聚醚/复盐离子液体基固载化催化剂的制备及在二氧化碳连续转化中应用

It will be an effective way to achieve the direct and efficient conversion of consecutive reaction when carbon dioxide is as novel immobilized polyether/composite ionic liquids catalysts. Based on our previous work, a new method has been proposed that polyether/composite ionic liquids will be immobilized on molecular sieve within supercages coupling silane, whose aim is to convert carbon dioxide and the corresponding substrate into the target product by fixed bed. According to the strategy of shipbuilding in the yarn, the chemical bond is produced between designed functional ionic liquids and the channels of molecular sieve with the help of silane coupling agent, and the molecular structure model of silane coupling molecular sieve-ionic liquids is controlled through adjusting the structures and ratios of both ionic liquids as well as molecular sieve, or through selecting silane coupling agent types. Above processes realize the control of catalyst functional range effective size, active component and overall performance. The new type catalyst could be applied in the consecutive reaction of carbon dioxide and epoxides to synthesize cyclic carbonate. Some effects would be studied on the catalytic performance, including the changes of functional groups, molecular chain structure, the size of molecular sieves, and the bonding methods. In addition, catalytic mechanism model of novel immobilized ionic liquids catalysts will be proposed. Accordingly, the reaction process will be simulated by software to determined the consecutive conversion and efficient utilization for carbon dioxide.

新型聚醚/复盐离子液体基固载化催化剂的制备，将为二氧化碳实现连续反应，并进行直接高效转化提供有效途径。在前期工作的基础上，申请人提出利用硅烷偶联的办法原位将聚醚/复盐离子液体化学固载到超笼结构的分子筛中，并通过固定床连续催化工艺直接将二氧化碳与对应底物转化为目标产品的新方法。根据“瓮中造船”的理念，将设计的功能离子液体通过硅烷化学键键合到超笼的分子筛孔道内，并通过对二者化学结构和比例的调控及硅烷种类的筛选，建立硅烷偶联分子筛-离子液体的分子结构模型，实现对催化剂功能区间的有效尺寸、活性组分和整体性能的调控。利用该催化剂连续催化转化二氧化碳与环氧烷烃合成环状碳酸酯的羰基化反应，探讨离子液体功能基团及分子链结构变化、分子筛微孔尺寸调整及键接方式对催化性能的影响规律，建立催化机理模型，采用化工流程模拟软件对设计的二氧化碳连续转化过程进行模拟，并确定二氧化碳的连续反应与直接高效利用率。

新型聚醚/复盐离子液体基固载化催化剂的制备，为二氧化碳直接高效转化合成环状碳酸酯，实现其工业化连续清洁生产提供新技术。该项目从设计离子液体基体的化学结构和优化分子筛孔道结构出发，制备了18种分子筛固载离子液体催化剂，其创新之处在于通过特定结构的硅烷偶联剂增强离子液体与分子筛之间的化学键能，提高固载化催化剂分子间的作用力，解决固载化离子液体催化剂在连续反应过程中出现的结构脱落及活性组分逐渐流失等问题。利用制备的固载化催化剂固定床连续催化二氧化碳与环氧化合物合成环状碳酸酯，优化了工艺参数，探讨了离子液体功能基团及分子链结构变化、分子筛微孔尺寸调整及键接方式对催化性能的影响规律。研究结果表明：利用硅烷偶联可有效提高分子筛和离子液体之间的化学键能，延长了固载化离子液体催化剂的使用寿命。对于课题选用的三种分子筛，SBA-15固载离子液体制备的催化剂效果优于MCM-22和ZSM-5。对于硅烷偶联分子筛聚醚离子液体催化剂，SBA-15-CPTES-HOOC-[PECH-MIM]Cl/[ZnBr2]的催化二氧化碳和环氧化合物（以PO为例）性能最好，最佳反应条件是温度120℃，压力3.0MPa，液时空速为0.50h-1，反应时间5.0h对应转化率为85.8%，选择性为94.5%。连续催化使用50h后，离子液体仅有很少量的流失，催化性能稳定。对于硅烷偶联的分子筛复盐离子液体催化剂，SBA-15-CPTES-[AeMIM][Zn2Br5]的催化效果最佳，最优反应条件是温度为130℃，压力为2.0MPa，液时空速为0.75h-1，反应时间5.0h对应转化率为88.2%，选择性为98.1%。连续催化200h后，对应产物的产率仍保持在80%左右。.该项目的研究，获得了新型固载化催化剂连续催化转化CO2的最优工艺条件，确定了催化剂分子结构模型和催化机理模型，完成了催化工艺的流程模拟，形成了新型固载化离子液体基催化剂的制备技术及其连续催化CO2合成环状碳酸酯的清洁生产小试技术。