Preparation And Performance Of Supported Catalysts For Hydroformylation Of Higher Olefins

This dissertation has set the hydroformylation of higher olefins as the object of study. The organic-soluble phosphine-rhodium complex has been supported on the organo- and ionic liquid (IL)-grafted onto the surfaces of mesoporous silicas such as MCM-41, MCM-48 and SBA-15 and conventional SiO₂. Thereafter, supported IL phase catalysts (SILPCs) have been prepared by direct co-immobilization of water-soluble phosphine-rhodium complex and IL onto the mesoporous silicas and SiO₂. The supports and the catalysts were characterized by means of XRD, BET, FTIR, AAS, XPS, SEM, HRTEM, TAG-DSC and NMR to correlate the catalytic performance and the structure of catalysts. The aim of the studies was to explore the possibility of developing novel heterogenized catalysts for the hydroformylation of higher olefins.1. Organo-functionalized mesoporous silicas with silanes containing (mono-, di-)amino, mercapto and nitrile groups, respectively, were used as supports to prepare heterogeneized Wilkinson phosphine-rhodium complex catalysts. Evidences from the experiments revealed that the mesoporous silicas retained their skeleton and ordered mesoporous structures after the organo-functionalization and Rh-P complex encapsulation. The remained channels were enough for the diffusion and reaction of substrates. The catalytic performance was influenced by the structure of organic groups and those containing di-amino and nitrile groups as supports showed better catalytic activity. A strong interaction occurred between the amino-groups, particularly those at the internal walls of mesoporous silicas, and P-Rh complex, resulting in forming the stable heterogenized catalysts. Such catalysts afforded relatively lower TOF than that of the corresponding homogeneous complex, but they could be easily separated from the reactants and reused many times without significant deactivation. The accumulative TON was higher than that of homogeneous counterpart.2. The mesoporous silicas grafted with IL were used as supports for immobilization of Rh-P complex. The results showed that the Rh-P complex could stay stably in the IL layer at the surfaces, forming an alternative kind of heterogenized catalysts that were active for the hydroformylation of higher olefins and showed no significant leaching of active species in the process of reaction. Moreover, they exhibited better catalytic activity than that of above heterogenized catalysts and also could be reused several times without considerable reduction in the catalytic performance. In contrast, the drastic deactivation was observed during the catalyst recycling with the non-grafted mesoporous silicas as supports.