Method for producing alpha - hydroxycarboxylate

An α-hydroxycarboxylic acid condensate selected from (I) to (III) below:

• (I) an α-hydroxycarboxylic acid condensate having an α-hydroxycarboxylic acid condensate portion represented by General Formula 2:
• wherein R is hydrogen or C1-5 alkyl, and the alkyl may be substituted and
• a 1,2-diol chain represented by General Formula 3:
• wherein R is hydrogen or C1-5 alkyl, and the alkyl may be substituted,
• both terminals being represented by General Formula 4:
• wherein R is hydrogen or C1-5 alkyl, and the alkyl may be substituted, or
• General Formula 5:
• wherein each R is hydrogen or C1-5 alkyl, and the alkyl may be substituted;
• (II) an α-hydroxycarboxylic acid condensate represented by General Formula 6:
• wherein each R is hydrogen or C1-5 alkyl, the alkyl may be substituted, and n is within the range of 1 to 200;
• and
• (III) an α-hydroxycarboxylic acid condensate represented by General Formula 7:
• wherein each R is hydrogen or C1-5 alkyl, the alkyl may be substituted, both n1 and n2 are 1 or more, and n1+n2 is within the range of 2 to 200.

An α-hydroxycarboxylic acid condensate obtained by condensing, through a 1,2-diol eliminating reaction of an α-hydroxycarboxylic hydroxyalkyl ester prepared according to a process for producing an α-hydroxycarboxylic acid ester comprising reacting, in the presence of a catalyst, 1,2-diols represented by General Formula 1:

• wherein R is hydrogen or C1-5 alkyl, and the alkyl may be substituted,
• the α-hydroxycarboxylic acid condensate being selected from (I) to (III) below:
• (I) an α-hydroxycarboxylic acid condensate having an α-hydroxycarboxylic acid condensate portion represented by General Formula 2:
• wherein R is hydrogen or C1-5 alkyl, and the alkyl may be substituted and
• a 1,2-diol chain represented by General Formula 3:
• wherein R is hydrogen or C1-5 alkyl, and the alkyl may be substituted,
• both terminals being represented by General Formula 4:
• wherein R is hydrogen or C1-5 alkyl, and the alkyl may be substituted, or
• General Formula 5:
• wherein each R is hydrogen or C1-5 alkyl, and the alkyl may be substituted;
• (II) an α-hydroxycarboxylic acid condensate represented by General Formula 6:
• wherein each R is hydrogen or C1-5 alkyl, the alkyl may be substituted, and n is within the range of 1 to 200;
• and
• (III) an α-hydroxycarboxylic acid condensate represented by General Formula 7:
• wherein each R is hydrogen or C1-5 alkyl, the alkyl may be substituted, both n1 and n2 are 1 or more, and n1+n2 is within the range of 2 to 200.