溴代甲基咪唑修饰的蜜勒胺低聚物催化CO2环加成反应性能

Preparation of Bromomethylimidazole/Melamine Oligomer Composite Catalyst and Its Catalytic Performance for CO2 Cycloaddition Reaction

摘要:

采用二步法合成了溴代甲基咪唑 修饰的蜜勒胺低聚物催化剂(CN-MIm)，利用FTIR、XRD、SEM、TG和XPS等手段对其结构、形貌和热稳定性等进行了表征。结果表明，咪唑基离子液体成功负载在蜜勒胺低聚物上，且具有较好的热稳定性。考察了反应工艺条件对环氧氯丙烷（ECH）和CO2环加成活性的影响，以CN-MIm为催化剂，在反应温度为120 ℃，反应时间为1.5 h，CO2压力为2.0 MPa，催化剂与ECH质量比为0.036条件下，ECH转化率和氯代碳酸丙烯酯（CPC）产率分别为99%和98%。实验表明，CN-MIm对不同环氧化物均具有良好的普适性。此外，提出了蜜勒胺低聚物中含有的羟基、氨基及咪唑基离子液体中溴离子对环氧化物和CO2环加成的协同催化反应机理。

Abstract:

Bromomethylimidazole modified melamine oligomer catalyst(CN MIm) was prepared by two-step method. The structure, morphology and thermal stability of catalyst were characterized by FTIR, XRD, SEM, TG and XPS. The results showed that the imidazole based ionic liquid was successfully loaded on the oligomer of melamine and had good thermal stability. The effects of reaction conditions on the cycloaddition performance of epichlorohydrin(ECH)and CO2 were investigated. Using CN MIm as catalyst, under the conditions of reaction temperature of 120 ℃, reaction time of 1.5 h, CO2 pressure of 2.0 MPa and mass ratio of catalyst to ECH of 0.036, the conversion of ECH and the yield of chloropropylene carbonate(CPC) were 99% and 98%, respectively. Meanwhile, CN MIm had good universality for different epoxides. In addition, the synergistic catalytic reaction mechanism of cycloaddition of epoxide and CO2 by bromine ion in hydroxyl, amino and imidazole based ionic liquids contained in melamine oligomers was proposed.