Study On Environmentally Benign Catalytic Property Of Heteropolyacid-Ionic Liquids And Polymer Ionic Liquid

Room-temperature ionic liquids are liquids containing only ions at and below room temperature. The use of room-temperature ionic liquids as environmentally benign media for catalytic processes or chemical extractions is becoming widely recognized and accepted.Based on the review on recent achievements about classic synthetic method, properties of ionic liquids, and applications in catalysis of heteropolyacid. We integrated the heteropolyacid, hydrogen peroxide with ionic liquids (named "heteropolyacid-ionic liquids-hydrogen peroxide" system) for the first time, which is a new kind of "environmentally benign" catalytic oxidation system. The characteristic of this system is that the above substance could form homogeneous phase. The product could be easily separated. The dissertation presents here the following main points:(1) Room temperature ionic liquids including 1-alkyl-3-methylimidazolium halogen, tetrafluoroborate, trifluoroacetate (alkyl=methyl, ethyl, isopropyl, n-butyl, n-octyl, n-decyl or n-dodecyl) were prepared according to improved the procedures reported in literatures, and were characterized by IR and element analysis. The Keggin heteropolyacid was also prepared and characterized by IR.(2) Catalytic oxidation of styrene in "heteropolyacid-ionic liquids-hydrogen peroxide" system. The result shows that the major product is benzadehyde. The benzeneacetaldehyde, acetophenone, benzoic acid and 2-hydroxyacetophenone were obtained. The conversion reached to 31.6% in 1,3-diimidazolylpropane tetrafluoroborate ([MIm-(CH2)3-MIm]2[BF4]). The effect of using different ionic liquids, temperature, reaction time, additive, and the amount of catalyst and oxidant on the reaction results had been investigated.(3) Catalytic oxidation of a-methylstyrene in "heteropolyacid-ionic liquids-hydrogen peroxide" system. The result shows that the major products were acetophenone, a-methylbenzeneacetaldehyde, cc-methylbenzeneacetic acid, 2-phenyl-1,2-propanediol and 2-hydroxy-2-phenytpropionic acid. It was found that the conversion was highest in the l-octyl-3-methylimidazolium tetrafluoroborate ([OMIm][BF4]). The effect of using different ionic liquids, temperature, reaction time, additive, and the amount of catalyst and oxidant on the reaction results had been investigated.(4) The "heteropolyacid-ionic liquids-hydrogen peroxide" system was also applied in catalytic oxidation of benzoic alcohol. The major products were benzadehyde with high selectivity. The conversion was highest in [BMIm][TA]. The effect of using different ionic liquids, temperature, reaction time, additive, and the amount of catalyst and oxidant on the reaction results had been investigated.(5) The polymer ionic liquid was successfully synthesized for the first time. The oligomeric acrylic acid used as the anion and N-methylimidazolium used as the cation ([HMim]n[CH2CHCOO]m). The polymer ionic liquid was characterized by IR, NMR, Mass Spectrum and element analysis. Catalytic oxidation of benzoic alcohol in polymer ionic liquids was also studied.