Synthesis of polyaspartic acid in solution under microwave irradiation

The microwave power was researched as a new heating way in the synthesis of polyaspartic acid from maleic anhydride and ammonia in solution. The optimal reaction condition was given, i.e. ammonia: maleic anhydride = 1.2:1, 2450 MHz microwave output power 900 W, irradiation 3 min. The results of calcium carbonate inhibition tests showed that the product is also a good scale-inhibitor as the product of traditional process, e.g. inhibition ratio is approximately 100% while [Ca²⁺] = 300 mg/L. It indicated that this method has some advantages such as faster reaction rate, high yield, energy saving and reduction of pollution.