Theoretical Kinetic Study of the Unimolecular Keto–Enol Tautomerism Propen-2-ol ↔ Acetone. Pressure Effects and Implications in the Pyrolysis of tert- and 2-Butanol

Handle URI:
http://hdl.handle.net/10754/627478
Title:
Theoretical Kinetic Study of the Unimolecular Keto–Enol Tautomerism Propen-2-ol ↔ Acetone. Pressure Effects and Implications in the Pyrolysis of tert- and 2-Butanol
Authors:
Grajales Gonzalez, Edwing ( 0000-0002-2317-0884 ) ; Monge Palacios, Manuel ( 0000-0003-1199-5026 ) ; Sarathy, Mani ( 0000-0002-3975-6206 )
Abstract:
The need for renewable and cleaner sources of energy has made biofuels an interesting alternative to fossil fuels, especially in the case of butanol isomers, with its favorable blend properties and low hygroscopicity. Although C4 alcohols are prospective fuels, some key reactions governing their pyrolysis and combustion have not been adequately studied, leading to incomplete kinetic models. Enols are important intermediates in the combustion of C4 alcohols, as well as in atmospheric processes. Butanol reactions kinetics is poorly understood. Specifically, the unimolecular tautomerism of propen-2-ol ↔ acetone, which is included in butanol combustion kinetic models, is assigned rate parameters based on the tautomerism vinyl alcohol ↔ acetaldehyde as an analogy. In an attempt to update current kinetic models for tert- and 2-butanol, a theoretical kinetic study of the titled reaction was carried out by means of CCSD(T,FULL)/aug-cc-pVTZ//CCSD(T)/6-31+G(d,p) ab initio calculations, with multistructural torsional anharmonicity and variational transition state theory considerations in a wide temperature and pressure range (200-3000 K; 0.1-108 kPa). Results differ from vinyl alcohol ↔ acetaldehyde analogue reaction, which shows lower rate constant values. It was observed that decreasing pressure leads to a decrease in rate constants, describing the expected falloff behavior. Tunneling turned out to be important, especially at low temperatures. Accordingly, pyrolysis simulations in a batch reactor for tert- and 2-butanol with computed rate constants showed important differences in comparison with previous results, such as larger acetone yield and quicker propen-2-ol consumption.
KAUST Department:
Physical Sciences and Engineering (PSE) Division; Chemical and Biological Engineering Program; Clean Combustion Research Center
Citation:
Grajales-González E, Monge-Palacios M, Sarathy SM (2018) Theoretical Kinetic Study of the Unimolecular Keto–Enol Tautomerism Propen-2-ol ↔ Acetone. Pressure Effects and Implications in the Pyrolysis of tert- and 2-Butanol. The Journal of Physical Chemistry A 122: 3547–3555. Available: http://dx.doi.org/10.1021/acs.jpca.8b00836.
Publisher:
American Chemical Society (ACS)
Journal:
The Journal of Physical Chemistry A
KAUST Grant Number:
OSR-2016-CRG5-3022
Issue Date:
21-Mar-2018
DOI:
10.1021/acs.jpca.8b00836
Type:
Article
ISSN:
1089-5639; 1520-5215
Sponsors:
This work was supported by King Abdullah University of Science and Technology (KAUST), Office of Sponsored Research (OSR), under Award No. OSR-2016-CRG5-3022. We appreciate the resources of the Supercomputing Laboratory at KAUST.
Additional Links:
https://pubs.acs.org/doi/10.1021/acs.jpca.8b00836
Appears in Collections:
Articles; Physical Sciences and Engineering (PSE) Division; Chemical and Biological Engineering Program; Clean Combustion Research Center

Full metadata record

DC FieldValue Language
dc.contributor.authorGrajales Gonzalez, Edwingen
dc.contributor.authorMonge Palacios, Manuelen
dc.contributor.authorSarathy, Manien
dc.date.accessioned2018-04-16T07:49:42Z-
dc.date.available2018-04-16T07:49:42Z-
dc.date.issued2018-03-21en
dc.identifier.citationGrajales-González E, Monge-Palacios M, Sarathy SM (2018) Theoretical Kinetic Study of the Unimolecular Keto–Enol Tautomerism Propen-2-ol ↔ Acetone. Pressure Effects and Implications in the Pyrolysis of tert- and 2-Butanol. The Journal of Physical Chemistry A 122: 3547–3555. Available: http://dx.doi.org/10.1021/acs.jpca.8b00836.en
dc.identifier.issn1089-5639en
dc.identifier.issn1520-5215en
dc.identifier.doi10.1021/acs.jpca.8b00836en
dc.identifier.urihttp://hdl.handle.net/10754/627478-
dc.description.abstractThe need for renewable and cleaner sources of energy has made biofuels an interesting alternative to fossil fuels, especially in the case of butanol isomers, with its favorable blend properties and low hygroscopicity. Although C4 alcohols are prospective fuels, some key reactions governing their pyrolysis and combustion have not been adequately studied, leading to incomplete kinetic models. Enols are important intermediates in the combustion of C4 alcohols, as well as in atmospheric processes. Butanol reactions kinetics is poorly understood. Specifically, the unimolecular tautomerism of propen-2-ol ↔ acetone, which is included in butanol combustion kinetic models, is assigned rate parameters based on the tautomerism vinyl alcohol ↔ acetaldehyde as an analogy. In an attempt to update current kinetic models for tert- and 2-butanol, a theoretical kinetic study of the titled reaction was carried out by means of CCSD(T,FULL)/aug-cc-pVTZ//CCSD(T)/6-31+G(d,p) ab initio calculations, with multistructural torsional anharmonicity and variational transition state theory considerations in a wide temperature and pressure range (200-3000 K; 0.1-108 kPa). Results differ from vinyl alcohol ↔ acetaldehyde analogue reaction, which shows lower rate constant values. It was observed that decreasing pressure leads to a decrease in rate constants, describing the expected falloff behavior. Tunneling turned out to be important, especially at low temperatures. Accordingly, pyrolysis simulations in a batch reactor for tert- and 2-butanol with computed rate constants showed important differences in comparison with previous results, such as larger acetone yield and quicker propen-2-ol consumption.en
dc.description.sponsorshipThis work was supported by King Abdullah University of Science and Technology (KAUST), Office of Sponsored Research (OSR), under Award No. OSR-2016-CRG5-3022. We appreciate the resources of the Supercomputing Laboratory at KAUST.en
dc.publisherAmerican Chemical Society (ACS)en
dc.relation.urlhttps://pubs.acs.org/doi/10.1021/acs.jpca.8b00836en
dc.rightsThis document is the Accepted Manuscript version of a Published Work that appeared in final form in The Journal of Physical Chemistry A, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see https://pubs.acs.org/doi/10.1021/acs.jpca.8b00836.en
dc.titleTheoretical Kinetic Study of the Unimolecular Keto–Enol Tautomerism Propen-2-ol ↔ Acetone. Pressure Effects and Implications in the Pyrolysis of tert- and 2-Butanolen
dc.typeArticleen
dc.contributor.departmentPhysical Sciences and Engineering (PSE) Divisionen
dc.contributor.departmentChemical and Biological Engineering Programen
dc.contributor.departmentClean Combustion Research Centeren
dc.identifier.journalThe Journal of Physical Chemistry Aen
dc.eprint.versionPost-printen
kaust.authorGrajales Gonzalez, Edwingen
kaust.authorMonge Palacios, Manuelen
kaust.authorSarathy, Manien
kaust.grant.numberOSR-2016-CRG5-3022en
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