METHOD FOR PRODUCING 2-CYANOPIPERAZINE ACID ADDITION SALT

摘要

PROBLEM TO BE SOLVED: To provide a method for obtaining a 2-cyanopiperazine acid addition salt of higher cohesive force and larger particle size than those afforded by conventional methods through acid deposition of 2-cyanopiperazine. SOLUTION: This method for depositing the objective 2-cyanopiperazine acid addition salt comprises adding an acid to an aqueous solution of 2- cyanopiperazine with >=pH 7; wherein in lowering the hydrogen ion concentration of the aqueous solution from pH 7 to pH 1, the acid is added thereto taking 2 h or longer.