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:
Dec. 29, 1981
Filed:
Jul. 02, 1980
Bayer Aktiengesellschaft, Leverkusen, DE;
Abstract
A process is described for the isolation of pyrocatechol and hydroquinone from mixtures containing the same, and phenol and higher boiling accompanying substances. The mixture can be one obtained by reacting phenol with a peroxidic hydroxylating agent and removing some of the phenol and the substances which have a lower boiling point than phenol. The mixture is subjected to a first rectification in which phenol and substances which have a boiling point between phenol and pyrocatechol are obtained overhead to leave behind a bottom product containing pyrocatechol and hydroquinone. The bottom product is subjected to a second rectification in which the pyrocatechol is obtained overhead to leave behind a bottom product containing hydroquinone and higher boiling accompanying substances. This bottom product is fed to a concentrating unit in which hydroquinone is evaporated overhead to leave behind high boiling accompanying substances as residue.