Tailoring nanoscopic confines to maximize catalytic activity of hydronium ions
- Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Inst. for Integrated Catalysis; DOE/OSTI
- Technische Univ. Munchen, Garching (Germany). Dept. of Chemistry and Catalysis Research Center
- Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Inst. for Integrated Catalysis
- Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Inst. for Integrated Catalysis; Technische Univ. Munchen, Garching (Germany). Dept. of Chemistry and Catalysis Research Center
Acid catalysis by hydronium ions is ubiquitous in aqueous-phase organic reactions. Here we show that hydronium ion catalysis, exemplified by intramolecular dehydration of cyclohexanol, is markedly influenced by steric constraints, yielding turnover rates that increase by up to two orders of magnitude in tight confines relative to an aqueous solution of a Brønsted acid. The higher activities in zeolites BEA and FAU than in water are caused by more positive activation entropies that more than offset higher activation enthalpies. The higher activity in zeolite MFI with pores smaller than BEA and FAU is caused by a lower activation enthalpy in the tighter confines that more than offsets a less positive activation entropy. Molecularly sized pores significantly enhance the association between hydronium ions and alcohols in a steric environment resembling the constraints in pockets of enzymes stabilizing active sites.
- Research Organization:
- Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES). Chemical Sciences, Geosciences & Biosciences Division
- Grant/Contract Number:
- AC05-76RL01830
- OSTI ID:
- 1623891
- Alternate ID(s):
- OSTI ID: 1735943
OSTI ID: 1643787
- Report Number(s):
- PNNL-SA--121731; PII: BFncomms15442
- Journal Information:
- Nature Communications, Journal Name: Nature Communications Journal Issue: 1 Vol. 8; ISSN 2041-1723
- Publisher:
- Nature Publishing GroupCopyright Statement
- Country of Publication:
- United States
- Language:
- English
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Tailoring nanoscopic confines to maximize catalytic activity of hydronium ions
Journal Article
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Thu May 25 00:00:00 EDT 2017
· Nature Communications
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OSTI ID:1643787