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 [Ca~(2+)]=300 mg/L.It indicated that this method has some advantages such as faster reaction rate,high yield,energy saving and reduction of pollution.