Synthesis of 1,3,5-Tris(phenylamino) Benzene Derivatives and Experimental and Theoretical Investigations of Their Antioxidation Mechanism

1,3,5-Tris(phenylamino) benzene and a series of its substitution derivatives were synthesized. The structure of the as-synthesized products was confirmed by nuclear magnetic resonance spectroscopy and high resolution mass spectra. Moreover, the antioxidation behavior of 1,3,5-tris(phenylamino) benzene and its substitution derivatives as antioxidants in several ester oils was evaluated by a rotary oxygen bomb test and pressurized differential scanning calorimetry, while theoretical calculations were conducted to examine their antioxidation mechanism. It was found that 1,3,5-tris(phenylamino) benzene exhibits better antioxidation ability at elevated temperature (150 and 210 degrees C) than commonly used commercial antioxidant diphenylamine. In the meantime, the substitution groups exhibit significant effects on the antioxidation behavior of 1,3,5-tris(phenylamino) benzene and its derivatives. This is because the substituents result in changes in the molecular structure and electronic effect of the as synthesized products, thereby causing s change in their antioxidation behavior.