Palladium-iminodiacetic acid immobilized on pH-responsive polymeric microspheres: Efficient quasi-homogeneous catalyst for Suzuki and Heck reactions in aqueous solution
作者：Zhang, Jianzheng; Zhang, Wangqing; Wang, Yao; 等.
關鍵字：microspheres
論文來源：期刊
具體來源：ADVANCED SYNTHESIS & CATALYSIS
發表時間：2008年
onlinelibrary.wiley.com/doi/10.1002/adsc.200800304/abstract
The pH-responsive core-shell microspheres of poly(styrene-co-methylacrylic acid) (PS-co-PMAA) containing a polystyrene (PS) core and a poly(methylacrylic acid) (PMAA) shell are synthesized by one-stage soap-free copolymerization and the catalyst system palladium-iminodiacetic acid (IDA-Pd) is immobilized on the outer shell-layer of the core-shell microspheres to form the quasi-homogeneous and easily accessible catalyst PS-co-PMAA-IDA-Pd. This quasi-homogeneous PS-co-PMAA-IDA-Pd catalyst is highly dispersed in the reaction medium just like a homogeneous one and can be separated like a heterogeneous catalyst by adjusting the pH of the reaction medium. Suzuki reactions employing the quasi-homogeneous PS-co-PMAA-IDA-Pd catalyst are efficiently performed in water as the sole solvent under mild conditions such as room temperature. The PS-co-PMAA-IDA-Pd catalyst is also used in Heck reactions of a wide range of aryl halides with styrene and proves to be efficient in aqueous solution. The PS-co-PMAA-IDA-Pd catalyst has a low leaching loss and can be reused at least 4 times without loss of activity.