Purification of sulfuric acid containing acetic acid

US4045295A · kind A · utility

Assignee

• Hoechst GmbH · DE

Inventors

• Stefan Schafer · Aachen, DE
• Alexander Ohorodnik · Lechenich, DE
• Klaus Gehrmann · Lechenich, DE
• Albert Mainski · Cologne, DE

Key dates

• Filing date: Jun 10, 1976
• Grant date: Aug 30, 1977
• Expiry date: Jun 10, 1996

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C07C51/44
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

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.