Nof Corporation

Tsunekatsu Maruyama

Tohru Yasukohchi

Kei-ichi Maruyama

A process for producing a polyoxyalkylenecarboxylic acid which comprises: (A) a step of obtaining a salt of a polyoxyalkylenecarboxylic acid by reacting a polyoxyalkylene compound having hydroxyl group at one or both ends of the molecule with a salt of a halogenated acetic acid or a salt of a halogenated propionic acid in an amount of 4 to 50 mol per 1 mol of the polyoxyalkylene compound and an alkali metal hydroxide in an amount of 8 to 70 mol per 1 mol of the polyoxyalkylene compound in the presence of an organic solvent at 80.degree. to 150.degree. C.; (B) a step of converting the obtained salt of a polyoxyalkylenecarboxylic acid into the polyoxyalkylenecarboxylic acid by adjusting pH of the reaction mixture obtained in step (A) to 3 or less by adding an inorganic acid; (C) a step of removing byproducts and the like by washing the obtained solution containing the polyoxyalkylenecarboxylic acid with an aqueous solution of an inorganic salt; and (D) a step of removing the organic solvent and water at a decreased pressure at 50.degree. to 120.degree. C. and removing precipitated salts by filtration. A high purity, high molecular weight polyoxyalkylenecarboxylic acid which contains only small amounts of unreacted starting materials or byproducts can easily be obtained.

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Tokyo, Japan

Tsunekatsu Maruyama