Novel phenylboronic acid derivatives containing phosphorous and nitrogen as lubricant additives: Synthesis, characterization, and tribological behaviors

Abstract

Three phenylboronic acid derivatives containing phosphorous and nitrogen with chlorine (BNP1), methyl (BNP2), and nitro (BNP3) were successfully prepared and applied to evaluate the tribological behaviors as additives in liquid paraffin. Three derivatives exhibited high thermal stability. The tribological tests indicated that three derivatives lead to a substantial improvement in anti-friction and anti-wear properties of liquid paraffin. In comparison to BNP1 and BNP3, BNP2 performs best on friction-reducing and wear resistance performances. This is caused by the strong electron-donating ability of the methyl group in BNP2. The analysis of worn surfaces demonstrated that three derivatives could form a protective tribofilm containing boron, nitrogen, and phosphorus elements on the rubbing surfaces. Thus, three phenylboronic acid derivatives could be potential lubricant additives in industrial applications.