PURPOSE: To advantageously obtain chlorinated naphthoquinones by chlorinating the subject compounds with a hydrochloric acid solution at a specific concentration and hydrogen peroxide solution using a metal and metal chloride as a catalyst, simultaneously filtering crystals of the product and circulating the resultant filtrate for use.
CONSTITUTION: A solution of hydrogen peroxide at 5-60% concentration is fed to an aqueous solution containing 1,4-naphthoquinones and a 5-38% hydrochloric acid solution or a solution containing the 5-38% hydrochloric acid solution and a solvent to produce chlorinated naphthoquinones. Crystals thereof are simultaneously filtered and taken out to provide a filtrate (the solvent or hydrochloric acid solution), which is then circulated for use to economically afford the chlorinated naphthoquinones useful as an intermediate for agricultural chemicals, medicines and dyes in high yield without causing pollution.
KITAHARA SATORU
MINEMURA MUNEHARU
AKIYAMA UKICHI
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