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Title: The influence of chemisorbed molecules on mass transfer in H-ZSM-5-type zeolites and the location of Broensted acid sites

Abstract

Heterogeneous catalysis is one of the most important applications of zeolites. Therefore, various methods have been developed to determine the strength and concentration of Bronsted acid sites in zeolites. Among them, in the last few years, {sup 1}H MAS NMR has become a powerful tool. In addition to the accessibility of the acid sites probed by chemisorption of N-bases, the steric environment of these catalytically active sites is of importance since it imposes constraints on the geometry of the transition state. However, only a few studies have been reported on this topic. Information was obtained from quantum chemical calculations, catalytic experiments, I.R. spectroscopy, and the arrangement of guest molecules. From these investigations it has been concluded that in H-ZSM-5 the channel intersections should be preferential location centers for the Bronsted acid sites. In adsorption technology, in the use of zeolites as shape-selective adsorbents, modification of the molecular sieve properties by chemisorption of nitrogen-containing bases (N-compounds) has become a common technique. The authors have applied the NMR pulsed field gradient technique to study the influence of chemisorbed N-compounds on transport properties of molecular sieves, considering the chemisorbed compounds as transport obstacles.

Authors:
;  [1]; ;  [2]
  1. Zentralinstitut fuer Physikalische Chemie der AdW der DDR, Berlin (Germany, F.R.)
  2. Karl-Marx-Universitaet, Leipzig (Germany, F.R.)
Publication Date:
OSTI Identifier:
6945445
Resource Type:
Journal Article
Journal Name:
Journal of Catalysis; (USA)
Additional Journal Information:
Journal Volume: 114:1; Journal ID: ISSN 0021-9517
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; ZEOLITES; SURFACE PROPERTIES; CHEMISORPTION; HETEROGENEOUS CATALYSIS; MASS TRANSFER; METHANE; MOLECULAR SIEVES; NITROGEN; NITROGEN COMPOUNDS; NUCLEAR MAGNETIC RESONANCE; PH VALUE; SAMPLE PREPARATION; SELF-DIFFUSION; ADSORBENTS; ALKANES; CATALYSIS; CHEMICAL REACTIONS; DIFFUSION; ELEMENTS; HYDROCARBONS; INORGANIC ION EXCHANGERS; ION EXCHANGE MATERIALS; MAGNETIC RESONANCE; MATERIALS; MINERALS; NONMETALS; ORGANIC COMPOUNDS; RESONANCE; SEPARATION PROCESSES; SORPTION; 400201* - Chemical & Physicochemical Properties

Citation Formats

Caro, J, Buelow, M, Kaerger, J, and Pfeifer, H. The influence of chemisorbed molecules on mass transfer in H-ZSM-5-type zeolites and the location of Broensted acid sites. United States: N. p., 1988. Web. doi:10.1016/0021-9517(88)90020-6.
Caro, J, Buelow, M, Kaerger, J, & Pfeifer, H. The influence of chemisorbed molecules on mass transfer in H-ZSM-5-type zeolites and the location of Broensted acid sites. United States. https://doi.org/10.1016/0021-9517(88)90020-6
Caro, J, Buelow, M, Kaerger, J, and Pfeifer, H. 1988. "The influence of chemisorbed molecules on mass transfer in H-ZSM-5-type zeolites and the location of Broensted acid sites". United States. https://doi.org/10.1016/0021-9517(88)90020-6.
@article{osti_6945445,
title = {The influence of chemisorbed molecules on mass transfer in H-ZSM-5-type zeolites and the location of Broensted acid sites},
author = {Caro, J and Buelow, M and Kaerger, J and Pfeifer, H},
abstractNote = {Heterogeneous catalysis is one of the most important applications of zeolites. Therefore, various methods have been developed to determine the strength and concentration of Bronsted acid sites in zeolites. Among them, in the last few years, {sup 1}H MAS NMR has become a powerful tool. In addition to the accessibility of the acid sites probed by chemisorption of N-bases, the steric environment of these catalytically active sites is of importance since it imposes constraints on the geometry of the transition state. However, only a few studies have been reported on this topic. Information was obtained from quantum chemical calculations, catalytic experiments, I.R. spectroscopy, and the arrangement of guest molecules. From these investigations it has been concluded that in H-ZSM-5 the channel intersections should be preferential location centers for the Bronsted acid sites. In adsorption technology, in the use of zeolites as shape-selective adsorbents, modification of the molecular sieve properties by chemisorption of nitrogen-containing bases (N-compounds) has become a common technique. The authors have applied the NMR pulsed field gradient technique to study the influence of chemisorbed N-compounds on transport properties of molecular sieves, considering the chemisorbed compounds as transport obstacles.},
doi = {10.1016/0021-9517(88)90020-6},
url = {https://www.osti.gov/biblio/6945445}, journal = {Journal of Catalysis; (USA)},
issn = {0021-9517},
number = ,
volume = 114:1,
place = {United States},
year = {Tue Nov 01 00:00:00 EST 1988},
month = {Tue Nov 01 00:00:00 EST 1988}
}