The following sinthetic compounds: 2,6-di-tert-butylphenol (1), 2,4-di-tert-butylphenol
(2), N,N-dimethyl-3,5-di-tert-butyl-4-hydroxybenzylamine (3); 3,5-di-tert-butyl-4-
hydroxybenzyl hydrazine (4); 1-(3’,5’-di-tert-butyl-4’-hydroxybenzyl)-3,5-dimethylpyrazole (5);
1-(3’,5’-di-tert-butyl-4’-hydroxybenzyl)-3-methylpyrazol-5-one (6) and 1-(3’,5’-di-tertbutyl-4’-
hydroxybenzyl)-3,5-diphenylpyrazole (7) were studied for their total antioxidant capacity (TAC).
All compounds are sterically hindered phenols. Of these the first two are commercially available
and (3) - (7) were syhthesized in laboratory [1]. TAC of the compounds dissolved in ethanol :
EDTA 2x10-4M=80% (v/v) solution was studied by means of an „in batch” chemiluminometric
method based on luminol-Co(II)/EDTA-H2O2 system [2]. Calibration curves for trolox (5x10-6
and 10-3M) and gallic acid (10-5 and 2x10-3M) were drawn and results were expressed as %
Trolox equivalents (TE) and % gallic acid equivalents (GAE). Of the seven compounds
analyzed, (5) has the highest antioxidant capacity (% TE = 27.3 ± 2.4 and % GAE = 63.7 ± 5.5)
followed by (2) (% TE = 2.31 ± 0.13 and % GAE = 6.10 ± 0.030) and the other compounds with
smaller values (< 0.5 % TE and <1.7% GAE) of TAC.
References:
1. V. Dinoiu, J. Herdan, A. Meghea, M.D. Gheorghiu, A.T. Balaban, Rev. Roum. Chim., 39, 1994,
949.
2. C.V. Popa, I.C. Farcasanu, S. Jipa, T. Zaharescu, A.F. Danet, Rev Chim. 63, 2012, 715.