Process for the preparation of tetrachloro-1,4-benzoquinone

US5525744A · kind A · utility

Assignee

• Hoechst GmbH · DE

Inventors

• Otto Arndt · Hofheim, DE
• Hans H. Schubert · Tokyo, JP

Key dates

• Filing date: Oct 21, 1994
• Grant date: Jun 11, 1996
• Expiry date: Oct 21, 2014

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C10M2211/06
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

Abstract

A process for the preparation of tetrachloro-1,4-benzoquinone of high purity by the action of chlorine and concentrated hydrochloric acid on hydroquinone, by introducing a part of the hydroquinone to be employed into an initially introduced 4- to 6-fold molar amount--based on the total amount of hydroquinone--of 20 to 37 % aqueous hydrochloric acid containing catalytic amounts of iron(III) ions and an anionic dispersant, introducing 1.5 to 2.0 times the molar amount--based on total hydroquinone--of chlorine as a gas into this solution at a temperature of 20.degree. to 90.degree. C., then adding the residual amount of hydroquinone as a solid or in dissolved form, introducing 1.5 to 2.0 times the molar amount of chlorine as a gas, keeping the concentration of the hydrochloric acid here at 23-25% by addition of water and finally raising the temperature to 100.degree. to 107.degree. C. with further introduction of chlorine as a gas (1.7 to 2.5 times the molar amount) and dilution with water to a hydrochloric acid concentration of 20 to 22%.