Quantitative structure-properties relationship and molecular design of some anti-wear lubricant additives

Abstract

In-silico QSPR and MD simulation methods were adopted to effectively design new lubricant anti-wear additive compounds as an alternative to zinc dialkyl dithiophosphate (ZDDP) which was reported to contribute to environmental pollution. Some QSPR linear models were developed out of which the best model (With statistical analysis R2 = 0.990, R2pred. = 0.818, R2adj = 0.979, R2cv = 0.748) was used to design three new additive structures with an improved anti-wear lubricant properties. Three lubricant additives such as 2-(hept‑1-en-2 ylthio)benzo[d]oxazole, 2-((5-methylhex-5-en-1-yl)thio)benzo[d]oxazole and 2-((5-methyl-2-methylenehex-5-en-1-yl)thio)benzo[d]oxazole were designed and revealed to have anti-wear properties of 0.593, 0.512, and 0.367 mm respectively. These anti-wear lubricant properties of all the designed additives were found to be better than the bench-mark anti-wear additive, ZDDP (3.284 mm) and what other researchers proposed. Moreover, The dynamic binding energies of all the designed anti-wear lubricant additives were found to be bound better than the one calculated by other researchers and was found to be excellently bound also than the commercially sold (benchmark additive) additive (ZDDP) 24,365.405. The addition of acceptor substituent like =CH2 groups to the hydrocarbon chain structures of all the newly designed additives was noticed to have improved lubricant wear-reduction properties and binding dynamic energies of the new additives on the simulated steel coated surface. Therefore, these QSPR and MD methods could be used to provide a theoretical framework for researchers and industrialists to design an improved anti-wear additive properties and save resources before expensive laboratory trial and error method.