Process for preparing a particularly pure glycolic acid

US5723662A · kind A · utility

Assignee

• Hoechst GmbH · DE

Inventors

• Frank Ebmeyer · Hattersheim, DE
• Harald Haberlein · Gersthofen, DE
• by Hans Harald Haberlein, heir · Neu-Ulm, DE
• by Jorg Thomas Haberlein, heir · Allersberg, DE
• by Mark Christian Haberlein, heir · Glückstadt, DE
• Holger Mohn · Gelnhausen, DE

Key dates

• Filing date: Jan 9, 1997
• Grant date: Mar 3, 1998
• Expiry date: Jan 9, 2017

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C07C51/42
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

Abstract

The present invention relates to a process for preparing a particularly pure glycolic acid by saponification with chloroacetic acid with an excess of alkali metal hydroxide, with the resulting alkali metal chloride being filtered off, and the 20 to 70% strength by weight glycolic acid solution being subsequently subjected to an electrodialysis at 20.degree. to 40.degree. C. and a cell voltage of 0.5 to 2.5 V per cell pair. The process of the invention permits optimum removal of sodium chloride and chloroacetic acid as necessary for preparing a particularly pure glycolic acid. Other organic acids, nitrogen compounds, aldehydes and salts are not produced in this process and thus do not affect the product quality.