Molecular Design and Dynamic Simulations of Some Novel Antioxidant Lubricant Additives

Abstract

A quantitative structure-property relationship (QSPR) in-silico study was performed to develop a mathematical model that correlates 2D and 3D descriptors of 37 antioxidant lubricant additives (compounds) with their properties. A molecular dynamics simulation study was also carried out to access these additives' binding strength on diamond-like carbon (DLC) and steel crystal surfaces. Five novel antioxidant lubricant additives were designed from the information derived from the QSPR mathematical model’s high coefficient molecular descriptors. All the novel lubricant additive’s antioxidant properties were found to be better than our previous study, with the lubricant additive (Z)-3-(4-(5-amino-1-phenyl-1H-pyrazol-3-yl)-3,5-dimethylphenyl)-2-phenyl-5-(thiophen-2-ylmethylene)-3,5-dihydro-4H-imidazol-4-one found to possessed excellent antioxidant properties of 0.850281 total acid values (T.A.V 0.1g/L) than its co-additives.  Moreover, all the designed additives dynamically bind to steel crystal surfaces excellently from our dynamic simulation study than the DLC crystal surface. The molecular dynamics simulation results were found to be better than the one reported by our previous study. This investigation will help synthesize novel and excellent antioxidant lubricant additives that will hinder the base oil from undergoing a complete oxidation cycle and meet environmental requirements as these novel additives do not contain Zinc and Phosphorus, which often rendered exhaust pipes catalytic converter inactive, thereby increasing environmental pollution.