Preparation of melamine from cyanuric acid by sublimation and decomposition to cyanic acid and contact with an alumina-type catalyst

摘要

Preparation of melamine comprises sublimation and decomposition of cyanuric acid. Gaseous cyanic acid is directed through anhydrous catalyst comprising boehmite, crystallized alpha , beta and gamma alumina, amorphous alumina, thermally treated (hydr)oxides of aluminum, (non-)crystallized aluminas, silico-aluminates, doped- or non-doped alumino-silicates or silico-aluminates. Melamine formed is recovered by condensation of gaseous stream. Preparation of melamine by the sublimation and decomposition of cyanuric acid, the gaseous cyanic acid formed being directed through an anhydrous catalyst consisting of boehmite, crystallized alpha , beta and gamma alumina, amorphous alumina, thermally treated oxides and hydroxides of aluminum, crystallized or non-crystallized aluminas, silico-aluminates, doped- or non-doped alumino-silicates or silico-aluminates; the melamine formed is recovered by condensation of the gaseous stream. An independent claim is also included for the purification of the melamine produced.