1129.    GALL, D.  Production of Lubricating Oils From the Olefins Produced in the Fischer-Tropsch Synthesis.  Jour. Soc. Chem. Ind., vol. 65, 1946, pp. 185-189; Chem. Abs., vol. 40, 1946, p. 7582.

        Preparation of lubricating oils by polymerization with AlCl₃ of the olefins present in the primary product obtained by synthesis from CO and H₂ (1:2) over a Co catalyst at atmospheric pressure has been carried out in 2-gal. batches.  The effect of varying the temperature, catalyst, and boiling range of the starting material on the reaction and its products is described.  Two fractions b. 40°-140° and 140°-210°, with 8.6 and 28% by weight, respectively, of olefins were polymerized at the reflux point to a material apparently above the original boiling range.  The yield of lubricating oil of similar viscosity is much lower from the higher-boiling fraction; this is due partly to the relatively higher proportion of olefins which are lost as AlCl₃ complex and partly to a tendency of the olefins of higher molecular weight to give oils of lower viscosity, so that these have to be topped to a higher initial boiling point to give the same viscosity as the polymers from the lower olefins.  The use of higher olefins gives a lubricating-oil fraction of higher viscosity index, but there appears to be little difference in the other properties tested.  Investigations on the effect of varying the reaction temperature and the proportion of catalyst with the 40°-140° fraction were made.  It was found that increasing the proportion of catalyst increases the reaction velocity and the viscosity of the product but lowers the yield, whereas increasing the temperature increases the rate of reaction but decreases both the yield and the viscosity of the lubricating-oil fraction but has little effect on the viscosity index.  The oils obtained possess properties which approximate the requirements of Air Ministry Spec. D. T. D. 109 for aircraft lubricants in all respects except the increase in viscosity on oxidation.  It was found possible to overcome this disability by subjecting the oils to a carefully controlled hydrogenation in the presence of MoS₂ at 200° and 200 atm.  H₂ pressure, using 20% by weight of catalyst calculated on the oil charged.