Improvements relating to lubricating oils

摘要

Mineral lubricating-oils are stabilized by adding diarylthio-ethers in which both aryl groups contain a nucleus-substituted hydroxy group. Substances of the following general formula are preferred in which the group R is in the para-position relative to the hydroxy group, and is an alkyl group such as ethyl, isopropyl, tertiary amyl or butyl, or normal butyl. Other substituents such as an aralkyl, aryl, cyano or halogen group may be present. Substances specified are: 2 : 2<1>-dihydroxy(-5 : 5<1>-ditertiary butyl) diphenyl thioether or the corresponding ditertiary amyl compound, 4 : 4<1>-dihydroxy diphenyl thio ether, dicresol thio ether, or di-b -naphthol thio ether. These are added to mineral oil distillates or residues which may be refined by selective solvent extraction, chemical reagents, voltolization, hydrogenation, or de-waxing, or to mixtures of these oils Dyes, soaps, pour-point depressant, resins, rubber, fatty oils, organometallic compounds, waxes, graphite or zinc oxide may be added The lubricating-compositions are stable to heat, air, and resist sluding in the presence of metals.