Gas Phase Reaction of Trimethylenediamine and Formalin in the Reactor packed with Alumina Catalyst

Abstract

By gas phase reaction of trimethylenediamine and formaldehyde on alumina catalyst, 1-methyl-hexahydro-pyrimidine (I) and 1, 3-dimethyl-hexahydropyrimidine (II) were obtained in a good yield. In a molar ratio of ECHO to trimethylenediamine (TMDA) of 1.34, I was obtained selectively and in the highest yield when reacted at 220°. At the temperature higher than 350°, 2-methylpyridine was obtained. In molar ratio of 2.68, I was obtained more than II in the temperature range of 180° to 240°, but II was obtained more than I in the range of 250° to 290°. At 230°, only I was obtained from a molar ratio of 1.8, and only II in a molar ratio of 4.0. The yield of I and II increased with W/F, and the yield of I was maximum W/F : of 180, but that of II was maximum at W/F : of 220.