Research Of Selective Catalytic Oxidation Of Toluene To Benzaldehyde

Synthesized a series of ionic liquids of metal chloride and complex substances of metal chloride and ionic liquid, bromide 1 - butyl -3- methylimidazol - cobalt chloride (bmimBr-CoCl₂), bromide 1 - butyl -3- methylimidazol - zinc chloride (bmimBr-ZnCl₂), bromide 1 - butyl -3- methylimidazol - manganese chloride (bmimBr-MnCl₂), bromide 1 - butyl -3- methylimidazol - copper chloride (bmimBr-CuCl₂), bromide 1 - butyl -3—methylimidazol - nickel chloride (bmimBr-NiCl₂), bromide 1 - butyl -3- methylimidazol - ferric chloride (bmimBr-FeCl₃), bromide 1 - benzyl -3- methylimidazol - ferric chloride (bzmimCl-FeCl₃), triethylamine hydrochloride - ferric chloride (Et3NHCl-FeCl₃), 1 - butyl -3-- methylimidazol tetrafluoroborate - ferric chloride (bmimBF4-FeCl₃), bromide 1 - ethyl -3-- methylimidazol - ferric chloride (emimBr-FeCl₃) and the bromide 1 - acetyl -3-- methylimidazol - chloro of iron (acmimCl-FeCl₃) and so on. After investigated the properties of synthetic ionic liquid solvents for catalysis for selective oxidation of toluene catalytic benzaidehyde, the results show that, bmimBr-FeCl₃ was prepared by a selective oxidation of toluene, benzene, formaldehyde catalyst. After investigated the composition of the ionic liquid and reaction conditions on the catalytic reaction, we have obtained the optimum reaction conditions. That is, ionic liquid bmimCl-FeCl₃ (1:2) as the catalyst, the amount of toluene 5mL, hydrogen peroxide 15mL, reaction temperature 100℃, reaction time 6 h. Under the optimum reaction conditions, the conversion rate of toluene is 10.21%, selectivity of benzene methylal and benzyl alcohol is 98.69%. In addition, the preparation of a Keggin-type structure polyoxometalate structure of Co₃ (PW₁₂O₄₀)₂·16H₂O, and application of FT-IR, XRD and TG-DTA were characterized to determine its composition and structure. The effects of Co₃ (PW₁₂O₄₀)₂·16H₂O as a catalyst when the performance of catalytic oxidation of toluene to determine the optimum reaction conditions were: toluene amount 5mL, hydrogen peroxide 15mL, reaction temperature 80℃, reaction time 4h.Meanwhile, we evaluated the cycle of the two catalysts that the catalyst could be reused four times and did not lead to significantly reduced catalytic activity.