HIGHLY SELECTIVE METHYLAMINE SYNTHESIS OVER MODIFIED MORDENITE CATALYSTS

Methylamine syntheses from methanol and ammonia on various zeolite catalysts have been studied over a temperature range of 573-673 K at atmospheric pressure. The mordenite catalysts were treated with silicon tetrachloride in sodium form and then ion-exchanged to the acid form; such catalysts have been shown to suppress trimethylamine production almost completely and to generate enhanced yields of dimethylamine and/or monomethylamine. The formation of TMA has been extremely retarded because the pore openings of the catalyst are smaller than TMA molecules. The sorption data of methylamines and IR spectroscopy studies suggest that the more bulky base molecules, such as trimethylamine or pyridine, cannot penetrate into mordenite channels after treatment with silicon tetrachloride. The 29Si- and 27Al-MASNMR studies showed that silicon tetrachloride treatment caused less dealumination of zeolite framework for sodium mordenite than for H mordenite. © 1991.