3026. ----- [RUHRCHEMIE, A. G.] [Process for Improving the Age Stability of Lubricating Oils.] German Patent Appl. --, R 717, filed June 8, 1944, FIAT Reel K-30, frames 7,801-7,804; PB 73,587; TOM Reel 37, bag 3,451, item 36, 4 pp.

In improving the age stability of lubricating oils obtained by the condensation of olefinic hydrocarbon mixtures in the presence of AlCl₃ in accordance with German Patent Appl. R 108,370 (abs. 3028), such oils are treated at about 170° for a long time with small amounts of AlCl₃ and elementary S. Finally they are subjected, at about the same temperature, to the action of bleaching earth and ZnO and /or MgO, after which they are heated for a longer time to about 260° and then vacuum distilled in the usual manner. In this addition to the main patent, the method is so changed that in the 2d step instead of a mixture of bleaching earth and ZnO and/or MgO, a mixture of bleaching earth and Zn or Zn alone is used. When bleaching earth and Zn are used the preferred temperature is about 170°, and when Zn is used alone about 220°-240° is recommended.