Variation of the activity of СuO·ZnO·K2O/SiO2 catalysts during generation in dehydrogenation of methanol to formaldehyde

The development of the catalytic properties of supported model catalysts СuO·ZnO·K2O/SiO2 with different component ratios in methanol dehydrogenation was studied. In the temperature interval 400–500°С, the formation of the target product, formaldehyde, is accompanied by the formation of surface polymeric hydrocarbons, which undergo gradual condensation to coke with the evolution of hydrogen and carbon dioxide. By properly combining the concentrations of the supported components and the sequence of the deposition of zinc, copper, and potassium oxides, it is possible to reduce the time in which the steady-state catalyst operation mode is reached and to improve the catalyst selectivity with respect to formaldehyde formation.