Heterocyclic thioethers as additives for lubricants

Abstract

This invention relates to compounds which are suitable as ash-free antiwear additives and antioxidants, to lubricant compositions comprising said compounds as well as to their use. Compounds of formulae ##STR1## are particularly preferred. In the preferred compounds I', R.sub.2 is isooctyloxycarbonylmethyl, R.sub.3 is isooctyloxycarbonylmethylthiomethyl and R.sub.4 is hydrogen; or R.sub.2 is tert-nonyl and R.sub.3 is tert-nonylthiomethyl and R.sub.4 is hydrogen; or R.sub.2 is isooctyloxycarbonylmethyl, R.sub.3 is hydrogen and R.sub.4 is isooctyloxycarbonylmethylthiomethyl; or R.sub.2 is tert-nonyl, R.sub.3 is hydrogen and R.sub.4 I is tert-nonylthiomethyl. In the preferred compounds II', R.sub.2 and R.sub.2 ' are isooctyloxycarbonylmethyl, R.sub.3 and R.sub.3 ' are isooctyloxycarbonylmethylthiomethyl and R.sub.4 and R.sub.4 ' are hydrogen; or R.sub.2 and R.sub.2 ' are tert-nonyl, R.sub.3 and R.sub.3 ' are tert-nonylthiomethyl and R.sub.4 and R.sub.4 ' are hydrogen; or R.sub.2 and R.sub.2 ' are isooctyloxycarbonylmethyl, R.sub.3 and R.sub.3 ' are hydrogen and R.sub.4 and R.sub.4 ' are isooctyloxycarbonylmethylthio; or R.sub.2 and R.sub.2 ' are tert-nonyl, R.sub.3 and R.sub.3 ' are hydrogen and R.sub.4 and R.sub.4 ' are tert-nonylthiomethyl.

Dependencies are inferred from the claim text.