Figure 3

Effect of the DMC/HDA molar ratio on HDA conversion, yield of dicarbamate and selectivity for reaction products. Reaction conditions: HDA, 200 mmol; ZnAlPO4, 1.0 g; timeframe, 8 h; temperature, 353 K. (Legend: (□) HDA conversion; (○) yield of dicarbamate; (■), (●) and (▲) denote selectivity for dicarbamate, monocarbamate and N-methylated-carbamate, respectively.)