| This dissertation consists of three parts (1) oxidation of substituted toluenes to the corresponding benzoic acids in non-acid solvents (2) oxidation of alkylarenes with molecular oxygen hi ionic liquids (3) Oxidation of alkyl aromatic compounds using H2O2 or NaCIO as oxidant and Ruthenium(III) as catalyst in ionic liquid.1. Oxidation of substituted toluenes with molecular oxygen to corresponding substituted benzoic acids under normal pressure hi non-acid solvents was investigated. Satisfactory results for oxidation of halo-toluenes, methoxy-toluenes and cyano-toluenes were obtained using Co(C18h35O2)/NH4Br or Co(OAc)2/NaBr/HOAc as catalysts in the presence of a radical initiator. The influence of substituted groups on benzene, solvents, cocatalysts and initiator on the oxidation result was studied. The selectivity of the oxidation system was also studied. The oxidation of para- substituted toluenes gave good yields, such as 92%, 94% and 96% for p-bromotoluene, p-methoxytoluene and p-cyanotoluene respectively. Radical initiator is the key species in the reaction.2. Oxidation of alkylarenes with molecular oxygen was investigated in neutral ionic liquid [Hex-mim]+BF4- for the first time. Using N-hydroxyphthalimide (NHPI) as catalysts, alkylarenes could be oxidized to the corresponding aromatic acids (or aromatic ketones) under normal pressure. Electron-withdrawing groups and steric effect decreased the reactivities while electron-donating groups were favorable for the oxidation.3. Oxidation of alkyl aromatic compounds in ionic liquid was studied tentatively using Ruthenium( III) as catalyst with hydrogen Peroxide and NaCIO as oxidant, respectively. Only <14% of conversions were obtained when H2O2 as oxidant, and a little chloride compounds were detected while using NaCIO as oxidant. |
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