3114.----- [RUHRCHEMIE, A. G.] [Process for Improving Lubricating Oils.] German Patent Appl. --, R 405, filed Sept. 19, 1938. TOM Reel 37, bag 3,451, item 35, 4 pp.

Lubricants, which have been prepared by the polymerization of unsaturated hydrocarbons obtained by the careful cracking of a synthetic gasoline fraction b. 200°-300°, are improved by treating the finished polymerizate with elementary S at a raised temperature. Before the S treatment, the oil is subjected to a treatment with activated bleaching earth followed by vacuum disillation to the desired flame point. Then about 0.1-1% of S and 20-100% of the S of a vulcanization accelerator such as diphenylithiovren are added to the oil with heating to 160° for 5 hr. After sulfurization is completed the oil is steam distilled at 180° for 30 min. under an absolute pressure of 3 mm. Hg. In this manner the saponification number, as well as the Cu test to active S, is brought to the desired point. The oil thus obtained shows a high aging stability. No H₂S is split off by heating and no attack by S on metal is seen.