Antimony Pentafluoride/Graphite Catalyzed Oxidative Conversion of Methyl Halides with Copper Oxides (or Copper/Oxygen) to Dimethyl Ether

Article abstract of DOI:10.1021/jo00301a016

Nonaqueous conversion of methyl halides into dimethyl ether in good to excellent yield was achieved by their superacidic, antimony pentafluoride/graphite catalyzed reaction with copper oxides or with copper metal and oxygen.The reaction was studied in static batch-wise experiments at pressures of 2 to 150 atm and temperatures of 100 to 265 deg C, as well as in flow system.The reaction of methyl bromide (MeBr) with Cu2O at 220 deg C and 140 atm gives a >90percent yield of dimethyl ether.Methyl fluoride (MeF) and methyl chloride (MeCl) being less reactive gave yields of 50-60 molpercent.The reaction involves initial formation of a polarized methyl halide-SbF5 complex, which then O-methylates copper oxide and subsequently yields dimethyl ether.Copper bromides formed as byproducts can be oxidatively recycled for oxybromination of methane and regeneration of copper oxide, thus allowing a selective, catalytic oxidation of methane into dimethyl ether.