Oligomerisation process

Abstract

A process is provided for the selective oligomerisation of C5 to C20 alpha-olefins to produce polyalphaolefin oligomers with a molecular weight distribution that is suitable for use in lubricant base oils.

Claims

1. A process for the preparation of alpha-olefin oligomers, comprising contacting an olefinic feedstock comprising C.sub.5 to C.sub.20 alpha-olefins with a liquid complex catalyst consisting essentially of: (i) at least one metal halide salt of the formula MX.sub.3, wherein M is selected from aluminium and gallium, and each X is independently selected from chlorine, bromine and iodine; and (ii) at least one Lewis basic donor ligand containing a donor atom selected from oxygen, sulphur, nitrogen, phosphorus, arsenic and selenium; wherein the molar ratio of the at least one metal halide salt to the at least one Lewis basic donor ligand is in the range of from 1:1 to 4:1, and wherein the at least one Lewis basic donor ligand is selected from the group of compounds consisting of ketones, sulfoxides, phosphine-oxides, ureas, amides, thioketones, thioureas, thioamides, thioethers, amines, nitriles and phosphines; and wherein the contacting produces a product having a fraction which comprises dimers, trimers, and tetramers, wherein the product predominantly comprises the fraction.

2. The process according to claim 1, wherein M represents aluminium.

3. The process according to claim 2, wherein the molar ratio of the at least one metal halide salt to the at least one Lewis basic donor ligand is in the range of from 1:1 to 2:1.

4. The process according to claim 3, wherein the molar ratio of the at least one metal halide salt to the at least one Lewis basic donor ligand is from about 55:45 to about 65:35.

5. The process according to claim 4, wherein the molar ratio of the at least one metal halide salt to the at least one Lewis basic donor ligand is about 3:2.

6. The process according to claim 1, wherein X represents bromine or chlorine.

7. The process according to claim 6, wherein MX.sub.3 represents AlCl.sub.3.

8. The process according to claim 1, wherein the at least one Lewis basic donor ligand is selected from compounds having a formula selected from R.sup.1C(O)R.sup.1, R.sup.1S(O)R.sup.1, R.sup.2NHC(O)NHR.sup.2, R.sup.2NHC(S)NHR.sup.2, R.sub.1C(O)NR.sup.2.sub.2, (R.sup.3).sub.3P(O) and R.sup.1CN wherein: each R.sup.1 independently represents a C.sub.1 to C.sub.10 alkyl group; R.sup.2 is selected from hydrogen or a C.sub.1 to C.sub.10 alkyl group; and R.sup.3 represents a C.sub.4 to C.sub.10 alkyl group; wherein any of R.sup.1, R.sup.2 and R.sup.3 may optionally be substituted by one or more fluorine atoms.

9. The process according to claim 8, wherein the at least one Lewis basic donor ligand is selected from urea, N,N-dimethylurea, N,N-dimethylthiourea, acetamide, dimethylacetamide, acetone, dimethylsulfoxide and trioctylphosphine oxide.

10. The process according to claim 1, wherein the olefinic feedstock comprises at least 50 wt % of one or more C.sub.5 to C.sub.20 alpha-olefins.

11. The process according to claim 1, wherein the olefinic feedstock comprises at least 30 wt % C.sub.8 to C.sub.14 alpha-olefins.

12. The process according to claim 11, wherein the olefinic feedstock comprises at least 30 wt % 1-decene.

13. The process according to claim 11, wherein the olefinic feedstock comprises at least 30 wt % 1-dodecene.

14. The process according to claim 1, wherein the olefinic feedstock comprises at least 30 wt % C.sub.16 to C.sub.18 alpha-olefins.

15. The process according to claim 14, wherein the olefinic feedstock comprises at least 30 wt % 1-hexadecene.

16. The process according to claim 14, wherein the olefinic feedstock comprises at least 30 wt % 1-octadecene.

17. The process according to claim 1, wherein the olefinic feedstock is contacted with the liquid complex catalyst at a temperature of from 0 to 160 C.

18. The process according to claim 1, wherein the olefinic feedstock is contacted with the liquid complex catalyst at a pressure of from 10 to 1000 kPa.

19. The process according to claim 1, wherein the olefinic feedstock is contacted with from 0.01 to 5 wt % of the liquid complex catalyst based on the total weight of the liquid complex catalyst and olefinic feedstock.

20. The process according to claim 1, wherein the olefinic feedstock further includes paraffins.

Description

(1) The present invention will now be illustrated by reference to the following Examples and the accompanying figures, in which:

(2) FIG. 1 shows the overlaid .sup.27Al NMR spectra for LC compositions obtained from AlCl.sub.3 and acetamide (AcA) where .sub.AlCl3 is 0.50 and 0.60.

(3) FIG. 2 shows the simulated distillation (SimDist) analysis of the product distribution obtained by oligomerising 1-decene in the presence of [C.sub.2mim][Al.sub.2Cl.sub.7] (i.e. [C.sub.2mim]ClAlCl.sub.3, .sub.AlCl3=0.67).

(4) FIG. 3 shows the SimDist analysis of the product distribution obtained by oligomerising 1-decene in the presence of a LC prepared from AlCl.sub.3 and urea (Ur) (.sub.AlCl3=0.60). The product distribution obtained using [C.sub.2mim][Al.sub.2Cl.sub.7] is also shown for reference.

(5) FIG. 4 shows the SimDist analyses of the product distributions obtained by oligomerising 1-decene in the presence of LCs prepared from AlCl.sub.3 and a ligand selected from urea (Ur), trioctylphosphine oxide (P.sub.888O), dimethylthiourea (SUr), and acetone (Act) (.sub.AlCl3=0.60 in each case).

(6) FIG. 5 shows the SimDist analyses of the product distributions obtained by oligomerising 1-decene in the presence of LCs prepared from AlCl.sub.3 and a ligand selected from urea (Ur), ethyl acetate (EtOAc), dimethylsulfoxide (DMSO) and dimethylacetamide (DMA) (.sub.AlCl3=0.60 in each case).

(7) FIG. 6 shows the SimDist analyses of the product distributions obtained by oligomerising 1-decene in the presence of LCs prepared from AlCl.sub.3 and a ligand selected from acetamide (AcA), urea, a 1:1 binary mixture of acetone and urea, and a 1:1 binary mixture of acetamide and urea, (.sub.AlCl3=0.60 in each case).

(8) FIG. 7 shows the SimDist analyses of the product distributions obtained by oligomerising 1-decene in the presence of a LC prepared from AlCl.sub.3 and urea (.sub.AlCl3=0.60) at a range of temperatures.

(9) FIG. 8 shows the SimDist analyses of the product distributions obtained by oligomerising 1-decene in the presence of a LC prepared from AlCl.sub.3 and urea (.sub.AlCl3=0.60) with catalyst loadings of 1.85 mol % and 0.19 wt %.

(10) FIG. 9 shows the SimDist analyses of the product distributions obtained by oligomerising 1-decene in the presence of a LC prepared from AlCl.sub.3 and urea (.sub.AlCl3=0.60) with reaction times of 10 minutes and 150 minutes.

(11) FIG. 10 shows the gas chromatograms of the products obtained by oligomerising pure 1-decene and 10 mol % 1-decene in decane in the presence of a LC prepared from AlCl.sub.3 and urea (.sub.AlCl3=0.60).

(12) FIG. 11 shows the SimDist analyses of the product distributions obtained by oligomerising 1-decene in the presence of a LC prepared from AlCl.sub.3 and urea (.sub.AlCl3=0.55) in parallel reactions.

(13) FIG. 12 shows the gas chromatogram of the product obtained by oligomerising 1-decene in the presence of a LC prepared from AlCl.sub.3 and urea (.sub.AlCl3=0.60) compared to the gas chromatograms of commercial PAOs.

(14) FIG. 13 shows the SimDist analysis of the product distribution obtained by oligomerising 1-decene in the presence of a LC prepared from AlCl.sub.3 and urea (.sub.AlCl3=0.60) compared to the SimDist analyses of commercial PAOs.

(15) FIG. 14 shows the gas chromatograms of the products obtained by oligomerising C.sub.16 alpha-olefins, C.sub.16 alpha-olefins diluted with decane (1:1 by volume) and C.sub.18 alpha-olefins in the presence of a LC catalyst prepared from AlCl.sub.3 and urea (.sub.AlCl3=0.60).

(16) FIG. 15 shows the SimDist analysis of the product distribution obtained by oligomerising 1-hexadecene in the presence of the ionic liquid [C.sub.2mim][Al.sub.2Cl.sub.7] compared to the product distribution obtained using a LC catalyst prepared from AlCl.sub.3 and urea (Ur) (.sub.AlCl3=0.60).

EXAMPLES

Reference Example 1Synthesis of [C.SUB.2.mim][Al.SUB.2.Cl.SUB.7.]

(17) The ionic liquid 1-ethyl-3-methylimidazolium chloride-AlCl.sub.3 with .sub.AlCl3=0.67 (referred to herein as [C.sub.2mim][Al.sub.2Cl.sub.7]) was prepared by slowly adding of aluminium (III) chloride (33.60 g, 0.252 mol) to [C.sub.2mim]Cl (18.46 g, 0.126 mol) under an inert atmosphere. A clear, light brown, mobile ionic liquid was generated in the course of an exothermic reaction.

Example 2Synthesis of AlCl.SUB.3.-Urea Liquid Complexes

(18) LCs having .sub.AlCl3 values of from 0.5 to 0.67 were prepared from aluminium (III) chloride and urea by slowly adding 1 molar equivalent of urea to 1 to 2 molar equivalents of aluminium (III) chloride with stirring under an inert atmosphere. Once addition of the urea ligand was complete, the resulting mixture was stirred at 80 C. for 1 hour to provide a homogeneous, mobile, colourless liquid. The LCs were stored under an inert atmosphere until used.

Example 3Synthesis of Other Liquid Complexes

(19) LCs containing ligands selected from dimethylacetamide, trioctylphosphine oxide, dimethyl sulfoxide, ethyl acetate, N,N-dimethylthiourea, acetone and acetonitrile and each having .sub.AlCl3=0.60 were prepared by an analogous procedure to Example 2, using 3 molar equivalents of aluminium (III) chloride and two molar equivalents of the ligand. The properties of the different liquid complexes are described in Table 1.

(20) TABLE-US-00001 TABLE 1 Ligand Result Dimethylacetamide Colourless, mobile liquid Trioctylphosphine Yellow, slightly viscous liquid oxide Dimethyl sulfoxide Dark brown, mobile liquid Ethyl acetate, Yellow, mobile liquid N,N-dimethylthiourea Colourless, mobile liquid Acetone Yellow, mobile liquid Acetonitrile Room temperature solid, melting point ca. 80 C.

Example 4Generic Procedure for Oligomerisation Reactions

(21) Oligomerisation reactions were conducted in a battery of computer-controlled reactors, each having a volume of 120 mL. Due to the corrosive nature of the catalyst, the reactors are designed for high corrosion resistance, with the sample remaining in contact only with glass, Teflon and HasteHoy. Prior to the reaction, the reactor vessels and stirrer propellers are dried overnight in an oven, and subsequently cooled to ambient temperature in a desiccator containing phosphorus(V) oxide. The remaining parts are dried with a heat gun immediately before assembly.

(22) 1-Decene (40 mL, dry by Karl-Fisher analysis) is added to each reactor vessel and the reactors are purged with dry argon. The reactors are then equilibrated to the required reaction temperature with vigorous stirring (600 rpm).

(23) Immediately prior to use, the liquid complex or ionic liquid is loaded into a gas-tight syringe in a glovebox. Prior to use, the syringe is dried overnight in an oven, cooled in a desiccator and then transferred directly to the glovebox. The tip of the needle is plunged into a small flask closed with a septum to protect it from contact with the atmosphere. Subsequently, the loaded syringe is removed from the glovebox and the needle is immediately plunged through a septum into a reactor containing the 1-decene feedstock at the required reaction temperature and stirred at 600 rpm.

(24) The liquid complex or ionic liquid catalyst is added drop-wise to the vigorously stirred feedstock as quickly as possible, but maintaining a substantially constant reaction temperature (i.e. avoiding exotherms greater than 10 C.). After stirring at the required reaction temperature for the specified reaction time, the reaction mixture is quenched by vigorous stirring (600 rpm, 10 min, ambient temperature) with deionised water (30 mL). Aqueous ammonia (10%, 10 mL) added and the mixture is subsequently centrifuged to fully partition the aqueous and organic phases.

(25) The boiling point distribution of oligomerised products was generated by simulated distillation (SimDist) according to ASTM 6352. Simulated distillation is a technique widely used in the petroleum industry for evaluation of hydrocarbon products in which the boiling point distribution of a mixture of hydrocarbons is calibrated to the gas chromatographic analysis of the mixture. Samples of SimDist analysis were dissolved in toluene (100 mg.Math.cm.sup.3), dried over magnesium sulphate and filtered prior to analysis. SimDist analyses are shown as cumulative distributions with the maximum molecular weight of the oligomers suitable for use as lubricant base stocks indicated by a horizontal line at a boiling point of ca. 580 C. Highly oligomerised products having a boiling point above 580 C. are referred to herein as heavies.

(26) Pour points were measured in accordance with ASTM D97-11 or by a simulation thereof using a series of ice salt and dry ice-solvent baths from 0 C. down to 51 C.

(27) Kinematic viscosity (Kv) is measured at 40 C. and 100 C. using the appropriate Cannon-Fenske kinematic viscosity glassware and a dedicated, precisely-controlled heating bath. Kinematic viscosity is found by timing the gravitational flow of the sample through a capillary, with temperature maintained using a high accuracy heating bath.

(28) In order to select appropriate Cannon-Fenske tubes, dynamic viscosity of some samples was measured using Bohlin Gemini cone-and-plate viscometer with a Bohlin Instruments Peltier temperature control and a stainless steel 4/40 spindle. Dynamic viscosity was measured within a temperature range of 20-95 C., in 5 C. increments. From dynamic viscosity () and density () kinematic viscosity, Kv was estimated using the following relationship: Kvp1, to select the appropriate Cannon-Fenske tubes.

(29) Viscosity Index (VI) was calculated from the measured Kv40 and Kv100 values according to ASTM D2270.

Reference Example 5Oligomerisation of 1-Decene Using [C.SUB.2.mim]ClAlCl.SUB.3.(.SUB.AlCl3.=0.55)

(30) Oligomerisation of 1-decene was carried out in the presence of 1.5 wt % of the ionic liquid of Reference Example 1 according to the general procedure of Example 4 with a reaction temperature of 120 C. and a reaction time of 20 minutes. The results of the SimDist analysis are provided in FIG. 2. While the conversion of starting materials is found to be very high, the oligomeric product obtained using this ionic liquid contains a large proportion of highly oligomerised products, with approximately 80 wt % of the products in the heavies range.

Example 6Oligomerisation of 1-Decene Using LC Catalyst

(31) Oligomerisation of 1-decene was carried out according to the general procedure of Example 4 in the presence of a LC catalyst prepared from AlCl.sub.3 and urea (Ur), (.sub.AlCl3=0.60). The reaction was carried out at 120 C. for a period of 20 minutes using 1.85 wt % of the LC catalyst.

(32) The SimDist results are provided in FIG. 3 (the results for Reference Example 5 are also shown in FIG. 3 for reference). It is found that the LC system of the present invention provides oligomerised products with conversions of starting material as high as 85 wt % and with far lower production of heavies than the ionic liquid system of Reference Example 5. Numerical results are also provided in Table 2 below (see Example 7).

Example 7Oligomerisation of 1-Decene Using LC Catalysts

(33) Oligomerisation of 1-decene was carried out according to the general procedure of Example 4 in the presence of LC catalysts prepared from AlCl.sub.3 and a ligand selected from trioctylphosphine oxide (P.sub.888O), dimethylthiourea (SUr), acetone (Act), ethyl acetate (EtOAc), dimethylsulfoxide (DMSO) and dimethylacetamide (DMA) with .sub.AlCl3=0.60 in each case. The reactions were carried out at 120 C. for a period of 20 minutes using 1 mol % (ca. 1.8 wt %) of the LC catalyst.

(34) The SimDist results are provided in FIGS. 4 and 5 (the results for urea are shown in both Figures for reference). It is found that the LC systems of the present invention provide oligomerised products with conversions of starting material as high as 85 wt % and with far lower production of heavies than the ionic liquid system of Reference Example 5. Numerical results are also provided in Table 2.

(35) TABLE-US-00002 TABLE 2 Conversion C20 C30 C40 C50 C60 C70+ Ligand mass % mass % of product Ur 71.0 47.1 38.6 11.4 2.9 DMSO 82.0 28.4 32.1 23.5 11.1 4.9 EtOAc 82.0 27.2 33.3 21.0 9.9 6.2 2.5 Act 85.0 21.4 32.1 22.6 13.1 6.0 4.8 SUr 22.0 14.3 33.3 28.6 19.0 4.8 P.sub.888O 74.0 35.6 43.8 16.4 4.1 DMA 80.0 27.8 29.1 21.5 12.7 6.3 2.5

Example 8Oligomerisation of 1-Decene Using Further LC Catalysts

(36) Oligomerisation of 1-decene was carried out according to the general procedure of Example 4 in the presence of further LC catalysts prepared from AlCl.sub.3 and a ligand selected from acetamide (AcA), urea, a 1:1 binary mixture of acetone and urea, and a 1:1 binary mixture of acetamide and urea, with .sub.AlCl3=0.60 in each case. The reaction times were 1 hour for the LC containing only acetamide as a ligand and 20 minutes in all other cases. The reaction temperature was 80 C. for the LC containing a 1:1 mixture of acetone and urea, and the catalyst loading was 2.77 wt %. In all other cases a temperature of 100 C. and a catalyst loading of 1.85 wt % was used. The SimDist results are provided in FIG. 6. The result obtained at 80 C. indicates that lower temperatures provide a greater proportion of heavy oligomers.

Example 9Temperature Dependence of LC Catalysed Oligomerisation of 1-Decene

(37) Oligomerisation of 1-decene was carried out according to the general procedure of Example 4 in the presence of 1.85 wt % of a LC catalyst prepared from AlCl.sub.3 and urea (.sub.AlCl3=0.60). The reactions were carried out at 120 C., 130 C. and 140 C. and over a period of 20 minutes in each case. The SimDist results are provided in FIG. 7. Within this temperature range, no significant variation in results was observed.

Example 10Effect of Catalyst Loading in the LC Catalysed Oligomerisation of 1-Decene

(38) Oligomerisation of 1-decene was carried out according to the general procedure of Example 4 in the presence of a LC catalyst prepared from AlCl.sub.3 and urea (.sub.AlCl3=0.60) and with catalyst loadings of 0.19 wt % and 1.85 wt %. The reaction was carried out at 140 C. and over a period of 20 minutes in the case of 1.85 wt % catalyst loading, and over a period of 30 minutes in the case of 0.19 wt % catalyst loading. The SimDist results are provided in FIG. 8. No significant difference in conversion was observed.

Example 11Effect of Reaction Time in the LC Catalysed Oligomerisation of 1-Decene

(39) Oligomerisation of 1-decene was carried out according to the general procedure of Example 4 in the presence of a LC catalyst prepared from AlCl.sub.3 and urea (.sub.AlCl3=0.60) and over a period of 10 minutes and 150 minutes. The reaction temperature was 120 C. in each case and the catalyst loading was 0.93 wt %. The SimDist results are provided in FIG. 9. Although the reaction time was increased by a factor of 15, only a small increase in conversion was observed. The product distribution is substantially unchanged, however, with only a low level of heavies produced. The physical properties of the oligomeric product after removal of monomer and most of the dimer are provided in Table 3.

(40) TABLE-US-00003 TABLE 3 Reaction time conversion Kv.sub.40 Kv.sub.100 VI 150 82 33.5271 5.7535 113 10 73 24.6905 4.7272 110

Example 12Effect of Paraffins in the Feedstock in the LC Catalysed Oligomerisation of 1-Decene

(41) Oligomerisation of 1-decene in the form of a mixture of 10 wt % decene in decane was carried out according to the general procedure of Example 4 in the presence of 1.85 wt % of a LC catalyst prepared from AlCl.sub.3 and urea (.sub.AlCl3=0.60) and at a reaction temperature of 120 C. over a period of 20 minutes. The results are provided in FIG. 10 in the form of a gas chromatography (GC) trace alongside the result obtained using only 100% 1-decene as the feedstock under corresponding conditions. The presence of decane is observed to shift the product distribution towards shorter oligomers.

Example 13Reproducibility of the LC Catalysed Oligomerisation of 1-Decene

(42) Oligomerisation of 1-decene according to the general procedure of Example 4 was carried out in triplicate in the presence of 3.71 wt % of a LC catalyst prepared from AlCl.sub.3 and urea (.sub.AlCl3=0.55). The reaction temperature was 80 C. and the reaction was conducted over a period of 1 hour. The SimDist results are provided in FIG. 11 and show excellent reproducibility, with minor variations in conversion believed to be due to the presence of trace amounts of water.

Example 14Comparison to Commercial PAOs

(43) The product of the oligomerisation of 1-decene prepared according to the general procedure of Example 4 in the presence of 0.93 wt % of a LC catalyst prepared from AlCl.sub.3 and urea (.sub.AlCl3=0.60) at 120 C. and with a reaction time of 1 hour, was compared to commercial samples of PAO 4, 6 and 8. The product distribution of the oligomerised product obtained according to the process of the invention, following the removal of unreacted monomer and most of the dimer by distillation, was found to correspond closely to the product distribution of commercial PAOs, as shown by the GC traces in FIG. 12 and the SimDist results in FIG. 13.

Example 15Oligomerisation of Mixed Alpha-Olefins Using LC Catalysts

(44) An industrial alpha-olefin feedstock having a composition of 30% 1-decene, 50% 1-dodecene, 2% 1-tridecene, 12% 1-pentadecene and 6% C.sub.18 1-octadecene was carried out according to the general procedure of Example 4 in the presence of a LC catalyst prepared from AlCl.sub.3 and urea (.sub.AlCl3=0.60) and at a range or reaction times, catalyst loadings and reaction temperatures. Due to the presence of higher alpha-olefins, lower reactivity and therefore the need for a more active system was anticipated. In view of the composition of the feedstock, the product would be expected to contain oligomers of various carbon numbers. Reaction conditions examined and the product distributions obtained are summarised in Table 4

(45) TABLE-US-00004 TABLE 4 Reaction Catalyst time loading Temp. <C15 C15-C25 C26-C35 C36-C45 C46-C55 min wt % C. wt % wt % of product 120.0 0.19 120 76.0 20.0 3.0 1.0 0.0 120.0 0.37 120 54.0 24.0 10.0 6.0 2.0 120.0 0.37 120 54.0 26.0 12.0 6.0 2.0 120.0 0.37 120 53.0 26.0 12.0 7.0 2.0 120.0 1.85 120 30.0 27.0 23.0 14.0 6.0 60.0 5.56 140 14.0 26.0 31.0 28.0 1.0

(46) As shown in Table 4, optimum conversion and product distribution was obtained at 140 C. and with a catalyst concentration of 3 mol %.

Example 16Oligomerisation of C.SUB.16 .Olefinic Feedstocks

(47) The oligomerisation of 1-hexadecene was carried out according to the general procedure of Example 4 in the presence of a LC catalyst prepared from AlCl.sub.3 and urea (.sub.AlCl3=0.60) and at a range or reaction times, catalyst loadings and reaction temperatures. Heavier alpha-olefins are less chemically active than alpha-olefins of lower molecular weight. Oligomerisation of heavier alpha-olefins is therefore expected to require a more active catalytic system. Reaction conditions examined and the product distributions obtained are summarised in Table 5.

(48) TABLE-US-00005 TABLE 5 Reaction Catalyst con- tri- time loading temp. version dimer mer tetramer >tetramer min wt % C. wt % wt % of product 30.0 0.5 70 82.0 8.6 40.7 28.4 22.2 30.0 1.74 120 76.0 48.0 40.0 10.7 1.0 15.0 1.74 140 75.0 55.4 36.5 8.1 0.0 30.0 1.74 140 75.0 60.8 33.8 5.4 0.0 120.0 1.74 140 86.0 49.4 40.0 9.4 1.2 120.0 3.48 140 89.0 45.5 43.2 10.2 1.1 15.0 3.48 140 80.0 55.7 38.0 6.3 0.0 30.0 1.74 160 81.0 57.5 36.3 6.3 0.0

Example 17Oligomerisation of C.SUB.18 .Olefinic Feedstocks

(49) The oligomerisation of 1-octadecene was carried out according to the general procedure of Example 4 in the presence of a LC catalyst prepared from AlCl.sub.3 and urea (.sub.AlCl3=0.60) and at a range or reaction times, catalyst loadings and reaction temperatures. Reaction conditions examined and the product distributions obtained are summarised in Table 6.

(50) TABLE-US-00006 TABLE 6 Reaction Catalyst con- tri- time loading temp. version dimer mer tetramer >tetramer min wt % C. wt % wt % of product 15.0 1.55 140 77.0 55.3 36.8 7.9 0.0 15.0 3.09 140 78.0 53.2 39.0 7.8 0.0 20.0 0.21 160 43.0 78.6 21.4 2.4 0.0 20.0 1.03 160 50.0 53.1 34.7 12.2 0.0

Example 18Oligomerisation of Mixed C.SUB.16 .and C.SUB.18 .Olefinic Feedstocks

(51) The oligomerisation of a 1:1 mixture by volume of 1-hexadecene and 1-octadecene was carried out according to the general procedure of Example 4 in the presence of a LC catalyst prepared from AlCl.sub.3 and urea (.sub.AlCl3=0.60) at a catalyst concentration of 1.64 wt %. The reaction temperature was 140 C. and the reaction was carried out over a period of 60 minutes. Analysis of the product by SimDist showed 74.0% conversion of starting material and a product distribution of 57.7 wt % dimer, 35.6 wt % trimer and 6.8 wt % tetramer. The formation of higher oligomers was not observed.

Example 19Oligomerisation of C.SUB.16 .Olefinic Feedstocks

(52) The oligomerisation of a 1:1 mixture by volume of 1-hexadecene and decane was carried out according to the general procedure of Example 4 in the presence of a LC catalyst prepared from AlCl.sub.3 and urea (.sub.AlCl3=0.60) at a catalyst concentration of 1.64 wt %. The reaction temperature was 140 C. and the reaction was carried out over a period of 20 minutes. Analysis of the product by SimDist showed 80.0% conversion of starting material and a product distribution of 59.0 wt % dimer and 41.0 wt % trimer. The presence of the paraffin decane in the reaction mixture is thus observed to suppress the formation of tetramers and higher oligomers from C.sub.16 alpha-olefins. The SimDist gas chromatograms for products obtained according to Examples 16, 17 and 19 are provided as FIG. 14.

Reference Example 20Oligomerisation of 1-Hexadecene Using [C.SUB.2.mim][Al.SUB.2.Cl.SUB.7.]

(53) Oligomerisation of 1-decene was carried out in the presence of 1.5 wt % of the ionic liquid of Reference Example 1 according to the general procedure of Example 4 with a reaction temperature of 120 C. and a reaction time of 20 minutes. The results of the SimDist analysis are provided in FIG. 15.

Example 21Oligomerisation of 1-Hexadecene Using LC Catalyst

(54) Oligomerisation of 1-hexadecene was carried out according to the general procedure of Example 4 in the presence of a LC catalyst prepared from AlCl.sub.3 and urea (Ur), (.sub.AlCl3=0.60). The reaction was carried out at 120 C. for a period of 20 minutes using 1.5 wt % of the LC catalyst. The results of the SimDist analysis are provided in FIG. 15 alongside the results for Reference Example 20. It is found that the LC system of the present invention provides an improved product distribution compared to the ionic liquid system.

Example 22Physical Properties of Oligomeric Products

(55) Oligomerisation of 1-decene was carried out according to the general procedure of Example 4 in the presence of a LC catalyst prepared from AlCl.sub.3 and urea at a range of .sub.AlCl3 values, reaction times and catalyst loadings. The reaction temperature was 120 C. in each case. The physical properties of the oligomeric products obtained after removal of 1-decene monomer and most of the dimer are provided in Table 7.

(56) TABLE-US-00007 TABLE 7 Time Catalyst Kv.sub.40 Kv.sub.100 Pour Point X.sub.AlCl3 min mol % cSt cSt VI C. 0.550 20.0 1.000 25.4610 5.0124 125 <43 0.550 60.0 0.500 24.6813 5.0124 133 <43 0.600 60.0 0.500 27.2205 5.0796 115 <43 0.575 40.0 0.750 27.5310 5.2404 124 <43 0.600 20.0 0.500 23.1840 4.4741 104 <43 0.575 40.0 0.750 26.4056 5.0693 121 <43 0.575 40.0 0.750 32.3900 5.9206 129 <43 0.575 40.0 0.750 33.7870 5.9868 123 <43 0.575 40.0 1.170 40.8043 6.8576 126 <43 0.600 20.0 1.000 29.6286 5.7535 140 <43 0.617 40.0 0.750 33.7870 5.8313 115 <43 0.575 73.6 0.750 40.2845 6.7176 122 <43 0.550 20.0 0.500 24.1707 4.6806 111 <43 0.575 6.4 0.750 32.7474 5.8002 120 <43 0.575 40.0 0.750 30.9281 5.6447 124 <43 0.575 40.0 0.330 37.1657 6.3600 122 <43 0.575 40.0 0.750 27.5494 5.2248 123 <43 0.550 60.0 1.000 33.5271 5.8624 118 <43 0.600 60.0 1.000 56.3983 8.8635 134 <43