DYNAMIC KINETICS OF CATALYTIC DEHYDROGENATION OF METHANOL TO FORMALDEHYDE

Methanol dehydrogenation to formaldehyde was operated in a continuous fixed-bed reactor with external recycling in the presence of sodium ca rbonate catalyst supported on active carbon. Due to the importance of gas phase decompositions of methanol and mainly formaldehyde, selectiv ity of formaldehyde in such a reactor is small compared to that obtain ed in a fixed-bed reactor. Furthermore, the contribution of gas phase reactions to formaldehyde synthesis through global dehydrogenation of methanol complicates steady-state kinetic studies. However, transient and methanol isotope (CD3OD and CH3OD) transient experiments showed th at a hydrogen species and also a methoxy and/or a hydroxymethyl interm ediate(s) are strongly adsorbed on the catalyst surface. Based on thes e facts, a mechanism of methanol dehydrogenation on sodium carbonate c atalyst supported on active carbon is proposed.