KF/Al2O3催化剂上苯脲醇解合成苯氨基甲酸甲酯的研究

采用浸渍法制备负载KF固体碱催化剂，应用于苯脲和甲醇制备苯氨基甲酸甲酯的反应，考察了氧化物载体、卤化钾种类对催化剂性能的影响，KF/Al₂O₃催化剂显示出良好的催化活性和苯氨基甲酸甲酯的选择性。通过对KF/Al₂O₃催化剂中KF的负载量和催化剂焙烧温度的研究发现，在500 ℃焙烧4 h、负载质量分数50%KF的催化剂能够更好地促进MPC生成，苯脲转化率和苯氨基甲酸甲酯选择性分别达到96.5%和86.3%。XRD分析表明，KF与Al₂O₃之间存在较强的相互作用，部分转化为K₃AlF₆。KF与K₃AlF₆分别对甲醇的活化和苯脲的选择性起促进作用，两者的协同效应共同促进了目标产物苯氨基甲酸甲酯的生成。

Synthesis of methyl N-phenyl carbamate from phenyl urea and methanol over the KF/Al2O3 catalyst

The solid alkaline catalysts of supported potassium halides were prepared by impregnation method and used in the methanolysis of phenyl urea with methanol to synthesize methyl N-phenyl carbamate (MPC); the influence of oxide supports and potassium halides on the catalyst performance was investigated. The results indicated that KF/Al₂O₃ exhibits high catalytic activity and selectivity to MPC; the KF/Al₂O₃ catalyst containing 50% KF and calcined at 500 ℃ for 4 h performs best in the methanolysis of phenyl urea, over which the conversion of phenyl urea and selectivity to MPC reach 96.5% and 86.3%, respectively. The XRD results proved that KF and Al₂O₃ are partially transformed to K₃AlF₆ due to the strong interaction between KF and Al₂O₃. Both KF and K₃AlF₆ are active for the activation of methanol and selective conversion of phenyl urea; the excellent performance of KF/Al₂O₃ catalyst in the methanolysis of phenyl urea to MPC can be ascribed to the synergy of KF and K₃AlF₆.