| Ionic liquids with task-specific functionality have showed fascinating prospects in fine chemical and catalysis fields due to their unprecedented properties, such as high chemical and thermal stability, favorable solubility, tunable physical and chemical properties by the choice of organic cation and/or inorganic anion etc. However, such homogeneous species possess a number of inherent shortcomings, including high price, large consumption, and difficulties in separation and/or recovery. In order to overcome the above-mentioned problems, attempts have been, in this dissertation, made to combine mesoporous silicas having tunable nano-channel and rather high surface area with ionic liquids of task-specific functionality, aiming to fabricate the task-specific active sites on pore surface and/or in framework of mesostructure. As such, a series of novel mesoporous silica-supported functionalized ionic liquids were designed and prepared. The resultant immobilized functionalized ionic liquids not only remain high catalytic activity often observed for homogeneous functionalized ionic liquids, but also possess facility of separation. In relative reactions, such catalysts showed superior catalytic activities and reusabilities.Chloroferrate ionic liquid was grafted onto pore surface of MCM-41 via imidazolium cation by using a post-synthesis procedure. The obtained materials were well characterized by means of XRD, N2 adsorption-desorption, FT-IR, and TG-DTG. It was found that chloroferrate ionic liquid has been incorporated onto the support intactly and that the support remains its structural integrity during the grafting process. In comparison with pure chloroferrate ionic liquid, the immobilized ionic liquid showed much higher catalytic efficiency and more excellent reusability in Friedel-Crafts benzylation reactions. The consumption of ionic liquid in the immobilized chloroferrate ionic liquid was much lower than the pure ionic liquid (ca.1/50) and the solid catalyst could be reused for 10 times without significant loss of catalytic activity. Also, the immobilized chloroferrate ionic liquid possessed better reusability than siliceous MCM-41-supported FeCl3.An organic bridged silsesquioxane precursor containing ionic liquid unit was synthesized and successively co-condensed with tetraethyl orthosilicate, leading to a periodic mesoporous organosilica (PMO) material of SBA-15 incorporating ionic liquid moieties. The combination of the resultant PMO material with InCl3 gave rise to a immobilized Lewis acidic chloroindate(III) ionic liquid catalyst. The obtained materials were well characterized by means of XRD, N2 adsorption-desorption, TEM, FT-IR, and NMR. The immobilized chloroindate(III) ionic liquid showed rather good catalytic performance in the Friedel-Crafts reaction between benzene and benzyl chloride and could be reused at least for 6 times. In comparison with siliceous SBA-15-supported InCl3, the immobilized ionic liquid revealed higher selectivity and lower leaching of active species during the reuse process. It should be noted that such immobilized chloroindate(â…¢) ionic liquids had low moisture sensitivity, showing the great potential for practical applications.Three organic-inorganic hybrid mesoporous silicas incorporated with NH2-functionalized ionic liquid moieties were prepared via either post-synthesis or sol-gel procedure by using a synthesized organotrialkoxysilane as organosilane source. The obtained immobilized ionic liquids showed higher catalytic efficiency than their homogeneous counterpart in Knoevenagel condensations with water as solvent. Among them, the catalysts prepared by post-synthesis procedure, particularly that using siliceous SBA-15 as support, revealed better catalytic performance than that prepared by sol-gel procedure. Moreover, in comparison with NH2-functionalized mesoporous silicas, the immobilized ionic liquids possessed much better reusability, for example, the catalyst using siliceous SBA-15 as support could be reused for 10 times without significant loss of catalytic activity.Imidazolium-based ionic liquid was grafted onto pore surface of siliceous SBA-15. Then, the silanols presented in the organic-inorganic hybrid mesoporous silica were eliminated by reacting with 1,1,1,3,3,3-hexamethyldisilazane. The combination of the material so-obtained with phosphotungstic acid led to a series of immobilized phosphotungstic acid ionic liquids. It was found that weak complexation between the imidazolium cations and meter centre of phosphotungstic acid and polarity of the ionic liquid moieties are conducive to stabilizing reaction inter-mediate. As such, the immobilized phosphotungstic acid ionic liquids showed higher catalytic performance than siliceous SBA-15-supported phosphotungstic acid did in the oxidation of benzyl alcohol with water as media in the presence of 30% H2O2. Under optimum conditions, the conversion of benzyl alcohol and the selectivity to benzaldehyde were as high as 97% and 96%, respectively. The elimination of silanols forced phosphotungstic acid to interact with the ionic liquid moieties incorporated in the mesostructure exclusively, therefore, the immobilized phosphotungstic acid ionic liquid showed good reusability. Indeed, the optimum catalyst could be reused for 7 times without significant loss of catalytic activity.
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