The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 11, 1996
Filed:
Oct. 21, 1994
Otto Arndt, Hofheim, DE;
Hans Schubert, Kelkheim, DE;
Hoechst Aktiengesellschaft, , DE;
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%.