Calorimetric Investigation of the Acidity of Dealuminated Y-Type Zeolites using Various Basic Probes

摘要: Abstract Y-type zeolites of various Si/Al ratios have been obtained by dealumination NaY using silicon tetrachloride as the dealuminating agent at reaction temperatures. All samples were highly crystalline. Microcalorimetric measurements ammonia, pyrrole, dimethylether and acetonitrile adsorption unveiled strength distributions among acid population these samples. Ammonia proved to be a reliable probe when Bronsted sites investigated. It helped unveil two site populations whose proportions varied in ratio. These differ local environment associated AlO 4 tetrahedra. Ammonia, however, failed reveal inhomogeneity one particular population. Dimethylether, too weak base, did not appear any better than whereas pyrrole appeared rather acidic which visualize basicity difference between parent material dealuminated Acetonitrile monitor quantitatively qualitatively Lewis acidity.