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Title: Mechanism of selective benzene hydroxylation catalyzed by iron-containing zeolites

Abstract

A direct, catalytic conversion of benzene to phenol would have wide-reaching economic impacts. Fe zeolites exhibit a remarkable combination of high activity and selectivity in this conversion, leading to their past implementation at the pilot plant level. There were, however, issues related to catalyst deactivation for this process. Mechanistic insight could resolve these issues, and also provide a blueprint for achieving high performance in selective oxidation catalysis. Recently, we demonstrated that the active site of selective hydrocarbon oxidation in Fe zeolites, named α-O, is an unusually reactive Fe(IV)=O species. Here in this paper, we apply advanced spectroscopic techniques to determine that the reaction of this Fe(IV)=O intermediate with benzene in fact regenerates the reduced Fe(II) active site, enabling catalytic turnover. At the same time, a small fraction of Fe(III)-phenolate poisoned active sites form, defining a mechanism for catalyst deactivation. Density-functional theory calculations provide further insight into the experimentally defined mechanism. The extreme reactivity of α-O significantly tunes down (eliminates) the rate-limiting barrier for aromatic hydroxylation, leading to a diffusion-limited reaction coordinate. This favors hydroxylation of the rapidly diffusing benzene substrate over the slowly diffusing (but more reactive) oxygenated product, thereby enhancing selectivity. This defines a mechanism to simultaneously attain highmore » activity (conversion) and selectivity, enabling the efficient oxidative upgrading of inert hydrocarbon substrates.« less

Authors:
 [1];  [2];  [1];  [3];  [1];  [1]; ORCiD logo [1];  [1];  [1]; ORCiD logo [4];  [4];  [4];  [5];  [6];  [2];  [2]; ORCiD logo [6]
  1. Stanford Univ., CA (United States). Dept. of Chemistry
  2. Katholieke Univ. Leuven, Leuven (Belgium). Dept. of Microbial and Molecular Systems, Centre for Surface Chemistry and Catalysis
  3. Stanford Univ., CA (United States). Dept. of Chemistry; Katholieke Univ. Leuven, Leuven (Belgium). Dept. of Microbial and Molecular Systems, Centre for Surface Chemistry and Catalysis
  4. Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS)
  5. SLAC National Accelerator Lab., Menlo Park, CA (United States). Stanford Synchrotron Radiation Lightsource (SSRL)
  6. Stanford Univ., CA (United States). Dept. of Chemistry; SLAC National Accelerator Lab., Menlo Park, CA (United States). Stanford Synchrotron Radiation Lightsource (SSRL)
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States); SLAC National Accelerator Lab., Menlo Park, CA (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1490638
Alternate Identifier(s):
OSTI ID: 1482162; OSTI ID: 1490261
Grant/Contract Number:  
AC02-06CH11357; AC02-76SF00515; DGE-11474; CHE-1660611; Munger; Pollock; Reynolds; Robinson; Smith & Yoedicke Stanford Graduate Fellowship; 12L0715N; V417018N; G0A2216N; Gerhard Casper Stanford Graduate Fellowship; P41GM103393
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Proceedings of the National Academy of Sciences of the United States of America
Additional Journal Information:
Journal Volume: 115; Journal Issue: 48; Journal ID: ISSN 0027-8424
Publisher:
National Academy of Sciences, Washington, DC (United States)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; catalysis; spectroscopy; zeolites

Citation Formats

Snyder, Benjamin E. R., Bols, Max L., Rhoda, Hannah M., Vanelderen, Pieter, Böttger, Lars H., Braun, Augustin, Yan, James J., Hadt, Ryan G., Babicz, Jeffrey T., Hu, Michael Y., Zhao, Jiyong, Alp, E. Ercan, Hedman, Britt, Hodgson, Keith O., Schoonheydt, Robert A., Sels, Bert F., and Solomon, Edward I.. Mechanism of selective benzene hydroxylation catalyzed by iron-containing zeolites. United States: N. p., 2018. Web. doi:10.1073/pnas.1813849115.
Snyder, Benjamin E. R., Bols, Max L., Rhoda, Hannah M., Vanelderen, Pieter, Böttger, Lars H., Braun, Augustin, Yan, James J., Hadt, Ryan G., Babicz, Jeffrey T., Hu, Michael Y., Zhao, Jiyong, Alp, E. Ercan, Hedman, Britt, Hodgson, Keith O., Schoonheydt, Robert A., Sels, Bert F., & Solomon, Edward I.. Mechanism of selective benzene hydroxylation catalyzed by iron-containing zeolites. United States. doi:10.1073/pnas.1813849115.
Snyder, Benjamin E. R., Bols, Max L., Rhoda, Hannah M., Vanelderen, Pieter, Böttger, Lars H., Braun, Augustin, Yan, James J., Hadt, Ryan G., Babicz, Jeffrey T., Hu, Michael Y., Zhao, Jiyong, Alp, E. Ercan, Hedman, Britt, Hodgson, Keith O., Schoonheydt, Robert A., Sels, Bert F., and Solomon, Edward I.. Wed . "Mechanism of selective benzene hydroxylation catalyzed by iron-containing zeolites". United States. doi:10.1073/pnas.1813849115.
@article{osti_1490638,
title = {Mechanism of selective benzene hydroxylation catalyzed by iron-containing zeolites},
author = {Snyder, Benjamin E. R. and Bols, Max L. and Rhoda, Hannah M. and Vanelderen, Pieter and Böttger, Lars H. and Braun, Augustin and Yan, James J. and Hadt, Ryan G. and Babicz, Jeffrey T. and Hu, Michael Y. and Zhao, Jiyong and Alp, E. Ercan and Hedman, Britt and Hodgson, Keith O. and Schoonheydt, Robert A. and Sels, Bert F. and Solomon, Edward I.},
abstractNote = {A direct, catalytic conversion of benzene to phenol would have wide-reaching economic impacts. Fe zeolites exhibit a remarkable combination of high activity and selectivity in this conversion, leading to their past implementation at the pilot plant level. There were, however, issues related to catalyst deactivation for this process. Mechanistic insight could resolve these issues, and also provide a blueprint for achieving high performance in selective oxidation catalysis. Recently, we demonstrated that the active site of selective hydrocarbon oxidation in Fe zeolites, named α-O, is an unusually reactive Fe(IV)=O species. Here in this paper, we apply advanced spectroscopic techniques to determine that the reaction of this Fe(IV)=O intermediate with benzene in fact regenerates the reduced Fe(II) active site, enabling catalytic turnover. At the same time, a small fraction of Fe(III)-phenolate poisoned active sites form, defining a mechanism for catalyst deactivation. Density-functional theory calculations provide further insight into the experimentally defined mechanism. The extreme reactivity of α-O significantly tunes down (eliminates) the rate-limiting barrier for aromatic hydroxylation, leading to a diffusion-limited reaction coordinate. This favors hydroxylation of the rapidly diffusing benzene substrate over the slowly diffusing (but more reactive) oxygenated product, thereby enhancing selectivity. This defines a mechanism to simultaneously attain high activity (conversion) and selectivity, enabling the efficient oxidative upgrading of inert hydrocarbon substrates.},
doi = {10.1073/pnas.1813849115},
journal = {Proceedings of the National Academy of Sciences of the United States of America},
issn = {0027-8424},
number = 48,
volume = 115,
place = {United States},
year = {2018},
month = {11}
}

Journal Article:
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