Antioxidant properties of butylatedhydroxytoluene refluxed in ferric chloride solution

1,2-Bis (3,5-di-tert-butyl-4-hydroxyphenyl)-ethane (BBH PE), 3,3',5,5'-tetra-tert-butyl-stilbene-4,4'-quinone (TBSQ), 3,3',5,5'-tetra-tert-butylhydroxy-stilbene-4,4'-quinone (TBHSQ) and 4-hydroxy-3,5-tert-butylbenzaldehyde (HBBA) were isolated from a mixture of butylatedhydroxytoluene (BHT) refluxed in ferric chloride solution by using TLC and identified by mass, NMR, IR and UV spectra. Their antioxidant properties were investigated individually and in comparison with BHT and butylatedhydroxyanisole (BHA) on the Oxidative Stability Instrument (OSI) at 95, 100 and 105 degrees C, separately. This demonstrated that BBHPE was the strongest antioxidant of the compounds isolated, much stronger even than BHT and as strong as BHA. The phenolic compound, HBBA, structurally similar to BHT, had much weaker antioxidant effect than BHT and even weaker than the quinones, TBSQ and TBHSQ. The strength of the antioxidant activity of the compounds decreased in the order: BHA, BBHPE > > BHT > TBSQ, TBHSQ > HBBA. As temperature increased, the protection factors (Pf) of BHA and BHT increased, but those of BBHPE, TBSQ, TBHSQ and HBBA decreased slightly. (C) 1998 Elsevier Science Ltd. All rights reserved.