Effects of Solid Acid Modification on Dimethyl ether Synthesis from Syngas

摘要

Dimethyl ether has been used as a commodity in the chemical industry such as a propellant in aerosol containers, because it is not harmful to the ozone layer and is easily degraded in the troposphere. On the other hand, many publications deal with DME for a intermediate in the manufacture of synthetic gasoline as well as in a process for the production of acetic acid and acetic anhydride. Recent investigations reveal that dimethyl ether should be used as a substitute for diesel fuel [1]. The conventional method of dimethyl ether production is based on the hydration of methanol, synthesized by syngas from a natural gas reforming process. The direct dimethyl ether synthesis from syngas has been developed to enhance the productivity of dimethyl ether. However, the physical mixture of the methanol synthesis catalyst and the solid acid catalyst was used for the direct dimethyl ether synthesis from syn-gas. H-ZSM-5 and gamma-alumina have been employed as solid acids [2-3]. Their strong acidity deteriorates the yield and selectivity to dimethyl ether because of the water reforming reaction of methanol/dimethyl ether producing carbon dioxide and hydrogen. The modification of these solid acids is a key to maximize the yield and selectivity to dimethyl ether from syngas. Herein, we have developed an effective and convenient method to modify solid acids.