Process for the preparation of aqueous solutions of methylglycine-N,N-diacetic acid trialkali metal salts

US8802894B2 · kind B2 · utility

Assignee

• BASF SE

Inventors

• Alfred Oftring · Bad Dürkheim, DE
• Gerold Braun · Ludwigshafen, DE
• Arnulf Lauterbach · Ludwigshafen, DE

Key dates

• Filing date: Mar 27, 2012
• Grant date: Aug 12, 2014
• Expiry date: Oct 27, 2032

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C07C227/26
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

Abstract

A process for preparing an aqueous solution of a methylglycine-N,N-diacetic acid trialkali metal salt at a high yield and purity by Strecker synthesis, the process including: reacting an aqueous solution containing α-alanine with formaldehyde and hydrocyanic acid, to obtain α-alanine-N,N-diacetonitrile in one reaction unit; and saponification of the α-alanine-N,N-diacetonitrile with a base, to obtain the methylglycine-N,N-diacetic acid trialkali metal salt, wherein the α-alanine is partially neutralized and the addition of formaldehyde and hydrocyanic acid are controlled such that a concentration of free hydrocyanic acid in the liquid reaction mixture at any time is limited such that secondary reactions that produce formaldehyde cyanohydrin, consecutive reactions of formaldehyde cyanohydrin, and the polymerization of hydrocyanic acid, only occur insofar as the specification requirements, such as nitrilotriacetic acid content and color, for methylglycine-N,N-diacetic acid trialkali metal salts are observed.