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Title: A temperature-programmed desorption study of olefin oligomerization in H-ZSM-5

Abstract

The authors have used temperature-programmed desorption and thermogravimetric analysis (TPD-TGA), with gas chromatographic analysis of products, to examine the low-temperature reaction of ethene, propene, and 2-methyl-2-propanol in H-ZSM-5. Propene reacts rapidly inside the zeolite at 295 K to form large oligomer chains, while the zeolite must be heated to above 370 K for ethene oligomerization to occur. In both cases, reaction does not stop until a coverage of 7.8g/100 g is reached on a zeolite with a SiO{sub 2}/Al{sub 2}O{sub 3} ratio of 70. This is a substantial fraction of the zeolite pore volume, >50% assuming that the density of the oligomers is similar to that of polypropylene, suggesting that reaction stops only when blocking prevents reactants from approaching the acid sites. In TPD carried out under vacuum, the oligomer chains from both ethene and propene are completely removed in two desorption features centered at 420 and 550 K. Analyses of the products from both ethene and propene show a similar mixture of olefin product ranging from C{sub 2} to C{sub 7}, with no noticeable preference for monomer, dimer, or trimer products. Analysis of the butene isomers in the products indicates that the concentrations are close to that obtained formore » equilibrium mixtures. With 2-methyl-2-propanol, adsorption and dehydration occur at 295 K. On a zeolite sample with a SiO{sub 2}/Al{sub 2}O{sub 3} ratio of 70, concentrations of the olefin desorption products formed in TPD are essentially identical to those observed for propene and ethene, suggesting that they are due to the formation and cracking of oligomeric species very similar to that observed following olefin adsorption. On a zeolite with a SiO{sub 2}/Al{sub 2}O{sub 3} ratio of 520, this oligomerization with 2-methyl-2-propanol can be minimized and methylpropene is a major product.« less

Authors:
;  [1]
  1. Univ. of Pennsylvania, Philadelphia (USA)
Publication Date:
OSTI Identifier:
6958425
Resource Type:
Journal Article
Journal Name:
Journal of Catalysis; (USA)
Additional Journal Information:
Journal Volume: 115:1; Journal ID: ISSN 0021-9517
Country of Publication:
United States
Language:
English
Subject:
02 PETROLEUM; ETHYLENE; POLYMERIZATION; PROPANOLS; PROPYLENE; ZEOLITES; CATALYTIC EFFECTS; ADSORPTION; ALKENES; ALUMINIUM OXIDES; BUTENES; CHEMICAL ANALYSIS; CHEMICAL REACTION YIELD; DEHYDRATION; DESORPTION; GAS CHROMATOGRAPHY; POLYMERS; POROSITY; QUANTITY RATIO; SILICON OXIDES; TEMPERATURE CONTROL; TEMPERATURE DEPENDENCE; THERMAL GRAVIMETRIC ANALYSIS; ALCOHOLS; ALUMINIUM COMPOUNDS; CHALCOGENIDES; CHEMICAL REACTIONS; CHROMATOGRAPHY; CONTROL; GRAVIMETRIC ANALYSIS; HYDROCARBONS; HYDROXY COMPOUNDS; INORGANIC ION EXCHANGERS; ION EXCHANGE MATERIALS; MATERIALS; MINERALS; ORGANIC COMPOUNDS; OXIDES; OXYGEN COMPOUNDS; QUANTITATIVE CHEMICAL ANALYSIS; SEPARATION PROCESSES; SILICON COMPOUNDS; SORPTION; THERMAL ANALYSIS; YIELDS; 020400* - Petroleum- Processing

Citation Formats

Kofke, T J.G., and Gorte, R J. A temperature-programmed desorption study of olefin oligomerization in H-ZSM-5. United States: N. p., 1989. Web. doi:10.1016/0021-9517(89)90021-3.
Kofke, T J.G., & Gorte, R J. A temperature-programmed desorption study of olefin oligomerization in H-ZSM-5. United States. https://doi.org/10.1016/0021-9517(89)90021-3
Kofke, T J.G., and Gorte, R J. 1989. "A temperature-programmed desorption study of olefin oligomerization in H-ZSM-5". United States. https://doi.org/10.1016/0021-9517(89)90021-3.
@article{osti_6958425,
title = {A temperature-programmed desorption study of olefin oligomerization in H-ZSM-5},
author = {Kofke, T J.G. and Gorte, R J},
abstractNote = {The authors have used temperature-programmed desorption and thermogravimetric analysis (TPD-TGA), with gas chromatographic analysis of products, to examine the low-temperature reaction of ethene, propene, and 2-methyl-2-propanol in H-ZSM-5. Propene reacts rapidly inside the zeolite at 295 K to form large oligomer chains, while the zeolite must be heated to above 370 K for ethene oligomerization to occur. In both cases, reaction does not stop until a coverage of 7.8g/100 g is reached on a zeolite with a SiO{sub 2}/Al{sub 2}O{sub 3} ratio of 70. This is a substantial fraction of the zeolite pore volume, >50% assuming that the density of the oligomers is similar to that of polypropylene, suggesting that reaction stops only when blocking prevents reactants from approaching the acid sites. In TPD carried out under vacuum, the oligomer chains from both ethene and propene are completely removed in two desorption features centered at 420 and 550 K. Analyses of the products from both ethene and propene show a similar mixture of olefin product ranging from C{sub 2} to C{sub 7}, with no noticeable preference for monomer, dimer, or trimer products. Analysis of the butene isomers in the products indicates that the concentrations are close to that obtained for equilibrium mixtures. With 2-methyl-2-propanol, adsorption and dehydration occur at 295 K. On a zeolite sample with a SiO{sub 2}/Al{sub 2}O{sub 3} ratio of 70, concentrations of the olefin desorption products formed in TPD are essentially identical to those observed for propene and ethene, suggesting that they are due to the formation and cracking of oligomeric species very similar to that observed following olefin adsorption. On a zeolite with a SiO{sub 2}/Al{sub 2}O{sub 3} ratio of 520, this oligomerization with 2-methyl-2-propanol can be minimized and methylpropene is a major product.},
doi = {10.1016/0021-9517(89)90021-3},
url = {https://www.osti.gov/biblio/6958425}, journal = {Journal of Catalysis; (USA)},
issn = {0021-9517},
number = ,
volume = 115:1,
place = {United States},
year = {Sun Jan 01 00:00:00 EST 1989},
month = {Sun Jan 01 00:00:00 EST 1989}
}