Preparation of Hydroquinone Dimethyl Ether from p-Anisidine.

Decomposition of Diazonium Compounds with UV light.

Abstract

The synthetic method of hydroquinone dimethyl ether (I) was studied. This method comprises two operations, diazotization of p-anisidine and decomposition of the diazonium salt in methanol.
Experiments were carried out in order to study the effects of kinds of acids, catalysts, illumination with UV light, concentration of acid and reaction temperature on diazotizing and decomposition of the diazonium compound in methanol.
Sulfuric acid was preferred for the diazotization and the decomposition.
No catalysts were effective in our experiments.
Under illumination with UV light, decomposition time of the diazonium compound was shortened and the formation of byproducts was decreased and the yield of (I) was increased.
The concentration of sulfuric acid in the reaction mixture was suitable in the range of 0.5 to 5%.
The temperature suitable for decomposition of the diazonium compound was 40°C.