SiO_2负载的磺化三苯膦铑配合物催化高碳烯氢甲酰化及反应中的氘逆同位素效应

水溶性磺化三苯膦铑配合物担载在SiO_2表面制得的负载化水溶性Wilkinson催化剂具较大的比表面积,当1-己烯、1-辛烯、1-庚烯和十一烯酸甲酯等液态高碳烯烃在这种催化剂上于固定床加压流动态反应器中连续进行氢甲酰化催化反应时,产物醛的选择性98～100%,并可在适当过量配体存在下保持较高的催化活性.在这种催化剂上分别于CO用/H_2和CO/D_2气氛下进行烯烃氢甲酰化反应,可观察到显著的氘逆同位素效应.根据分析,初步认为酰基物中间体氢解反应可能是SiO_2负载的磺化三苯膦铑配合物催化剂上高碳烯氢甲酰化的速控步骤.

Higher Olefin Hydrof ormylation Catalyzed by SiO_2 Supported Sulfonated-Triphenylphosphine-Rhodium-Complexes and Deuterium Inverse Isotope Effects for the Reaction

Supported water-soluble Wilkinson catalysts were prepared by means of immobilizing sulfonated-triphenylphosphine-rhodium-complexes on a high surface area support of SiO2. They show an excenllent catalytic activity for the hydroformylation of liquid olefins (higher olefins), such as 1-hexene, 1-heptene, 1-octene and methyl 10-undencenoate, in a fixed bed reactor. It was found that the aldehyde selectivity was stabilized in the range of 98 - 100% and high catalytic activity was maintained even when the ligands were present in excees . Appreciable deuterium inverse isotope effects for the aldehyde formation were observed when a series of olefine hydrofomylation upon the subtitution of CO/D2 for CO/H2 was carried out to study the isotope effect of deuterium. It was believed that the kinetic isotope effect of H2/D2 coordination in the rate-determining step (RDS) was responsible for the overall inverse isotope effect. The possible RDS invovled in aldehyde formation was proposed to be the last step of formyl species hydrogenolysis.