PURPOSE: To prepare the titled compound useful as an intermediate of vitamin E, in one stel and high yield, by oxidizing trimethylphenol with a mixture of nitric acid and hydrochloric acid.
CONSTITUTION: 2,3,5- Or 2,3,6-trimethylphenol is oxidized with a mixture of nitric acid and hydrochloric acid. The oxidation is pref. carried out at 25W35°C under stirring, adding the mixed acid dropwise to the reaction system. The composition of the mixture is pref. 20% of nitric acid, 20% of hydrochloric acid, and 60% of water. The end point of the oxidation reaction can be determined by the termination of the generation of Nox. The generated NOx is oxidized by mixing with air, absorbed in water, and recovered as nitric acid. After the reaction, the reaction system is separated into a water layer and an oil layer. The oil layer is neutralized and subjected to steam distillation to obtain the objective quinone. The water layer is an aqueous solution of hydrochloric acid containing little nitric acid, and can be recycled and reused.
KUNIHIRO HIROYUKI
KASAMATSU HARUO
