PATENTS

2961. ----- [RUHRCHEMIE, A. G.]  [Lubricating Oils.]  French  Patent  826,821, Apr. 11, 1938; appl. filed Sept. 16, 1937.  Chem. Zentralb., 1938, II, p. 2217.

Olefin mixtures, obtained by cracking the higher boiling portion of the synthetic hydrocarbons from the Fischer-Tropsch process, are polymerized with AlCl₃ at increasing temperatures.  If highly viscous oils are desired, large amounts of catalyst, low polymerization temperatures, and long polymerization times are employed: for less viscous oils, higher reaction temperatures, shorter contact periods, and smaller amounts of catalyst the catalyst can be renewed from time to time by adding fresh amounts of AlCl₃.