Anilinosilanes as thermo-oxidation stabilizers of commercial lubricating base oils

Abstract

Anilinosilanes with different substituents on the benzene ring and on the silicon atom were prepared and used as antioxidants for lubricating base oil. The prepared antioxidants were compared with a commercial antioxidant termed MOX. The base oil before and after MOX addition starts oxidation at 218 and 265°C, respectively; while addition of anilinosilanes with p-methyl and p-methoxy groups increased its oxidation stability up to 298 and 308°C, respectively. Silylation of the amino groups also improved the solubility in oils; most anilines used were insoluble while most anilinosilanes prepared were oil soluble. In addition, silylation increased the antioxidancy of amines; addition of p-toluidine or its silylated product for example stabilized the oil up to 251 and 298°C, respectively. Para substituents were more effective than their meta analogues. DSC technique were more sensitive test than TG method towards antioxidation effect. © 1997 Elsevier Science B.V.