053,532 is directed to a hydrodewaxing operation involving 
a Fischer-Tropsch synthesis procut utilizing ZSM-5 zeolite. 
U.S. Pat. No. 4,247,388 describes dewaxing operations utilizing ZSM-5 type 
zeolites of specific activity. 
U.S. Pat. No. 4,222,855 describes dewaxing operations to produce 
lubricating oils of low pour point and high V.I. utilizing zeolites 
including ZSM-23 and ZSM-35. U.S. Pat. No. 4,372,839 describes a method 
for dewaxing crude oils of high wax content by contacting the oils with 
two different zeolites, e.g., ZSM-5 and ZSM-35. 
U.S. Pat. Nos. 4,419,220, 4,501,926 and 4,554,065 each describes a dewaxing 
process utilizing a zeolite Beta catalyst. 
U.S. Pat. No. 4,541,919 describes a dewaxing process which utilizes a 
selectively coked large pore zeolite such as zeolite X, Y or Beta as 
catalyst. 
The modification of zeolites by exchange and similar technology with large 
cations such as N.sup.+ and P.sup.+ and large branched compounds such as 
polyamines and the like is described in U.S. Pat. No. 4,101,595. Bulky 
phenolic and silicating zeolite surface-modifying agents are described in 
U.S. Pat. Nos. 4,100,215 and 4,002,697, respectively. As disclosed in U.S. 
Pat. Nos. 4,520221 and 4,568,786, zeolites which have been 
surface-deactivated by treatment with bulky dialkylamines are useful as 
catalysts for the oligomerization of lower olefins such as propylene to 
provide lubricating oil stocks. 
As far as is known, surface-deactivated zeolites have heretofore not been 
known for use as hydrodewaxing catalysts. 
SUMMARY OF THE INVENTION 
It is an object of the present invention to provide an improved catalytic 
hydrodewaxing process for the selective dewaxing of a waxy 
component-containing hydrocarbon feed. 
It is another object of the invention to provide a process for the 
catalytic hydrodewaxing of a waxy component-containing lubricating oil 
stock, and in particular, one which is based on oligomerized lower olefin, 
to provide a high viscosity, low pour point lubricating oil product. 
It is a particular object of the invention to carry out the catalytic 
hydrodewaxing of a waxy component-containing hydrocarbon feed employing as 
catalyst, a surface-deactivated zeolite. 
By way of satisfying these and other objects of the invention, in a process 
for dewaxing a waxy component-containing hydrocarbon feed in which the 
feed is contacted with a zeolite hydrodewaxing catalyst under 
hydrodewaxing conditions to provide a dewaxed product, an improvement is 
provided which comprises employing a zeolite hydrodewaxing catalyst the 
zeolite surface of which has been at least partially deactivated for acid 
catalyzed reactions by chemisorption of a surface-deactivating agent which 
possesses an average cross section diameter greater than that of the 
zeolite pores. 
The use of a zeolite hydrodewaxing catalyst which has been at last 
partially surface-deactivated in accordance with the invention possesses a 
decided advantage over the same zeolites the acid sites of which remain 
substantially intact. In the case of the latter, the acid catalyst 
activity which is exhibited at the zeolite surface (which is all the 
greater as the average crystallite size of the zeolite is reduced) is 
responsible for an undesirable incidence of cracking which increases the 
amount of lower value products and decreases the amount of desired product 
resulting from the hydrodewaxing operation in which such zeolites are 
used. In contrast to such unmodified zeolites, the hydrodewaxing process 
herein employs a zeolite whose surface acid catalyst activity, and 
therefore cracking activity, has been significantly reduced by treatment 
with a surface-deactivating agent. The result, then, in the case of the 
hydrodewaxing process of the present invention is a higher yield of 
desired de waxed product and a reduced yield of undesired, low-value 
products.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
The improved catalytic hydrodewaxing process herein can be used to dewax a 
variety of waxy component-containing hydrocarbon feedstocks ranging from 
relatively light distillate fractions up to high boiling stocks such as 
whole crude petroleum reduced crudes, vacuum tower residua, propane 
deasphalted residua, e.g., brightstock, cycle oils, FCC tower bottoms, gas 
oils, vacuum gas oils, deasphalted residua and other heavy oils. The 
feedstock will normally be a C.sub.10 + feedstock since lighter oils will 
usually be free of significant quantities of waxy components. However, the 
process of this invention is also particularly useful with waxy distillate 
stocks such as gas oils, kerosenes, jet fuels, lubricating oil stocks, 
heating oils, hydrotreated oil stock, furfural-extracted lubricating oil 
stock and other distillate fractions whose pour point and viscosity need 
to be maintained within certain specification limits. Lubricating oils 
stocks, for example, will generally boil above about 450.degree. F. 
(230.degree. C.) and more easily above about 600.degree. F. (315.degree. 
C.). For purposes of this invention, lubricating oil, or lube oil, is that 
part of a hydrocarbon feedstock having a boiling point of 600.degree. F. 
(315.degree. C.) or higher, as determined by ASTM D-1160 test method. 
Also regarded as lubricating oils which are suitable as feeds herein are 
the waxy component-containing lube range olefin oligomers disclosed in 
U.S. Pat. No. 4,568,786 and U.S. Pat. application Ser. No. 140,361, field 
Jan. 4, 1988, the contents of which are incorporated by reference herein. 
These materials are derived from the catalytic oligomerization of a lower 
olefin such as propylene in the presence of a surface-deactivated olefin 
oligomerization catalyst to provide an intermediate olefin oligomer 
product at least a fraction of which is further oligomerized employing any 
known or conventional acidic olefin oligomerization/isomerization catalyst 
to provide a waxy lube range product. 
In general, hydrodewaxing conditions include a temperature between about 
450.degree. F. (230.degree. C.) and about 750.degree. F. (400.degree. C.), 
a pressure between 0 and about 3000 psig and preferably between about 100 
and about 1000 psig. The liquid hourly space velocity (LHSV), i.e., the 
volume of feedstock per volume of catalyst per hour, is generally between 
about 0.1 and about 10 and preferably between 0.2 and about 4 and the 
hydrogen to feed stock ratio is generally between about 500 and about 8000 
and preferably between about 800 and 4000 standard cubic feed (SCF) of 
hydrogen per barrel. 
A preliminary hydrotreating step to remove nitrogen and sulfur and to 
saturate aromatics to naphthenes without substantial boiling range 
conversion will usually improve catalyst performance and permit lower 
temperatures, higher space velocities, lower pressures or combinations of 
these conditions to be employed. 
The catalytic dewaxing process of this invention is conducted by contacting 
the feed to be dewaxed with the defined crystalline silicate zeolite 
dewaxing catalyst, e.g., provided as a slurry bed or a transport bed. The 
dewaxing catalyst which is employed in the improved hydrodewaxing process 
of this invention can be selected from among any of the many zeolites 
which have heretofore been disclosed as useful for the catalysis of 
hydrodewaxing operations provided its surface acidity has been at least 
partially reduced by prior and/or in situ treatment with a 
surface-deactivating agent, e.g., as disclosed in U.S. Pat. Nos. 4,520,221 
and 4,568,786, the contents of which are incorporated by reference herein. 
Thus, the useful zeolites include one or a combination of the following 
known zeolite hydrodewaxing catalysts: ZSM-5, ZSM-11, ZSM-12, ZSM-20, 
ZSM-23, ZSM-34, ZSM-35, ZSM-38, ZSM-48, ZSM-50 and zeolite Beta to name a 
few. 
Zeolite ZSM-5 is described in U.S. Pat. Nos. 3,702,886 and Re. 29,949, the 
disclosure of which is incorporated by reference herein. 
Zeolite ZEM-11 is described in U.S. Pat. No. 3,709,979, the disclosure of 
which is incorporated by reference herein. 
Zeolite ZSM-12 is described in U.S. Pat. No. 3,832,449, the disclosure of 
which is incorporated by reference herein. 
Zeolite ZSM-20 is described in U.S. Pat. No. 3,972,983, the disclosure of 
which is incorporated by reference herein. 
Zeolite ZSM-23 is described in U.S. Pat. No. 4,076,342, the disclosure of 
which is incorporated by reference herein. 
Zeolite ZSM-34 is described in U.S. Pat. No. 4,086,186, the disclosure of 
which is incorporated by reference herein. 
Zeolite ZSM-35 is described in U.S. Pat. No. 4,016,245the disclosure of 
which is incorporated by reference herein. 
Zeolite ZSM-38 is described in U.S. Pat. No. 4,046,859, the disclosure of 
which is incorporated by reference herein. 
Zeolite ZSM-48 is described in U.S. Pat. No. 4,397,827, the disclosure of 
which is incorporated by reference herein. 
Zeolite ZSM-38 is described in U.S. Pat. No. 4,046,859, the disclosure of 
which is incorporated by reference herein. 
Zeolite ZSM-50 is described in U.S. Pat. No. 4,640,829, the disclosure of 
which is incorporated by reference herein. 
Zeolite Beta is described in U.S. Pat. Nos. 3,308,069 and Re. 28,341, the 
entire contents of which are incorporated by reference herein. 
The extent to which the zeolite can be surface-deactivated can vary over 
considerable limits, depending on the conditions of the deactivation 
procedure, and still provide significant improvement over the same zeolite 
which has not been surface-deactivated. In general, a reduction in surface 
acid sites on the order of at least about 10%, and preferably at least 
about 20%, can be readily achieved employing the methods described below. 
Deactivation of the surface acid catalytic activity of the selected zeolite 
can be accomplished in accordance with known and conventional methods. 
Thus, treatment of the zeolite surface with basic compounds such as 
amines, phosphines, phenols, polynuclear hydrocarbons, cationic dyes, and 
the like, will provide the requisite reduction in surface acid catalytic 
activity. 
These surface deactivating agents should have an average cross section 
diameter of about 5 Angstroms or greater in order to prevent their being 
sorbed within the zeolite. Examples of suitable amines include monoamines, 
diamines, triamines, aliphatic and aromatic cyclic amines and heterocyclic 
amines, porphines, phthalocyanines, 1,10-phenanthroline, 
4,7-diphenyl-1,10-phenanthroline, 3,4,7,8-tetramethyl-1,10-phenanthroline, 
5,6-benzoquinoline, 2,2':6',2"-terpyridine, 
2,4,6-tris(2-pyridyl)-S-triazine and 2,3-cyclododecenopyridine. Examples 
of phosphines include triphenylphospine and 
1,2-bis(diphenylphosphine)ethane. Suitable phenols are, for example, 
di-t-butylphenol, alkylated naphthol and 2,4,6-trimethylphenol. 
Polynuclear hydrocarbons include substances such as pyrene and 
phenanthrene. Cationic dyes include thionine, methylene blue and 
triphenylmethane dyes, such as malachite green and crystal violet. Another 
surface modification technique is deactivation by treating with metal 
compounds. Suitable metal compounds are magnesium acetate, metal-porphines 
such as hemin or iron (III) porphine chloride, cobalticinium chloride 
(C.sub.5 H.sub.5).sub.2 CoCl and titanocene dichloride 
(biscyclopentadienyl titanium dichloride) and large complex cations such 
as [Co(NH.sub.2 R).sub.6 ].sup.2 + where R is H or alkyl, [Pt(NH.sub.2 
R).sub.4 ].sup.2 + where R is alkyl, ]Co(en).sub.3 ].sup.3 + where en is 
ethylenediamine and manganese (III) meso-tetraphenylporphine. 
The zeolites can also be treated with organic silicon compounds as 
described in U.S. Pat. Nos. 4,100,215 and 4,002,697, the contents of which 
are incorporated by reference herein, to impart the desired degree of 
surface deactivation while being essentially free of carbonaceous 
deposits. Such treatment involves contacting the catalyst with a silane 
surface-modifying agent capable of deactivating catalytic (acidic) sites 
located on the external surface of the zeolite by chemisorption. 
Amines having an average cross section diameter larger than about 5 
Angstroms are especially suitable for reducing zeolite surface acid 
catalysis activity. Examples of such amines include substituted 
quinolines, heterocyclic amines and alkyl-substituted pyridines such as 
2,4 or 1,6-dialkyl pyridines and 2,4,6-trialkyl pyridines. Preferred are 
bulky, sterically-hindered di-ortho-alkyl pyridines such as 
2,6-di-tert-butylpyridine as described in U.S. Pat. Nos. 4,520,221 and 
4,568,786 referred to above, and 2,4,6-collidine (2,4,6-trimethyl 
pyridine) as disclosed in U.S. Pat. application Ser. No. 140,361 referred 
to above. 
The zeolite is preferably associated with a hydrogenation-dehydrogenation 
component regardless of whether hydrogen is added during the isomerication 
process since the isomerization is believed to proceeds by dehydrogenation 
through an olefinic intermediate which is then dehydrogenated to the 
isomerized product, both these steps being catalyzed by the 
hydrogenation/dehydrogenation component. The hydrogenation/dehydrogenation 
component is preferably a noble metal such as platinum, palladium or other 
member of the platinum group such as rhodium. Combinations of noble metals 
such as platinum-rhenium, platinum-palladium, platinum-iridium or 
platinum-iridium-rhenium together with combinations with non-noble metals, 
particularly of Groups VIA and/or VIIA, are of interest, particularly with 
metals such as cobalt, nickel, vanadium, tungsten titanium and molybdenum, 
for example, platinum-tungsten, platinum-nickel or 
platinum-nickel-tungsten. 
The metal may be incorporated into the catalyst by any suitable method such 
as impregnation or exchange onto the zeolite. The metal may be 
incorporated in the form of a cationic, anionic or neutral complex such as 
Pt(NH.sub.3).sub.4.sup.2 + and cationic complexes of this type will be 
found convenient for exchaning metals onto the zeolite. Anionic complexes 
such as the vanadate or metatungstate ions are useful for impregnating 
these metals into the zeolites. 
The amount of the hydrogenation-dehydrogenation component is suitable from 
0.01 to 10 percent by weight, normally 0.1 to 5 percent by weight, 
although this will, of course, vary with the nature of the component, less 
of the highly active noble metals, particularly platinum, being required 
than of the less active base metals. 
Base metal hydrogenation/dehydrogenation components such as cobalt, nickel, 
molybdenum and tungsten may be subjected to a pre-sulfiding treatment with 
a sulfur-containing gas such as hydrogen sulfide in order to convert the 
oxide forms of the metal to the corresponding sulfides. 
It may be desirable to incorporate the catalyst in another material which 
is resistant to the temperature and other conditions employed in the 
process. Such matrix materials include synthetic or natural substances as 
well as inorganic materials such as clay, silica and/or metal oxides. The 
latter may be either naturally occurring or in the form of gelatinous 
precipitates or gels. Clays which can be composited with the catalyst 
include those of the montmorillonite and kaoline families. These clays can 
be sued in the raw state as originally mined or initially subjected to 
calcination, acid treatment or chemical modification. 
In addition to the foregoing materials, the zeolites can be composited with 
a metal oxide binder material such as alumina, silica-alumina, 
silica-magnesia, silica-zironcia, silica-thoria, silica-berylia, 
silica-titania as well as ternary compositions such as 
silica-alumina-thoria, silica-alumina-zirconia, silica-alumina-magnesia, 
and silica-magnesia-zirconia. The matrix can be in the form of cogel. It 
may also be advantageous to provide at least part of the metal oxide 
binder, e.g., an amount representing from about 1 to about 100 weight 
percent and preferably from about 2 to about 60 weight percent of total 
binder, in colloidal form so as to facilitate the extrusion of the bound 
zeolite. 
The relative proporations of zeolite component and binder material, on an 
anhydrous basis, can vary widely with the zeolite content ranging from 
about 1 to about 99 wt. %, and more usually from about 5 to about 90 wt. % 
of the dry composite. 
In the examples which follow, Example 1 is illustrative of the preparation 
of a propylene oligomer-based waxy lubricating oil stock, Examples 2 and 3 
illustrate the catalytic hydrodewaxing of said lubricating oil stock 
employing an unmodified zeolite, i.e., one retaining substantially its 
full original surface acid catalytic activity, and Example 4 is 
illustrative of the improved catalytic hydrodewaxing process of this 
invention, i.e., utilizing a surface-deactivated zeolite hydrodewaxing 
catalyst. 
EXAMPLE 1 
This example illustrates the preparation of a propylene oligomer-based waxy 
lubricating oil stock for use as feed in the catalytic hydrodewaxing 
operation illustrated in Examples 2 to 4. 
Propylene was oligomerized over 2,4,6-collidine-modified H-ZSM-23 at 
200.degree. C., 800 psig and a WHSV of 0.25 hr.sup.-1. The product, 
consisting of C.sub.6 -C.sub.30 olefins, was distilled and the 
.gtoreq.C.sub.12 fraction was oligomerized over H-ZSM-5 at 175.degree. C. 
and 0.1 hr.sup.-1 WHSV. This product was distilled, the 700.degree. F.+ 
fraction having the following properties: 
______________________________________ 
Kinematic viscosity @ 100.degree. C. (cSt) 
4.47 
Viscosity Index 137 
Pour Point (.degree.C.) 
-20 
Cloud Point (.degree.C.) 
+30 
______________________________________ 
EXAMPLE 2 
A platinum-containing ZSM-23 hydrodewaxing catalyst was activated as 
follows: Pt/ZSM-23 containing 0.22 wt. % Pt was dried over nitrogen for 1 
hour at 700.degree. F. and then reduced over hydrogen at 700.degree. F. 
for six hours. 
60 gm of the lube feedstock of Example 1 and 8 gm of the activated 
Pt/H-ZSM-23 catalyst were charged to a 450 cc autoclave reactor. Agitation 
was started and hydrogen was added to bring the system pressure to 400 
psig. The system was heated to 260-290.degree. C. (500-550.degree. F.) and 
opened to a hydrogen cylinder to maintain pressure at 400 psig. The 
reaction was carried out for 48 hours after which the system was cooled 
and vented. The liquid product was decanted/filtered away from the 
catalyst and distilled, the 700.degree. F.+ product having the following 
properties: 
______________________________________ 
Kinematic viscosity @ 100.degree. C. (cSt) 
4.69 
Viscosity Index 123 
Pour Point (.degree.C.) 
-50 
Cloud Point (.degree.C.) 
&lt;-50 
______________________________________ 
Gas chromatographic analysis of the dewaxed lubricating oil product (prior 
to distillation to give the 700.degree. F.+ lube product gave the 
following results: 
______________________________________ 
650.degree. F.+ 
700.degree. F.+ 
750.degree. F.+ 
______________________________________ 
Yield of Lube, Wt. % 
74 65 40 
______________________________________ 
EXAMPLE 3 
61 gm of the lube feedstock of Examples 1 and 7.9 gm of the activated 
Pt/H-ZSM-23 catalyst of Example 2 were charged to a 450 cc autoclave 
reactor. Agitation was started and hydrogen was added to bring the system 
pressure to 200 psig. The system was heated to 275.degree. C. (525.degree. 
F.) and opened to a hydrogen cylinder to maintain pressure at 420 psig. 
The reaction was carried out for 12 hours after which the system was 
cooled and vented. The liquid product was decanted/filtered away from the 
catalyst and distilled, the 700.degree. F.+ product having the following 
properties: 
______________________________________ 
Kinematic viscosity @ 100.degree. C. (cSt) 
4.60 
Viscosity Index 133 
Pour Point (.degree.C.) 
-50 
Cloud Point (.degree.C.) 
-30 
______________________________________ 
Gas chromatographic analysis of the dewaxed lubricating oil product (prior 
to distillation to give the 700.degree. F.+ lube product) gave the 
following results: 
______________________________________ 
650.degree. F.+ 
700.degree. F.+ 
750.degree. F.+ 
______________________________________ 
Yield of Lube, Wt. % 
78 73 55 
______________________________________ 
EXAMPLE 4 
The hydrodewaxing catalyst of Examples 2 and 3 was surface-deactivated and 
employed in the dewaxing of the waxy lubricating oil of Example 1 under 
essentially the same conditions as in Examples 2 and 3. 
The catalyst was modified as follows: 8.5 gm of the catalyst was contacted 
with a solution containing 0.0517 gm of 2,4,6-collidine and 75 ml pentane 
followed by evaporation of the pentane to provide the surface acid 
catalytic activity-deactivated zeolite. 
61 gm of the waxy component-containing feedstock from Example 1 and 8.5 gm 
of surface acid catalytic activity-deactivated Pt/ZSM-23 were charged to a 
450 cc autoclave reactor. Agitation was started and hydrogen was added to 
bring the system pressure to 200 psig. The sy stem was heated to 
290-310.degree. C. (550-590.degree. F.) and opened to a hydrogen cylinder 
to maintain pressure at 420 psig. The reaction was carried out for 21 
hours after which the system was cooled and vented. The liquid product was 
decanted/filtered away from the catalyst and distilled, the 700.degree. 
F.+ product having the following properties: 
______________________________________ 
Kinematic viscosity @ 100.degree. C. (cSt) 
4.76 
Viscosity Index 130 
Pour Point (.degree.C.) 
-52 
Cloud Point (.degree.C.) 
-35 
______________________________________ 
Gas chromatographic analysis of the dewaxed lubricating oil product (prior 
to distillation to give the 700.degree. F.+ lube product) gave the 
following results: 
______________________________________ 
650.degree. F.+ 
700.degree. F.+ 
750.degree. F.+ 
______________________________________ 
Yield of Lube, Wt. % 
84 80 61 
______________________________________ 
Thus, with the same or better product properties compared to Examples 2 and 
3 (i.e., higher V.I., lower pour point and lower cloud point), the 
700.degree. F.+ lube yield of this example was 7-15% higher.