abstract |
(57) Abstract: An N- (3,3-dimethylbutyl) -APM crystal having excellent stability is obtained stably at low cost. SOLUTION: N- (3,3-dimethylbutyl) -AP When crystallizing M crystals, water or a mixture of water and a lower alcohol is used as a crystallization solvent, and the crystallization point in crystallization is controlled to 30 ° C. or higher. |