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Title: Catalysis by zeolites - active sites, kinetics, mechanisms

Abstract

In the past twenty five years, zeolites have become very important catalysts for the petroleum and petrochemical industry as a result of their high activity and shape selectivity. They have also enabled us to gain new insight into fundamental aspects of acid catalysts and to rationally design new catalysts. In contrast to large pore zeolites such as faujasite and mordenite, medium pore zeolites such as ZSM-5 exhibit very much lower catalyst deactivation rates. Our studies indicate that this is largely a consequence of their much lower activity for hydrogen transfer as a result of steric inhibition of this bimolecular reaction. High SiO{sub 2}/Al{sub 2}O{sub 3} zeolites can be prepared with well-defined catalytic sites of uniform activity whose number can be changed over four orders of magnitude. The most striking feature of zeolite catalysis is that of shape selectivity. It can result from the relative diffusion rates of various feed and product molecules or from a steric constraint of the reaction transition state. The distinction between the cause of an observed shape selectivity is of fundamental interest and has important consequences for catalyst design. Using medium pore zeolites we have identified a novel olefin interconversion reaction which equilibrates olefins to amore » pseudo-equilibrium mixture of all carbon numbers with a minimum of side reaction, and have elucidated its mechanism. A new process for the conversion of light olefins to gasoline, jet fuel and distillates has been developed based on this discovery.« less

Authors:
 [1]
  1. (Mobile Research and Development Corporation, Princeton, NJ (USA))
Publication Date:
OSTI Identifier:
5238024
Alternate Identifier(s):
OSTI ID: 5238024
Report Number(s):
CONF-8806304--
Journal ID: ISSN 0569-3799; CODEN: ACPCA
Resource Type:
Conference
Journal Name:
American Chemical Society, Division of Petroleum Chemistry, Preprints; (USA)
Additional Journal Information:
Journal Volume: 33:2; Conference: Symposium on characterization and chemistry of tar sand, Toronto (Canada), 5-10 Jun 1988; Journal ID: ISSN 0569-3799
Country of Publication:
United States
Language:
English
Subject:
02 PETROLEUM; CATALYTIC CRACKING; REVIEWS; GASOLINE; PRODUCTION; JET ENGINE FUELS; ZEOLITES; CATALYTIC EFFECTS; CATALYSIS; CATALYSTS; CHEMICAL REACTION KINETICS; DIFFUSION; EQUILIBRIUM; CHEMICAL REACTIONS; CRACKING; DECOMPOSITION; DOCUMENT TYPES; FUELS; INORGANIC ION EXCHANGERS; ION EXCHANGE MATERIALS; KINETICS; LIQUID FUELS; MATERIALS; MINERALS; PETROLEUM PRODUCTS; PYROLYSIS; REACTION KINETICS; THERMOCHEMICAL PROCESSES 020400* -- Petroleum-- Processing; 020500 -- Petroleum-- Products & By-Products

Citation Formats

Haag, W.O. Catalysis by zeolites - active sites, kinetics, mechanisms. United States: N. p., 1988. Web.
Haag, W.O. Catalysis by zeolites - active sites, kinetics, mechanisms. United States.
Haag, W.O. Wed . "Catalysis by zeolites - active sites, kinetics, mechanisms". United States.
@article{osti_5238024,
title = {Catalysis by zeolites - active sites, kinetics, mechanisms},
author = {Haag, W.O.},
abstractNote = {In the past twenty five years, zeolites have become very important catalysts for the petroleum and petrochemical industry as a result of their high activity and shape selectivity. They have also enabled us to gain new insight into fundamental aspects of acid catalysts and to rationally design new catalysts. In contrast to large pore zeolites such as faujasite and mordenite, medium pore zeolites such as ZSM-5 exhibit very much lower catalyst deactivation rates. Our studies indicate that this is largely a consequence of their much lower activity for hydrogen transfer as a result of steric inhibition of this bimolecular reaction. High SiO{sub 2}/Al{sub 2}O{sub 3} zeolites can be prepared with well-defined catalytic sites of uniform activity whose number can be changed over four orders of magnitude. The most striking feature of zeolite catalysis is that of shape selectivity. It can result from the relative diffusion rates of various feed and product molecules or from a steric constraint of the reaction transition state. The distinction between the cause of an observed shape selectivity is of fundamental interest and has important consequences for catalyst design. Using medium pore zeolites we have identified a novel olefin interconversion reaction which equilibrates olefins to a pseudo-equilibrium mixture of all carbon numbers with a minimum of side reaction, and have elucidated its mechanism. A new process for the conversion of light olefins to gasoline, jet fuel and distillates has been developed based on this discovery.},
doi = {},
journal = {American Chemical Society, Division of Petroleum Chemistry, Preprints; (USA)},
issn = {0569-3799},
number = ,
volume = 33:2,
place = {United States},
year = {1988},
month = {6}
}

Conference:
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