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:
Aug. 30, 1977
Filed:
Jun. 10, 1976
Stefan Schafer, Bruhl, DT;
Alexander Ohorodnik, Erftstadt-Liblar, DT;
Klaus Gehrmann, Erftstadt-Lechenich, DT;
Albert Mainski, Rodenkirchen, DT;
Hoechst Aktiengesellschaft, Frankfurt am Main, DT;
Abstract
Dilute sulfuric acid contaminated with acetic acid and hydrogen chloride is purified with the resultant formation of concentrated sulfuric acid and acetic acid. To this end, the contaminated sulfuric acid is heated in a first step to at most 60.degree. C under 25-30 mm Hg so as to expel all of the hydrogen chloride together with minor proportions of acetic acid and water. In a second step, the sulfuric acid is heated to at most 165.degree. C under 20-25 mm Hg so as to distil off the bulk of acetic acid together with water. In a third step, the sulfuric acid is cooled down to 60.degree.-90.degree. C, diluted with 10-30 wieght % of water with agitation and while cooling is continued. Following this, the sulfuric acid is heated to 160.degree.-165.degree. C under 20-25 mm Hg and thereby freed from the water and residual acetic acid.