Alkyl hydroxyanisoles as antioxidants

Abstract

Summary The antioxidant potency of a substituted hydroxyanisole greatly depends on the orientation of the substituents which make up the molecule. This fact is demonstrated by the synthesis and evaluation of a number of alkyl substituted hydroxyanisoles as to antioxidant effectiveness in the stabilization of lard. In the case of the derivatives of 4‐hydroxyanisole, maximum potency is realized by placement of a t‐butyl group in the number 3 position relative to the methoxy group. The substitution of other groups such as one or two methyl groups, a butyl group of normal, iso, or secondary configuration, or a t‐butyl group in the number 2 position leads to an antioxidant of lower potency. The potencies of the three t‐butylhydroxyphenetoles are comparable to those of the corresponding t‐butylhydroxyanisoles. The effectiveness of butylated 2‐ and 3‐hydroxyanisoles are all low; it is essential that the hydroxy group be in the 4‐position relative to the methoxy group. The stability of baked goods (soda crackers) is greater with lard inhibited with 3‐t‐butyl‐4‐hydroxyanisole than with 2‐t‐butyl‐4‐hydroxyanisole.