1
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Zeng M, Wilson KR. Evaluating Possible Formation Mechanisms of Criegee Intermediates during the Heterogeneous Autoxidation of Squalene. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2024; 58:11587-11595. [PMID: 38900151 DOI: 10.1021/acs.est.4c02590] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/21/2024]
Abstract
Organic molecules in the environment oxidatively degrade by a variety of free radical, microbial, and biogeochemical pathways. A significant pathway is heterogeneous autoxidation, in which degradation occurs via a network of carbon and oxygen centered free radicals. Recently, we found evidence for a new heterogeneous autoxidation mechanism of squalene that is initiated by hydroxyl (OH) radical addition to a carbon-carbon double bond and apparently propagated through pathways involving Criegee Intermediates (CI) produced from β-hydroxy peroxy radicals (β-OH-RO2•). It remains unclear, however, exactly how CI are formed from β-OH-RO2•, which could occur by a unimolecular or bimolecular pathway. Combining kinetic models and multiphase OH oxidation measurements of squalene, we evaluate the kinetic viability of three mechanistic scenarios. Scenario 1 assumes that CI are formed by the unimolecular bond scission of β-OH-RO2•, whereas Scenarios 2 and 3 test bimolecular pathways of β-OH-RO2• to yield CI. Scenario 1 best replicates the entire experimental data set, which includes effective uptake coefficients vs [OH] as well as the formation kinetics of the major products (i.e., aldehydes and secondary ozonides). Although the unimolecular pathway appears to be kinetically viable, future high-level theory is needed to fully explain the mechanistic relationship between CI and β-OH-RO2• in the condensed phase.
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Affiliation(s)
- Meirong Zeng
- College of Smart Energy, Shanghai Jiao Tong University, Shanghai 200240, PR China
| | - Kevin R Wilson
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
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2
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Jiang H, Liu Y, Xiao C, Yang X, Dong W. Reaction Kinetics of CH 2OO and syn-CH 3CHOO Criegee Intermediates with Acetaldehyde. J Phys Chem A 2024; 128:4956-4965. [PMID: 38868987 DOI: 10.1021/acs.jpca.4c01374] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2024]
Abstract
Criegee intermediates exert a crucial influence on atmospheric chemistry, functioning as powerful oxidants that facilitate the degradation of pollutants, and understanding their reaction kinetics is essential for accurate atmospheric modeling. In this study, the kinetics of CH2OO and syn-CH3CHOO reactions with acetaldehyde (CH3CHO) were investigated using a flash photolysis reaction tube coupled with the OH laser-induced fluorescence (LIF) method. The experimental results indicate that the reaction of syn-CH3CHOO with CH3CHO is independent of pressure in the range of 5-50 Torr when using Ar as the bath gas. However, the rate coefficient for the reaction between CH2OO and CH3CHO at 5.5 Torr was found to be lower compared to the near-constant values observed between 10 and 100 Torr. Furthermore, the reaction of syn-CH3CHOO with CH3CHO demonstrated positive temperature dependence from 283 to 330 K, with a rate coefficient of (2.11 ± 0.45) × 10-13 cm3 molecule-1 s-1 at 298 K. The activation energy and pre-exponential factor derived from the Arrhenius plot for this reaction were determined to be 2.32 ± 0.49 kcal mol-1 and (1.66 ± 0.61) × 10-11 cm3 molecule-1 s-1, respectively. In comparison, the reaction of CH2OO with CH3CHO exhibited negative temperature dependence, with a rate coefficient of (2.16 ± 0.39) × 10-12 cm3 molecule-1 s-1 at 100 Torr and 298 K and an activation energy and a pre-exponential factor of -1.73 ± 0.31 kcal mol-1 and (1.15 ± 0.21) × 10-13 cm3 molecule-1 s-1, respectively, over the temperature range of 280-333 K.
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Affiliation(s)
- Haotian Jiang
- Department of Chemical Physics, School of Chemistry and Materials Science, University of Science and Technology of China, Hefei 230026, China
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
| | - Yue Liu
- Department of Chemical Physics, School of Chemistry and Materials Science, University of Science and Technology of China, Hefei 230026, China
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
| | - Chunlei Xiao
- Department of Chemical Physics, School of Chemistry and Materials Science, University of Science and Technology of China, Hefei 230026, China
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
- Hefei National Laboratory, Hefei 230088, China
| | - Xueming Yang
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
- Department of Chemistry, Southern University of Science and Technology, Shenzhen 518055, China
| | - Wenrui Dong
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
- Hefei National Laboratory, Hefei 230088, China
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3
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Qian Y, Nguyen TL, Franke PR, Stanton JF, Lester MI. Nonstatistical Unimolecular Decay of the CH 2OO Criegee Intermediate in the Tunneling Regime. J Phys Chem Lett 2024; 15:6222-6229. [PMID: 38838341 DOI: 10.1021/acs.jpclett.4c01401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2024]
Abstract
Unimolecular decay of the formaldehyde oxide (CH2OO) Criegee intermediate proceeds via a 1,3 ring-closure pathway to dioxirane and subsequent rearrangement and/or dissociation to many products including hydroxyl (OH) radicals that are detected. Vibrational activation of jet-cooled CH2OO with two quanta of CH stretch (17-18 kcal mol-1) leads to unimolecular decay at an energy significantly below the transition state barrier of 19.46 ± 0.25 kcal mol-1, refined utilizing a high-level electronic structure method HEAT-345(Q)Λ. The observed unimolecular decay rate of 1.6 ± 0.4 × 106 s-1 is 2 orders of magnitude slower than that predicted by statistical unimolecular reaction theory using several different models for quantum mechanical tunneling. The nonstatistical behavior originates from excitation of a CH stretch vibration that is orthogonal to the heavy atom motions along the reaction coordinate and slow intramolecular vibrational energy redistribution due to the sparse density of states.
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Affiliation(s)
- Yujie Qian
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, United States
| | - Thanh Lam Nguyen
- Department of Chemistry, University of Florida, Gainesville, Florida 32611 United States
| | - Peter R Franke
- Department of Chemistry, University of Florida, Gainesville, Florida 32611 United States
| | - John F Stanton
- Department of Chemistry, University of Florida, Gainesville, Florida 32611 United States
| | - Marsha I Lester
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, United States
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4
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Zou M, Hassan Y, Roy TK, McCoy AB, Lester MI. Infrared spectroscopy of the syn-methyl-substituted Criegee intermediate: A combined experimental and theoretical study. J Chem Phys 2024; 160:204309. [PMID: 38818894 DOI: 10.1063/5.0210122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2024] [Accepted: 05/06/2024] [Indexed: 06/01/2024] Open
Abstract
An IR-vacuum ultraviolet (VUV) ion-dip spectroscopy method is utilized to examine the IR spectrum of acetaldehyde oxide (CH3CHOO) in the overtone CH stretch (2νCH) spectral region. IR activation creates a depletion of the ground state population that reduces the VUV photoionization signal on the parent mass channel. IR activation of the more stable and populated syn-CH3CHOO conformer results in rapid unimolecular decay to OH + vinoxy products and makes the most significant contribution to the observed spectrum. The resultant IR-VUV ion-dip spectrum of CH3CHOO is similar to that obtained previously for syn-CH3CHOO using IR action spectroscopy with UV laser-induced fluorescence detection of OH products. The prominent IR features at 5984 and 6081 cm-1 are also observed using UV + VUV photoionization of OH products. Complementary theoretical calculations utilizing a general implementation of second-order vibrational perturbation theory provide new insights on the vibrational transitions that give rise to the experimental spectrum in the overtone CH stretch region. The introduction of physically motivated small shifts of the harmonic frequencies yields remarkably improved agreement between experiment and theory in the overtone CH stretch region. The prominent features are assigned as highly mixed states with contributions from two quanta of CH stretch and/or a combination of CH stretch with an overtone in mode 4. The generality of this approach is demonstrated by applying it to three different levels of electronic structure theory/basis sets, all of which provide spectra that are virtually indistinguishable despite showing large deviations prior to introducing the shifts to the harmonic frequencies.
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Affiliation(s)
- Meijun Zou
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, USA
| | - Yarra Hassan
- Department of Chemistry, University of Washington, Seattle, Washington 98195-1700, USA
| | - Tarun Kumar Roy
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, USA
| | - Anne B McCoy
- Department of Chemistry, University of Washington, Seattle, Washington 98195-1700, USA
| | - Marsha I Lester
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, USA
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5
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Song K, Upadhyay M, Meuwly M. OH-Formation following vibrationally induced reaction dynamics of H 2COO. Phys Chem Chem Phys 2024; 26:12698-12708. [PMID: 38602285 DOI: 10.1039/d4cp00739e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/12/2024]
Abstract
The reaction dynamics of H2COO to form HCOOH and dioxirane as first steps for OH-elimination is quantitatively investigated. Using a machine learned potential energy surface (PES) at the CASPT2/aug-cc-pVTZ level of theory vibrational excitation along the CH-normal mode νCH with energies up to 40.0 kcal mol-1 (∼5νCH) leads almost exclusively to HCOOH which further decomposes into OH + HCO. Although the barrier to form dioxirane is only 21.4 kcal mol-1 the reaction probability to form dioxirane is two orders of magnitude lower if the CH-stretch mode is excited. Following the dioxirane-formation pathway is facile, however, if the COO-bend vibration is excited together with energies equivalent to ∼2νCH or ∼3νCOO. For OH-formation in the atmosphere the pathway through HCOOH is probably most relevant because the alternative pathways (through dioxirane or formic acid) involve several intermediates that can de-excite through collisions, relax via internal vibrational relaxation (IVR), or pass through loose and vulnerable transition states (formic acid). This work demonstrates how, by selectively exciting particular vibrational modes, it is possible to dial into desired reaction channels with a high degree of specificity.
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Affiliation(s)
- Kaisheng Song
- Department of Chemistry, University of Basel, Klingelbergstrasse 80, CH-4056 Basel, Switzerland.
- School of Chemistry and Chemical Engineering & Chongqing Key Laboratory of Theoretical and Computational Chemistry, Chongqing University, Chongqing 401331, China
| | - Meenu Upadhyay
- Department of Chemistry, University of Basel, Klingelbergstrasse 80, CH-4056 Basel, Switzerland.
| | - Markus Meuwly
- Department of Chemistry, University of Basel, Klingelbergstrasse 80, CH-4056 Basel, Switzerland.
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6
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Zhang YQ, Francisco JS, Long B. Rapid Atmospheric Reactions between Criegee Intermediates and Hypochlorous Acid. J Phys Chem A 2024; 128:909-917. [PMID: 38271208 DOI: 10.1021/acs.jpca.3c06144] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2024]
Abstract
Hypochlorous acid (HOCl) is a paramount compound in the atmosphere due to its significant contribution to both tropospheric oxidation capacity and ozone depletion. The main removal routes for HOCl are photolysis and the reaction with OH during the daytime, while these processes are unimportant during the nighttime. Here, we report the rapid reactions of Criegee intermediates (CH2OO and anti/syn-CH3CHOO) with HOCl by using high-level quantum chemical methods as the benchmark; their accuracy is close to coupled cluster theory with single, double, and triple excitations and quasiperturbative connected quadruple excitations with a complete basis limit by extrapolation [CCSDT(Q)/CBS]. Their rate constants have been calculated by using a dual-level strategy; this combines conventional transition state theory calculated at the benchmark level with variational transition state theory with small-curvature tunneling by a validated density functional method. We find that the introduction of the methyl group into Criegee intermediates not only affects their reactivities but also exerts a remarkable influence on anharmonicity. The calculated results uncover that anharmonicity increases the rate constants of CH2OO + HOCl by a factor of 18-5, while it is of minor importance in the anti/syn-CH3CHOO + HOCl reaction at 190-350 K. The present findings reveal that the loose transition state for anti-CH3CHOO and HOCl is a rate-determining step at 190-350 K. We also find that the reaction of Criegee intermediates with HOCl contributes significantly to the sink of HOCl during the nighttime in the atmosphere.
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Affiliation(s)
- Yu-Qiong Zhang
- College of Physics and Mechatronic Engineering, Guizhou Minzu University, Guiyang 550025, China
| | - Joseph S Francisco
- Department of Earth and Environmental Sciences and Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Bo Long
- College of Physics and Mechatronic Engineering, Guizhou Minzu University, Guiyang 550025, China
- College of Materials Science and Engineering, Guizhou Minzu University, Guiyang 550025, China
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7
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Liu T, Lester MI. Roaming in the Unimolecular Decay of syn-Methyl-Substituted Criegee Intermediates. J Phys Chem A 2023; 127:10817-10827. [PMID: 38109698 DOI: 10.1021/acs.jpca.3c05859] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2023]
Abstract
Alkene ozonolysis generates transient carbonyl oxide species, known as Criegee intermediates, which are a significant nonphotolytic source of OH radicals in the troposphere. This study demonstrates that unimolecular decay of syn-methyl-substituted Criegee intermediates proceeds via 1,4 H atom transfer to vinyl hydroperoxides, resulting in OH fission to O-O products or, alternatively, OH roaming to hydroxycarbonyl products. Newly generated Criegee intermediates are shown to yield hydroxycarbonyls with sufficient internal excitation to dissociate via C-C fission to acyl and hydroxymethyl (CH2OH) radicals. The stabilized Criegee intermediates and unimolecular products are rapidly cooled in a pulsed supersonic expansion for photoionization detection with time-of-flight mass spectrometry. CH2OH products are identified by 2 + 1 resonance-enhanced multiphoton ionization via the 3pz Rydberg state upon unimolecular decay of CH3CHOO, (CH3)2COO, (CH3)(CH3CH2)COO, and (CH3)(CH2═CH)COO (methyl vinyl ketone oxide). The stabilized Criegee intermediates are separately detected using 10.5 eV photoionization. This study provides the first experimental evidence of roaming in the unimolecular decay of isoprene-derived methyl vinyl ketone oxide and extends earlier studies that reported stabilized hydroxycarbonyl products.
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Affiliation(s)
- Tianlin Liu
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, United States
| | - Marsha I Lester
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, United States
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8
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Wu YJ, Takahashi K, Lin JJM. Kinetics of the Simplest Criegee Intermediate Reaction with Water Vapor: Revisit and Isotope Effect. J Phys Chem A 2023; 127:8059-8072. [PMID: 37734061 DOI: 10.1021/acs.jpca.3c03418] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/23/2023]
Abstract
The kinetics of the simplest Criegee intermediate (CH2OO) reaction with water vapor was revisited. By improving the signal-to-noise ratio and the precision of water concentration, we found that the kinetics of CH2OO involves not only two water molecules but also one and three water molecules. Our experimental results suggest that the decay of CH2OO can be described as d[CH2OO]/dt = -kobs[CH2OO]; kobs = k0 + k1[water] + k2[water]2 + k3[water]3; k1 = (4.22 ± 0.48) × 10-16 cm3 s-1, k2 = (10.66 ± 0.83) × 10-33 cm6 s-1, k3 = (1.48 ± 0.17) × 10-50 cm9 s-1 at 298 K and 300 Torr with the respective Arrhenius activation energies of Ea1 = 1.8 ± 1.1 kcal mol-1, Ea2 = -11.1 ± 2.1 kcal mol-1, Ea3 = -17.4 ± 3.9 kcal mol-1. The contribution of the k3[water]3 term becomes less significant at higher temperatures around 345 K, but it is not ignorable at 298 K and lower temperatures. By quantifying the concentrations of H2O and D2O with a Coriolis-type direct mass flow sensor, the kinetic isotope effect (KIE) was investigated at 298 K and 300 Torr and KIE(k1) = k1(H2O)/k1(D2O) = 1.30 ± 0.32; similarly, KIE(k2) = 2.25 ± 0.44 and KIE(k3) = 0.99 ± 0.13. These mild KIE values are consistent with theoretical calculations based on the variational transition state theory, confirming that the title reaction has a broad and low barrier, and the reaction coordinate involves not only the motion of a hydrogen atom but also that of an oxygen atom. Comparing the results recorded under 300 Torr (N2 buffer gas) with those under 600 Torr, a weak pressure effect of k3 was found. From quantum chemistry calculations, we found that the CH2OO + 3H2O reaction is dominated by the reaction pathways involving a ring structure consisting of two water molecules, which facilitate the hydrogen atom transfer, while the third water molecule is hydrogen-bonded outside the ring. Furthermore, analysis based on dipole capture rates showed that the CH2OO(H2O) + (H2O)2 and CH2OO(H2O)2 + H2O pathways will dominate in the three water reaction.
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Affiliation(s)
- Yen-Ju Wu
- Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 106923, Taiwan
- Department of Chemistry, National Taiwan University, Taipei 106923, Taiwan
| | - Kaito Takahashi
- Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 106923, Taiwan
| | - Jim Jr-Min Lin
- Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 106923, Taiwan
- Department of Chemistry, National Taiwan University, Taipei 106923, Taiwan
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9
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Su ZS, Lee YP. Infrared Characterization of the Products of the Reaction between the Criegee Intermediate CH 3CHOO and HCl. J Phys Chem A 2023; 127:6902-6915. [PMID: 37561815 DOI: 10.1021/acs.jpca.3c03527] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/12/2023]
Abstract
The rapid reactions between Criegee intermediates and hydrogen halides play important roles in atmospheric chemistry, particularly in the polluted urban atmosphere. Employing a step-scan Fourier transform spectrometer, we recorded infrared absorption spectra of transient species and end products of the reaction CH3CHOO + HCl in a flowing mixture of CH3CHI2/HCl/O2/N2 irradiated at 308 nm. Bands at 1453.6, 1383.7, 1357.9, 1323.8, 1271.8, 1146.2, 1098.2, 1017.5, 931.5, and 847.0 cm-1 were observed and assigned to the anti-conformer of chloroethyl hydroperoxide (anti-CEHP or anti-CH3CHClOOH). In addition, absorption bands of H2O and acetyl chloride [CH3C(O)Cl, at 1819.1 cm-1] were observed; some of them were produced from the secondary reactions of CH3CHClO + O2 → CH3C(O)Cl + HO2 and OH + HCl → H2O + Cl, according to temporal profiles of H2O and CH3C(O)Cl. These secondary reactions are conceivable because the nascent formation of CH3CHClO + OH via decomposition of internally excited CEHP was predicted by theory, and both HCl and O2 are major species in the system. The nascent formation of CH3CHClO + OH appears to be more important than that of CH3C(O)Cl + H2O, consistent with theoretical predictions. By adding methanol to deplete some anti-CH3CHOO, we observed only anti-CEHP with a reduced proportion; this observation indicates that the conversion from syn-CEHP, expected to be produced from syn-CH3CHOO + HCl, to anti-CEHP is facile. We also estimated the overall rate coefficient of the reaction syn-/anti-CH3CHOO + HCl to be kHCl = (2.7 ± 1.0) × 10-10 cm3 molecule-1 s-1 at ∼70 Torr and 298 K; this rate coefficient is about six times the only literature value kHClsyn = (4.77 ± 0.95) × 10-11 cm3 molecule-1 s-1 reported for syn-CH3CHOO + HCl by Liu et al., indicating that anti-CH3CHOO reacts with HCl much more rapidly than syn-CH3CHOO.
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Affiliation(s)
- Zih-Syuan Su
- Department of Applied Chemistry and Institute of Molecular Science, National Yang Ming Chiao Tung University, Hsinchu 300093, Taiwan
| | - Yuan-Pern Lee
- Department of Applied Chemistry and Institute of Molecular Science, National Yang Ming Chiao Tung University, Hsinchu 300093, Taiwan
- Center for Emergent Functional Matter Science, National Yang Ming Chiao Tung University, Hsinchu 300093, Taiwan
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10
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Robinson C, Onel L, Newman J, Lade R, Au K, Sheps L, Heard DE, Seakins PW, Blitz MA, Stone D. Unimolecular Kinetics of Stabilized CH 3CHOO Criegee Intermediates: syn-CH 3CHOO Decomposition and anti-CH 3CHOO Isomerization. J Phys Chem A 2022; 126:6984-6994. [PMID: 36146923 PMCID: PMC9549458 DOI: 10.1021/acs.jpca.2c05461] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Revised: 09/11/2022] [Indexed: 11/30/2022]
Abstract
The kinetics of the unimolecular decomposition of the stabilized Criegee intermediate syn-CH3CHOO has been investigated at temperatures between 297 and 331 K and pressures between 12 and 300 Torr using laser flash photolysis of CH3CHI2/O2/N2 gas mixtures coupled with time-resolved broadband UV absorption spectroscopy. Fits to experimental results using the Master Equation Solver for Multi-Energy well Reactions (MESMER) indicate that the barrier height to decomposition is 67.2 ± 1.3 kJ mol-1 and that there is a strong tunneling component to the decomposition reaction under atmospheric conditions. At 298 K and 760 Torr, MESMER simulations indicate a rate coefficient of 150-81+176 s-1 when tunneling effects are included but only 5-2+3 s-1 when tunneling is not considered in the model. MESMER simulations were also performed for the unimolecular isomerization of the stabilized Criegee intermediate anti-CH3CHOO to methyldioxirane, indicating a rate coefficient of 54-21+34 s-1 at 298 K and 760 Torr, which is not impacted by tunneling effects. Expressions to describe the unimolecular kinetics of syn- and anti-CH3CHOO are provided for use in atmospheric models, and atmospheric implications are discussed.
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Affiliation(s)
- Callum Robinson
- School
of Chemistry, University of Leeds, Woodhouse Lane, Leeds LS2 9JT, U.K.
| | - Lavinia Onel
- School
of Chemistry, University of Leeds, Woodhouse Lane, Leeds LS2 9JT, U.K.
| | - James Newman
- School
of Chemistry, University of Leeds, Woodhouse Lane, Leeds LS2 9JT, U.K.
| | - Rachel Lade
- School
of Chemistry, University of Leeds, Woodhouse Lane, Leeds LS2 9JT, U.K.
| | - Kendrew Au
- Combustion
Research Facility, Sandia National Laboratories, Livermore, California 94551, United States
| | - Leonid Sheps
- Combustion
Research Facility, Sandia National Laboratories, Livermore, California 94551, United States
| | - Dwayne E. Heard
- School
of Chemistry, University of Leeds, Woodhouse Lane, Leeds LS2 9JT, U.K.
| | - Paul W. Seakins
- School
of Chemistry, University of Leeds, Woodhouse Lane, Leeds LS2 9JT, U.K.
| | - Mark A. Blitz
- School
of Chemistry, University of Leeds, Woodhouse Lane, Leeds LS2 9JT, U.K.
- National
Centre for Atmospheric Science, School of Chemistry, University of Leeds, Woodhouse Lane, Leeds LS2 9JT, U.K.
| | - Daniel Stone
- School
of Chemistry, University of Leeds, Woodhouse Lane, Leeds LS2 9JT, U.K.
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11
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Yang J, Li Y, Makroni L, Liu F. The photoisomerization mechanism of methacrolein oxide (MACR-OO): the cyclic dioxole formation pathway revealed. Phys Chem Chem Phys 2022; 24:22531-22537. [PMID: 36111632 DOI: 10.1039/d2cp03028d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Methacrolein oxide (MACR-OO), the isopropenyl substituted Criegee intermediate (CI), is one product of isoprene ozonolysis. In this work, we report MACR-OO's photo-isomerization paths with electronic structure calculation at the CASSCF and MS-CASPT2 levels and trajectory surface-hopping (TSH) nonadiabatic dynamics simulation at the CASSCF level. Our calculated results show that the ring-closure is the dominant photo-induced unimolecular isomerization of MACR-OO in the S1 state. In addition, a new photo-induced ring-closure to heterocyclopentane dioxole in syn_syn-MACR-OO is found. The findings of MACR-OO are expected to deepen the understanding of the substituted CIs and their photochemistry.
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Affiliation(s)
- Jiawei Yang
- Key Laboratory of Applied Surface and Colloid Chemistry of Ministry of Education, Key Laboratory for Macromolecular Science of Shaanxi Province, School of Chemistry & Chemical Engineering, Shaanxi Normal University, Xi'an, Shaanxi 710119, People's Republic of China.
| | - Yazhen Li
- Key Laboratory of Applied Surface and Colloid Chemistry of Ministry of Education, Key Laboratory for Macromolecular Science of Shaanxi Province, School of Chemistry & Chemical Engineering, Shaanxi Normal University, Xi'an, Shaanxi 710119, People's Republic of China.
| | - Lily Makroni
- Key Laboratory of Applied Surface and Colloid Chemistry of Ministry of Education, Key Laboratory for Macromolecular Science of Shaanxi Province, School of Chemistry & Chemical Engineering, Shaanxi Normal University, Xi'an, Shaanxi 710119, People's Republic of China.
| | - Fengyi Liu
- Key Laboratory of Applied Surface and Colloid Chemistry of Ministry of Education, Key Laboratory for Macromolecular Science of Shaanxi Province, School of Chemistry & Chemical Engineering, Shaanxi Normal University, Xi'an, Shaanxi 710119, People's Republic of China.
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12
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Lawrence JE, Richardson JO. Improved microcanonical instanton theory. Faraday Discuss 2022; 238:204-235. [PMID: 35929848 DOI: 10.1039/d2fd00063f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Canonical (thermal) instanton theory is now routinely applicable to complex gas-phase reactions and allows for the accurate description of tunnelling in highly non-separable systems. Microcanonical instanton theory is by contrast far less well established. Here, we demonstrate that the best established microcanonical theory [S. Chapman, B. C. Garrett and W. H. Miller, J. Chem. Phys., 1975, 63, 2710-2716], fails to accurately describe the deep-tunnelling regime for systems where the frequencies of the orthogonal modes change rapidly along the instanton path. By taking a first principles approach to the derivation of microcanonical instanton theory, we obtain an improved method, which accurately recovers the thermal instanton rate when integrated over energy. The resulting theory also correctly recovers the separable limit and can be thought of as an instanton generalisation of Rice-Ramsperger-Kassel-Marcus (RRKM) theory. When combined with the density-of-states approach [W. Fang, P. Winter and J. O. Richardson, J. Chem. Theory Comput., 2021, 17, 40-55], this new method can be straightforwardly applied to real molecular systems.
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13
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Wang PB, Truhlar DG, Xia Y, Long B. Temperature-dependent kinetics of the atmospheric reaction between CH 2OO and acetone. Phys Chem Chem Phys 2022; 24:13066-13073. [PMID: 35583864 DOI: 10.1039/d2cp01118b] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Criegee intermediates are important oxidants produced in the ozonolysis of alkenes in the atmosphere. Quantitative kinetics of the reactions of Criegee intermediates are required for atmospheric modeling. However, the experimental studies do not cover the full relevant range of temperature and pressure. Here we report the quantitative kinetics of CH2OO + CH3C(O)CH3 by using our recently developed dual strategy that combines coupled cluster theory with high excitation levels for conventional transition state theory and well validated levels of density functional theory for direct dynamics calculations using canonical variational transition theory including tunneling. We find that the W3X-L//DF-CCSD(T)-F12b/jun-cc-pVDZ electronic structure method can be used to obtain quantitative kinetics of the CH2OO + CH3C(O)CH3 reaction. Whereas previous investigations considered a one-step mechanistic pathway, we find that the CH2OO + CH3C(O)CH3 reaction occurs in a stepwise manner. This has implications for the modeling of Criegee-intermediate reactions with other ketones and with aldehydes. In the kinetics calculations, we show that recrossing effects of the conventional transition state are negligible for determining the rate constant of CH2OO + CH3C(O)CH3. The present findings reveal that the rate ratio between CH2OO + CH3C(O)CH3 and OH + CH3C(O)CH3 has a significant negative dependence on temperature such that the CH2OO + CH3C(O)CH3 reaction can contribute as a significant sink for atmospheric CH3C(O)CH3 at low temperature. The present findings should have broad implications in understanding the reactions of Criegee intermediates with carbonyl compounds and ketones in the atmosphere.
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Affiliation(s)
- Peng-Biao Wang
- Department of Physics, Guizhou University, Guiyang, 550025, China.
| | - Donald G Truhlar
- Department of Chemistry, Chemical Theory Center, and Supercomputing Institute, University of Minnesota, Minneapolis, Minnesota 55455-0431, USA
| | - Yu Xia
- College of Materials Science and Engineering, Guizhou Minzu University, Guiyang 550025, China
| | - Bo Long
- Department of Physics, Guizhou University, Guiyang, 550025, China. .,College of Materials Science and Engineering, Guizhou Minzu University, Guiyang 550025, China
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14
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Hansen AS, Qian Y, Sojdak CA, Kozlowski MC, Esposito VJ, Francisco JS, Klippenstein SJ, Lester MI. Rapid Allylic 1,6 H-Atom Transfer in an Unsaturated Criegee Intermediate. J Am Chem Soc 2022; 144:5945-5955. [PMID: 35344666 DOI: 10.1021/jacs.2c00055] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
A novel allylic 1,6 hydrogen-atom-transfer mechanism is established through infrared activation of the 2-butenal oxide Criegee intermediate, resulting in very rapid unimolecular decay to hydroxyl (OH) radical products. A new precursor, Z/E-1,3-diiodobut-1-ene, is synthesized and photolyzed in the presence of oxygen to generate a new four-carbon Criegee intermediate with extended conjugation across the vinyl and carbonyl oxide groups that facilitates rapid allylic 1,6 H-atom transfer. A low-energy reaction pathway involving isomerization of 2-butenal oxide from a lower-energy (tZZ) conformer to a higher-energy (cZZ) conformer followed by 1,6 hydrogen transfer via a seven-membered ring transition state is predicted theoretically and shown experimentally to yield OH products. The low-lying (tZZ) conformer of 2-butenal oxide is identified based on computed anharmonic frequencies and intensities of its conformers. Experimental IR action spectra recorded in the fundamental CH stretch region with OH product detection by UV laser-induced fluorescence reveal a distinctive IR transition of the low-lying (tZZ) conformer at 2996 cm-1 that results in rapid unimolecular decay to OH products. Statistical RRKM calculations involving a combination of conformational isomerization and unimolecular decay via 1,6 H-transfer yield an effective decay rate keff(E) on the order of 108 s-1 at ca. 3000 cm-1 in good accord with the experiment. Unimolecular decay proceeds with significant enhancement due to quantum mechanical tunneling. A rapid thermal decay rate of ca. 106 s-1 is predicted by master-equation modeling of 2-butenal oxide at 298 K, 1 bar. This novel unimolecular decay pathway is expected to increase the nonphotolytic production of OH radicals upon alkene ozonolysis in the troposphere.
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Affiliation(s)
- Anne S Hansen
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323 United States
| | - Yujie Qian
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323 United States
| | - Christopher A Sojdak
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323 United States
| | - Marisa C Kozlowski
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323 United States
| | - Vincent J Esposito
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323 United States
| | - Joseph S Francisco
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323 United States
| | - Stephen J Klippenstein
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439 United States
| | - Marsha I Lester
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323 United States
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15
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Vereecken L, Novelli A, Kiendler-Scharr A, Wahner A. Unimolecular and water reactions of oxygenated and unsaturated Criegee intermediates under atmospheric conditions. Phys Chem Chem Phys 2022; 24:6428-6443. [DOI: 10.1039/d1cp05877k] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Ozonolysis of unsaturated hydrocarbons (VOCs) is one of the main oxidation processes in the atmosphere. The stabilized Criegee intermediates (SCI) formed are highly reactive oxygenated species that potentially influence the...
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16
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Marchetti B, Esposito VJ, Bush RE, Karsili TNV. The states that hide in the shadows: the potential role of conical intersections in the ground state unimolecular decay of a Criegee intermediate. Phys Chem Chem Phys 2021; 24:532-540. [PMID: 34904596 DOI: 10.1039/d1cp02601a] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Criegee intermediates are of great significance to Earth's troposphere - implicated in altering the tropospheric oxidation cycle and in forming low volatility products that typically condense to form secondary organic aerosols (SOAs). As such, their chemistry has attracted vast attention in recent years. In particular, the unimolecular decay of thermal and vibrationally-excited Criegee intermediates has been the focus of several experimental and computational studies, and it is now recognized that Criegee intermediates undergo unimolecular decay to form OH radicals. In this contribution we reveal insight into the chemistry of Criegee intermediates by highlighting the hitherto neglected multi-state contribution to the ground state unimolecular decay dynamics of the Criegee intermediate products. The two key intermediates of present focus are dioxirane and vinylhydroperoxide - known to be active intermediates that mediate the unimolecular decay of CH2OO and CH3CHOO, respectively. In both cases the unimolecular decay path encounters conical intersections, which may play a pivotal role in the ensuing dynamics. This hitherto unrecognized phenomenon may be vital in the way in which the reactivity of Criegee intermediates are modelled and is likely to affect the ensuing dynamics associated with the unimolecular decay of a given Criegee intermediate.
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Affiliation(s)
| | | | - Rachel E Bush
- University of Louisiana at Lafayette, Louisiana, LA 70504, USA.
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17
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Esposito VJ, Werba O, Bush SA, Marchetti B, Karsili TNV. Insights into the Ultrafast Dynamics of CH 2 OO and CH 3 CHOO Following Excitation to the Bright 1 ππ* State: The Role of Singlet and Triplet States. Photochem Photobiol 2021; 98:763-772. [PMID: 34767632 DOI: 10.1111/php.13560] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Accepted: 11/09/2021] [Indexed: 12/11/2022]
Abstract
Criegee intermediates make up a class of molecules that are of significant atmospheric importance. Understanding their electronically excited states guides experimental detection and provides insight into whether solar photolysis plays a role in their removal from the troposphere. The latter is particularly important for large and functionalized Criegee intermediates. In this study, the excited state chemistry of two small Criegee intermediates, formaldehyde oxide (CH2 OO) and acetaldehyde oxide (CH3 CHOO), was modeled to compare their specific dynamics and mechanisms following excitation to the bright ππ* state and to assess the involvement of triplet states to the excited state decay process. Following excitation to the bright ππ* state, the photoexcited population exclusively evolves to form oxygen plus aldehyde products without the involvement of triplet states. This occurs despite the presence of a more thermodynamically stable triplet path and several singlet/triplet energy crossings at the Franck-Condon geometry and contrasts with the photodynamics of related systems such as acetaldehyde and acetone. This work sets the foundations to study Criegee intermediates with greater molecular complexity, wherein a bathochromic shift in the electron absorption profiles may ensure greater removal via solar photolysis.
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Affiliation(s)
| | | | - Sarah A Bush
- University of Louisiana at Lafayette, Lafayette, LA
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18
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Liu S, Zhou X, Chen Y, Liu Y, Yu S, Takahashi K, Ding H, Ding Z, Yang X, Dong W. Experimental and Computational Studies of Criegee Intermediate syn-CH 3CHOO Reaction with Hydrogen Chloride. J Phys Chem A 2021; 125:8587-8594. [PMID: 34558283 DOI: 10.1021/acs.jpca.1c05578] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Hydrogen chloride (HCl) contributes substantially to the atmospheric Cl; both species could affect the composition of Earth's atmosphere and the fate of pollutants. Here, we present the kinetics study for syn-CH3CHOO reaction with HCl using experimental measurement and theoretical calculations. The experiment was conducted in a flow tube reactor at a pressure of 10 Torr and temperatures ranging from 283 to 318 K by using the OH laser-induced fluorescence (LIF) method. Transition-state theory and quantum chemistry calculations with QCISD(T) were used to calculate the rate coefficients. Weak negative temperature dependence was observed with a measured activation energy of -(2.98 ± 0.12) kcal mol-1 and a calculated zero-point-corrected barrier energy of -3.29 kcal mol-1. At 298 K, the rate coefficient was measured to be (4.77 ± 0.95) × 10-11 cm3 s-1, which was in reasonable agreement with 2.2 × 10-11 cm3 s-1 from the theoretical calculation.
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Affiliation(s)
- Siyue Liu
- Key Laboratory of Materials Modification by Laser, Ion, and Electron Beams, Chinese Ministry of Education, School of Physics, Dalian University of Technology, Dalian 116024, China.,State Key Laboratory of Molecular Reaction Dynamics, Chinese Academy of Sciences, Dalian Institute of Chemical Physics, Dalian 116023, China
| | - Xiaohu Zhou
- State Key Laboratory of Molecular Reaction Dynamics, Chinese Academy of Sciences, Dalian Institute of Chemical Physics, Dalian 116023, China.,Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education), School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China.,Zhang Dayu School of Chemistry, Dalian University of Technology, Dalian 116024, China
| | - Yang Chen
- State Key Laboratory of Molecular Reaction Dynamics, Chinese Academy of Sciences, Dalian Institute of Chemical Physics, Dalian 116023, China.,Key Laboratory of Chemical Lasers, Chinese Academy of Sciences, Dalian Institute of Chemical Physics, Dalian 116023, China.,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yiqiang Liu
- State Key Laboratory of Molecular Reaction Dynamics, Chinese Academy of Sciences, Dalian Institute of Chemical Physics, Dalian 116023, China.,School of Materials Science and Engineering, Anyang Institute of Technology, Anyang 455000, China
| | - Shengrui Yu
- Hangzhou Institute of Advanced Studies, Zhejiang Normal University, 1108 Gengwen Road, Hangzhou 311231, Zhejiang Province, P. R. China
| | - Kaito Takahashi
- Institute of Atomic and Molecular Science, Academia Sinica, Taipei 10617, Taiwan
| | - Hongbin Ding
- Key Laboratory of Materials Modification by Laser, Ion, and Electron Beams, Chinese Ministry of Education, School of Physics, Dalian University of Technology, Dalian 116024, China
| | - Zhenfeng Ding
- Key Laboratory of Materials Modification by Laser, Ion, and Electron Beams, Chinese Ministry of Education, School of Physics, Dalian University of Technology, Dalian 116024, China
| | - Xueming Yang
- State Key Laboratory of Molecular Reaction Dynamics, Chinese Academy of Sciences, Dalian Institute of Chemical Physics, Dalian 116023, China.,Department of Chemistry, Southern University of Science and Technology, Shenzhen 518055, China
| | - Wenrui Dong
- State Key Laboratory of Molecular Reaction Dynamics, Chinese Academy of Sciences, Dalian Institute of Chemical Physics, Dalian 116023, China
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19
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Ji YT, Lee YP. Dynamics of Reaction CH 3CHI + O 2 Investigated via Infrared Emission of Products CO, CO 2, and OH. J Phys Chem A 2021; 125:8373-8385. [PMID: 34524829 DOI: 10.1021/acs.jpca.1c05610] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The reaction CH3CHI + O2 has been commonly employed in laboratories to produce a methyl-substituted Criegee intermediate CH3CHOO, but the detailed dynamics of this reaction remain unexplored. We carried out this reaction by irradiating a flowing mixture of CH3CHI2 (∼70 mTorr) and O2 (∼4 and 8 Torr) at 308 or 248 nm and observed infrared emission of the products with a step-scan Fourier-transform spectrometer. Upon irradiation at 248 nm with O2 ∼4 Torr, a Boltzmann distribution of CO (v ≤ 4, J ≤ 25) with average vibrational energy (12 ± 2) kJ mol-1 and of OH (v = 1, J ≤ 5.5) were observed and assigned to be produced from the decomposition of CH3C(O)OH* to form CO + CH3OH and OH + CH3CO, respectively. The observed broadband emission of CO2 was simulated with two vibrational distributions of average energies (42 ± 3) and (114 ± 6) kJ mol-1 and assigned to be produced from the decomposition of CH3C(O)OH* and (methyl dioxirane)*, respectively. The results upon irradiation of the sample at 308 nm are similar, likely indicating a small fraction of energy partition into these products and rapid thermalization of CH3CHI*. Compared with reaction CH2I + O2, the title reaction yielded products with much less internal excitation, consistent with the expectation that these observed products receive much less fraction of available energy upon fragmentation when an additional methyl moiety was present in the parent. The large-v component of CO observed in experiments of CH2I + O2 at 248 nm, produced from secondary reaction HCO + O2, was absent in this work because the corresponding secondary reaction CH3CO + O2 in decomposition of CH3CHOO* produces α-lactone + OH or H2CO + CO + OH.
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Affiliation(s)
- Ya-Tsang Ji
- Department of Applied Chemistry and Institute of Molecular Science, National Yang Ming Chiao Tung University, Hsinchu 300093, Taiwan
| | - Yuan-Pern Lee
- Department of Applied Chemistry and Institute of Molecular Science, National Yang Ming Chiao Tung University, Hsinchu 300093, Taiwan.,Center for Emergent Functional Matter Science, National Yang Ming Chiao Tung University, Hsinchu 300093, Taiwan.,Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 106319, Taiwan
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20
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Surprisingly long lifetime of methacrolein oxide, an isoprene derived Criegee intermediate, under humid conditions. Commun Chem 2021; 4:12. [PMID: 36697547 PMCID: PMC9814537 DOI: 10.1038/s42004-021-00451-z] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Accepted: 01/05/2021] [Indexed: 02/07/2023] Open
Abstract
Ozonolysis of isoprene, the most abundant alkene, produces three distinct Criegee intermediates (CIs): CH2OO, methyl vinyl ketone oxide (MVKO) and methacrolein oxide (MACRO). The oxidation of SO2 by CIs is a potential source of H2SO4, an important precursor of aerosols. Here we investigated the UV-visible spectroscopy and reaction kinetics of thermalized MACRO. An extremely fast reaction of anti-MACRO with SO2 has been found, kSO2 = (1.5 ± 0.4) × 10-10 cm3 s-1 (±1σ, σ is the standard deviation of the data) at 298 K (150 - 500 Torr), which is ca. 4 times the value for syn-MVKO. However, the reaction of anti-MACRO with water vapor has been observed to be quite slow with an effective rate coefficient of (9 ± 5) × 10-17 cm3 s-1 (±1σ) at 298 K (300 to 500 Torr), which is smaller than current literature values by 1 or 2 orders of magnitude. Our results indicate that anti-MACRO has an atmospheric lifetime (best estimate ca. 18 ms at 298 K and RH = 70%) much longer than previously thought (ca. 0.3 or 3 ms), resulting in a much higher steady-state concentration. Owing to larger reaction rate coefficient, the impact of anti-MACRO on the oxidation of atmospheric SO2 would be substantial, even more than that of syn-MVKO.
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21
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Fang W, Winter P, Richardson JO. Microcanonical Tunneling Rates from Density-of-States Instanton Theory. J Chem Theory Comput 2020; 17:40-55. [PMID: 33351621 DOI: 10.1021/acs.jctc.0c01118] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Semiclassical instanton theory is a form of quantum transition-state theory which can be applied to the computation of thermal reaction rates in complex molecular systems including quantum tunneling effects. There have been a number of attempts to extend the theory to treat microcanonical rates. However, the previous formulations are either computationally unfeasible for large systems due to an explicit sum over states or they involve extra approximations, which make them less reliable. We propose a robust and practical microcanonical formulation called density-of-states instanton theory, which avoids the sum over states altogether. In line with the semiclassical approximations inherent to the instanton approach, we employ the stationary-phase approximation to the inverse Laplace transform to obtain the densities of states. This can be evaluated using only post-processing of the data available from a small set of instanton calculations, such that our approach remains computationally efficient. We show that the new formulation predicts results that agree well with quantum scattering theory for an atom-diatom reaction and with experiments for a photoexcited unimolecular hydrogen transfer in a Criegee intermediate. When the thermal rate is evaluated from a Boltzmann average over our new microcanonical formalism, it can overcome some problems of conventional instanton theory. In particular, it predicts a smooth transition at the crossover temperature and is able to describe bimolecular reactions with pre-reactive complexes such as CH3OH + OH.
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Affiliation(s)
- Wei Fang
- Laboratory of Physical Chemistry, ETH Zürich, 8093 Zürich, Switzerland
| | - Pierre Winter
- Laboratory of Physical Chemistry, ETH Zürich, 8093 Zürich, Switzerland
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22
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Vansco MF, Caravan RL, Pandit S, Zuraski K, Winiberg FAF, Au K, Bhagde T, Trongsiriwat N, Walsh PJ, Osborn DL, Percival CJ, Klippenstein SJ, Taatjes CA, Lester MI. Formic acid catalyzed isomerization and adduct formation of an isoprene-derived Criegee intermediate: experiment and theory. Phys Chem Chem Phys 2020; 22:26796-26805. [PMID: 33211784 DOI: 10.1039/d0cp05018k] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Isoprene is the most abundant non-methane hydrocarbon emitted into the Earth's atmosphere. Ozonolysis is an important atmospheric sink for isoprene, which generates reactive carbonyl oxide species (R1R2C[double bond, length as m-dash]O+O-) known as Criegee intermediates. This study focuses on characterizing the catalyzed isomerization and adduct formation pathways for the reaction between formic acid and methyl vinyl ketone oxide (MVK-oxide), a four-carbon unsaturated Criegee intermediate generated from isoprene ozonolysis. syn-MVK-oxide undergoes intramolecular 1,4 H-atom transfer to form a substituted vinyl hydroperoxide intermediate, 2-hydroperoxybuta-1,3-diene (HPBD), which subsequently decomposes to hydroxyl and vinoxylic radical products. Here, we report direct observation of HPBD generated by formic acid catalyzed isomerization of MVK-oxide under thermal conditions (298 K, 10 torr) using multiplexed photoionization mass spectrometry. The acid catalyzed isomerization of MVK-oxide proceeds by a double hydrogen-bonded interaction followed by a concerted H-atom transfer via submerged barriers to produce HPBD and regenerate formic acid. The analogous isomerization pathway catalyzed with deuterated formic acid (D2-formic acid) enables migration of a D atom to yield partially deuterated HPBD (DPBD), which is identified by its distinct mass (m/z 87) and photoionization threshold. In addition, bimolecular reaction of MVK-oxide with D2-formic acid forms a functionalized hydroperoxide adduct, which is the dominant product channel, and is compared to a previous bimolecular reaction study with normal formic acid. Complementary high-level theoretical calculations are performed to further investigate the reaction pathways and kinetics.
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Affiliation(s)
- Michael F Vansco
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104-6323, USA.
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23
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Lin YH, Yang CH, Takahashi K, Lin JJM. Kinetics of Unimolecular Decay of Methyl Vinyl Ketone Oxide, an Isoprene-Derived Criegee Intermediate, under Atmospherically Relevant Conditions. J Phys Chem A 2020; 124:9375-9381. [PMID: 33138375 DOI: 10.1021/acs.jpca.0c07928] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Isoprene is the most abundant unsaturated hydrocarbon in the atmosphere. Ozonolysis of isoprene produces methyl vinyl ketone oxide (MVKO), which may react with atmospheric SO2, formic acid, and other important species at substantial levels. In this study, we utilized ultraviolet absorption to monitor the unimolecular decay kinetics of syn-MVKO in real time at 278-319 K and 100-503 Torr. After removing the contributions of radical reactions and wall loss, the unimolecular decay rate coefficient of syn-MVKO was measured to be kuni = 70 ± 15 s-1 (1σ uncertainty) at 298 K with negligible pressure dependence. In addition, kuni increases from ca. 30 s-1 at 278 K to ca. 175 s-1 at 319 K with an effective Arrhenius activation energy of 8.3 ± 2.5 kcal mol-1, kuni(T) = (9.3 × 107)exp(-4200/T) s-1. Our results indicate that unimolecular decay is the major sink of MVKO in the troposphere. The data would improve the estimation for the steady-state concentrations of MVKO and thus its oxidizing ability.
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Affiliation(s)
- Yen-Hsiu Lin
- Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 10617, Taiwan.,Department of Chemistry, National Taiwan University, Taipei 10617, Taiwan
| | - Chung-Hsin Yang
- Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 10617, Taiwan
| | - Kaito Takahashi
- Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 10617, Taiwan
| | - Jim Jr-Min Lin
- Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 10617, Taiwan
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24
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Li Y, Gong Q, Yang J, Feng Q, Song T, Wang W, Liu F. Hydrogen bond, ring tension and π-conjugation effects: methyl and vinyl substitutions dramatically change the photodynamics of Criegee intermediates. Phys Chem Chem Phys 2020; 22:15295-15302. [PMID: 32618986 DOI: 10.1039/d0cp01873b] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The substitution effect in chemistry is a concept that is probably too common to mention, while for a molecule with an elusive electronic structure, substitution can introduce an unusual effect that dramatically tunes the chemical process. To reveal the substitution effects on the photodynamics of Criegee Intermediates (CIs), we carried out the multireference CASSCF trajectory surface-hopping (TSH) molecular dynamics and CASPT2 electronic-structure calculations for a methyl-substituted CI (MCI) and a vinyl-substituted CI (VCI). The results show that for different substituents, the hydrogen bond, ring tension and π-conjugation not only alter the relative stabilities of the conformers/configurations, but also dramatically change the photo-induced channel of CIs. For an anti-MCI, the dominant channel starting from the S1 state is the ring-closure process leading to dioxirane, while in the syn configuration, the intramolecular CHO hydrogen bond hinders the rotation around the C-O bond and thus leads to a high yield of in-plane O-O dissociation towards acetaldehyde (X1A') and the O(1D) atom. In a VCI with an unsaturated substituent, the π-conjugation greatly strengthens the O-O bond and therefore no O-O dissociation is observed in all configurations. In addition, the CHO hydrogen bond in the syn(CO)-VCI further stabilizes the S1-state intermediates and makes them less reactive; in contrast, isomerization to dioxirane becomes the globally dominant channel in the anti(CO)-VCI. The dramatic substitution effects by saturated and unsaturated substituents on CIs found here will deepen the understanding of Criegee-intermediate chemistry.
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Affiliation(s)
- Yazhen Li
- Key Laboratory for Macromolecular Science of Shaanxi Province, School of Chemistry & Chemical Engineering, Shaanxi Normal University, Xi'an, Shaanxi 710062, P. R. China.
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25
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Hansen AS, Liu Z, Chen S, Schumer MG, Walsh PJ, Lester MI. Unraveling Conformer-Specific Sources of Hydroxyl Radical Production from an Isoprene-Derived Criegee Intermediate by Deuteration. J Phys Chem A 2020; 124:4929-4938. [PMID: 32449860 DOI: 10.1021/acs.jpca.0c02867] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Ozonolysis of isoprene, the most abundant volatile organic compounds emitted into the Earth's troposphere after methane, yields three distinct Criegee intermediates. Among these, methyl vinyl ketone oxide (MVK-oxide) is predicted to be the major source of atmospheric hydroxyl radicals (OH) from isoprene ozonolysis. Previously, Barber et al. [ J. Am. Chem. Soc., 2018, 140, pp 10866-10880] demonstrated that syn-MVK-oxide conformers undergo unimolecular decay via 1,4-hydrogen (H) transfer from the methyl group to the adjacent terminal oxygen atom, followed by the prompt release of OH radical products. Here, we selectively deuterate the methyl group of MVK-oxide (d3-MVK-oxide) and record its IR action spectrum in the vinyl CH stretch overtone (2νCH) region. The resultant time-dependent appearance of OD radical products, detected by laser-induced fluorescence, demonstrates that a unimolecular decay of d3-MVK-oxide proceeds by an analogous 1,4-deuterium (D) atom transfer mechanism anticipated for syn conformers. The experimental spectral and temporal results are compared with the calculated IR absorption spectrum and unimolecular decay rates predicted by the Rice-Ramsperger-Kassel-Marcus (RRKM) theory for syn-d3-MVK-oxide, as well as the prior study on syn-MVK-oxide. The d3-MVK-oxide IR action spectrum is similar to that for MVK-oxide, yet exhibits notable changes as the overtone and combination transitions involving CD stretch shift to a lower frequency. The unimolecular decay rate for d3-MVK-oxide is predicted to be a factor of 40 times slower than that for MVK-oxide in the 2νCH region. Experimentally, the temporal profile of the OD products reflects the slower unimolecular decay of d3-MVK-oxide compared to that for MVK-oxide to OH products as well as experimental factors. Both experiment and theory demonstrate that quantum mechanical tunneling plays a very important role in the 1,4-H/D-transfer processes at energies in the vicinity of the transition-state barrier. The similarities of the IR action spectra and changes in the unimolecular decay dynamics upon deuteration indicate that syn conformers make the main contribution to the IR action spectra of MVK-oxide and d3-MVK-oxide.
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Affiliation(s)
- Anne S Hansen
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, United States
| | - Ziao Liu
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, United States
| | - Shuguang Chen
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, United States
| | - Mac G Schumer
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, United States
| | - Patrick J Walsh
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, United States
| | - Marsha I Lester
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, United States
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26
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Barber VP, Hansen AS, Georgievskii Y, Klippenstein SJ, Lester MI. Experimental and theoretical studies of the doubly substituted methyl-ethyl Criegee intermediate: Infrared action spectroscopy and unimolecular decay to OH radical products. J Chem Phys 2020; 152:094301. [PMID: 33480748 DOI: 10.1063/5.0002422] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The infrared (IR) action spectrum of the doubly substituted methyl-ethyl Criegee intermediate (MECI) is observed in the CH stretch overtone region with detection of OH products. The MECI exhibits four conformers, all of which undergo unimolecular decay via a 1,4 H-atom transfer mechanism, followed by the rapid release of OH products. Conformers with different orientations of the carbonyl oxide group with respect to the methyl and ethyl substituents (i.e., anti and syn) decay via distinct transition state barriers (16.1 kcal mol-1 and 15.4 kcal mol-1, respectively). The observed IR action spectrum is in good agreement with the predicted anharmonic IR absorption spectrum, but exhibits significant congestion, which is attributed to couplings between spectroscopic bright states and nearby dark states. Energy-dependent OH appearance rates are measured upon IR excitation of the strongest features in the IR action spectrum and are found to be on the order of 106-107 s-1. The experimental rates are in good agreement with computed Rice-Ramsperger-Kassel-Marcus rates for the unimolecular decay of MECI at these energies, which incorporate quantum mechanical tunneling and sophisticated hindered rotor treatments, as well as high-level theoretical calculations of the TS barrier heights, rovibrational properties, and torsional barriers associated with the MECI conformers. Master equation modeling is used to predict thermal rates for the unimolecular decay of anti- and syn-MECI of 473 s-1 and 660 s-1, respectively. Comparison with other previously studied Criegee intermediate systems provides insights into substituent effects on unimolecular decay under both energy-dependent and thermal conditions.
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Affiliation(s)
- Victoria P Barber
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, USA
| | - Anne S Hansen
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, USA
| | - Yuri Georgievskii
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, USA
| | - Stephen J Klippenstein
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, USA
| | - Marsha I Lester
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, USA
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27
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Liu Y, Zhou X, Chen Y, Chen M, Xiao C, Dong W, Yang X. Temperature- and pressure-dependent rate coefficient measurement for the reaction of CH2OO with CH3CH2CHO. Phys Chem Chem Phys 2020; 22:25869-25875. [DOI: 10.1039/d0cp04316h] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The rate coefficients of the CH2OO + CH3CH2CHO reaction were studied at temperatures and pressures in the range of 283–318 K and 5–200 Torr.
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Affiliation(s)
- Yiqiang Liu
- Key Laboratory of Materials Modification by Laser, Ion and Electron Beams (Ministry of Education)
- School of Physics
- Dalian University of Technology
- Dalian
- China
| | - Xiaohu Zhou
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics
- Chinese Academy of Sciences
- Dalian
- China
- Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education), School of Environmental Science and Technology
| | - Yang Chen
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics
- Chinese Academy of Sciences
- Dalian
- China
- Key Laboratory of Chemical Lasers, Dalian Institute of Chemical Physics
| | - Maodu Chen
- Key Laboratory of Materials Modification by Laser, Ion and Electron Beams (Ministry of Education)
- School of Physics
- Dalian University of Technology
- Dalian
- China
| | - Chunlei Xiao
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics
- Chinese Academy of Sciences
- Dalian
- China
| | - Wenrui Dong
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics
- Chinese Academy of Sciences
- Dalian
- China
| | - Xueming Yang
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics
- Chinese Academy of Sciences
- Dalian
- China
- Department of Chemistry, Southern University of Science and Technology
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28
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Li YL, Kuo MT, Lin JJM. Unimolecular decomposition rates of a methyl-substituted Criegee intermediate syn-CH3CHOO. RSC Adv 2020; 10:8518-8524. [PMID: 35497839 PMCID: PMC9049986 DOI: 10.1039/d0ra01406k] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Accepted: 02/18/2020] [Indexed: 11/23/2022] Open
Abstract
Criegee intermediates play important roles in atmospheric chemistry. Methyl Criegee intermediate, CH3CHOO, has two conformers, syn- and anti-conformers. Syn-CH3CHOO would undergo fast unimolecular decomposition to form OH radical via 1,4 H-atom transfer. In this work, unimolecular decomposition of syn-CH3CHOO was probed in real time with UV absorption spectroscopy at 278–318 K and 100–700 torr. We used water vapor as the scavenger of anti-CH3CHOO to distinguish the absorption signals of the two conformers. After removing the contributions from reactions with radical byproducts, reaction with water vapor and wall loss, we obtained the unimolecular reaction rate coefficient of syn-CH3CHOO (at 300 torr), which increases from (67 ± 15) s−1 at 278 K, (146 ± 31) s−1 at 298 K, to (288 ± 81) s−1 at 318 K with an Arrhenius activation energy of ca. 6.4 kcal mol−1 and a weak pressure dependence for 100–700 torr. Compared to previous studies, this work provides temperature dependent unimolecular rates of syn-CH3CHOO at higher pressures, which are more relevant to atmospheric conditions. This work provides temperature dependent unimolecular rates of syn-CH3CHOO at higher pressures.![]()
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Affiliation(s)
- Yu-Lin Li
- Institute of Atomic and Molecular Sciences
- Academia Sinica
- Taipei 10617
- Taiwan
- Department of Chemistry
| | - Mei-Tsan Kuo
- Institute of Atomic and Molecular Sciences
- Academia Sinica
- Taipei 10617
- Taiwan
| | - Jim Jr-Min Lin
- Institute of Atomic and Molecular Sciences
- Academia Sinica
- Taipei 10617
- Taiwan
- Department of Chemistry
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29
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Stephenson TA, Lester MI. Unimolecular decay dynamics of Criegee intermediates: Energy-resolved rates, thermal rates, and their atmospheric impact. INT REV PHYS CHEM 2019. [DOI: 10.1080/0144235x.2020.1688530] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Affiliation(s)
- Thomas A. Stephenson
- Department of Chemistry and Biochemistry, Swarthmore College, Swarthmore, PA, USA
| | - Marsha I. Lester
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA, USA
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30
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Zhou X, Liu Y, Dong W, Yang X. Unimolecular Reaction Rate Measurement of syn-CH 3CHOO. J Phys Chem Lett 2019; 10:4817-4821. [PMID: 31382744 DOI: 10.1021/acs.jpclett.9b01740] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The unimolecular reactions of Criegee intermediates (CIs) are thought to be one of the significant sources of atmospheric OH radicals. However, stark discrepancies exist in the unimolecular reaction rate of the methyl-substituted CI CH3CHOO, typically from ozonolysis of alkenes such as trans-2-butene, between the results of ozonolysis of alkene experiments and the up-to-date theoretical calculations. That no further progress has been made since the method that directly produces CIs in the laboratory was developed is mostly attributed to the existence of two conformers, syn- and anti-CH3CHOO, and the methodological limitations of sensitive conformer-specific detection. We report a conformer-specific measurement of the unimolecular reaction rate of syn-CH3CHOO by using a high-repetition-rate laser-induced fluorescence method. At 298 K, the observed value of 182 ± 66 s-1 is in good agreement with recent theoretical calculations.
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Affiliation(s)
- Xiaohu Zhou
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
- State Key Laboratory of Fine Chemicals and Key Laboratory of Industrial Ecology and Environmental Engineering, School of Environmental Science & Technology, Dalian University of Technology, Dalian 116024, China
| | - Yiqiang Liu
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
- Key Laboratory of Materials Modification by Laser, Ion and Electron Beams (Ministry of Education), School of Physics, Dalian University of Technology, Dalian 116024, China
| | - Wenrui Dong
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
| | - Xueming Yang
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
- Department of Chemistry, Southern University of Science and Technology, Shenzhen 518055, China
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31
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Chao W, Lin YH, Yin C, Lin WH, Takahashi K, Lin JJM. Temperature and isotope effects in the reaction of CH 3CHOO with methanol. Phys Chem Chem Phys 2019; 21:13633-13640. [PMID: 31187818 DOI: 10.1039/c9cp02534k] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Carbonyl oxides, also known as Criegee intermediates, are generated from ozonolysis of unsaturated hydrocarbons in the atmosphere. Alcohols are often used as a scavenger of the Criegee intermediates in laboratory studies. In this work, the reaction kinetics of CH3CHOO with methanol vapor was investigated at various temperatures, pressures, and isotopic substitutions using time-resolved UV absorption spectroscopy. The observed rate coefficients of the reaction of anti-CH3CHOO with methanol show a linear dependence on [CH3OH]. The bimolecular rate coefficient was determined to be k1Ha = (4.8 ± 0.5) × 10-12 cm3 s-1 at 298 K and 250 Torr with a negative activation energy Ea = -2.8 ± 0.3 kcal mol-1 for T = 288-315 K [k(T) = A exp(-Ea/RT)]. For the reaction of syn-CH3CHOO with methanol vapor, the observed rate coefficients show a quadratic dependence on [CH3OH], indicating that two methanol molecules participate in the reaction. The termolecular rate coefficient was determined to be k2Hs = (8.0 ± 1.0) × 10-32 cm6 s-1 at 298 K and 250 Torr with a strong negative temperature dependence (Ea = -13.2 ± 0.3 kcal mol-1) at 273-323 K. No significant pressure effect was observed at 250-760 Torr. A kinetic isotope effect, k2Hs/k2Ds = 2.5, was observed by changing CH3OH to CH3OD. Quantum chemistry and transition state theory calculations suggest that the observed isotope effect is mainly attributed to the changes of the vibrational zero-point energies and partition functions while tunneling plays a very minor role. The reaction of syn-CH3CHOO with one CH3OH molecule was not observed in the studied concentration range.
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Affiliation(s)
- Wen Chao
- Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 10617, Taiwan.
| | - Yen-Hsiu Lin
- Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 10617, Taiwan. and Department of Chemistry, National Taiwan University, Taipei 10617, Taiwan.
| | - Cangtao Yin
- Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 10617, Taiwan.
| | - Wei-Hong Lin
- Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 10617, Taiwan.
| | - Kaito Takahashi
- Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 10617, Taiwan.
| | - Jim Jr-Min Lin
- Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 10617, Taiwan. and Department of Chemistry, National Taiwan University, Taipei 10617, Taiwan.
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32
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Shan X, Burd TAH, Clary DC. New Developments in Semiclassical Transition-State Theory. J Phys Chem A 2019; 123:4639-4657. [DOI: 10.1021/acs.jpca.9b01987] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Xiao Shan
- Physical and Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom
| | - Timothy A. H. Burd
- Physical and Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom
| | - David C. Clary
- Physical and Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom
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33
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Winter P, Richardson JO. Divide-and-Conquer Method for Instanton Rate Theory. J Chem Theory Comput 2019; 15:2816-2825. [DOI: 10.1021/acs.jctc.8b01267] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Pierre Winter
- Laboratory of Physical Chemistry, ETH Zürich, 8093 Zürich, Switzerland
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34
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Cabezas C, Guillemin JC, Endo Y. Fourier transform microwave spectroscopy of Criegee intermediates: The conformational behaviour of butyraldehyde oxide. J Chem Phys 2019; 150:104301. [DOI: 10.1063/1.5088566] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Carlos Cabezas
- Department of Applied Chemistry, Science Building II, National Chiao Tung University, 1001 Ta-Hsueh Rd., Hsinchu 30010, Taiwan
| | - Jean-Claude Guillemin
- Univ Rennes, Ecole Nationale Supérieure de Chimie de Rennes, CNRS, ISCR–UMR6226, F-35000 Rennes, France
| | - Yasuki Endo
- Department of Applied Chemistry, Science Building II, National Chiao Tung University, 1001 Ta-Hsueh Rd., Hsinchu 30010, Taiwan
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35
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Barber VP, Pandit S, Esposito VJ, McCoy AB, Lester MI. CH Stretch Activation of CH3CHOO: Deep Tunneling to Hydroxyl Radical Products. J Phys Chem A 2019; 123:2559-2569. [DOI: 10.1021/acs.jpca.8b12324] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Victoria P. Barber
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, United States
| | - Shubhrangshu Pandit
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, United States
| | - Vincent J. Esposito
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, United States
| | - Anne B. McCoy
- Department of Chemistry, University of Washington, Seattle, Washington 98195-1700, United States
| | - Marsha I. Lester
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, United States
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36
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Vansco MF, Marchetti B, Lester MI. Electronic spectroscopy of methyl vinyl ketone oxide: A four-carbon unsaturated Criegee intermediate from isoprene ozonolysis. J Chem Phys 2019; 149:244309. [PMID: 30599734 DOI: 10.1063/1.5064716] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Ozonolysis of isoprene, one of the most abundant volatile organic compounds in the atmosphere, proceeds through methyl vinyl ketone oxide (MVK-oxide), methacrolein oxide, and formaldehyde oxide (CH2OO) Criegee intermediates. The present study focuses on MVK-oxide, a four-carbon unsaturated carbonyl oxide intermediate, using vacuum ultraviolet photoionization at 118 nm and UV-visible induced depletion of the m/z = 86 mass channel to characterize its first π* ← π electronic transition. The electronic spectrum is broad and unstructured with its peak at 388 nm (3.2 eV). The MVK-oxide spectrum is shifted to a significantly longer wavelength than CH2OO and alkyl-substituted Criegee intermediates studied previously due to extended conjugation across the vinyl and carbonyl oxide groups. Electronic excitation results in rapid dissociation at λ ≤ 430 nm to methyl vinyl ketone and O 1D products, the latter detected by 2 + 1 resonance enhanced multiphoton ionization using velocity map imaging. Complementary electronic structure calculations (CASPT2(12,10)/AVDZ) predict two π* ← π transitions with significant oscillator strength for each of the four conformers of MVK-oxide with vertical excitation energies (and corresponding wavelengths) in the 3.1-3.6 eV (350-400 nm) and 4.5-5.5 eV (220-280 nm) regions. The computed electronic absorption profile of MVK-oxide, based on a Wigner distribution of ground state configurations and summed over the four conformers, is predicted to peak at 397 nm. UV-visible spectroscopy on the first π* ← π transition is shown by a combination of experiment and theory to provide a sensitive method for detection of the MVK-oxide Criegee intermediate that will enable further studies of its photochemistry and unimolecular and bimolecular reaction dynamics.
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Affiliation(s)
- Michael F Vansco
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, USA
| | - Barbara Marchetti
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, USA
| | - Marsha I Lester
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, USA
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37
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Hakala JP, Donahue NM. Pressure Stabilization of Criegee Intermediates Formed from Symmetric trans-Alkene Ozonolysis. J Phys Chem A 2018; 122:9426-9434. [PMID: 30441898 DOI: 10.1021/acs.jpca.8b09650] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We explore the pressure dependence of a stabilized Criegee Intermediate (sCI) formation from a sequence of trans-alkene ozonolysis reactions. To study the effect of carbon chain length on the stabilization, we select five symmetric trans-alkenes ranging from trans-2-butene (C4) through trans-7-tetradecene (C14). We measure the pressure falloff curves for each alkene from 50 to 900 Torr in a flow reactor using conversion of SO2 to H2SO4 with and without an OH scavenger, and subsequent detection of H2SO4 with a nitrate chemical ionization mass spectrometer to constrain sCI yields. As the length of the carbon chain increases, we observe a systematic increase in Criegee Intermediate stabilization at a given pressure, along with a systematic decrease in the low-pressure limit. Our results also suggest that for these symmetrical systems the anticonformer of the Criegee Intermediate stabilizes before (at lower pressure than) the syn conformer.
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Affiliation(s)
- Jani P Hakala
- Center for Atmospheric Particle Studies , Carnegie Mellon University , 5000 Forbes Avenue , Pittsburgh , Pennsylvania 15213 , United States.,Institute for Atmospheric and Earth System Research, Department of Physics , University of Helsinki , P.O. Box 64, Helsinki , 00014 , Finland
| | - Neil M Donahue
- Center for Atmospheric Particle Studies , Carnegie Mellon University , 5000 Forbes Avenue , Pittsburgh , Pennsylvania 15213 , United States.,Institute for Atmospheric and Earth System Research, Department of Physics , University of Helsinki , P.O. Box 64, Helsinki , 00014 , Finland
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38
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Cabezas C, Guillemin JC, Endo Y. Conformational preferences of Criegee intermediates: Isopropyl substituted carbonyl oxide. J Chem Phys 2018; 149:084309. [DOI: 10.1063/1.5045768] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Carlos Cabezas
- Department of Applied Chemistry, Science Building II, National Chiao Tung University, 1001 Ta-Hsueh Rd., Hsinchu 30010, Taiwan
| | - Jean-Claude Guillemin
- Univ Rennes, Ecole Nationale Supérieure de Chimie de Rennes, CNRS, ISCR—UMR6226, F-35000 Rennes, France
| | - Yasuki Endo
- Department of Applied Chemistry, Science Building II, National Chiao Tung University, 1001 Ta-Hsueh Rd., Hsinchu 30010, Taiwan
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39
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Barber VP, Pandit S, Green AM, Trongsiriwat N, Walsh PJ, Klippenstein SJ, Lester MI. Four-Carbon Criegee Intermediate from Isoprene Ozonolysis: Methyl Vinyl Ketone Oxide Synthesis, Infrared Spectrum, and OH Production. J Am Chem Soc 2018; 140:10866-10880. [PMID: 30074392 DOI: 10.1021/jacs.8b06010] [Citation(s) in RCA: 82] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The reaction of ozone with isoprene, one of the most abundant volatile organic compounds in the atmosphere, produces three distinct carbonyl oxide species (RR'COO) known as Criegee intermediates: formaldehyde oxide (CH2OO), methyl vinyl ketone oxide (MVK-OO), and methacrolein oxide (MACR-OO). The nature of the substituents (R,R' = H, CH3, CH═CH2) and conformations of the Criegee intermediates control their subsequent chemistry in the atmosphere. In particular, unimolecular decay of MVK-OO is predicted to be the major source of hydroxyl radicals (OH) in isoprene ozonolysis. This study reports the initial laboratory synthesis and direct detection of MVK-OO through reaction of a photolytically generated, resonance-stabilized monoiodoalkene radical with O2. MVK-OO is characterized utilizing infrared (IR) action spectroscopy, in which IR activation of MVK-OO with two quanta of CH stretch at ca. 6000 cm-1 is coupled with ultraviolet detection of the resultant OH products. MVK-OO is identified by comparison of the experimentally observed IR spectral features with theoretically predicted IR absorption spectra. For syn-MVK-OO, the rate of appearance of OH products agrees with the unimolecular decay rate predicted using statistical theory with tunneling. This validates the hydrogen atom transfer mechanism and computed transition-state barrier (18.0 kcal mol-1) leading to OH products. Theoretical calculations reveal an additional roaming pathway between the separating radical fragments, which results in other products. Master equation modeling yields a thermal unimolecular decay rate for syn-MVK-OO of 33 s-1 (298 K, 1 atm). For anti-MVK-OO, theoretical exploration of several unimolecular decay pathways predicts that isomerization to dioxole is the most likely initial step to products.
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Affiliation(s)
- Victoria P Barber
- Department of Chemistry , University of Pennsylvania , Philadelphia , Pennsylvania 19104-6323 , United States
| | - Shubhrangshu Pandit
- Department of Chemistry , University of Pennsylvania , Philadelphia , Pennsylvania 19104-6323 , United States
| | - Amy M Green
- Department of Chemistry , University of Pennsylvania , Philadelphia , Pennsylvania 19104-6323 , United States
| | - Nisalak Trongsiriwat
- Department of Chemistry , University of Pennsylvania , Philadelphia , Pennsylvania 19104-6323 , United States
| | - Patrick J Walsh
- Department of Chemistry , University of Pennsylvania , Philadelphia , Pennsylvania 19104-6323 , United States
| | - Stephen J Klippenstein
- Chemical Sciences and Engineering Division , Argonne National Laboratory , Argonne , Illinois 60439 , United States
| | - Marsha I Lester
- Department of Chemistry , University of Pennsylvania , Philadelphia , Pennsylvania 19104-6323 , United States
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40
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Yin C, Takahashi K. Effect of unsaturated substituents in the reaction of Criegee intermediates with water vapor. Phys Chem Chem Phys 2018; 20:20217-20227. [PMID: 30027942 DOI: 10.1039/c8cp02064g] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Criegee intermediates (CIs), formed in the reactions of unsaturated hydrocarbons with ozone, are very reactive carbonyl oxides and have recently been suggested as important oxidants in the atmosphere. In this work, we studied the substituent effect on the water monomer and dimer reaction with CIs which include up to three carbon atoms at the QCISD(T)/CBS//B3LYP/6-311+G(2d,2p) level. Our calculation showed that for saturated CIs with a hydrogen atom on the same side as the terminal oxygen atom, the reaction with water vapor would likely dominate the removal processes of these CIs in the atmosphere. On the other hand, for unsaturated CIs, the reactivity toward water vapor decreases compared to the saturated species allowing them to survive in humid atmospheric environments. We also evaluated the kinetic isotope effect in the reaction between CI and water vapor by performing calculations with deuterated water. We found that tunneling is not important and the kinetic isotope effect mainly comes from the difference in the zero point energy between water and deuterated water.
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Affiliation(s)
- Cangtao Yin
- Institute of Atomic and Molecular Sciences, Academia Sinica, PO-Box 23-166, Taipei, 10617, Taiwan.
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41
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Nandi S, Parui S, Halder R, Jana B, Bhattacharyya K. Interaction of proteins with ionic liquid, alcohol and DMSO and in situ generation of gold nano-clusters in a cell. Biophys Rev 2018; 10:757-768. [PMID: 29147940 PMCID: PMC5988615 DOI: 10.1007/s12551-017-0331-1] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2017] [Accepted: 10/23/2017] [Indexed: 12/27/2022] Open
Abstract
In this review, we give a brief overview on how the interaction of proteins with ionic liquids, alcohols and dimethyl sulfoxide (DMSO) influences the stability, conformational dynamics and function of proteins/enzymes. We present experimental results obtained from fluorescence correlation spectroscopy on the effect of ionic liquid or alcohol or DMSO on the size (more precisely, the diffusion constant) and conformational dynamics of lysozyme, cytochrome c and human serum albumin in aqueous solution. The interaction of ionic liquid with biomolecules (e.g. protein, DNA etc.) has emerged as a current frontier. We demonstrate that ionic liquids are excellent stabilizers of protein and DNA and, in some cases, cause refolding of a protein already denatured by chemical denaturing agents. We show that in ethanol-water binary mixture, proteins undergo non-monotonic changes in size and dynamics with increasing ethanol content. We also discuss the effect of water-DMSO mixture on the stability of proteins. We demonstrate how large-scale molecular dynamics simulations have revealed the molecular origin of this observed phenomenon and provide a microscopic picture of the immediate environment of the biomolecules. Finally, we describe how favorable interactions of ionic liquids may be utilized for in situ generation of fluorescent gold nano-clusters for imaging a live cell.
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Affiliation(s)
- Somen Nandi
- Department of Physical Chemistry, Indian Association for the Cultivation of Science, Jadavpur, Kolkata, 700 032, India
| | - Sridip Parui
- Department of Physical Chemistry, Indian Association for the Cultivation of Science, Jadavpur, Kolkata, 700 032, India
| | - Ritaban Halder
- Department of Physical Chemistry, Indian Association for the Cultivation of Science, Jadavpur, Kolkata, 700 032, India
| | - Biman Jana
- Department of Physical Chemistry, Indian Association for the Cultivation of Science, Jadavpur, Kolkata, 700 032, India.
| | - Kankan Bhattacharyya
- Department of Physical Chemistry, Indian Association for the Cultivation of Science, Jadavpur, Kolkata, 700 032, India.
- Department of Chemistry, Indian Institute of Science Education and Research Bhopal, Bhopal, Madhya Pradesh, 462 066, India.
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43
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Campos-Pineda M, Zhang J. Product yields of stabilized Criegee intermediates in the ozonolysis reactions of cis-2-butene, 2-methyl-2-butene, cyclopentene, and cyclohexene. Sci China Chem 2018. [DOI: 10.1007/s11426-017-9229-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
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Pfeifle M, Ma YT, Jasper AW, Harding LB, Hase WL, Klippenstein SJ. Nascent energy distribution of the Criegee intermediate CH2OO from direct dynamics calculations of primary ozonide dissociation. J Chem Phys 2018; 148:174306. [DOI: 10.1063/1.5028117] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Mark Pfeifle
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - Yong-Tao Ma
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, Texas 79409, USA
| | - Ahren W. Jasper
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - Lawrence B. Harding
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - William L. Hase
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, Texas 79409, USA
| | - Stephen J. Klippenstein
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
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Lester MI, Klippenstein SJ. Unimolecular Decay of Criegee Intermediates to OH Radical Products: Prompt and Thermal Decay Processes. Acc Chem Res 2018; 51:978-985. [PMID: 29613756 DOI: 10.1021/acs.accounts.8b00077] [Citation(s) in RCA: 83] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Alkene ozonolysis is a primary oxidation pathway for anthropogenic and biogenic alkenes emitted into the troposphere. It is also an important source of atmospheric hydroxyl (OH) radicals, often called the atmosphere's detergent. Alkene ozonolysis takes place through a highly exothermic reaction pathway with multiple intermediates and barriers prior to releasing the OH radical products. This Account focuses on a key reaction intermediate with a carbonyl oxide functional group (-COO), known as the Criegee intermediate, which is formed along with a carbonyl coproduct in alkene ozonolysis reactions. Under atmospheric conditions, the initially energized Criegee intermediates may promptly decay to OH products or be collisionally stabilized prior to thermal decay to OH radicals and other products. Alternatively, the stabilized Criegee intermediates may undergo bimolecular reactions with atmospheric species, including water vapor and sulfur dioxide, which can lead to nucleation and growth of aerosols. The dimethyl-substituted Criegee intermediate, (CH3)2COO, is utilized in this Account to showcase recent efforts to experimentally measure and theoretically predict the rates for prompt and thermal unimolecular decay processes of prototypical Criegee intermediates under laboratory and atmospheric conditions. The experimental laboratory studies utilize an alternative synthesis method to efficiently generate Criegee intermediates via the reaction of iodoalkyl radicals with O2. Infrared excitation is then used to prepare the (CH3)2COO Criegee intermediates at specific energies in the vicinity of the transition state barrier or significantly below the barrier for 1,4-hydrogen transfer that leads to OH products. The rate of unimolecular decay is revealed through direct time-domain measurements of the appearance of OH products utilizing ultraviolet laser-induced fluorescence detection under collision-free conditions. Complementary high-level theoretical calculations are carried out to evaluate the transition state barrier and the energy-dependent unimolecular decay rates for (CH3)2COO using Rice-Ramsperger-Kassel-Marcus (RRKM) theory, which are in excellent accord with the experimental measurements. Quantum mechanical tunneling through the barrier, incorporated through Eckart and semiclassical transition state theory models, is shown to make a significant contribution to the unimolecular decay rates at energies in the vicinity of and much below the barrier. Master equation modeling is used to extend the energy-dependent unimolecular rates to thermal decay rates of (CH3)2COO under tropospheric conditions (high pressure limit), which agree well with recent laboratory measurements [ Smith et al. J. Phys. Chem. A 2016 , 120 , 4789 and Chhantyal-Pun et al. J. Phys. Chem. A 2017 , 121 , 4 - 15 ]. Again, tunneling is shown to enhance the thermal decay rate by orders of magnitude. The experimentally validated unimolecular rates are also utilized in modeling the prompt and thermal unimolecular decay of chemically activated (CH3)2COO formed upon ozonolysis of 2,3-dimethyl-2-butene under atmospheric conditions [ Drozd et al. J. Phys. Chem. A 2017 , 121 , 6036 - 6045 ]. Future challenges lie in extension of these spectroscopic and dynamical methods to Criegee intermediates derived from more complex ozonolysis reactions involving biogenic alkenes.
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Affiliation(s)
- Marsha I. Lester
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, United States
| | - Stephen J. Klippenstein
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439, United States
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Jr-Min Lin J, Chao W. Structure-dependent reactivity of Criegee intermediates studied with spectroscopic methods. Chem Soc Rev 2018; 46:7483-7497. [PMID: 28840926 DOI: 10.1039/c7cs00336f] [Citation(s) in RCA: 87] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Criegee intermediates are very reactive carbonyl oxides that are formed in reactions of unsaturated hydrocarbons with ozone (ozonolysis). Recently, Criegee intermediates have gained significant attention since a new preparation method has been reported in 2012, which employs the reaction of iodoalkyl radical with molecular oxygen: for instance, CH2I + O2 → CH2OO + I. This new synthesis route can produce Criegee intermediates with a high number density, which allows direct detection of the Criegee intermediate via various spectroscopic tools, including vacuum UV photoionization mass spectrometry, absorption and action spectroscopy in the UV and IR regions, and microwave spectroscopy. Criegee intermediates have been thought to play important roles in atmospheric chemistry, such as in OH radical formation as well as oxidation of atmospheric gases such as SO2, NO2, volatile organic compounds, organic and inorganic acids, and even water. These reactions are relevant to acid rain and aerosol formation. Kinetics data including rate coefficients, product yields and their temperature and pressure dependences are important for understanding and modeling relevant atmospheric chemistry. In fundamental physical chemistry, Criegee intermediates have unique and interesting features, which have been partially revealed through spectroscopic, kinetic, and dynamic investigations. Although previous review articles have discussed Criegee intermediates, new data and knowledge on Criegee intermediates are still being accumulated. In this tutorial review, we have focused on structure-dependent reactivity of Criegee intermediates and various spectroscopic tools that have been utilized to probe the kinetics of Criegee intermediates.
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Affiliation(s)
- Jim Jr-Min Lin
- Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 10617, Taiwan.
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Li Y, Gong Q, Yue L, Wang W, Liu F. Photochemistry of the Simplest Criegee Intermediate, CH 2OO: Photoisomerization Channel toward Dioxirane Revealed by CASPT2 Calculations and Trajectory Surface-Hopping Dynamics. J Phys Chem Lett 2018; 9:978-981. [PMID: 29420035 DOI: 10.1021/acs.jpclett.8b00023] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The photochemistry of Criegee intermediates plays a significant role in atmospheric chemistry, but it is relatively less explored compared with their thermal reactions. Using multireference CASPT2 electronic structure calculations and CASSCF trajectory surface-hopping molecular dynamics, we have revealed a dark-state-involved A1A → X1A photoisomerization channel of the simple Criegee intermediate (CH2OO) that leads to a cyclic dioxirane. The excited molecules on the A1A state, which can have either originated from the B1A state via B1A → A1A internal conversion or formed by state-selective electronic excitation, is driven by the out-of-plane motion toward a perpendicular A/X1A minimal-energy crossing point (MECI) then radiationless decay to the ground state with an average time constant of ∼138 fs, finally forming dioxirane at ∼254 fs. The dynamics starting from the A1A state show that the quantum yield of photoisomerization from the simple Criegee intermediate to dioxirane is 38%. The finding of the A1A → X1A photoisomerization channel is expected to broaden the reactivity profile and deepen the understanding of the photochemistry of Criegee intermediates.
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Affiliation(s)
- Yazhen Li
- Key Laboratory for Macromolecular Science of Shaanxi Province, School of Chemistry & Chemical Engineering, Shaanxi Normal University , Xi'an, Shaanxi 710062, People's Republic of China
| | - Qianqian Gong
- Key Laboratory for Macromolecular Science of Shaanxi Province, School of Chemistry & Chemical Engineering, Shaanxi Normal University , Xi'an, Shaanxi 710062, People's Republic of China
| | - Ling Yue
- School of Sciences, Xi'an Jiaotong University , Xi'an, Shaanxi 710049, People's Republic of China
| | - Wenliang Wang
- Key Laboratory for Macromolecular Science of Shaanxi Province, School of Chemistry & Chemical Engineering, Shaanxi Normal University , Xi'an, Shaanxi 710062, People's Republic of China
| | - Fengyi Liu
- Key Laboratory for Macromolecular Science of Shaanxi Province, School of Chemistry & Chemical Engineering, Shaanxi Normal University , Xi'an, Shaanxi 710062, People's Republic of China
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Lin YH, Takahashi K, Lin JJM. Reactivity of Criegee Intermediates toward Carbon Dioxide. J Phys Chem Lett 2018; 9:184-188. [PMID: 29254332 DOI: 10.1021/acs.jpclett.7b03154] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Recent theoretical work by Kumar and Francisco suggested that the high reactivity of Criegee intermediates (CIs) could be utilized for designing efficient carbon capture technologies. Because the anti-CH3CHOO + CO2 reaction has the lowest barrier in their study, we chose to investigate it experimentally. We probed anti-CH3CHOO with its strong UV absorption at 365 nm and measured the rate coefficient to be ≤2 × 10-17 cm3 molecule-1 s-1 at 298 K, which is consistent with our theoretical value of 2.1 × 10-17 cm3 molecule-1 s-1 at the QCISD(T)/CBS//B3LYP/6-311+G(2d,2p) level but inconsistent with their results obtained at the M06-2X/aug-cc-pVTZ level, which tends to underestimate the barrier heights. The experimental result indicates that the reaction of a Criegee intermediate with atmospheric CO2 (400 ppmv) would be inefficient (keff < 0.2 s-1) and cannot compete with other decay processes of Criegee intermediates like reactions with water vapor (∼103 s-1) or thermal decomposition (∼102 s-1).
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Affiliation(s)
- Yen-Hsiu Lin
- Institute of Atomic and Molecular Sciences, Academia Sinica , Taipei 10617, Taiwan
- Department of Chemistry, National Taiwan University , Taipei 10617, Taiwan
| | - Kaito Takahashi
- Institute of Atomic and Molecular Sciences, Academia Sinica , Taipei 10617, Taiwan
| | - Jim Jr-Min Lin
- Institute of Atomic and Molecular Sciences, Academia Sinica , Taipei 10617, Taiwan
- Department of Chemistry, National Taiwan University , Taipei 10617, Taiwan
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Burd TAH, Shan X, Clary DC. Catalysis and tunnelling in the unimolecular decay of Criegee intermediates. Phys Chem Chem Phys 2018; 20:25224-25234. [DOI: 10.1039/c8cp05021j] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Semi-classical Transition State theory can be applied to catalysed atmospheric reactions, but reaction mode anharmonicity must be treated carefully.
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Affiliation(s)
- Timothy A. H. Burd
- Physical and Theoretical Chemical Laboratory
- University of Oxford
- Oxford
- UK
| | - Xiao Shan
- Physical and Theoretical Chemical Laboratory
- University of Oxford
- Oxford
- UK
| | - David C. Clary
- Physical and Theoretical Chemical Laboratory
- University of Oxford
- Oxford
- UK
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Affiliation(s)
- Martin Klussmann
- Max-Planck-Institut für Kohlenforschung Kaiser-Wilhelm-Platz 1 45470 Mülheim an der Ruhr Germany
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