Study of the condensation products of the alkylphenols with hexamethylene tetramine

Abstract

It is shown that in the reaction of 4-methyl-2-tert-butyl-phenol, o-cresol and o-tert-butyl-phenol with hexamethylene tetramine the primary reaction products formed are 3,4-dihydro-N-(hydroxybenzyl)-1,3,2-H-benzoxazines. For an excess of hexamethylamine tetramine, temperature 403–448 K and a duration of the experiments 0·25–5·0 hr. the benzoxazines are the main end reaction products. For an excess of 4-methyl-2-tert-butylphenol together with the benzoxazines appreciable amounts of tri-(2-hydroxy-3-tert-butyl-5-methylbenzyl)amine and di-(2-hydroxy-3-tert-butyl-5-methylphenyl)methane are isolated. The substance 2-hydroxy-3-tert-butyl-5-methylbenzylamine is found in small amounts. The substances isolated have constants identical with those for the products obtained by counter synthesis. The mechanism of the reaction is explained by the breakdown of the phenol complex with hexamethylene tetramine to triple and single charge ions. The latter form a further triple-charged ion with elimination of two ammonia molecules. The triphenyl ethers of trimethylolamine obtained are regrouped into the benzoxazines.