S,S-ETHYLENEDIAMINE-N,N'-DISUCCINIC ACID ANHYDRIDE CRYSTAL AND METHOD FOR PRODUCING THE SAME

摘要

PROBLEM TO BE SOLVED: To obtain S,S-ethylenediamine-N,N'-disuccinic acid (SS-EDDS) anhydride crystal containing little amount of cyclized compounds and provide a method for producing the same. SOLUTION: This SS-EDDS anhydride crystal contains <=1 mass% cyclized compound of SS-EDDS and <=10 mass% water. This method for producing SS-EDDS anhydride crystal has a heating process for heating wet crystal of SS-EDDS containing >=11 mass% water at 50-120 deg.C and hold the wet crystal in >=70% humidity for at least 10 minutes in the heating process.