A spectroscopic study of the chemical structure of the alkylphenols formed on alkylation of phenol with 1-hexene

Abstract

1. The chemical structure of the alkylphenol formed on alkylation of phenol with 1-hexene in the presence of benzenesulfonic acid has been studied by infrared and ultraviolet spectroscopic methods. The reaction leads to formation of alkylphenols of the following structure: di-ortho-, ortho-para-, ortho-, and para-. The spectroscopic method of analysis which was worked out can be used successfully together with chromatographic methods for control of the technological process and for directed synthesis of alkylphenols of definite structure. 2. The formation of di-ortho-alkylphenolic structures under acid catalysis of the alkylation of phenols with higher mono-olefins takes place also with olefins of normal structure. 3. It has been shown that under the alkylation conditions adopted in production of alky1 salicylate additives to motor oil (ASK or MASK), the phenol reacts withα-olefins of normal structure to form about 15% of di-orthoalkylphenols. Since the structure of the alkylphenols directly affects the additive synthesis process and the physicochemical and operational properties of the additives, it is necessary to strive for a minimum of di-ortho-alkylphenol structures by varying reaction conditions and by concentrating the alkylphenols which have high reactivity in subsequent stages of ASK or MASK synthesis.