Abstract
The alkylation of phenol by C1-C3 alcohols as alkylating reagents was examined on alumina and alumina containing catalysts. Alumina showed a significant activity to meta position, especially in methylation and ethylation. For instance, the composition of meta isomer was 38% in cresols formed at 450°. Alumina-silica (1: 1) yielded 48% meta isomer. The latter catalyst was an acidic one, and the formation of meta isomerin parallel with its acid strength.
To elucidate the mechanism of alkylation to meta position, the rearrangement of-phenylethers and the isomerization of ortho alkylphenols were investigated in the presence of phenol-14C. The 14C-distribution in the product was then determined by the radio-gaschromatography and the ratio of intramolecular to intermolecular rearrangement was evaluated. The adsorbed state of phenol and alcohols at the reaction temperature was investigated with the infrared method, and the mechanism of alkylation was discus-sed therefrom.
