Study On Catalytic Partial Oxidation Of Methane To Methanol In Gas-solid Phase

The current researching of catalytic partial oxidation of methane to methanol in gas-solid phase at home and abroad was reviewed . The development of novel catalysts is the key of the study. Up to now, the properties of catalysts such as transitional metal oxide , zeolite and so on were studied . In addition, reaction process condition and reactor shape were discussed.The Gas-Solid phase partial oxidation of methane to methanol without O₂ was investigated. According to above mentioned, the research work of this dissertation was consisted of three parts.In part one, The catalysts such as heteropoly compounds, solid superacid and transitional metal oxide were prepared and researched for partial oxidation of methane.Heteropoly compounds as catalyst is effective in methane partial oxidation.it is found H₅MgPW₁₂O₄₀/SiO₂ was optium catalyst, the amount of H₅MgPW₁₂O₄₀ was 15%(wt) immersion time was 4h, catalyst drying-time was 4h and drying-temperature was 120℃, catalyst calcinations-time was 5h and calcination-temperature was 350℃. The results show that the product yield using the SO₄^2-/ZrO₂-SiO₂ catalyst prepared with the concentration of H₂SO₄ by 1.5mol/L, the calcination time of 5 h and the calcination temperature of 500℃is higher than the other transitional metal oxide .The product yield using the ZnO/SiO₂ catalyst prepared with the amount of ZnO was 20%(wt), the calcination time of 4 h and the calcination temperature of 550℃is higher than the other transitional metal oxide.In part two, the process conditions was investigated when heteropoly compounds as catalyst. The results show that catalyst induction period was 3h, liquid reagent was acetic acid(1% iodine ). In the selected situation, at 280℃and atmospheric pressure, methane conversion was 19.91% and product yield was 17.92%.In part three, catalytic mechanism and thermodynamic of partial oxidation methane were discussed. In the study of catalytic mechanism, the electrophilic alternative mechanism was suggested. The thermodynamic of partial oxidation methane were analyzed. It result that the way methane was transformed into methyl acetate can be react spontaneity. If we only use iodine as catalysts it can not be react in this temperature range, but when we use some oxidant it can react spontaneity.