丙烯氢甲酰化HRh（CO）（PPh3）3／SiO2催化剂的NMR研究

用固定床加压气相连续流动微反－气相色谱组合装置评价了ＳｉＯ２负载铑膦配合物催化剂上丙烯氢甲酰化反应．通过溶液（或液膜）３１Ｐ（１Ｈ）ＮＭＲ谱表征，发现配合物ＨＲｈ（ＣＯ）（ＰＰｈ３）３负载于硅胶载体上之后，原负载前驱苯溶液３１Ｐ（１Ｈ）ＮＭＲ谱在４１．１ｐｐｍ处的特征峰消失，但在化学位移为３７．０ｐｐｍ附近出现一新的宽峰，后者可能缘于配合物与载体表面发生相互作用．反应４ｈ后工作态催化剂的ＮＭＲ测试表明，在丙烯氢甲酰化反应条件下，铑的三膦配合物发生部分解络；工作态催化剂表面上主要的铑膦催化活性物种是含双膦的配合物物种，并暗示存在着含双羰基或羰、酰基的反应中间态；同时也观察到可归属于解络后的游离三苯基膦物种的相应谱峰．反应９０ｈ后催化剂的ＮＭＲ谱显示，铑配合物催化剂中膦配体含量已相当低；反应过程中膦配位体被氧化及铑、磷组份的流失是负载型催化剂活性下降乃至失活的主要原因．

NMR Study of HRh(CO)(PPh 3) 3 /SiO 2 Catalyst for Propene Hydroformylation

By means of solution (or liquid film) 31 P( 1H) NMR spectroscopy, a SiO 2 supported rhodium phosphine complex catalyst for hydroformylation of propene and the related systems were investigated. The experimental results showed that, after the HRh(CO)(PPh 3) 3 complex was supported on SiO 2, the original characteristic 31 P NMR peak at 41.1 ppm for this complex in solution of benzene disappeared, and, instead, a new broadening peak appeared at 37.0 ppm, which originated most probably from the interaction between the rhodium phosphine complex supported and the surface of SiO 2 carrier. The NMR spectrum of the functioning catalyst after 4h of propene hydroformylation operation revealed that the dominant species of rhodium phosphine at the surface of functioning catalyst were the rhodium diphosphine complex species, and implied that there existed the intermediates containing two carbonyl ligands or carbonyl/acyl ligands.The NMR peak ( at 0.7 ppm ) assignable to free triphenylphosphine dissociated from the rhodium triphosphine complex was also observed on the sample of functioning catalyst. The NMR spectrum of the functioning catalyst after 90h of the operation showed that the concentration of the rhodium phosphine complex was under the limit for detection and that detectable phosphine species were the species of free phosphine oxidized. The experimental results suggested that being oxidized of the phosphine ligands and losing of the rhodium and /or phosphine components during the reaction process were the main reasons leading to deactivation of the catalyst.