Catalytic degradation of polyurea: synthesis of N-substituted carbamates with CuO–ZnO as the catalyst
A composite oxide CuO–ZnO catalyst was prepared and tested in the degradation of various polyureas using urea as the carbonyl source for the first time in this field. Under the optimized reaction conditions, a 96% diethyl hexamethylenedicarbamate (EHDC) yield was obtained with polyurea-hexamethylenediamine (PU-HDA) over the CuO–ZnO catalyst. The characterization results of the structural and component properties of the prepared catalyst indicated that the Zn-rich polycrystalline oxide with good dispersion exhibited enhanced catalytic activity in this reaction system. Moreover, the catalytic mechanism of the CuO–ZnO catalyst in polyurea degradation was proposed and investigated preliminarily.