摘要 |
Solvent-free alpha-lipoic acid is produced by dissolvinga) the alpha-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 alpha-lipoic acid by known methods.This results in a solvent-free alpha-lipoic acid with improved chemical purity.
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