Carbon-13 solid state MASNMR study on the role of pyrrolidine in various high silica zeolites

Abstract

The ¹³C CPMASNMR spectroscopy and thermal analysis of pyrrolidine present in the as-synthesized forms of ZSM-23, ZSM-5 and ZSM-51 zeolites demonstrate that the pyrrolidine is occluded as neutral, chemically intact species in the to-ring unidimensional, non-intersecting channels of ZSM-23. In ZSM-51 with its 6-membered channels pyrrolidine is located mainly in the large cages (probably as charged species). In ZSM-5, pyrrolidine molecules are present both as neutral molecules (in the channels) and probably as charged species (at the channel intersections).