Ab initio variational transition state theory and master equation study of the reaction (OH)3SiOCH2 + CH3 ⇌ (OH)3SiOC2H5

In this paper we use variable reaction coordinate variational transition state theory (VRC-TST) to calculate the reaction rate constants for the two reactions, R1: (OH)3SiOCH2 + CH3 ⇌ (OH)3SiOC2H5, and R2: CH2OH + CH3 ⇌ C2H5OH. The first reaction is an important channel during the thermal decomposit...

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Main Authors: Nurkowski, Daniel, Klippenstein, Stephen J., Georgievskii, Yuri, Verdicchio, Marco, Jasper, Ahren W., Akroyd, Jethro, Mosbach, Sebastian, Kraft, Markus
Other Authors: School of Chemical and Biomedical Engineering
Format: Article
Language:English
Published: 2015
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Online Access:https://hdl.handle.net/10356/98118
http://hdl.handle.net/10220/25660
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spelling sg-ntu-dr.10356-981182023-12-29T06:48:08Z Ab initio variational transition state theory and master equation study of the reaction (OH)3SiOCH2 + CH3 ⇌ (OH)3SiOC2H5 Nurkowski, Daniel Klippenstein, Stephen J. Georgievskii, Yuri Verdicchio, Marco Jasper, Ahren W. Akroyd, Jethro Mosbach, Sebastian Kraft, Markus School of Chemical and Biomedical Engineering DRNTU::Science::Medicine::Biomedical engineering In this paper we use variable reaction coordinate variational transition state theory (VRC-TST) to calculate the reaction rate constants for the two reactions, R1: (OH)3SiOCH2 + CH3 ⇌ (OH)3SiOC2H5, and R2: CH2OH + CH3 ⇌ C2H5OH. The first reaction is an important channel during the thermal decomposition of tetraethoxysilane (TEOS), and its rate coefficient is the main focus of this work. The second reaction is analogous to the first and is used as a basis for comparison. The interaction energies are obtained on-the-fly at the CASPT2(2e,2o)/cc-pVDZ level of theory. A one-dimensional correction to the sampled energies was introduced to account for the energetic effects of geometry relaxation along the reaction path. The computed, high-pressure rate coefficients were calculated to be, R1: k1 = 2.406 × 10−10T−0.301 exp (− 271.4/T) cm3 molecule–1 s–1 and R2: k2 = 1.316 × 10−10T−0.189 exp (− 256.5/T) cm3 molecule–1 s–1. These rates differ from each other by only 10% – 30% over the temperature range 300–2000 K. A comparison of the computed rates with experimental data shows good agreement and an improvement over previous results. The pressure dependency of the reaction R1 is explored by solving a master equation using helium as a bath gas. The results obtained show that the reaction is only weakly pressure dependent over the temperature range 300–1700 K, with the predicted rate constant being within 50% of its high-pressure limit at atmospheric pressure. Published version 2015-05-25T03:08:51Z 2019-12-06T19:50:47Z 2015-05-25T03:08:51Z 2019-12-06T19:50:47Z 2015 2015 Journal Article Nurkowski, D., Klippenstein, S. J., Georgievskii, Y., Verdicchio, M., Jasper, A. W., Akroyd, J., et al. (2015). Ab initio variational transition state theory and master equation study of the reaction (OH)3SiOCH2 + CH3 ⇌ (OH)3SiOC2H5. Zeitschrift fur physikalische chemie, 229(5), 691-708. https://hdl.handle.net/10356/98118 http://hdl.handle.net/10220/25660 10.1515/zpch-2014-0640 en Zeitschrift fur physikalische chemie © 2015 De Gruyter. This paper was published in Zeitschrift fur Physikalische Chemie and is made available as an electronic reprint (preprint) with permission of De Gruyter. The paper can be found at the following official DOI: [http://dx.doi.org/10.1515/zpch-2014-0640]. One print or electronic copy may be made for personal use only. Systematic or multiple reproduction, distribution to multiple locations via electronic or other means, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper is prohibited and is subject to penalties under law. application/pdf
institution Nanyang Technological University
building NTU Library
continent Asia
country Singapore
Singapore
content_provider NTU Library
collection DR-NTU
language English
topic DRNTU::Science::Medicine::Biomedical engineering
spellingShingle DRNTU::Science::Medicine::Biomedical engineering
Nurkowski, Daniel
Klippenstein, Stephen J.
Georgievskii, Yuri
Verdicchio, Marco
Jasper, Ahren W.
Akroyd, Jethro
Mosbach, Sebastian
Kraft, Markus
Ab initio variational transition state theory and master equation study of the reaction (OH)3SiOCH2 + CH3 ⇌ (OH)3SiOC2H5
description In this paper we use variable reaction coordinate variational transition state theory (VRC-TST) to calculate the reaction rate constants for the two reactions, R1: (OH)3SiOCH2 + CH3 ⇌ (OH)3SiOC2H5, and R2: CH2OH + CH3 ⇌ C2H5OH. The first reaction is an important channel during the thermal decomposition of tetraethoxysilane (TEOS), and its rate coefficient is the main focus of this work. The second reaction is analogous to the first and is used as a basis for comparison. The interaction energies are obtained on-the-fly at the CASPT2(2e,2o)/cc-pVDZ level of theory. A one-dimensional correction to the sampled energies was introduced to account for the energetic effects of geometry relaxation along the reaction path. The computed, high-pressure rate coefficients were calculated to be, R1: k1 = 2.406 × 10−10T−0.301 exp (− 271.4/T) cm3 molecule–1 s–1 and R2: k2 = 1.316 × 10−10T−0.189 exp (− 256.5/T) cm3 molecule–1 s–1. These rates differ from each other by only 10% – 30% over the temperature range 300–2000 K. A comparison of the computed rates with experimental data shows good agreement and an improvement over previous results. The pressure dependency of the reaction R1 is explored by solving a master equation using helium as a bath gas. The results obtained show that the reaction is only weakly pressure dependent over the temperature range 300–1700 K, with the predicted rate constant being within 50% of its high-pressure limit at atmospheric pressure.
author2 School of Chemical and Biomedical Engineering
author_facet School of Chemical and Biomedical Engineering
Nurkowski, Daniel
Klippenstein, Stephen J.
Georgievskii, Yuri
Verdicchio, Marco
Jasper, Ahren W.
Akroyd, Jethro
Mosbach, Sebastian
Kraft, Markus
format Article
author Nurkowski, Daniel
Klippenstein, Stephen J.
Georgievskii, Yuri
Verdicchio, Marco
Jasper, Ahren W.
Akroyd, Jethro
Mosbach, Sebastian
Kraft, Markus
author_sort Nurkowski, Daniel
title Ab initio variational transition state theory and master equation study of the reaction (OH)3SiOCH2 + CH3 ⇌ (OH)3SiOC2H5
title_short Ab initio variational transition state theory and master equation study of the reaction (OH)3SiOCH2 + CH3 ⇌ (OH)3SiOC2H5
title_full Ab initio variational transition state theory and master equation study of the reaction (OH)3SiOCH2 + CH3 ⇌ (OH)3SiOC2H5
title_fullStr Ab initio variational transition state theory and master equation study of the reaction (OH)3SiOCH2 + CH3 ⇌ (OH)3SiOC2H5
title_full_unstemmed Ab initio variational transition state theory and master equation study of the reaction (OH)3SiOCH2 + CH3 ⇌ (OH)3SiOC2H5
title_sort ab initio variational transition state theory and master equation study of the reaction (oh)3sioch2 + ch3 ⇌ (oh)3sioc2h5
publishDate 2015
url https://hdl.handle.net/10356/98118
http://hdl.handle.net/10220/25660
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