Esters of dicarboxylic acids as additives for lubricating oils

Five samples of dibasic acid esters with varied chemical structures were synthesized. These included didecyl carbonate, didecyl adipate and didecyl sebacate as well as modern oligomeric esters of adipic acid and sebacic acid. These esters were tested in terms of their suitability as additives of fully synthetic engine oils. It was noted that an addition of 10% of the respective esters to oils based on polyalphaolefins led to an improvement of their properties. The pour point of the oils as well as their low temperature viscosity were reduced. The viscosity index rose and oil lubricity improved. Esters of oligomeric structures synthesized by the transesterification of dimethyl adipate or dimethyl sebacate with a mixture of neopentyl glycol and decanol showed particularly suitable properties. The tested esters were compatible with the other oil components, forming a stable solution in a wide temperature range.