负载型水溶性铑膦配合物催化剂的结构和性能

Structure and Hydroformylation Performance of Supported Aqueous-phase Rh Catalyst

SiO2担载TPPTS（间-三苯基膦三磺酸钠盐）－Rh（acac）（CO）2制成的负载型水溶性催化剂进行1-己烯氢甲酰化催化反应时，引入适量水蒸气可显著提高催化活性．用魔角旋转固体核磁共振磷谱表征得到，在新制备的催化剂中，吸附于SiO2表面但未参与配位的TPPTS，约占总膦物种的70mol％以上，而位于δ=32．4处的表面配合物｛Rh（CO）（TPPTS）2｝膦物种量约为15mol％，其它膦10mol％左右．催化剂经干燥合成气在373K处理2h、或经湿合成气在较低温度（333K）下处理2h后，｛Rh（CO）（TPPTS）2｝的增加量仅约为10～15mol％，其它膦物种的变化量也较小，但催化剂经湿合成气于373K处理2h后，｛Rh（CO）（TPPTS）2｝的净增量大于40mol％；在工作态催化剂中，也观察到｛Rh（CO）（TPPTS）2）大量生成、未配位TPPTS量减小；经43h反应运转后，催化剂活性下降，归属为｛Rh（CO）（TPPTS）2）的磷谱峰宽化，揭示有部份配合物解络、部分TPPTS被氧化成OTTPTS．本研究结果证实，适量水可促进催化剂中具氢甲酰化催化活性的铑膦物种形成，提高活性，但随反应进行，配合物将逐渐解络、膦配体逐渐被氧化，从而使催化剂逐渐失活．

The catalytic activity of hydroformylation of 1-hexene over SiO2-supported TPPTSRh(acac)(CO)2 (SAPC) was found to be evidently promoted when a proper amount of water-vapor was introduced into the reactant. Characterization results by using MAS NMR 31p spectra revealed that there were three types of phosphine species in the as-prepared SAPC: uncoordinated ligand TPPTS (over 70 mol%), surface complex {Rll(CO)(TPPTS)2} (chemical shift at δ=32.4, about 15 mol%), and unknown (about 10 mol%). By pre-treatment at 373 K for 2 under dry-snygas or at 333 K for 2 h under wet-syngas, the amount of phosphine species of the surface complex{Rh(CO)(TPPTS)2} was slightly increased to 20-30mol%, accompanying a few changes in ratios of the other phsophine species. When the SAPC was pre-treated at 373 K for 2 h under wet-syngas,however, the phosphine species at chemical shift of 32.4 was increased by over 40 mol% due to the in-situ formation of the surface complex {Rh(CO)(TPPTS)2}. It was found that the peak at δ=32.4 was also a principal one in the MAS NMR 31P spectra of the working SAPC, which demonstrated that the surface complex of {Rh(CO)(TPPTS)2 } would be a catalytic active species for olefin hydroformyaltion. After hydroformylation for 43 h, the deactivation of the catalyst occurred, corresponding to the observations of a broadness in peak ascribed to the surface complex of {An(CO)(TPPTS)z} in the MAS NMR 31P spectra, indicating that there existed de-coordination of the surface complex and oxidation of the ligand TPPTS during the reaction. The results suggest that a proper amount of water-vapor was able to accelerate the formation of active Rh-complex on the catalyst surfaCe and thus increase the catalytic activity, whereas, it could be inevitably to cause the de-coordination of the surface complex and the oxidation of phosphine ligand under the reaction condition, hence leading to the deactivation of the catalyst.