Synthesis and application of some dianilinosilanes, bis (trimethylsilyl) phenylenediamines and dialkyl benzo-1,3,2-diazasilolines as antioxidants

Abstract

A number of dialkyl or diphenyl dianilinosilanes, bis (trimethylsilyl) phenylenediamines and dialkyl benzo-1,3,2-diazasilolines were synthesized and used as antioxidants for lubricating base oils. Thermal analysis methods (DSC, TG and DTG) and IR technique were used to follow the oil oxidation. The first peak in the DSC thermograms of oil with the additive antioxidants is the sum of the endothermic oil evaporation process and the exothermic oxidation process. The onset temperature of this peak was used as a sensitive measure of the thermo-oxidation stability of the oil. Results showed that the prepared antioxidants increased the oil thermo-oxidation stability from 218°C up to 270°C which is close to the temperature of the oil evaporation as indicated by the TG thermograms. The antioxidation effect of the anilinosilane derivatives was attributed to the extra stability of the amine radical by both the silyl and phenyl groups. This radical is formed after binding the peroxy radical responsible for the oil deterioration.