温控聚乙二醇两相体系中纳米钯催化肉桂醛选择性加氢反应

Thermoregulated poly(ethylene glycol) biphasic system with Pd nanoparticle catalysts for selective hydrogenation of cinnamaldehyde

将具有"高温混溶、室温分相"功能的聚乙二醇4000(PEG4000)与甲苯-正庚烷组成的两相体系用于纳米钯催化的肉桂醛选择性加氢反应中.在优化的反应条件下,肉桂醛转化率和氢化肉桂醛选择性分别为99%和98%.钯纳米催化剂经简单分相即可与产物分离,且循环使用8次,其活性和选择性基本保持不变.

Poly(ethylene glycol) (PEG)-stabilized Pd nanoparticles were prepared by simple hydrogen reduction of PdNa2Cl4 ·xH2O in the presence of PEG4000 (PEG with an average molecular mass of 4000 g/mol). These were shown to be efficient and recyclable catalysts for the selective hydrogenation of cinnamaldehyde in a thermoregulated PEG biphasic system, which allows for an efficient homogeneous catalytic reaction, easy biphasic separation and catalyst reuse. Under optimized reaction conditions, the conversion of cinnamaldehyde and the selectivity of hydrocinnamaldehyde (HCAL) were 99% and 98%, respectively. The PEG4000 -stabilized Pd nanoparticle catalyst could be easily separated from the product by phase separation and reused eight times without evident loss of activity and selectivity.