固体碱催化环己酮和碳酸二甲酯合成庚二酸二甲酯

以固体碱为催化剂,研究了环己酮与碳酸二甲酯(DMC)合成庚二酸二甲酯的反应性能,考察了反应温度、反应时间、催化剂用量和原料配比对合成反应的影响。实验结果表明,偏酸性的固体碱催化剂不利于庚二酸二甲酯的生成,而具有中强碱位的MgO对该合成反应具有较好的催化性能;得到了较适宜的工艺条件:MgO为催化剂,反应温度260℃,反应时间5h,催化剂用量为反应物质量的1.5%,n(环己酮)∶n(DMC)=1∶4,在此条件下,环己酮的转化率为83.6%,庚二酸二甲酯的选择性为51.8%;该反应的主要副产物为环己酮自身缩合产物(2-环己烯基环己酮)和环己酮甲基化产物(2-甲基环己酮和2,6-二甲基环己酮)等。

Synthesis of Dimethyl Pimelate from Cyclohexanone and Dimethyl Carbonateover Solid Base Catalysts

Synthesis of dimethyl pimelate (DMP) from cyclohexanone and dimethyl carbonate(DMC) was investigated over solid acid and solid base catalysts. Effects of reaction temperature, catalyst dosage, reaction time and mole ratios of cyclohexanone to DMC on the synthesis were studied. Only aldol condensation of cyclohexanone was observed over Al2O3 solid acid catalyst. Among solid base catalysts tested, namely ZrO2, La2O3, MgO and CaO, MgO with moderate basic strength shows highest catalytic activity and selectivity to DMP in the synthesis. Under optimal reaction conditions: temperature 260 ℃, time 5 h, catalyst mass fraction in reactants 1.5% and n(cyclohexanone) ∶n(DMC) 1 ∶4, conversion of cyclohexanone and selectivity to DMP are 83.6% and 51.8%, respectively. The main by-products synthesized include methylation products (2-methyl cyclohexanone and 2,6-dimethyl cyclohexanone), self-condensation product of cyclohexanone (2-(1-cyclohexenyl)- cyclohexanone) and etherification product (1-methoxy-cyclohexene).