Action mechanism of antioxidation and anticorrosion and molecular design for perfluoropolyether fluid additives (I) - Action mechanism of additive and property of donating-accepting electron

The combination energy and chemical adsorption energy of N-substituted perf luoropolyalkyletherphenylamide (PFPEA) additive to perfluoropolyalkylether oxygen radical (RfO.) and to Fe atom have been calculated by quantum chemic al methods. Structural characteristics, action mechanism, property of donat ing-accepting electron and substituent effect for antioxidant and anticorro sive additive are investigated. It is found that HOMO of the additives. is a pi -molecular orbital with lone pair electron of heteroatom. The HOMO of PFPEA additive reacts with LUMO of Fe atom to result in chemical adsorption . The LUMO of additive can interact with the SOMO of RfO. and accept electr on of RfO. to form stable addition product. The additives have the property of donating-accepting electron. The electron-releasing group, particularly , the phenyl group, introduced to N atom of phenylamide can increase the co mbination energy and chemical adsorption energy, and enhance the antioxidan t and anticorrosive efficiency. The research achievements can provide usefu l information for the designing of new antioxidant and anticorrosive additi ve. Based on the calculated results, antioxidant and anticorrosive efficien cy can be predicted roughly as the following order: compounds III>II>I>IV>V .