Methylamine synthesis over solid acid catalysts: Reaction kinetic measurements

Kinetic studies were performed over silica-alumina and acidic zeolites to determine the effects of temperature (from 600 to 700 K) and reactant pressures ( < 80 Torr) on the rates of methylamine synthesis from methanol and ammonia. Related kinetic studies were conducted of methylamine disproportionation reactions, methanol dehydration, and reactions of methanol and dimethyl ether with methylamines. The results suggest that the reactive species for methylamine synthesis are adsorbed nitrogenous bases, while methoxy groups are reactive species for dimethyl ether production. Disproportionation reactions may be important pathways for the production of the higher-substituted amines during methylamine synthesis. The combination of microcalorimetric measurements, reported elsewhere, and kinetic studies suggests that acid sites are required in these reactions for the strong adsorption of ammonia and methylamines, and weak adsorption sites are required to facilitate desorption of adsorbed amine species from the acid sites.