苯乙烯-丁二烯-苯乙烯嵌段共聚物负载Pt催化肉桂醛制备肉桂醇的研究

Selective Hydrogenation of Cinnamaldehyde over Pt-Supported Styrene-Butadiene-Styrene Block Copolymer

用紫外光交联的方法制备不同交联度的苯乙烯-丁二烯-苯乙烯嵌段共聚物(SBS)负载Pt的催化膜并探讨其对肉桂醛选择性加氢制备肉桂醇的催化效果.其中催化剂Pt纳米簇用微波法制备,XRD测其平均粒径为3.7nm.膜载催化剂的负载量、光交联剂三羟甲基丙烷三丙烯酸酯(TMPTA)和光引发剂二苯甲酮(BP)的用量均为3%.用色谱质谱联用、XRD、紫外分光光度计对膜载催化剂和反应产物进行了表征,结果表明,随着交联度的增加,肉桂醇的催化选择性先增后减,紫外光光照80s时,负载膜交联度23.63%,肉桂醛转化率为91.46,肉桂醇选择性80.98%.质谱分析表明交联度大于30%后,催化产物中开始有膜分解产生的小分子杂质出现,并随交联度的进一步增大而增多;显微镜检测同时说明此时膜结构发生变化,造成肉桂醇选择性的降低.

Photocrosslinked styrene-butadiene-styrene block copolymer （SBS） membrane supported nano platinum catalysts was prepared and their catalytic activity on the selective hydrogenation of cinnamaldehyde was investigated. The platinum nanoclusters with an average diameter of ca 3,7 nm were obtained by reaction of H2PtCl6 with polyols, assisted by microwave irradiation （MW）. The SBS membrane was loaded with 3.0 wt% of Pt, benzophenone （BP） and 1,1,1-trimethylolpropane triacrylate （TMPTA）, respectively, and varing crosslinking ratios were achieved by adjusting the radiation time. The hydrogenation products were investigated by gas chromatography and mass spectrometry （GC-MS） and UV techniques. As the crosslinking ratio increases, the selectivity for cinnamyl alcohol first increases and reaches 80.98% at a crosslinking ratio of 23.63%, and then decreases. Decomposition products of the SBS meambrane itself begin to appear as the radiaton time is over 30 min （corresponding to a crossling ratio of sightly above 30%）. The deterioration of the membrane structure is also evidenced by transmission electron microscope （TEM） measurement.