Patent · US Expired

Method for the production of a solvent-free &agr;-liponic acid

US6462202B1 · kind B1 · utility

5Cited by

0References

22Claims

0Family size

Assignee

Degussa AG · DE

Inventors

Hans Schuhbauer · Trostberg, DE
Stefan Winkler · Madison, US
Ansgar Gruber · Trostberg, DE

Key dates

Filing date	Oct 25, 2001
Grant date	Oct 8, 2002
Priority date	—
Expiry date	Oct 25, 2021

Classification

Technology area (CPC C)Chemistry; Metallurgy
CPC primaryC07D339/04
WIPO fieldOrganic fine chemistry
WIPO sectorChemistry

Abstract

Solvent-free &agr;-lipoic acid is produced by dissolvinga) the &agr;-lipoic acid to be purified in aqueous alkaline solution, or dissolving the salt thereof in water and adjusting an alkaline pH,b) removing solid impurities present where appropriate from the aqueous solution from stage a),c) adjusting the aqueous solution from stage a) or b) to a pH of from 1.0 to 5.0 with the aid of an acid andd) isolating the precipitated &agr;-lipoic acid by known methods.This results in a solvent-free &agr;-lipoic acid with improved chemical purity.

Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.