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. 29, 1992
Filed:
Jun. 27, 1991
Otto Arndt, Hofheim am Taunus, DE;
Theodor Papenfuhs, Frankfurt am Main, DE;
Hoechst Aktiengesellschaft, Frankfurt am Main, DE;
Abstract
A process for the preparation of high-purity tetrachloro-1,4-benzoquinone by the action of hydrogen peroxide and hydrochloric acid on hydroquinone, which comprises causing 3.8 top 4.2 times the molar quantity of 30 to 37% hydrochloric acid and 1.9 to 2.1 times the molar quantity of 50 to 35% hydrogen peroxide, to act at 5 to 50.degree. C. on 1 mole of hydroquinone in at least 12 times the molar quantity of 30 to 37% hydrochloric acid, then heating the resulting suspension, which essentially contains 2,5-dichlorohydroquinone, to 45 to 55.degree. C. and again causing to act on it, at 50 to 95.degree. C., 3.8 to 4.2 times the molar quantity of 30 to 37% hydrochloric acid and 1.9 to 2.1 times the molar quantity of 50 to 35% hydrogen peroxide, in each case based on the hydroquinone used, and finally adding to the suspension, which is now essentially composed of trichloro-1,4-benzoquinone, 1.9 to 2.1 times the molar quantity of hydrochloric acid of the said concentration range, and 0.95 to 1.05 times the molar quantity of hydrogen peroxide of the said concentration range, in each case based on the hydroquinone used, at 95 to 115.degree. C., sufficiently slowly for no chlorine to escape.