Vapour-phase condensation of methyl propionate with trioxane over alumina-supported potassium catalyst

Alumina-supported potassium (K/Al 2 O 3 ) catalysts using pseudo-boehmite as the precursor were prepared by the impregnation/calcination method, characterised by XRD, SEM, ICP, N 2 adsorption/desorption, CO 2 -TPD methods and TG analysis, and applied to the vapour-phase condensation of methyl propionate with trioxane to produce methyl methacrylate. The results showed the catalysts’ properties to be mainly affected by the calcined temperature ( T C ) and the crystal structure. The sample calcined at 1100°C exhibited the highest catalytic activity when mixed phases were formed and provided the appropriate specific surface area ( S BET ) and surface basic properties. The effects of T C , K-loading and reaction conditions on the catalytic performance were also investigated in a fixed-bed reactor. The yield of methyl methacrylate attained 29.2 % under the optimised conditions, and the deactivated catalyst could be completely regenerated by calcination.