METHOD OF PREPARING MULTIFUNCTIONAL ADDITIVE FOR LUBRICATING OILS Russian patent published in 2001 - IPC

FIELD: organic synthesis and lubricants. SUBSTANCE: additive is prepared by interaction of dialkyldithiophosphoric acid, wherein alkyl is linear or branched alkyl having 4-8 carbon atoms, with zinc oxide in presence of aliphatic alcohol, 2-mercaptobenzothiazole, and water at 80-95 C followed by modifying formed products with boric acid at 90-110 C. The following molar ratio should be observed: dialkyldithiophosphoric acid : zinc oxide : alcohol : water : 2-mercaptobenzothiazole : boric acid = 1:(0.6- 0.75):(0.10-0.2): (0.2-0.8): (0.015-0.06): (0.05-0.1). Aliphatic is 2- ethylhexanol or mixture of aliphatic C5-C8-alcohols. Resulting dithiophosphate additive contains more than 80% principal material. EFFECT: improved tribological and antioxidant properties of doped lubricating oil. 3 cl, 4 tbl, 5 ex