METHOD FOR MANUFACTURING HETEROPOLYTUNGSTIC ACID

摘要

PROBLEM TO BE SOLVED: To provide a method to industrially manufacture heterotungstic acid with high purity having a stable Keggin structure which is optimum for a cata lyst for organic synthesis or a catalyst source material and having desired water of crystallization. SOLUTION: In the method, tungsten trioxide is dissolved in an alkali hydroxide aqueous solution in an amount less than the stoichiometric amount to the tungsten trioxide in the presence of phosphoric acid or silicic acid or water-soluble alkali salts of these. The obtained solution is subjected to cation exchange and condensed by heating to crystallize heteropolytungstic acid.