S-substituted mercaptoacetic esters as anticorrosion additives to lubricating oils

Abstract

1. 1. S-substituted mercaptoacetic esters possess high anticorrosion properties and are more effective than corresponding derivatives of mercaptopropionic esters and unsubstituted sulphides. 2. 2. The linear dependence of chemical shifts of methylene protons of the —SCH 2— COO group of S-substituted mercaptoacetic esters on the induction constants of the substituent has been found. This is characterized by a fairly high correlation coefficient ( r=0·98) and indicates that the effect of substituent R at the sulphur atom on screening of methylene protons is communicated by the system of chemical bonds mainly by an induction mechanism. 3. 3. The combined presence of the sulphide sulphur atom and an ester group leads to an increase in the anticorrosion activity of the sulphides on account of the electronic interactions arising between these groups and occurring by a π-induction mechanism.