IMPROVEMENT OF HYDROLYTIC STABILITY OF BORATE ESTERS USED AS LUBRICANT ADDITIVES

Borate esters posses friction-reducing, antiwear and antioxidant chara cteristics when blended in lubricating oils. However, they are suscept ible to hydrolysis. Eleven borate ester compounds were synthesized and their hydrolytic stabilities were compared. The results indicated tha t the hydrolysis problem of borate esters can be better solved by intr oducing N,N-dialkylamino-ethyl with alkyl radicals containing more tha n three carbon atoms. It is believed that the formation of a stable fi ve-member ring structure in molecules involving coordination of nitrog en with boron substantially contributes to the resistance to hydrolysi s of such type compounds.