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:
Sep. 22, 1992
Filed:
Jun. 28, 1991
Otto Arndt, Hofheim am Taunus, DE;
Theodor Papenfuhs, Frankfurt am Main, DE;
Hoechst Aktiengesellschaft, Frankfurt am Main, DE;
Abstract
A process for the production of high-purity tetrachloro-1,4-benzoquinone by the action of chlorine and hydrochloric acid on hydroquinone which comprises causing 1.9 to 2.1 times the molar quantity of gaseous chlorine to act at temperatures from 5.degree. to 15.degree. C. on 1 mol of hydroquinone in 6 to 7 times the molar quantity of 30 to 37% hydrochloric acid, then diluting the resulting suspension, essentially containing 2,5-dichlorohydroquinone, with 2 to 3 parts of water, relative to hydroquinone employed, and initially warming to a temperature from 20.degree. to 30.degree. C., subsequently introducing 1.9 to 2.1 times the molar quantity of chlorine gas in an air atmosphere while raising the temperature to 90.degree.-100.degree. C. with simultaneous dilution with 3.5 to 4.5 parts of water, relative to hydroquinone employed, and finally introducing 1 to 2 times the molar quantity of gaseous chlorine, relative to hydroquinone employed, at temperatures from 100.degree. to 115.degree. C.