Tellurium-loaded zeolites: II. The nature of the dehydrocyclization site

Abstract

A study of the elution of tellurium from TeNaX and TeKX by hydrogen at elevated temperature has shown that the reducing atmosphere can prevent complete elution of tellurium from the catalyst. The inferred necessity of hydrogen for the formation of the aromatization site has been combined with the results of a separate crystallographic analysis and leads to a model for the active entity that rationalizes essentially all of our knowledge on these systems. The catalytically active entity is believed to be a tellurium ion, in the supercage of the zeolite base, coordinated to Site II and Site III cations. Support for this model comes from catalytic experiments designed to show the criticality of the presence of Site III cations.