The Effction Of Ionic Liquid On Directly Catalytic Oxidation Of Methane In Liquid Phase

Methane as the main component of natural gas is an important chemical raw material for C1chemistry. Conventionally, methanol is synthesized at high temperatures and pressures. Direct oxidative conversion of methane is characterized by less greenhouse gas emissions under mild conditions, which is becoming a research focus in C1chemical technology. The use of sulfuric acid or heavy metals’as catalyst systems will bring problems of strong corrosion and serious pollution. Accordingly, the exploring of green processes for methane conversion has attracted considerable interest.Ionic liquids are ionic molten salts that are liquids at normal temperature. They are nonvolatile, nonflammable, extremely high boiling point, recyclable, thermally, chemically stable that are widely accepted as alternatives to conventional organic solvents in many areas of organic, organometallic. and enzymatic synthesesas well as in analytical applications.This article describes a chemical processes for the catalytic oxidation of methane to methanol. The catalytic reaction was carried out in a100ml autoclave filled with2MPa of CH4gas, together with nano-particle gold supported on SiO2as the catalyst,[Bmim]C1as the solvent, trifluoroacetic acid(TFA) and trifluoro acetic anhydride(TFAA) as the acidic reagent, and K2S2O8as the oxidant. The effects of SiO2-supported different metal(Au/SiO2, Au-Cu/SiO2, Ag/SiO2, Ag-Cu/SiO2), different type carrier of gold(SiO2,A12O3), different anions of ionic liquids, and amount of Au/SiO2and the ionic liquid on the conversion of methane were investigated at reaction temperature of90℃, respectively. The experimental results show that the catalytic effect of gold on SiO2is the best, the catalytic effect of Ag/SiO2, Au-Cu/SiO2, Ag-Cu/SiO2decreases progressively, the carrier of SiO2is better than Al2O3, the anion of ionic liquids is Cl-with best catalytic effect, the best amount of Au/SiO2and ILs are0.01g and1g. Under. optimal reaction conditions, the methane conversion is24.9%, the selectivity of product is up to71.5%and the yield is up to17.8%. The main product is methanol. which exists as the methyl group of the methyl trifluoroacetate. In the reaction system, the gold particles and IL can be recycled. which recovery is about96.9%. The conversion of methane in the recycled system remains as high as21.75%. The mechanism of methane to methanol, as well as the catalytic action of the nano-gold, was also discussed.