微流控技术制备微胶囊负载钯催化剂  

Preparation of microcapsule-supported Pd catalyst using a microfluidic platform

作　　者：刘莹[1] 吕阳成[1] 骆广生[1] 

机构地区：[1]清华大学化学工程系化学工程联合国家重点实验室,北京100084

出　　处：《催化学报》2013年第9期1635-1643,共9页

基　　金：国家自然科学基金(21036002; 21176136);中国博士后科学基金(2012M520295)~~

摘　　要：采用微流控技术结合悬浮聚合方法实现了百微米级含膦配体聚苯乙烯微胶囊的可控制备, 微胶囊尺寸在320～420 μm范围内可调, 且单分散性好. 扫描电子显微镜、能量散射光谱和电感耦合等离子发射光谱结果证实了其形貌和组成的均匀性及钯负载的可控性和有效性. 以溴代芳烃与苯硼酸的Suzuki偶联反应为模型反应评价了负载Pd(PPh3)4的百微米级微胶囊的催化性能, 发现其性能与文献报道的7～8 μm的同类催化剂微胶囊接近, 且均优于均相催化剂; 该催化剂经简单过滤后, 可实现多次循环使用, 未发现活性物种的流失. 该法实现了连续制备, 因而有助于提高制备的效率和可控性. 另外, 所制百微米级催化剂微胶囊在固定床反应器内具有较高催化剂浓度和机械性能, 且优于浆态床中使用的微米级催化剂微胶囊.A phosphine-functionalized polystyrene microcapsule with hundreds of microns in size was prepared using a microfluidic platform. The size distribution was narrow and the average size could be adjusted in the range 300 400 μm. The morphology and composition of the microcapsules were characterized using scanning electron microscopy, energy-dispersive X-ray spectroscopy, and inductively coupled plasma atomic emission spectroscopy. The results verified the effectiveness of the strategy we proposed for preparing uniform microcapsules with stable Pd immobilization. A Suzuki coupling reaction between aryl halides and phenylboronic acid was used as the model to evaluate their catalytic activity after Pd(PPh3) 4 immobilized onto the microcapsule. It was found that the catalytic activity of microcapsule-supported Pd was always higher than that of the corresponding homogeneous catalyst, and was similar with that of the literature reported microcapsule-supported catalyst with about 7-8 μm particle size. Microcapsule-supported Pd with microcapsules of hundreds of microns in size, being easy to recover, showed good reusability and undetected active species loss, its productivity effect and controllability of the microcapsule-supported Pd catalyst were also expected to benefit from continuous preparation using the microfluidic platform. Moreover, they could be potentially exploited in a fixed-bed reactor with high catalyst density and good mechanical stability.

关 键 词：微胶囊 钯 负载型催化剂 微流控技术 粒径调控 SUZUKI偶联反应 催化活性 

分 类 号：O643.36[理学—物理化学]