Towards a Sustainable Synthesis of Oxymethylene Dimethyl Ether by Homogeneous Catalysis and Uptake of Molecular Formaldehyde.

Oxymethylene dimethyl ethers (OMEn ; CH3 (-OCH2 -)n O-CH3 , n=3-5) are a novel class of sustainable synthetic fuels, which are of increasing interest due to their soot-free combustion. Herein a novel anhydrous OMEn synthesis route is presented. Catalyzed by trimethyloxonium salts, dimethoxymethane takes up monomeric gaseous formaldehyde instantaneously and forms high purity OMEn at temperatures of 25-30 °C. This new anhydrous approach using molecular formaldehyde and catalytic amounts of highly active trimethyloxonium salts represents a promising new step towards a sustainable formation of OMEn emanating from CO2 and H2 .