Development of N, P and S-containing multifunctional additives for lubricants

Metallic dialkyldithiophosphates, namely, ZDDP, are widely used in formulating lubricants to enhance their antioxidant, antiwear, extreme pressure and antifriction properties. These ash bearing additives lead to operational problems and the use of some metals is being restricted for environmental resasons. This paper describes the synthesis and evaluation of a new class of alkulamino phosphorodithioates for use as additives in lubricant formulations. Eight ashless alkylamino phosphorodithioates with varying alkyl chain lengths from C85 to C18 have been synthesized and their antiwear, antifriction, extreme pressure and antioxidant performance examined compared to a commercial ZDDP in a mineral base oil. The synthesized products have been found to exhibit appreciable antiwear and antioxidant properties and mild antifriction/extreme pressure performance.