Effect of dealumination of mordenite by acid-leaching for selective synthesis of ethylenediamine from ethanolamine

The synthesis of ethylenediamine (EDA) from ethanolamine (EA) with ammonia over acidic types of zeolite catalyst was investigated. Among the zeolites tested in this study, the protonic form of mordenite catalyst (MOR) that wa s dealuminated by HCl (H-HCI-MOR) showed increase in activity (from 12% of conversion (H-MOR) to 52% (H-HCl-MOR)). Out of the framework of the parent MOR, around 10% of the framework aluminum was leached by the acid treatment . The reaction proved to be highly selective for EA over H-HCI-MOR, with sm all amounts of ethyleneimine (EI) and piperazine (PA) derivatives as the si de products, compared with other processes. IR spectroscopic data provided evidence that the increase of Bronsted acid amount raised the activity and selectivity for EDA after dealumination. Along with the studies of adsorpti on of pyridine and ammonia, the heterogeneity of the OH band was also inves tigated. (C) 2000 Elsevier Science B.V. All rights reserved.