The present invention relates to:
a method for producing &agr;-hydroxycarboxylic acid, which comprises hydrolyzing cyanohydrin in the presence of a hydrocarbon solvent;
a method for producing optically active &agr;-hydroxycarboxylic acid, which comprises: producing optically active cyanohydrin by performing a reaction between a carbonyl compound and hydrogen cyanide, using a solvent comprising at least one organic solvent selected from a group consisting of an alcoholic solvent, an ester solvent, an ethereal solvent and a carboxylic solvent; removing said organic solvent from said reaction solvent; and hydrolyzing the remaining reaction mixture without isolating optically active cyanohydrin;
a method for producing optically active &agr;-hydroxycarboxylic acid, which comprises hydrolyzing optically active cyanohydrin, using at most 10 equivalents of mineral acid relative to said optically active cyanohydrin under the condition that maximum temperature when reacting is 90° C. or less; and
a method for producing optically active crystalline &agr;-hydroxycarboxylic acid, which comprises crystallizing optically active &agr;-hydroxycarboxylic acid in an aqueous solution.
本发明涉及以下内容:
一种制备α-羟基
羧酸的方法,包括在烃溶剂存在下
水解腈醇;
一种制备光学活性α-羟基
羧酸的方法,包括:使用至少一种有机溶剂所组成的溶剂,所述有机溶剂选自
醇类溶剂、
酯类溶剂、
醚类溶剂和
羧酸类溶剂,通过在碳酰化合物和
氢氰酸之间进行反应来制备光学活性腈醇;从反应溶剂中去除有机溶剂;在不分离光学活性腈醇的情况下
水解剩余反应混合物;
一种制备光学活性α-羟基
羧酸的方法,包括在最多使用10当量矿酸相对于所述光学活性腈醇的情况下
水解,反应时的最高温度为90°C或更低;
一种制备光学活性结晶α-羟基
羧酸的方法,包括在
水溶液中结晶光学活性α-羟基
羧酸。