Effect of preadsorbed ammonia on isomerization of but-1-ene on NaHY zeolite

Abstract

The selective poisoning by ammonia of the active sites responsible for isomerization of but-1-ene on zeolite NzHY has been studied by a temperature programmed desorption method combined with gas liquid chromatography and fourier transform infrared spectroscopy in an attempt to obtain additional and more detailed information about the system. Two different types of surface centres involved in the chemisorption of ammonia and at least two different types of chemisorbed ammonia, “weak” and “strong”, were revealed. On the basis of the above results the isomerization of but-1-ene was carried out with preadsorbed ammonia as a poison. It was found that the stronger chemisorbed ammonia efficiently blocked the isomerization. The weakly adsorbed ammonia blocked the centres involved in the adsorption of but-1-ene.