Theoretical Evaluation on the Performance of TBHQ and BHA in Inhibiting the Autoxidation of Linoleic Acid-Rich Vegetable Oils

摘要

The aim of this paper is to disclose the major physical parameters responsible in determining the effectiveness of TBHQ (1) andBHA (2) as a hydroperoxyl C9-OO methyl linoleate radical (3) scavenger. In this study, Gaussian 09 software package at thetheoretical level of DFT B3LYP/6-31G (d,p) were used to evaluate the physical parameters of antioxidants and the complexesformed with hydroperoxyl methyl linoleate radical of C9-OO such as SCF energy, hydrogen bonding strength, and the O-Hbond order of antioxidants. Results of the geometry optimization combined with Natural Bond Orbital analyses of antioxidantsand their complexes revealed that even though the hydrogen bonding with BHA is stronger than with TBHQ (EBHA= 31.9043kJ/mol; ETBHQ= 31.6793 kJ/mol), but the O-H sigma bond order of TBHQ is about the same as of BHA (TBHQ= 0.6731;BHA= 0.6736). These findings are in agreement with previously reported experimental results where TBHQ performs betterthan or equally as good as BHA.