CA2086038A1 - Process for oligomerizing olefins using novel blends of acidic montmorillonite clays and sulfate-activated group iv oxides - Google Patents

Abstract

D# 81,065-F

ABSTRACT
An improved process is disclosed for preparing synthetic lubricant base stocks. Synthetic lubricant base stocks are prepared in good yield by oligomerizing linear olefins using a catalyst consisting essentially of a physical blend of a sulfate-activated Group IV oxide and an acidic montmorillonite clay.

Description

20~6~3~

PROCESS FOR OLIGOMERIZING OLEFINS USING NOVEL BLENDS OF ACIDIC
MONTMORILLONITE CLAYS AND SULFATE-ACTIVATED GROUP IV OXIDES
(D# 81,065-F) Background of the Invention Field of the Invention The invention relates to the preparation of synthetic lubricant base stocks, and more particularly to synthetic lubricant base stocks made by oligomerizing linear olefins.
Description of Related Methods Synthetic lubricants are prepared from man-made base stocks having uniform molecular structures and, therefore, well-defined properties that can be tailored to specific applications.
Mineral oil base stocks, on the other hand, are prepared from crude oil and consist of complex mixtures of naturally occurring hydrocarbons. The higher degree of uniformity found in synthetic lubricants generally results in superior performance properties.
For example, synthetic lubricants are characterized by excellent thermal stability. As automobile engines are reduced in size to save weight and fuel, they run at higher temperatures, therefore requiring a more thermally stable oil. Because lubricants made from synthetic base stocks have such properties as excellent oxidative/thermal stability, very low volatility, and good viscosity indices over a wide range of temperatures, they offer better lubricatlon, and permit longer drain intervals with less oil vaporization loss between oil changes, than mineral oil base stocks.

~6~38 Synthetic base stocks may be prepared by oligomerizing internal and alpha-olefin monomers to form a mixture of dimers, trimers, tetramers, and pentamers, with minimal amounts of higher oligomers. The unsaturated oligomer products are then hydrogenated to improve their oxidative stability. The resulting synthetic base stocks have uniform isoparaffinic hydrocarbon structures similar to high quality paraffinic mineral base stocks, but have the superior properties mentioned due to their higher degree of uniformity.
Synthetic base stocks are produced in a broad range of viscosity grades. It is common practice to classify the base stocks by their viscosities, measured in centistokes (cSt) at 100 C. Those base stocks with viscosities less than or equal to about 4 cSt are commonly referred to as "low viscosity" base stocks, whereas base stocks having a viscosity in the range of around 40 to 100 cSt are commonly referred to as "high viscosity"
base stocks. Base stocks having a viscosity of about 4 to about 8 cSt are referred to as "medium viscosity" base stocks. The low viscosity base stocks generally are recommended for low temperature applications. Higher temperature applications, such as motor oils, automatic transmission fluids, turbine lubricants, and other industrial lubricants, generally require higher viscosities, such as those provided by medium viscosity base stocks (i.e. 4 to 8 cSt grades). High viscosity base stocks are used in gear oils and as blending stocks.
The viscosity of a base stock is determined by the length of the oligomer molecules formed during the oligomerization 2~86~3g reaction. The degree of oligomerization is affected by the catalyst and reaction conditions employed during the oligomerization reaction. The length of the carbon chain of the monomer starting material also has a direct influence on the properties of the oligomer products. Fluids prepared from short-chain monomers tend to have low pour points and moderately low viscosity indices, whereas fluids prepared from long-chain monomers tend to have moderately low pour points and higher viscosity indices. Oligomers prepared from long-chain monomers generally are more suitable than those prepared from shorter-chain monomers for use as medium viscosity synthetic lubricant base stocks.
One known approach to oligomerizing long-chain olefins to prepare synthetic lubricant base stocks is to contact the olefins with boron trifluoride together with a promotor at a reaction temperature sufficient to effect oligomerization of the olefins.
See, for example, co-assigned U.S. Patent Nos. 4,400,565;
4,420,646; 4,420,647; and 4,434,308. However, boron trifluoride gas (BF3) is a pulmonary irritant, and breathing the gas or fumes formed by hydration of the gas with atmospheric moisture poses hazards preferably avoided. Additionally, the disposal/neutralization of BF3 raises environmental concerns.
Thus, a method for oligomerizing long-chain olefins using a less hazardous catalyst would be a substantial improvement in the art.
Kuliev et al. attempted to prepare synthetic lubricants by oligomerizing long-chain (Cg-Cl4) olefins using non-hazardous and non-polluting acidic clays comprising sulfuric and hydrochloric acid-activated bentonites from the Azerbaidzhan SSR. See Kuliev, Abasova, Gasanova, Kotlyarevskaya, and Valiev, "Preparation of High-Viscosity Synthetic Lubricants Using an Aluminosilicate Catalyst," Institute of Petrochemical Processes of the ~cademy of Sciences of the Azerbaidzhan SSR, Azer. Neft. Khoz., 1983, No. 4, pages 40-43. However, Kuliev et al. concluded that "it was not possible to prepare viscous or high-viscosity oils by olefin polymerization over an aluminosilicate catalyst" and that "hydrogen redistribution reactions predominate with formation of aromatic hydrocarbon, coke, and paraffinic hydrocarbon." Gregory et al., on the other hand, used Wyoming bentonite to oligomerize shorter-chain olefins. (See U.S. Patent No. ~,531,014.) However, like Xuliev et al., they also were unable to obtain a product high in dimer, trimer and tetramer, and low in disproportionation products.
Applicants discovered that it is possible to prepare synthetic :Lubricant base stocks in good yield by oligomerizing long-chain olefins using certain acidic montmorillonite clay catalysts. Applicants found that a high conversion of long-chain olefins to dimer, trimer, and tetramer may be obtained with formation of very little concomitant hydrogen redistribution by-product by using an acidic calcium montmorillonite clay having a moisture content ranging up to about 20 wt.%, a residual acidity in the range of about 3 to about 30 mg KOH/g (when titrated to a phenolphthalein end point), and a surface area of about 300 M2/g or greater. In addition to being excellent catalysts, these clays are non-hazardous and non-polluting.

20g6Q38 With respect to the present invention, Applicants have discovered, surprisingly, that an even higher conversion of olefins to oligomer may be obtained by contacting the olefin with a catalyst prepared by blending a minor amount of a sulfate-activated group IV oxide with the clay prior to its use as an oligomerization catalyst. Moreover, the process of the present invention results in a higher percentage of trimer and higher oligomers, i.e., a lower dimer to trimer ratio, another desirable feature.
Summary of the Invention The invention relates to a process for the preparation of oligomers, comprising contacting at a temperature in the range of 50 C to 300 C (1) linear olefins containing from 10 to 24 carbon atoms with (2) a catalyst consisting essentially of a physical blend of a sulfate-activated Group IV oxide and an acidic montmorillonite clay having a moisture content ranging up to about 20 wt.%, a residual acidity in the range of about 3 to about 30 mg KOH/g, and a surface area of about 300 m2/g or greater, wherein the catalyst contains said Group IV oxide and said acidic montmorillonite clay in a weight ratio of Group IV oxide to clay of about 1:1000 to about 1:4. The invention further relates to a process for the preparation of oligomers, comprising oligomerizing linear olefins containing from 10 to 24 carbon atoms in the presence of a catalyst consisting essentially of a physical blend of sulfate-activated zirconium oxide and an acidic montmorillonite clay having a moisture content ranging up to about 20 wt.%, a residual acidity in the range of about 3 to about 30 mg KOH/g, and `"` 2~6~
a surface area of about 300 m2/g or greater, wherein the catalyst contains said zirconium oxide and said acidic montmorillonite clay in a weight ratio of zirconium oxide to clay of about 1:1000 to about 1:5. The invention also relates to a process for the preparation of oligomers, comprising oligomerizing linear olefins containing from 10 to 24 carbon atoms in the presence of a catalyst consisting essentially of a physical blend of a silicon dioxide-supported sulfate-activated zirconium oxide and an acidic montmorillonite clay having a moisture content ranging up to about 20 wt.%, a residual acidity in the range of about 3 to about 30 mg KOH/g, and a surface area of about 300 m2/g or greater, wherein the catalyst contains said silicon dioxide-supported zirconium oxide and said acidic montmorillonite clay in a weight ratio of silicon dioxide-supported zirconium oxide to clay of about 1:1000 to about 1:4, and wherein the olefins are oligomerized at a temperature in the range of about 120 C to about 250 C.
Description of the Preferred Embodiments The olefin monomer feed stocks used in the present invention may be selected from compounds comprising (1) alpha-olefins having the formula R"CH=CH2, where R" is an alkyl radicalof 8 to 22 carbon atoms, and (2) internal olefins having the formula RCH=CHR', where R and R' are the same or different alkyl radicals of 1 to 21 carbon atoms, provided that the total number of carbon atoms in any one olefin molecule shall be within the range of 10 to 24, inclusive. A preferred range for the total number of carbon atoms in any one olefin molecule is 12 to 18, inclusiv~, 20~g~3~
with an especially preferred range being 14 to 16, inclusive.
Mixtures of internal and alpha-olefins may be used, as well as mixtures of olefins having different numbers of carbon atoms, provided that the total number of carbon atoms in any one olefin molecule shall be within the range of 10 to 24, inclusive. The alpha and internal-olefins to be oligomerized in this invention may be obtained by processes well-known to those sXilled in the art and are commercially available.
The oligomerization reaction may be represented by the following general equation:
catalyst nCmH2m ----~~~~~~~~ CmnH2mn where n represents moles of monomer and m represents the number of carbon atoms in the monomer. Thus, the oligomerization of l-decene may be represented as follows:

catalyst nClOH20 ~~~~~~~~~--> C10 H
where n represents moles of l-decene. The r~action occurs sequentially. Initially, olefin monomer reacts with olefin monomer to form dimers. Some of the dimers that are formed then react with additional olefin monomers to form trimers, and so on. This results in an oligomer product distribution that varies with reaction time. As the reaction time increases, the olefin monomer conversion increases, and the selectivities for the heavier oligomers increase. Generally, each resulting oligomer contains one double bond.

~0~38 The catalyst used in the present inventive process is a physical blend of an acidic montmorillonite clay and a sulfate-activated Group IV oxide. Preferably, the catalyst contains the sulfate-activated Group IV oxide and the acidic montmorillonite clay in a weight ratio of Group IV oxide to clay of about 1:1000 to about 1:4 or, more preferably, of about 1:1000 to about 1:5. It is more preferred that the catalyst contains the sulfate-activated Group IV oxide in a weight ratio of Group IV oxide to clay of about 1:50 to about 1:9 or, more preferably, about 1:50 to abou~ 1:10.
It is especially preferred that the catalyst contains the sulfate-activated Group IV oxide and the acidic montmorillonite clay in a weight ratio of Group IV oxide to clay of about 1:50 to about 1:25 or, still more preferably, about 1:50 to about 1:40. The catalysts of the present inventive process contain essentially no chromium, and are non-halogenated, non-polymeric, and non-organometallic.
~ Optionally, the sulfate-activated Group IV oxide component may be supported on a high surface area Group III or IV
oxide, such as high surface area silicon dioxide. The supported sulfate-activated Group IV oxide is then blended with the acidic montmorillonite clay. Applicants have discovered, surprisingly, that excellent yields of oligomers are obtained when the sulfate-activated Group IV oxide component is supported on silicon dioxide.
The high surface area of the silicon dioxide support unexpectedly permits one skilled in the art to obtain substantially the same benefits of blending unsupported sulfate-activated Group IV oxides with acidic clays, but requires less of the expensive sulfate-2~86Q~Y

activated Group IV oxide. When the sulfate-activated Group IV
oxide is supported on silicon dioxide, it is preferred that the catalyst contains the silicon dioxide-supported Group IV oxide and the acidic montmorillonite clay in a weight ratio of silicon dioxide-supported Group IV oxide to clay of about 1:1000 to about 1:4. It is more preferred that the catalyst contains the silicon dioxide-supported Group IV oxide and the acidic montmorillonite clay in a weight ratio of silicon dioxide-supported Group IV oxide to clay of about 1:50 to about 1:9. It is more preferred that the catalyst contains the silicon dioxide-supported Group IV oxide and the acidic montmorillonite clay in a weight ratio of silicon dioxide-supported Group IV oxide to clay of about 1:50 to about 1:20.
The montmorillonite clays used in the present inventive process are certain silica-alumina clays. Silica-alumina clays, also called aluminosilicates, are useful cation-exchangeable iayered clays. Silica-alumina clays primarily are composed of silicon, aluminum, and oxygen, with minor amounts of magnesium and iron in some cases. Variations in the ratios of these constituents, and in their crystal lattice configurations, result in some fifty separate clays, each with its own characteristic properties.
One class of silica-alumina clays comprises smectite clays. Smectite clays have unusual intercalation properties that afford them a hi~h surface area. Smectites comprise layered sheets of octahedral sites between sheets of tetrahedral sites, where the 2~8~03~
distance between the layers can be adjusted by swelling, using an appropriate solvent. Three~layered sheet-type smectites include montmorillonites. The montmorillonite structure may be represented by the following formula:

n+
MX/n~ yH20 (A14_xMgx) (Sig) O20(OH)4 where M represents the interlamellar (balancing) cations, normally sodium or lithium; and x, y and n are integers.
Montmorillonite clays may be acid-activated by such mineral acids as sulfuric acid, hydrochloric acid, and the like.
Mineral acids activate montmorillonites by attacking and solubilizing structural cations in the octahedral layers. This opens up the clay structure and increases surface area. These acid-treated clays act as strong Bronsted acids. Suitable acid-treated clays include, for example, acidic calcium montmorillonite clays having a moisture content ranging up to about 20 wt.%, a residual acidity in the range of about 3 to about 30 mg KOH/g (when titrated to a phenolphthalein end point), and a surface area of about 300 m2/g or greater. Illustrative examples of commercially available acid-treated clays include Engelhard Corporation's Grade F24, having a moisture content of 12 wt.%, a residual acidity of 16 mg KOH/g, and a surface area of 350 m2/g; Grade F124, having a moisture content of 4 wt.%, a residual acidity of 14 mg KOH/g, and a surface area of 350 m2/g; Grade F13, having a moisture content of 12 wt.%, a residual acidity of ~5 mg KOH/g, and a surface area of 300 m2/g; Grade F113, having a moisture content of 2~038 wt.%, a residual acidity of lS mg KOH/g, and a surface area of 300 m2/g; and Grade F224, having virtually no moisture, and having a residual acidity of 5 mg KOH/g, and a surface area of 350 m2/g.
Preferably, the acidic montmorillonite clay is activated by heat treatment before being blended with the sulfate-activated Group IV oxide component. Applicants have found, surprisingly, that heat treatment of the clay component prior to being blended with the sulfate-activated Group IV oxide component causes the catalyst to be more active and produce higher olefin conversions.
Additionally, clays heat treated in this manner are more stable, remaining active during the oligomerization reaction for a longer period of time. The clays may be heat treated at temperatures in the range of about 50 to 400 C, with or without the use of a vacuum. A more preferred temperature range is 50 to 300 C.
Optionally, an inert gas may be used during heat treatment as well.
Preferably, the clay should be heat treated under conditions and for a length of time that will reduce the water content of the clay to approximately 1 wt.~ or less.
In one embodiment, the sulfate-activated Group IV oxide component of the blended catalyst may be prepared by treating a Group IV oxide with a sulfate-containing compound. Preferably, the sulfate-containing compound is selected from the group consisting of ammonium sulfate, ammonium hydrogen sulfate, sulfuric acid, sulfur trioxide, sulfur dioxide, and hydrogen sulfide. Especially preferred su~fating agents are ammonium sulfate and sulfuric acid.
Said agents may be employed neat, or as an aqueous, ketonic, 2~ 038 alcoholic, or ether solution, but preferably as an aqueous solution. Said sulfating agents also may be employed as mixtures of the sulfating agents listed above. Excess sulfating agent may be removed by known procedures, such as filtration.
Preferably, the sulfated Group IV oxide is then calcined prior to being blended with the acidic clay component of the oligomerization catalyst. Calcination in air or in an inert gas environment, such as nitrogen, may be conducted at a temperature of at least 100 C, but below the temperature at which thermal destruction leads to deactivation. The optimal temperature range can be determined by routine experimentation for a particular catalyst. Typically, the sulfated catalyst is calcined for about 1 to 24 hours, preferably around lS hours, at a temperature of from about 500 to 800 C, preferably around 650 C, in a stream of nitrogen. Temperatures above 900 C should be avoided.
Suitable Group IV oxides used in conjunction with said sulfur-containing compounds include, for example, the oxides of silicon, titanium, zirconium, hafnium, germanium, tin, and lead, as well as combinations thereof. Particularly preferred are oxides of titanium and zirconium, such as the anatase or rutile forms of titania and zirconia. Zirconia is especially preferred.
In a more specific embodiment, the Group IV oxide is treated with sulfuric acid by adding said acid neat or, if desired, diluted with distilled water, to the oxide extrudates. The slurry is then mixed for about 1 to 24 hours, filtered, washed, and calcined in a stream of air for about 1 to 24 hours. The prepared 20~3~

sulfuric acid-treated oxide should then have a titratable acidity of at least 0.1 meq/g.
The weight percent of sulfuric acid to Group IV oxide should be such that the concentration of the sulfur in the formulated sulfate-activated Group IV oxide is in the range of about 0.1 wt.% to 30 wt.~, although concentrations outside this range also may be employed.
A suitable procedure to be used is to immerse zirconia pellets, for example, in an aqueous or polar organic solvent solution of the acid, preferably at ambient temperature. Higher temperatures of about 100 C to about 150 C may be used, if desired. This treatment should be continued, preferably with agitation, for about 0.1 to about 5 hours. The conditions should be sufficient to permit the solution to penetrate the pores of the zirconia pellet. The amount of acid solution that is used should be adequate to permit full immersion of the zirconia pellets.
Larger amounts of the solution can be used, if desired, but there is no particular advantage in doing so. At the end of the immersion step, the excess solution can be evaporated from the treated pellets, or the pellets can be removed from the solution and permitted to dry (e.g., in a drying oven).
The Group IV oxide may be in the form of powders, pellets, spheres, shapes and extrudates. Pellets may be prepared by extrusion or by compaction in conventional pelleting apparatus using a pelleting aid such as graphite. Extrudates which work well include HSA titania carrier extrudate from Norton Company, with a 208~Q~
surface area of 51 m2/g, and zirconia extrudates from Norton having a surface area of 77 m2/g.
In a second embodiment, the sulfate-activated Group IV
oxide component may be prepared by a one-step process, comprising heating a compound such as titanium sulfate hydrate at a temperature in the range of about 500 C to about 625 C. Sulfate-activated zirconium dioxide compounds may be prepared in a similar manner using, for example, zirconium sulfate hydrate.
In a third embodiment, the sulfate-activated Group IV
oxide is supported on a silicon dioxide substrate, and the silicon dioxide-supported sulfate-activated Group IV oxide is blended with the acidic clay. The silicon dioxide substrate may be any of the various - primarily amorphous - forms of sio2. See Kirk-Othmer, Encyclopedia of Chemical Technoloay, 3d. ed., vol. 20, pp. 748-764 (1981), incorporated herein by reference. Silica gels, which contain three-dimensional networks of aggregated silica particles of colloidal dimensions, are preferred. Silica gels are commercially available in at least the following mesh sizes: 3-8;
6-16; 14-20; 14-42; and 28-200 and greater. A suitable commercially available silica gel is the grade 12, 28-200 mesh, silica gel available from Aldrich Chemical Co., Inc.
The silica gel should be added to a solution of about 0.05 to about 25 wt.%, preferably from about 10 to about 20 wt.%
Group IV sulfate in water. The ratio of silica gel to Group IV
sulfate solution should be sufficient to provide a quantity of Group IV sulfate deposited on the silica gel ranging from about 2086~3~
0.05 to about 15 wt.%, preferably from about 0.05 to about 5.0 wt.%. The silica gel should remain in the Group IV sulfate solution for a period of time and under agitation to the extent necessary to meet these requirements, and then filtered and dried.
5Optionally, after filtration, the silica gel may be washed with distilled water before being dried, preferably under mild conditions. Preferably, the Group IV sulfate is titanium sulfate or zirconium sulfate. Zirconium sulfate is especially preferred.
The silicon dioxide substrate having the Group IV sulfate 10deposited thereon should be calcined prior to use as a component in the blended oligomerization catalyst. Calcination in air or in an inert gas environment, such as nitrogen, may be conducted at a temperature of at least 100 C, but below the temperature at which thermal destruction leads to deactivation. Typically, the silicon 15dioxide substrates having the Group IV sulfate deposited thereon are calcined for about 1 to 24 hours, preferably from about 15 to about 20 hours, at a temperature of from about 400 to 800 C, preferably from about 500 to about 800 C, more preferably at about 650 C for 18 hours. Temperatures above 900 C should be avoided.
20Once prepared, the sulfate-activated Group IV oxide component, whether supported on silicon dioxide or unsupported, is physically blended with the acidic montmorillonite clay in the proportions disclosed above. Optionally, the blended components may then be pelletized for easier handling. Diameters ranging from 25about 0.794 mm (1/32 inch) to about 9.525 mm (3/8 inch) possess desirable dimensions. The shape and dimensions of the pellets are 2a~
not critical to the present invention; pellets of any suitable shape and dimensions may be used.
When cylindrical pellets of catalyst of the type described above are used in a fixed bed continuous flow reactor, the liquid hourly space velocity may be varied within wide limits (e.g., 0.1 to 10) in order to obtain a desired rate of conversion.
Normally, space velocities of about 0.5 to 2 LHSV will be employed.
The oligomerization reaction may be carried out either batchwise, in a stirred slurry reactor, or continuously, in a fixed bed continuous flow reactor. The catalyst concentration should be sufficient to provide the desired catalytic effect. The temperatures at which the oligomerization may be performed are between about 50 and 300O C, with the preferred range being about 120 to 250 C, a more preferred range being about 140 to 180 C, and an especially preferred range being about 160 to about 180 C.
At temperatures of about 200 C or greater, the amount of unsaturation remaining in the products of the oligomerization reaction may decrease, thus reducing the degree of hydrogenation necessary to remove unsaturation from the base stocks. However, at temperatures above 200 C, the olefin conversion may decrease. The dimer to trimer ratio may increase. Applicants have found that the addition of a hydrocarbon containing a tertiary hydrogen, such as methylcyclohexane, may further reduce the amount of unsaturation present in the base stocks. One skilled in the art may choose the reaction conditions most suited to the results desired for a 2~a3g particular application. The reaction may be run at pressures of from 0 to 1000 psig.
Following the oligomerization reaction, the unsaturated oligomers may be hydrogenated to improve their thermal stability and to guard against oxidative degradation during their use as lubricants. The hydrogenation reaction for 1-decene oligomers may be represented as follows:

catalyst C10nH20n + H2 ~~~~~~----> C10 H
where n represents moles of monomer used to form the oligomer.
Hydrogenation processes known to those skilled in the art may be used to hydrogenate the oligomers. A number of metal catalysts are suitable for promoting the hydrogenation reaction, including nickel, platinum, palladium, copper, and Raney nickel. These metals may be supported on a variety of porous materials such as kieselguhr, alumina, or charcoal, or they may be formulated into a bulk metal catalyst. A particularly preferred catalyst for this hydrogenation is a nickel-copper-chromia catalyst described in U.S.
Patent No. 3,152,998, incorporated by reference herein. Other U.S.
patents disclosing known hydrogenation procedures include U.S.
Patent Nos. 4,045,508; 4,013,736; 3,997,622; and 3,997,621.
Unreacted monomers may be removed either prior to or after the hydrogenation step. Optionally, unreacted monomers may be stripped from the oligomers prior to hydrogenation and recycled to the catalyst bed for oligomerization. The removal or recycle of unreacted monomers or, if after hydrogenation, the removal of non-oligomerized alkanes, should be conducted under mild conditions 8~03~
using vacuum distillation procedures known to those skilled in the art. Distillation at temperatures exceeding 250 C may cause the oligomers to break down in some fashion and come off as volatiles.
Preferably, therefore, the reboiler or pot temperature should be kept at or under about 225 C when stripping out the monomers.
Procedures known by those skilled in the art to be alternatives to vacuum distillation also may be employed to separate unreacted components from the oligomers.
While it is known to include a distillation step after the hydrogenation procedure to obtain products of various 100 C
viscosities, it is preferred in the method of the present invention that no further distillation (beyond monomer flashing) be conducted. In other words, the monomer-stripped, hydrogenated bottoms are the desired synthetic lubricant components. Thus, the method of this invention does not require the costly, customary distillation step, yet, surprisingly, produces a synthetic lubricant component that has excellent properties and that performs in a superior fashion. However, in some contexts, one skilled in the art may find subsequent distillation useful in the practice of this invention.
The invention will be further illustrated by the following examples, which are given by way of illustration and not as limitations on the scope of this invention. The entire text of every patent, patent application or other reference mentioned above is hereby incorporated herein by reference.

208~3~
EXAMPLES
In the examples detailed in Table I below, the following procedures were used:
Preparation of Catalysts Zr2 catalyst component #1: Norton ZrO2 pellets were placed in a crucible and covered with 10 ~ (NH4)2SO4, and let stand for an hour, and then heated to 650 C. The crucible was held at this temperature for 15 hours under nitrogen flow, and then cooled and placed in a stoppered bottle until use.
Zr2 catalyst component ~2: Johnson Matthey 97 %
Zr(SO4)2-4H2O was placed in a crucible and set in an oven and heated to 650 C. The crucible was held at this temperature for 15 hours under nitrogen flow, and then cooled and placed in a stoppered bottle until use.
Oligomeriz~ation of Olefins Samples of the ZrU2 catalyst components prepared above were ground to a fine powder with Engelhard Corporation's Grade F13 acidic montmorillonite clay, in the proportions listed in the table below. Olefin and blended catalyst were charged to a flask equipped with an overhead stirrer, thermometer, heating mantle, and a water-cooled condenser (N2 purge). The mixture was vigorously stirred and heated to the desired temperature for the desired time.
The mixture was then cooled to ambient temperature and filtered with suction. The liquid was analyzed by liquid chromatography.
The results obtained are detailed in the following table.

2~o~

Tabld I
l ~ -- ---- - ~--- --- --- --Ex. OlcGn (by(g) o8 Calrlys~ (8) of Timd/Tcmp. Con. D/T+
No. carbonOldfin Calalyst (~r)/(C) (%) Ralio numbc r) Compone nts l C-14 a 100 ZrO, ~2 10 5/160 66.8 3.04 l I . . __ 2 C-14 n 100 Dry Clay-13 10 5/160 83.1 1.81 l l _ 3 C-14 a 100 Dry Clay-13 10 5/160 84.6 1.73 l I _ 4 C-14 a 100 Dry Cl~y-13/ZrO. #7 9.8/0.2 5/160 85.6 1.35 l I_ I
C-14 a 100 Dry Clay-13/ZrO. ~2 9.2/0.8 5/160 85.2 1.17 _ . _ _ 6 C-10 a 100 Dry Clay-13/ZrO~ #2 10 5/160 89.8 1.04 7 C-10 a 100 Dry Clay-13/ZrO2 #2 9.8/0.2 5/160 91.6 0.76 8 C-10 a 100 Dry Clay-13/ZrO2 ~2 9.6/0.4 5/160 91.9 0.77 ___ I
9 C-10 a 100 Dry Clay-13/ZrO. #2 9.2/0.5 S/160 93.8 0.74 l I _ , I
C-14 a 100 Dry Clay-13/ZrO2 ~2 10 4/180 84.5 1.12 l I _ I
11 C-14 a 100 Dry Clay-13/ZrO. #2 9.8/0.2 4/180 87.6 1.10 l I .. _ . I
lS 12 C-14 a 100 Dry Cl~y-13/ZrO~ #2 9.6/0.4 4/180 86.9 1.47 13 C-14 a 100 Dry Clry-13/ZrO. #2 9.2/0.8 4/180 86.6 1.17 14 C-10 a 100 Dry Clay-13/ZrO. #2 10 4/180 88.4 1.16 _ _ 1S C-10 G 1OO Dry Clay-13/ZrO2 ~2 9 8/0.2 4/180 90.8 0.95 16 C-10 1 100 Dry Clay-13/ZrO, #2 9.6/0.4 4/180 91.4 0.70 2 0 17 C-10 a 100 Dry Clay-13/ZrO. A~2 9.2/0.8 4/180 92.1 0.93 18 C-1314 i 100 Dry Clay-13/ZrO. #2 10 4/-180 79.2 3.22 __ 19 C-1314 1 100 Dry Clay-13/ZrO. ~2 9.8/0.2 4/180 85.1 1.56 I
C-1314 1 100 Dry Clay-13/ZrO2 ~2 9.6/0.4 4/180 84.2 1.73 21 C-1314 1 100 Dry Cl~y-13/ZIO, #2 9.2/0.4 4/180 81.7 2.70 ¦ 22 C-14 a 100 Dry Clay-13/ZrO1 ~1 9.0/1.0 S/160 88.3 1.15 _ _ _ ___ _ _ __ - -7 a = Alpha Oldfin; I = Inlcrnal Olcfin; Con. = Olcfin Convcrsion:
DiT+ = R~fio ol Dimcr: Tlimdr + Tdlr~mdr + Pdmamdr, ~Ic.
In the examples detailed in Table II below, the following procedures were used:
Pre~aration of Catalyst Aldrich silica gel (Grade 12, 28-200 mesh) in a crucible, was treated with 500 g of 20 % ZrSO4 in D.M. water. The crucible was placed in an oven, heated to 650 C, and held at this -\ 2~g~Q~

temperature for lB hours under a flow of nitrogen. The white solid was cooled under nitrogen and stored in a stoppered bottle until used. Atomic absorption analysis showed 4.8 % zirconium.
Oliqomerization of Olefins Samples of the ZrO2lSiO2 catalyst components prepared above were ground to a fine powder with Engelhard Corporation's Grade F13 acidic montmorillonite clay, in the proportions listed in the table below. Olefin and blended catalyst were charged to a flask equipped with an overhead stirrer, thermometer, heating mantle, and a water-cooled condenser (N2 purge). The mixture was vigorously stirred and heated to the desired temperature for the desired time. The mixture was then cooled to ambient temperature and filtered with suction. The liquid was analyzed by liquid chromatography. The results obtained are detailed in the table below.

2~6038 _ _ - __ _ _ E.~. Olcfiln (by (g) of C~lys~ (~) of Time/Tdmp. Con. DIT+
No. cnrbon Olefiln C~talyst (Hr)/(~C) (%) R~lio numbcr) Componenls C-14 a 100 Dry Cl;ly-13 9.5 5/160 86.8 1.26 l ZrO21SiO2 0.5 ¦~ C-14 a 100 Dry Chly-13 2 0 5/160 86.2 H46 ¦~ C-14 a 100 Dry Cllly-13i0 5/160 83.1 1.81 ¦~ C-14 100 Dry Clay-13 10 5/160 84.6 R73 ¦~ C-14 a 100 ZrO lSiO2 - 5/160 54 3 4 95 ¦~ C- 14 a 100 ZrO~lSIO, 0 ~ 5/ i 60 84.7 1.57 ¦ 7 C-14 a 100 Dry Clr~y 13 9.5 5/160 85.9 1.44 ZrO2/SiO2 0 .5 ¦ 8 C-li a 100 Dry Clrly-139.0 5/160 85.3 1.38 l ZrO ISiO, 1.0 ¦~ C-14 a 100 D''Y'/C5jo i3 8 5 5/160 84.0 1.53 r C-IS a 100 ZrO.lSiO, 2 0 51160 83.8 1.45 ¦~ C-14 a 100 Dry Cl~y-13 9 5 4/180 89.1 1.16 ¦~ C-14 a 100 Dry Clry-1391 O 4/180 85.2 2.05 ¦~ C-1314 1 100 Dry Cl~y-13 5/160 46.3 4.02 14 ¦ C-1314 1 100 Dry Clrly-139.5 5/160 42.0 6.W
ZrO,lSiO. 0 .5 ¦ C-1314 1 100 Dry Cby-13 9.0 51160 45.8 4.16 ZrO,lSiO, 1.0 .
16 ¦ C-i314 1 100 ZrO lSIO. 2 0 51160 34 ~ 3.89 - 17 ¦ C-1314 1 100 Dry Cl~y 13 10 41180 73.4 3.95 18 C-1314 1 100 DzrrOJcs~lo;l3 0 5 4il80 79.8 3.0 19 C-131-11 100 Dry Cl~y-13 1 0 41180 83.7 R77 C-131-11 100 ZDrrO./CSll~O i3 2 0 41180 8NI 2.76 ~ C-14 a 100 ZDrrO.ClSI10;l3 0 2 51160 83.3 1.47 2 5 ~ C-14 100 Dry Cl~ly 13 9.6 51160 83.6 1.55 ZrO.lSiO. 0.4 ¦~ G 1-1 a 100 Dry Clsy 13 9? 51160 85.3 1.30 ZrO.lSiO. 0.8 C-14 ~ 1 7 D~y Cl-7-13 9 0 51160 ~7~7 I IS

a = Alph~ Olclin: I = Inlernsl Olcr~n; Con. = Ohrtn Convcrsion;
DiT+ = R~io ot Dimcr: Tnmor + Tolr~mer + Pcmrlmcr, elc.

Claims (20)

1. A process for the preparation of oligomers, comprising contacting at a temperature in the range of 50° C to 300° C (1) linear olefins containing from 10 to 24 carbon atoms with (2) a catalyst consisting essentially of a physical blend of a sulfate-activated Group IV oxide and an acidic montmorillonite clay having a moisture content ranging up to about 20 wt.%, a residual acidity in the range of about 3 to about 30 mg KOH/g, and a surface area of about 300 m2/g or greater, wherein the catalyst contains said Group IV oxide and said acidic montmorillonite clay in a weight ratio of Group IV oxide to clay of about 1:1000 to about 1:4.

2. The process of Claim 1, wherein the Group IV oxide is selected from the group consisting of titanium dioxide and zirconium dioxide.

3. The process of Claim 1, wherein the catalyst contains said Group IV oxide and said acidic montmorillonite clay in a weight ratio of Group IV oxide to clay of about 1:50 to about 1:9.

4. The process of Claim 1, wherein the catalyst contains said Group IV oxide and said acidic montmorillonite clay in a weight ratio of Group IV oxide to clay of about 1:50 to about 1:10.

5. The process of Claim 1, wherein the catalyst contains said Group IV oxide and said acidic montmorillonite clay in a weight ratio of Group IV oxide to clay of about 1:50 to about 1:25.

6. The process of Claim 1, wherein the catalyst contains said Group IV oxide and said acidic montmorillonite clay in a weight ratio of Group IV oxide to clay of about 1:50 to about 1:40.

7. The process of Claim 1, wherein the acidic montmorillonite clay has a moisture content of about 16 wt.%, a residual acidity of about 15 mg KOH/g, and a surface area of about 300 m2/g.

8. The process of Claim 1, wherein the olefins are oligomerized at a temperature in the range of about 140° C to about 180° C.

9. A process for the preparation of oligomers, comprising oligomerizing linear olefins containing from 10 to 24 carbon atoms in the presence of a catalyst consisting essentially of a physical blend of sulfate-activated zirconium oxide and an acidic montmorillonite clay having a moisture content ranging up to about 20 wt.%, a residual acidity in the range of about 3 to about 30 mg KOH/g, and a surface area of about 300 m2/g or greater, wherein the catalyst contains said zirconium oxide and said acidic montmorillonite clay in a weight ratio of zirconium oxide to clay of about 1:1000 to about 1:5.

10. The process of Claim 9, wherein the olefins are oligomerized at a temperature in the range of about 140° C to about 180° C.

11. The process of Claim 9, wherein the catalyst contains said zirconium oxide and said acidic montmorillonite clay in a weight ratio of zirconium oxide to clay of about 1:50 to about 1:9.

12. The process of Claim 9, wherein the catalyst contains said zirconium oxide and said acidic montmorillonite clay in a weight ratio of zirconium oxide to clay of about 1:50 to about 1:10 and the olefins have 10 carbon atoms.

13. The process of Claim 9, wherein the catalyst contains said zirconium oxide and said acidic montmorillonite clay in a weight ratio of zirconium oxide to clay of about 1:50 to about 1:25.

14. The process of Claim 9, wherein the catalyst contains said zirconium oxide and said acidic montmorillonite clay in a weight ratio of zirconium oxide to clay of about 1:50 to about 1:40 and the olefins have 14 carbon atoms.

15. The process of Claim 9, wherein the acidic montmorillonite clay has a moisture content of about 16 wt.%, a residual acidity of about 15 mg KOH/g, and a surface area of about 300 m2/g.

16. A process for the preparation of oligomers, comprising oligomerizing linear olefins containing from 10 to 24 carbon atoms in the presence of a catalyst consisting essentially of a physical blend of a silicon dioxide-supported sulfate-activated zirconium oxide and an acidic montmorillonite clay having a moisture content ranging up to about 20 wt.%, a residual acidity in the range of about 3 to about 30 mg KOH/g, and a surface area of about 300 m2/g or greater, wherein the catalyst contains said silicon dioxide-supported zirconium oxide and said acidic montmorillonite clay in a weight ratio of silicon dioxide-supported zirconium oxide to clay of about 1:1000 to about 1:4, and wherein the olefins are oligomerized at a temperature in the range of about 120° C to about 250° C.

17. The process of Claim 16, wherein the catalyst contains said silicon dioxide-supported zirconium oxide and said acidic montmorillonite clay in a ratio of silicon dioxide-supported zirconium oxide to clay of about 1:50 to about 1:9.

18. The process of Claim 16, wherein the catalyst contains said silicon dioxide-supported zirconium oxide and said acidic montmorillonite clay in a ratio of silicon dioxide-supported zirconium oxide to clay of about 1:50 to about 1:20.

19. The process of Claim 16, wherein the olefins are oligomerized at a temperature in the range of about 140° C to about 180° C.

20. The process of Claim 16, wherein the olefins are oligomerized at a temperature in the range of about 160° C to about 180° C.