HETEROGENEOUS SELECTIVE OXIDATION OF FORMALDEHYDE OVER OXIDE CATALYSTS .2. CATALYTIC PROPERTIES OF A V-TI-OXIDE CATALYST

Catalytic properties of a V-Ti-O catalyst and individual V2O5 and TiO2 (anatase) oxides were studied in formaldehyde oxidation at 120-160 de grees C. Over V2O5 and V-Ti-O samples containing more than 5 wt % of V 2O5, the products of the formaldehyde oxidation were formic acid and t races of CO, CO2, and methyl formate. For the samples of the compositi on V2O5 (10-75%) + TiO2 (90-25%), the selectivity to formic acid was c onstant (98-93%) at 120 degrees C over the range of conversions from 1 0 to 75%, V2O5 exhibited high selectivity and low activity. Over TiO2, the dimerization of formaldehyde occurs, which led to the formation o f methanol, methyl formate, methylal, and a minor amount of formic aci d.