Synthesis of Polyoxymethylene Dimethyl Ethers from Dimethyl Ether Direct Oxidation over Carbon-Based Catalysts

The synthesis of polyoxymethylene dimethyl ethers (DMMx) with a selectivity of 84.3% by direct oxidation of dimethyl ether (DME) was realized over 30%Ti(SO4)(2)/active carbon (AC) catalyst. This process also significantly promotes the growth of the C-O chain. The catalytic performances of Ti(SO4)(2)/AC and Ti(SO4)(2)/graphene (G) catalysts differ largely for DME oxidation reaction, although both AC and G are carbon materials. The carbonyl and hydroxyl groups on the surface of the carbon-based catalysts play an important role in DME direct oxidation to DMMx. Owing to the differences of surface structure and chemical properties of AC and G materials, the different interaction between the Ti(SO4)(2) and supports remarkably affects the sulfate structures on the supports surface and leads to the large differences in the acid and redox properties of catalysts.