Selective oxidation of methanol to dimethoxymethane over acid-modified V_2O_5/TiO_2 catalysts

摘要

Selective oxidation of methanol to dimethoxymethane (DMM) was conducted in a fixed-bed reactor over an acid-modified V_2O_5/TiO_2 catalyst. The influence of the acid modification on its structure, redox and acidic properties, and catalytic performance for methanol oxidation were investigated. The results indi cated that the content of vanadia in the catalyst exhibits a vital influence on the dispersion of vanadium species, while the acid modification can enhance its surface acidity. Proper amounts of the acid (W(SC>_4~(2-)) = 15%) and V_5O_5 (W(V_2O_5) = 15%) components loaded in the acid-modified V_2O_5/TiO_2 catalyst are able to build a bi-functional circumstance that is favorable for the formation of DMM with high activity and selectivity. As a result, for the selective oxidation of methanol, the H_2SO_4modified V_2O_5/TiO_2 cat alyst gives a much higher DMM yield at 150°C than the unmodified one.