A comparative study of methylamines synthesis over zeolites H-rho and H-PST-29

Abstract

A comparative study was performed not only on the proton form of rho and PST-29, the first and second generations of the RHO family of embedded isoreticular zeolites, respectively, but also on their steam-dealuminated analogues, as catalysts for methylamines synthesis at 400 degrees C from ammonia and methanol. A similar yield in the sum of monomethylamine plus dimethylamine was observed for H-rho and H-PST-29. Steam treatment at 600 degrees C gave both zeolites an increase in catalyst lifetime, but which is much more apparent in H-PST-29, probably due to a larger decrease in strength of medium and strong acid sites, together with the mesopore formation. Dealumianted PST-29 showed a somewhat lower catalyst stability than H-mordenite, the former commercial catalyst for this reaction. However, it was found to exhibit a much higher yield in smaller methylamines and a comparable regenerability.