GB1081952A - Method of preparing synthetic lubricating oil - Google Patents

Abstract

A synthetic lubricating oil is prepared by contacting C6-C14 straight chain alpha olefins in a liquid reaction medium which comprises a saturated hydrocarbon, a halobenzene having 1 or 2 halogen atoms, a trihaloethane, a tetrahaloethane, a tri- or tetra-haloethylene in which halohydrocarbons the halogen is chlorine and/or fluorine at 0 DEG to 50 DEG C. with a catalyst system formed from an aluminium alkyl sesquichloride, titanium tetrachloride and a tetra-alkyl silicate, in which the alkyl groups have one to four carbon atoms and are unbranched, and thereafter separating from the reaction mixture olefin polymer of lubricating oil boiling range. Preferably the proportions of the catalyst components are such that the atomic ratio Al:Ti is 0.8-2.5:1 and the atomic ratio O:Al is 0.4-0.8:1. The weight ratio of olefin monomer to solvent is in the range 5:95 to 95:5 and the weight ratio of olefin to titanium tetrachloride is 25-100: 1 using a hydrocarbon solvent at 100-500: 1 in a halohydrocarbon. The oil product boiling above 650 DEG F. has a viscosity index above 140 and may be hydrogenated to saturate double bonds. Comparative examples describe the use of catalysts not containing tetra-alkyl silicates.ALSO:Catalysts, used in the polymerisation of C6 - C14 straight chain alpha olefins to prepare lubricating oils, are formed from an aluminium alkyl sesquichloride, the alkyl group preferably containing 1 to 10 carbon atoms titanium tetrachloride and a tetraalkyl silicate containing C1 - C4 alkyl groups. Preferably, the proportions of the catalyst components are such that the atomic ratio O:Ad is 0.4 to 0.8:1 and the atomic ratio Al:Ti is 0.8 to 2.5:1.