3029. ----- [RUHRCHEMIE, A. G.] [Process for Increasing the Aging Stability of Lubricating Oils.] German Patent Appl.--, R691, filed Sept. 9, 1943. FIAT Reel K-30, frames 7,884-7,886; PB 73,587; Tom Reel 37, bag 3,452, item 36, 3 pp.

Lubricating oils obtained synthetically or from petroleum are 1^st diluted with miscible liquids removable by distillation such as low-boiling saturated hydrocarbons and then passed through layers of highly porpous, active material containing silicic acid or Al₂O₃ at normal, sub- or super-pressure and room temperature. Before using, the adsorbent material is dried for a short time at increased temperature, preferably > 150°. Desorption of the absorbates takes place through displacement by H₂O, after which a hot or cold extraction with low-boiling organic solvents such as chloroform or the like is carried out. If necessary, the adsorbent material can be reactivated by acid treatment.