Impact of zeolite aging in hot liquid water on activity for acid-catalyzed dehydration of alcohols
Abstract
The catalytic performance of zeolite in aqueous medium depends on a multitude of factors, such as the concentration and distribution of active sites and framework integrity. Al K–edge extended X–ray absorption fine structure and 27Al MAS NMR spectroscopies in combination with DFT calculations are used to determine the distribution of tetrahedral Al sites both qualitatively and quantitatively for both parent and 48 h 160 ºC water treated HBEA catalysts. There is no evidence of Al coordination modification after aging in water. The distribution and concentration of Al T–sites, active centers for the dehydration of cyclohexanol, do not markedly impact the catalytic performance in water, because the Brønsted acidic protons are present in the form of hydrated hydronium ions and thus have very similar acid properties. The results suggest that all Brønsted acid sites are equally active in aqueous medium. The decrease of zeolite catalytic performance after water treatment is attributed to the reduced concentration of Brønsted acid sites. Increasing the stability of pore walls and decreasing the rate of Si–O–Si group hydrolysis may result in improved apparent zeolite catalytic performance in aqueous medium. Authors thank B. W. Arey (PNNL) for HIM measurements, T. Huthwelker for support during Al XAFS measurementsmore »
- Authors:
- Publication Date:
- Research Org.:
- Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
- Sponsoring Org.:
- USDOE
- OSTI Identifier:
- 1229991
- Report Number(s):
- PNNL-SA-107507
Journal ID: ISSN 0002-7863; KC0302010
- DOE Contract Number:
- AC05-76RL01830
- Resource Type:
- Journal Article
- Journal Name:
- Journal of the American Chemical Society
- Additional Journal Information:
- Journal Volume: 137; Journal Issue: 32; Journal ID: ISSN 0002-7863
- Publisher:
- American Chemical Society (ACS)
- Country of Publication:
- United States
- Language:
- English
- Subject:
- alcohol dehydration; catalysis; aqueous medium; zeolite stability
Citation Formats
Vjunov, Aleksei, Derewinski, Miroslaw A., Fulton, John L., Camaioni, Donald M., and Lercher, Johannes A. Impact of zeolite aging in hot liquid water on activity for acid-catalyzed dehydration of alcohols. United States: N. p., 2015.
Web. doi:10.1021/jacs.5b06169.
Vjunov, Aleksei, Derewinski, Miroslaw A., Fulton, John L., Camaioni, Donald M., & Lercher, Johannes A. Impact of zeolite aging in hot liquid water on activity for acid-catalyzed dehydration of alcohols. United States. https://doi.org/10.1021/jacs.5b06169
Vjunov, Aleksei, Derewinski, Miroslaw A., Fulton, John L., Camaioni, Donald M., and Lercher, Johannes A. 2015.
"Impact of zeolite aging in hot liquid water on activity for acid-catalyzed dehydration of alcohols". United States. https://doi.org/10.1021/jacs.5b06169.
@article{osti_1229991,
title = {Impact of zeolite aging in hot liquid water on activity for acid-catalyzed dehydration of alcohols},
author = {Vjunov, Aleksei and Derewinski, Miroslaw A. and Fulton, John L. and Camaioni, Donald M. and Lercher, Johannes A.},
abstractNote = {The catalytic performance of zeolite in aqueous medium depends on a multitude of factors, such as the concentration and distribution of active sites and framework integrity. Al K–edge extended X–ray absorption fine structure and 27Al MAS NMR spectroscopies in combination with DFT calculations are used to determine the distribution of tetrahedral Al sites both qualitatively and quantitatively for both parent and 48 h 160 ºC water treated HBEA catalysts. There is no evidence of Al coordination modification after aging in water. The distribution and concentration of Al T–sites, active centers for the dehydration of cyclohexanol, do not markedly impact the catalytic performance in water, because the Brønsted acidic protons are present in the form of hydrated hydronium ions and thus have very similar acid properties. The results suggest that all Brønsted acid sites are equally active in aqueous medium. The decrease of zeolite catalytic performance after water treatment is attributed to the reduced concentration of Brønsted acid sites. Increasing the stability of pore walls and decreasing the rate of Si–O–Si group hydrolysis may result in improved apparent zeolite catalytic performance in aqueous medium. Authors thank B. W. Arey (PNNL) for HIM measurements, T. Huthwelker for support during Al XAFS measurements at the Swiss Light Source (PSI, Switzerland), J. Z. Hu and S. D. Burton (PNNL) for support during NMR experiments. This work was supported by the U. S. Department of Energy (DOE), Office of Science, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences & Biosciences. MD acknowledges support by the Materials Synthesis and Simulation Across Scales (MS3 Initiative) conducted under Laboratory Directed Research & Development Program at PNNL. HIM imaging and NMR experiments were performed at the Environmental Molecular Sciences Laboratory, a national scientific user facility sponsored by the DOE Office of Science, Office of Biological and Environmental Research, located at Pacific Northwest National Laboratory (PNNL). PNNL is a multiprogram national laboratory operated for the DOE by Battelle Memorial Institute under contract # DE-AC05-76RL0-1830},
doi = {10.1021/jacs.5b06169},
url = {https://www.osti.gov/biblio/1229991},
journal = {Journal of the American Chemical Society},
issn = {0002-7863},
number = 32,
volume = 137,
place = {United States},
year = {Wed Aug 19 00:00:00 EDT 2015},
month = {Wed Aug 19 00:00:00 EDT 2015}
}