CA2039555A1 - Production of high viscosity index lubricating oil stock - Google Patents

Abstract

ZEOLITE ZSM-48, ITS SYNTHESIS AND ITS USE IN THE
PRODUCTION OF HIGH VISCOSITY INDEX
LUBRICATION OIL STOCK

ABSTRACT

Zeolite ZSM-48 having a silica/alumina molar ratio of 100 to 250 is synthesized in the presence of an organic linear diquaternary ammonium compound of the formula:

[(R')3N+(Z)mN+(R')3](X-)2 wherein R' is alkyl group of 1 to 20 carbon atoms, Z is a bridging member including an alkyl group of 1 to 20 carbon atoms and m is 5, 6, 8, 9 or 10.
The resultant zeolite is useful in the catalytic dewaxing of lubricating oil charge stocks.

Description

ZEOLITE ZSM-48~ ITS SYNTHESIS AND ITS USE IN THE
PRODUCTION OF HIGH VISCOSITY INDEX
LUBRICATING OIL STOCK

This invention is concerned with the zeolite ZSM-48, its synthesis and its use in the catalytic dewaxing of a waxy hydrocarbon oil to produce a lubricating oil of low pour point and high viscosity index ~V.I.).
ZSM-48 is a known zeolite which, in its calcined, sodium-exchanged form is characterized by an X-ray diffraction pattern having the lines listed in Table l:
TABL~ 1 d(A) Relative Intensity (I/Io) ll.~ + 0.2 S
15 10.2 + 0.2 W-M
7.2 + 0.15 W
4.2 + 0.08 VS
3.9 + 0.08 VS
3.6 + 0.06 W
3.1 + 0.05 W

2.85 + 0.05 W

These values were determined by standard technigues. The radiation was the K-alpha doublet of copper, and a diffractometer equipped with a scintillation counter and a strip chart pen recorder was used. The peak heights, I, and the positions as a function of two times theta, where theta is the Bragg angle, were read from the spectrometer chart. From these, the relative intensities, l00 I~Io, where Io is the intensity of the strongest line or peak, and d ~ 3 F-570~ -2-(obs.), the interplanar spacing in A corresponding to the recorded lines, were calculated. In Table 1 the relative intensities are given in terms of the symbols W=weak, V~=very strong, M=medium and W-S=weak-to-strong-From Table 1 it will be seen that the X-ray diffraction pattern of ZSM-48 exhibits only a single line within the range of 11.8 + 0.2 Angstrom units.
This feature structurally distinguishes ZSN-48 from closely related materials such as ZSM-12 (U.S. Patent No. 3,832,449) which has a doublet at 11.8 + 0.2 Angstrom units and high silica ZSM-12 (U.S. Patent No.
4,104,294) which also exhibits a doublet at 11.8 ~ 0.2 Angstrom units.
ZSM-48 and its synthesis in the presence of a mixture of a C2-C12 alkylamine and a tetramethyl-ammonium compound is disclosed in U.S. Patent No.
4,397,827. U.S. Patent No. 4,423,021 discloses an alternative synthesis route for ZSM-48, in which the organic directing agent is a C4-C12 alkyldiamine-However, these known synthesis routes produce ZSM-48 with a low catalytic activity as a result of a limited aluminum content (the silica/alumina molar ratio is generally in excess of 500). Moreover, attempts to increase the aluminum content in the these prior art processes tends to result in the production of unwanted impurities, such as ZSM-5 and ZSM-11. In addition, the ZSM-48 produced by these known techniques has an undesirable rod- or needle-like morphology.

3~ The present invention seeks to provide ZSN-48 which can have a higher catalytic activity (lower silica/alumina molar ratio) and a different crystal morphology than those obtainable by conventional technique~. The resultant zeolite is particularly useful ln dewaxing of lubricating oils.
Accordingly, the invention resides in one aspect in ZSM-48 prepared with an organic linear diquaternary ammonium compound as directing agent and having a silica/alumina molar ratio of l00 to 250.
The ZSM-48 produced according to the invention has the X-ray lines listed in Table l and has a plate-like or irregular crystal morphology depending on its silica/alumina molar ratio.
In a further aspect, the invention resides in a process for preparing ZSM-48 comprising the steps of preparing a reaction mixture containinq a source of silica, a source of trivalent metal oxide Ne2O3, an alkali metal oxide, an organic linear diquaternary ammonium compound, and water, and having a composition in terms of mole ratios within the following ranges:
SiO2/Me2O3 = l00 to infinity H2o/Si2 = s to 400 OH /SiO2 = 0 to 2.0 M /Sio2 = 0 to 2.0 R/Sio2 = 0.005 to 2.0 wherein Ne is a trivalent metal, M is an alkali metal, and R is an organic linear diquaternary ammonium compound of the formula:
t(R')3N (Z)mN (R )3](X )2 wherein R' is alkyl group of l to 20 carbon atoms, Z is a bridging member including an alkyl group of l to 20 carbon atoms and m is 5, 6, 8, 9 or l0.
According to yet a further aspect of the invention, there is provided a process for catalyti-cally dewaxing a waxy hydrocarbon oil to provide a lubricating oil which comprises contacting said waxy hydrocarbon oil with a catalyst comprising acidic æeolite ZSM-48 which has been prepared with a linear diquaternary ammonium compound as the directing agent.
The invention will now be more particularly described with reference to the accompanying drawings, 3s in which:

~ig. 1 is a photomicrograph of about 3000X
magnification illustrating the crystal morphology of prior art ZSM-48 prepared with a diamine directing agent;
Fig. 2 is a photomicrograph illustrating the crystal morphology of ZSM-48 prepared with a tetramethyl ammonium compound as the directing agent;
Fig. 3 is a photomicrograph of about 6700X
magnification illustrating the platelet crystal morphology of ZSM-48 of the present invention prepared at high silica/alumina ratios;
Fiq. 4 is a photomicrograph of about lO,OOOX
magnification illustrating the irregular crystal morphology of ZSM-48 of the present invention prepared at low silica/alumina ratios;
Fig. 5 is a graphical comparison of V.I. versus pour point for ZSM-5 versus ZSM-48 in a hydrodewaxing operation carried out under substantially similar conditions with both catalysts;
Fig. 6 is a graphical comparison of lube yield versus product pour point for ZSM-5 versus ZSM-48 in said hydrodewaxing operation; and, Fig. 7 is a graphical summary of aging rate data for ZSM-48 in said hydrodewaxing operation.
Referring to the drawings, Fig. 1 is a photomicrograph of ZSM-48 prepared with a diamine directing agent in accordance with the method of U.S.
Patent No. 4,423,021. Fig. 2 is a photomicrograph of ZSM-48 prepared with a mixture of an alkylamine and a tetramethyl ammonium compound in accordance with the procedure described in U.S. Patent No. 4,397,827. As can be seen from Figs. 1 and 2, the prior known zeolite ZSM-48 possesses a rod-like or needle-like crystal morphology.
In contrast, the ZSM-48 prepared with a linear diquaternary ammonium compound as the directing agent possesses a platelet-like crystal morphology at high silica/alumina mole ratios above about 200. Fig. 3 is a photomicrograph illustrating the crystal morphology of ZSM-48 prepared in accordance with the present method with a silica/alumina mole ratio of about 420.
Silica/alumina mole ratios below 200 produce aggregates of small irregularly shaped crystals, as can be seen from Fig. 4, which is a photomicrograph of ZSM-48 prepared with a silica/alumina mole ratio of about 126.
Macroscopic crystal structure influences the packing characteristics of a catalyst: platelet type crystals are easier to stack, and easier to filter and settle. Also of significance are environmental characteristics: needle like crystals, such as erionite, and prior art ZSM-48, have produced concern as to the health effects of inhalation over a long period of time.
The organic directing agent required in producing the ZSM-48 of the invention is a linear diquaternary ammonium compound expressed by the formula:
t(R')3N (Z)mN (R )3~(X )2 wherein R' is alkyl of 1 to 20 carbon atoms, Z is a bridging member in the form of an alkyl group of 1 to 20 carbon atoms, and m is 5, 6, 8, 9 or lO.
Particularly preferred diquaternary compounds have X being halide, e.g., chloride, bromide or iodide, and R' and Z being lower alkyl of 1 to 4 carbon atoms, e.g., methyl, ethyl, propyl or butyl.
According to the process of the invention, ZSM-48 is preferably obtained from a crystallization reaction 3Q medium having a composition, in terms of mole ratios, falling within the following ranges:

BROAD PREFERRED
SiO2/Me2O3 at least 100 to infinity 100 to 10,000 H2~/Sio2 5 to 400 20 to 100 oH-/Sio2 0 to 2.0 0.1 to 1.0 M+/SiO2 0 to 2.0 0.1 to 1.0 R/Sio2 0.005 to 2.0 0.1 to 1.0 Preferably, crystallization is carried out under pressure in an autoclave or a static bomb reactor at 80 to 200C. The resultant ZSM-48 crystals are then separated from the mother liquor, wahed and dried. The crystals are then normally calcined to effect removal of the organic diecting agent and at least partial dehydration of the zeolite by heating to 200 to 600C
in an inert atmosphere, such as air or nitrogen, and at atmospheric or subatmospheric pressures for between 1 and 48 hours.
Acidic zeolite ZSM-48 produced by the above process is particularly useful for the catalytic dewaxing of lubricating oil stocks. When used in dewaxing, the zeolite is desirably combined with 0.1 to 5 wt% of a hydrogenation component, such as tungsten, vanadium, zinc, molybdenum, rhenium, nickel, cobalt, chromium, manganese, or a noble metal such as platinum or palladium. Such component can be exchanged into the composition, impregnated thereon or physically intimately admixed therewith. Such component can be impregnated in or onto the zeolite such as, for example, in the case of platinum, by treating the zeolite with a platinum metal-containing ion. Thus, suitable platinum compounds include chloroplatinic acid, platinous chloride and various compounds containing the platinum amine complex. Platinum, palladium and zinc are preferred hydrogenation components.
As in the case of many other zeolite catalysts, it may be desirable to incorporate the ZSM-48 with a F-5702 -7- ~t~ ~ 3 '`f '';

matrix material which is resistant to the temperatures and other conditions employed in the dewaxing process.
Such matrix materials include active and inactive materials and synthetic or naturally occurring zeolites as well as inorganic materials such as clays, silica and/or metal oxides, e.g. alumina. The latter may be either naturally occurring or in the form of gelatinous precipitates, sols or gels including mixtures of silica and metal oxides. Use of a material in conjunction with the ZSM-48, i.e., combined therewith, which is active, may enhance the conversion and/or selectivity of the catalyst herein. Inactive materials suitably serve as diluents to control the amount of conversion in a given process so that products can be obtained economically and orderly without employing other means for controlling the rate or reaction. Frequently, crystalline silicate materials have been incorporated into naturally occurring clays, e.g., bentonite and kaolin. These materials, i.e., clays, oxides, etc., function, in part, as binders for the catalyst. It is desirable to provide a catalyst having good crush strength since in a petroleum refinery the catalyst is often subject to rough handling which tends to break the catalyst down into powder-like materials which cause problems in processing.
Naturally occurring clays which can be composited with ZSM-48 include the montmorillonite and kaolin families which include the sub-bentonites, and the kaolins commonly known as Dixie, McNamee, Georgia and Florida clays, or others in which the main mineral constituent is halloysite, kaolinite, dickite, nacrite or anauxite. Such clays can be used in the raw state as originally mined or initially subjected to calcination, acid treatment or chemical modification.
In addition to the foregoing materials, ZSM-48 can be composited with a porous matrix material such as silica-alumina, silica-magnesia, silica-zirconia, silica-thoria, silica-beryllia, 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 a cogel. Mixtures of these components can also be used. The relative proportions of finely divided crystalline silicate ZSN-48 and inorganic oxide gel matrix vary widely with the crystalline silicate content ranging from 1 to 90 percent by weight, and more usually 2 to 80 percent by weight, of the composite.
The ZSM-48 of the present invention can be used to dewax a variety of charge stocks, including processed heavy oils derived from tar sands, coal and other sources. However, as is conventional in the production of high grade distillate lubricating oils, the charge stock preferably boils in the range 230 to to 570C
(~50 to 1050-F).
In a preferred embodiment of this invention, the charge stock is the raffinate obtained after selective solvent extraction of a viscous distillate fraction of crude petroleum oil isolated ~y vacuum distillation of a reduced crude from atmospheric distillation.
Preferably solvent extaction is effected by counter current extraction of the distillate fraction with at least an equal volume (100 volume percent), and preferably 1.5 to 2.5 volumes, of a selective solvent such as furfural.
In some instances, it may be desirable to partially dewax the solvent-refined stock by conventional solvent dewaxing te~hniques prior to catalytic dewaxing. The higher melting point waxes so removed are those of greater hardness and higher market value than the waxes removed in taking the product to a still lower pour point.
In general, hydrodewaxing conditions include a temperature of 260 to 455C (500 to 850F), a pressure 3~

of 790 to 20800 kPa (100 to 3000 psig), preferably 1480to 7000 kPa (200 to 1000 psig), a liquid hourly space velocity of 0.1 to 10, preferably 0.5 to 4, and a hydrogen to feedstock ratio of 70 to 1420 Nm3/m3 (400 to 8000 standard cubic feet of hydrogen per barrel of feed), preferably 140 to 710 Nm3/m3 (800 to 4000 standard cubic feet of hydrogen per barrel of feed).
The catalytic de~axing process of this invention can be conducted by contacting the feed to be dewaxed with a fixed stationary bed or with a transport bed of the ZSM-48 catalyst, as desired. A simple, and therefore preferred, configuration is a trickle-bed operation in which the feed is permitted to trickle through a stationary fixed bed, preferably in the presence of hydrogen. With such a configuration, it is of considerable importance in order to obtain the benefits of this invention to initiate the reaction with fresh catalyst at a temperature of less than about 31SC (600-F). This te~perature is, of course, raised as the catalyst ages in order to maintain catalytic activity. In general, the run is terminated at an end-of-run temperature less than about 400-C (750-F), at which time the catalyst can be regenerated by contact at elevated temperature with hydrogen.

The linear diquaternary ammonium compound employed in this zeolite crystallization example (Diquat 6) has the structure [( 3)3N (CH2)6N (CH3)3] (I )2 and was prepared by refluxing N,N-tetramethyl-1, 6-hexanediamine overnight with excess methyliodide in absolute ethanol followed by quenching of the reaction mixture in a dry ice-acetone bath to -20-C prior to filtration of the crystalline product.

~ 3~

Q-brand sodium silicate (PQ Corporation: 27.8%
SiO2; 8.4% Na2O; 63.8% H2O; 200 ppm Al) and colloidal silica sol (30% SiO2) were used as the silica sources, while A12(SO4)3.x H2O and sodium aluminate were employed as the alumina sources in the crystallization.
A typical mixture was prepared as follows:
A solution A was prepared by dissolving 863.3g of Q-brand sodium silicate in 1500 g of deionized water.
After the sodium silicate dissolution was complete, 10182.48 g of the salt Diquat-6I2 (the organic directing agent, R) was dissolved in the silicate solution.
Another solution B was prepared by dissolving 12-12g A12(SO4)3.18H2O and 71.15g conc. H2SO4 in 826.32g deionized water.
15Solutions A and B were then mixed directly into a one-liter stainless-steel autoclave until the hydrogel was of uniform consistency. The composition of the aluminosilicate hydrogel produced possessed the following mole ratios:

2Q sio2 H2o OH- Na+ R
~1203 : Sio2 : sio2 : sio2 : sio2 220 40 0.20 0.59 0.10 Zeolite synthesis was carried out over a period of 24 hours in a 1000 ml stirred (400 rpm) stainless-steel autoclave operating at 160C at autogenous pressure.
At the termination of the run, the autoclave was quenched in a water-ice bath prior to filtration of the ZSM-48 aluminosilicate. After washing and drying under an infrared heat lamp, the crystalline product was submitted for x-ray powder diffraction scans which confirmed its structure as that of ZSM-48. A sample of the product zeolite was also submitted for chemical analysis. The product zeolite possessed a SiO2:A12O3 ratio of 170 and contained 0.78 weight percent sodium in the as-synthesized form.
The zeolite was then calcined in flowing air at a heating rate of l-C/min to 538C and held at this temperature for 12 hours to remove the organic directing agent. Approximately 11 grams of the calcined zeolite was placed in a beaker and ion exchanged with 55 ml of 1.0 N NH4Cl which had been neutralized to a pH of 8 by titration with NH40H. The zeolite was then rinsed twice with 200 ml of deionized water, dried and reexchanged with 1.0 N NH4Cl employing the same procedure. Following the drying step, the zeolite was calcined in air at 1C/min to 538C and held at this temperature for one hour to convert the zeolite to the hydrogen form. -The entire exchange and calcination procedure was then carried out a second time to reduce the Na content of the zeolite to a low level. Sodium analysis (via Atomic Adsorption Spectrophotometry) showed the Na level of the exchanged and calcined zeolite to be 35 ppm. This material had an alpha value of 23. Eight grams of the foregoing zeolite was admixed with 4.2 grams of powdered 0.5 weight percent Pd/A1203 catalyst ("Girdler T-368D Palladium on Gamma Alumina" from The Chemtron Corporation - Catalyst Division). The physical mixture was then ground in a mortar and pestle and pelleted using a conventional tabletting machine.
The resulting tablets were ground and sieved to 14/40 mesh (Tyler).

The combined ZSN-48 and Pd/A1203 catalyst from Example 1 was loaded into a 1.3 cm (1/2") ID
microreactor and presulfided with a 2% H2S/98% H2 mixture overnight at 343C (650F). The catalyst was then streamed with an Arab Light light neutral raffinate at 0.5 LHSV, 2860 kPa (400 psig) and 445 Nm3/m3 (2500 scf H2/BBL) at an initial temperature of 258C (496~F~. Properties of the Arab Liqht light neutral raffinate are given in Table 2 as follows:

Properties of Arab Light Neutral Raffinate Total H-MMR, % 13.6 Nitrogen (ppm) 49.0 Sulfur, % 0.930 API Gravity 30.4 Refractive Index 1.464 Flash Point (Cleveland Open Cup) 446 Total Acid No. 0.12 Bromine No. 0.9 KV Q lOO-C., cs 5.553 KV @ 300F., cs 2.489 Furfural (ppm) 7.0 Metals Iron 0.6 Copper 0.04 Sodium 5 0 The reactor temperature was then raised progressively over the next 26 days to attain and maintain a -7~C (20F) pour point product. The lube properties of the hydrodewaxed products are set forth in Table 3 as follows:

Properties of the Hydrodewaxed Products Product No. 1 2 3 4 5 Reactor temp., F 655 667 675 675 675 C ~46 353 357 357 357 LHSV 0.54 0.54 0.54 0.540.54 Days on Stream 8 9 11 12 13 Pour Point F (C) Herzog 37~3) 23(-5) 20(-7) 20(-7)23(-5) ASTM D-97 45(7) 25(-4) 20(-7) 25(-4)25(-4) KV @ 40C, cs 32.44 44.57 33.19 33.3132.70 KV @ 100C, cs 5.507 5.574 5.523 5.5435.489 Cloud Pt, F (C) 56(13)40(4) 28(-2) 27(-2)44(7) Lube Yield, wt% 91.9 85.2 81.0 83.1 85.9 V.I. 105.7 102.7 102.1 102.5 103.1 Figure 5 shows the VI vs pour point response of the ZSM-48 catalyst and compares this to a conventional Ni/ZSM-5 catalyst for dewaxing the same feedstock. The conditions used in the ZSM-5 hydrodewaxing run were essentially the same except that the liquid hourly space velocity (LHSV) was maintained at 1.0 hr 1 instead of 0.5 hr 1. This data demonstrates that the ZSM-48 catalyst produces a higher viscosity index material than ZSM-5 at eguivalent pour points.
Additional data are plotted in Figure 6 and compare the lube yield vs product pour point data for the ZSM-48 and ZSM-5 catalysts. These data show that the lube yields from both catalysts are equivalent at the target -7C (20F) pour point although there is an apparent yield advantage for the ZSM-48 catalyst at higher pour points. Figure 7 summarizes the aging rate data from the ZSM-48 hydrodewaxing run.

`` ?~

ZSM-48 was synthesized according to procedures described in U.S. Patent No. 4,423,021 as follows:
The following solutions were prepared:
Solution A: 6.6 g of concentrated H2S04 was added dropwise with stirring to 85.0 g of deionized H20, followed by 6.1 g of 1,4-butanediamine as the organic templating agent. Solution B: 50.0 g of Q-Brand sodium silicate (27.8% SiO2; 8.4~ Na20; 63.8% H20; 200 ppm Al) was stirred into 50.0 g deionized H20.
Solutions A and B were mixed directly into an autoclave equipped with a stirrer. The reaction mixture was stirred for 2 minutes before sealing the autoclave. Heating and stirring of the autoclave were begun immediately. The mixture was crystallized for seven days at 160DC, with stirring (400 rpm) before quenching the autoclave in an ice water bath. The resulting crystalline product was filtered, washed with deionized water and dried in an air stream under an infrared lamp. The dried product was analyzed to be 100% zeolite ZSM-48.
The as-synthesized zeolite was then calcined in flowing air at a heating rate of l-C/min to 538'C and held at this temperature for 12 hours to remove the 2s templating agent. Approximately 11 grams of this calcined zeolite was placed in a beaker and ion exchanged with 55 ml of 1.0 N NH4Cl which had been neutralized to pH 8 by titration with NH40H. This zeolite was then rinsed twice with 20 ml of deionized water dried and reexchanged with 1.0 N NH4Cl using the same procedure. Following the drying step, the zeolite was calcined in air at lDC/min to 538DC in air and held in air at this temperature for one hour to convert the zeolite to the hydrogen form. The foregoing exchange and calcination procedure was repeated to reduce the Na content of the zeolite to 49 ppm. The zeolite had an alpha value of 7 and a SiO2/A1203 ratio of 910. The zeolite was then tableted and crushed to provide 5.6 cc (3.4 grams) of 14/40 mesh catalyst.
The foregoing ZSM-48 catalyst was loaded into a 1.3 cm (1/2") ID microreactor and then streamed with the same Arab Light light neutral raffinate as in Example 2 and under the same hydrodewaxing conditions.
~he reactor temperature was then raised progressively over the next 16 days in an attempt to achieve a -7'C
(20DF) pour point product. Table 4 below compares the reaction temperature with the lubricating oil pour point obtained with the ZSM-48 catalyst prepared according to Example 1 of the subject application and that obtained with the ZSM-48 catalyst prepared as described above, i.e., by the procedures described in U.s. Patent No. 4,423,021.

Comparison of Reaction~ Temperature vs. Pour Point Response of ZSM-48 Catalysts Prepared By Different Procedures ZSM-48 Catalyst From ZSM-48 Catalyst Of Example 1 Herein U.S. Patent No. 4,423,021 Reaction Reaction Days on Temp. Pour Pt. Days on Temp. Pour Pt.
Stream F (C) F (C) StreamF (-C) F (C) 1 498(259) 89(32) 1 495(257) 99(37) 3 527(275) 90(32) 2 538(281) 97(36) 4 529(276) 93(34) 5 579(304) 98(37) 594(312) 84(29) 6 628(331) 92(33) 6 621(327) 68(20) 7 673(356) 92(33) 7 639(338) 57(14) 12 730(388) 91(33) 8 655(346) 41(5) 13 731(388) 89(32) 9 667(353) 23(-5) 14 731(388) 87(31) 11 675(357) 20(-7) 15 754(401) 71(22) 12 675(357) 18(-8) 13 674(357) 23(-5) 680(360) 23(-5) 18 680(360) 23(-5) 19 683(362) 19(-7) 21 685(363) 18(-8) 22 689(365) 17(-8) 687(364) 21(-6) 26 687(364) 23(-5) As the data in the Table 4 shows, the use of ZSM-48 catalyst prepared as described in ~xample 1 of the application in hydrodewaxing provided superior results, expressed in terms of reduced pour point, compared to ZSM-48 catalyst prepared in accordance with U.S. Patent No. 4,423,021.

EXAMPLE_~
Example 10.3 g of the zeolite from Example 3 (95.4% ash) was admixed with 5. 36 g of the same powdered commercial 0.5% Pd/A1203 catalyst (99.1% ash) described in Example 1. This physical mixture was then ground in a mortar and pestle and pelleted using a conventional tabletting machine. The resulting tablets were crushed and sieved to 14/40 mesh (Tyler).

The ZSM-48 + Pd/A1203 catalyst of Example 4 was loaded into a 1.3 cm (1~2-inch) ID microreactor in the same fashion as described in Example 2 and presulfided with a 2~ H2S/98% H2 mixture overnight at 343C
( 650 F). The catalyst was then streamed under the same conditions and with the same Arab Light light neutral (150 SUS) feedstock used in Example 2. The reactor temperature was then raised progressively over the next seven days in an attempt to obtain a -7'C (20F) pour point material. The data in Table 5 show that even at temperatures as high as 391C (735F) this catalyst could not produce the required pour point reduction.

~ABLE 5 Catalyst of Example 5 Days on Temp.Pour Pt.
Stream F (-C) F (-C) 1 495(257) 98(37) 3 642~339) 90(32) S 658(348) 95(35) 6 675(357) 89(32) 7 735(391) 85(29) Comparison of pour point reduction of the prior art catalyst with added palladium (Table 5) and without added palladium (Table 4) illustrates that the palladium has no effect on pour point reduction.

Claims (10)

1. ZSM-48 prepared with an organic linear diquaternary ammonium compound as directing agent and having a silica/alumina molar ratio of 100 to 250.

2. ZSM-48 as claimed in claim 1 wherein the directing agent obeys the formula:

[(R')3N+(Z)mN+(R')3](X-)2 wherein R' is alkyl group of 1 to 20 carbon atoms, Z is a bridging member including an alkyl group of 1 to 20 carbon atoms and m is 5, 6, 8, 9 or 10.

3. A process for preparing ZSM-48 comprising the step of crystallizing a reaction mixture containing a source of silica, a source of trivalent metal oxide Me2O3, an alkali metal oxide, an organic linear diquaternary ammonium compound, and water, and having a composition in terms of mole ratios within the following ranges:
SiO2/Me2O3 = 100 to infinity H2O/SiO2 = 5 to 400 OH-/SiO2 = 0 to 2.0 M+/SiO2 = 0 to 2.0 R/SiO2 = 0.005 to 2.0 wherein Me is a trivalent metal, M is an alkali metal, and R is an organic linear diquaternary ammonium compound of the formula:

[(R')3N+(Z)mN+(R')3](X-)2 wherein R' is alkyl group of 1 to 20 carbon atoms, Z is a bridging member including an alkyl group of 1 to 20 carbon atoms and m is 5, 6, 8, 9 or 10.

4. A process for catalytically dewaxing a waxy hydrocarbon oil to produce a lubricating oil comprising contacting said waxy hydrocarbon oil with a catalyst comprising acidic zeolite ZSM-48 which has been prepared with a linear diquaternary ammonium compound as the directing agent.

5. The process of Claim 4 wherein the directing agent obeys the formula:

[(R')3N+(Z)mN+(R')3](X-)2 wherein R' is alkyl group of 1 to 20 carbon atoms, Z is a bridging member including an alkyl group of 1 to 20 carbon atoms and m is 5, 6, 8, 9 or 10.

6. The process of Claim 4 or Claim 5 wherein the ZSM-48 has a silica to alumina mole ratio of 100 to 250.

7. The process of any one of Claims 4 to 6 wherein said contacting is effected in the presence of hydrogen and said zeolite is associated with a hydrogenation component.

8. The process of Claim 7 wherein said hydrogenation component is a metal species selected from the group consisting of platinum, palladium and zinc.

9. The process of any one of Claims 4 to 8 wherein said contacting is carried out at a temperature of 260 to 455°C (500 to 850°F), a pressure of 790 to 20800 kPa (100 to 3000 psig), a liquid hourly space velocity of 0.1 to 10, and a hydrogen to feedstock ratio of 70 to 1420 Nm3/m3 (400 to 8000 standard cubic feet of hydrogen per barrel of feed).

10. The process of any one of Claims 4 to 9 wherein said contacting is carried out at pressure of 1480 to 7000 kPa (200 to 1000 psig), a liquid hourly space velocity of 0.5 to 4 and a hydrogen to feedstock ratio of 140 to 710 Nm3/m3 (800 to 4000 standard cubic feet of hydrogen per barrel of feed).