Products of the gas-phase reaction of the OH radical with 3-methyl-1-butene in the presence of NO

Atkinson, Roger; Tuazon, Ernesto C.; Aschmann, Sara M.

doi:10.1002/(sici)1097-4601(1998)30:8<577::aid-kin7>3.0.co;2-p

Cited by 24 publications

(3 citation statements)

References 32 publications

(42 reference statements)

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“…However, the ability of previous experiments to observe abstraction was probably not any better than 5%, so our present estimate of ∼3% does not contradict previous studies. We note that OH abstraction from 3-methyl-1-butene has been verified in a chamber study and product analysis reveals that the allylic H abstraction accounts for 5–10% of the overall OH reaction. Also, while no previous study has observed abstraction via , studies on the isoprene + Cl reaction indicate significant abstraction at room temperature (∼15%). , The stable product of Cl abstraction at the CH 3 site, 2-methylene-3-butenal, was tentatively identified via atmospheric pressure ionization mass spectrometry …”

Section: Resultsmentioning

confidence: 61%

Kinetics of the Reaction of OH with Isoprene over a Wide Range of Temperature and Pressure Including Direct Observation of Equilibrium with the OH Adducts

et al. 2018

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The reaction of the OH radical with isoprene, CH (R1), has been studied over the temperature range 298-794 K and bath gas pressures of nitrogen from 50 to 1670 Torr using laser flash photolysis (LFP) to generate OH and laser-induced fluorescence (LIF) to observe OH removal. Measurements have been made using both a conventional LFP/LIF apparatus and a new high pressure system. The measured rate coefficient at 298 K ( k = (9.90 ± 0.09) × 10 cm molecule s) in the high pressure apparatus is in excellent agreement with the literature, confirming the accuracy of measurements made with this instrument. Above 700 K, the OH decays were no longer single exponentials due to regeneration of OH from adduct decomposition and the establishment of the OH + CH ⇌ HOCH equilibrium (R1a, R-1a). This equilibrium was analyzed by comparison to a master equation model of reaction R1 and determined the well depth for OH addition to carbon C and C to be equal to 153.5 ± 6.2 and 143.4 ± 6.2 kJ mol, respectively. These well depths are in excellent agreement with the present ab initio-CCSD(T)/CBS//M062X/6-311++G(3df,2p)-calculations (154.1 kJ mol for the C adduct). Addition to the less stable C and C adducts is not important. The data above 700 K also indicated that a minor but significant direct abstraction channel, R1b, was also operating with k = (1.3 ± 0.3) × 10 exp(-3.61 kJ mol/ RT) cm molecule s. Additional support for the presence of this abstraction channel comes from our ab initio calculations and from room-temperature proton transfer mass spectrometry product analysis. The literature data on reaction R1 together with the present data were assessed using master equation analysis, using the MESMER package. This analysis produced a refined data set that generates our recommended k( T, [ M]). An analytical representation of k( T, [ M]) and k( T, [ M]) is provided via a Troe expression. The reported experimental data (the sum of addition and abstraction), k = (9.5 ± 0.2) × 10( T/298 K) + (1.3 ± 0.3) × 10 exp(-3.61 kJ mol/ RT) cm molecule s, significantly extend the measured temperature range of R1.

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Section: Resultsmentioning

confidence: 61%

Kinetics of the Reaction of OH with Isoprene over a Wide Range of Temperature and Pressure Including Direct Observation of Equilibrium with the OH Adducts

et al. 2018

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“…The R radicals react with O 2 to form peroxy radicals, which undergo self-and cross-reactions to form C 30 H 49 OH alcohol products. 28−32 It is possible that the R radicals are also formed by H atom abstraction reactions by OH radicals (for brevity this pathway is not explicitly shown in Figure 4), even though studies by Atkinson et al 33,34 suggest that this is a minor reaction pathway. It remains unclear how well these studies on small gas phase alkenes (≤C 5 ) extrapolate to the heterogeneous oxidation of large alkenes (i.e., squalene).…”

Section: Resultsmentioning

confidence: 99%

Isomeric Product Detection in the Heterogeneous Reaction of Hydroxyl Radicals with Aerosol Composed of Branched and Linear Unsaturated Organic Molecules

Nah¹,

Zhang²,

Worton

et al. 2014

J. Phys. Chem. A

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The influence of molecular structure (branched vs linear) on product formation in the heterogeneous oxidation of unsaturated organic aerosol is investigated. Particle phase product isomers formed from the reaction of squalene (C30H50, a branched alkene with six C═C double bonds) and linolenic acid (C18H30O2, a linear carboxylic acid with three C═C double bonds) with OH radicals are identified and quantified using two-dimensional gas chromatography-mass spectrometry. The reactions are measured at low and high [O2] (∼1% vs 10% [O2]) to understand the roles of hydroxyalkyl and hydroxyperoxy radical intermediates in product formation. A key reaction step is OH addition to a C═C double bond to form a hydroxyalkyl radical. In addition, allylic alkyl radicals, formed from H atom abstraction reactions by hydroxyalkyl or OH radicals play important roles in the chemistry of product formation. Functionalization products dominate the squalene reaction at ∼1% [O2], with the total abundance of observed functionalization products being approximately equal to the fragmentation products at 10% [O2]. The large abundance of squalene fragmentation products at 10% [O2] is attributed to the formation and dissociation of tertiary hydroxyalkoxy radical intermediates. For linolenic acid aerosol, the formation of functionalization products dominates the reaction at both ∼1% and 10% [O2], suggesting that the formation and dissociation of secondary hydroxyalkoxy radicals are minor reaction channels for linear molecules. The distribution of linolenic acid functionalization products depends upon [O2], indicating that O2 controls the reaction pathways of the secondary hydroxyalkyl radical. For both reactions, alcohols are formed in favor of carbonyl functional groups, suggesting that there are some key differences between heterogeneous reactions involving allylic radical intermediates and those reactions of OH radicals with simple saturated hydrocarbons.

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“…Rate constant placed on an absolute basis using the estimated rate constant for the O 2 reaction. 4 Derived from the ratios of yields of 2-propanal / glycolaldehyde observed from OH + 3-methyl-1-butene measured by Atkinson et al (1998), assuming that the formation of both products are from decompositions of CH 3 CH(CH 3 )CH(O. )CH 2 OH, and placed on an absolute basis using the estimated rate constant for the reaction forming CH 3 CH(.…”

Section: A52 Radical Rate Constants and Branching Ratiosmentioning

confidence: 99%

Supplementary material to "Derivation of Atmospheric Reaction Mechanisms for Volatile Organic Compounds by the SAPRC Mechanism Generation System (MechGen)"

Carter,

Jiang,

Orlando

et al. 2023

Preprint

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A1. Chemical Mechanism Assignments and Estimates A1.1. Specification of ReactantsMechGen identifies the structure of organic reactants or radicals by specifying "groups" in the molecule, indicating the groups each is bonded to, and the type of bond. Groups are parts of molecules that are treated as units in the system and contain no more than one carbon or nitrogen, and also can contain zero to three hydrogen atoms and zero to three oxygen atoms. These group and molecule designations are used in the tables giving the parameters and assignments since these are how the parameters are assigned. The list of groups that can be used is given in Table A-1; illustrative examples are shown in Table A-2. Note also the following:• Neighboring groups in non-branched and non-cyclic structures are separated by either "-", "=", or "#" symbols depending on whether their bonds are single, double, or triple.• Branched structures are indicated using "( )" to show third or fourth groups bonded to groups with more than two neighbors. If the bond between the center group and the 3rd or 4th group is a double or triple bond it is indicated using a "=" or "#" after the "(", as shown for isoprene in Table A-2. This is similar to the treatment of branched structure using the SMILES notation (SMILES, 2022). Other examples are also shown in Table A-2.• Monocyclic structures are indicated using "*" symbols to indicate groups bonded to other groups using single bonds. The "*" can be before or after the group name, but the standard format is after the name. Bi-and polycyclic structures are indicated using "*1", "*2", etc. symbols to indicate groups that are bonded together, and should always be given after the group name but before any bond designation.• Aromatic structures can be created using "CH" and "C" groups with alternating single or double bonds as with other cyclic polyalkenes. However the standard designation, which reflects the fact that separate groups are used for aromatic carbons, is to designate carbons in aromatic rings using "aCH" or "aC" depending on whether it has a hydrogen or a third group bonded to it, with the aromatic bonds designated as if they were single bonds. See the example for toluene and naphthalene in Table A-2.• Allylic radicals can be created using carbon-centered radical groups and alkene groups to designate one of the resonance structures, and it does not matter which structure is used for this purpose. However the standard designation, which reflects the fact that separate groups are used for such radicals and the radical center is at more than one location, is to designate carbons where the radical center may be located as ".aCH2", "aCH[.]", or "aC[.]" and the other carbons in the allylic structure as if they are aromatic (i.e., alternating double and single bonds). This is only applicable for carbon-centered radicals with conjugated C=C double bonds. See, for example, the structures shown for methyl allyl radicals and the OH+benzene adduct in Table A-2.• Cis and trans isomerization about a double bond ar...

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Products of the gas-phase reaction of the OH radical with 3-methyl-1-butene in the presence of NO

Cited by 24 publications

References 32 publications

Kinetics of the Reaction of OH with Isoprene over a Wide Range of Temperature and Pressure Including Direct Observation of Equilibrium with the OH Adducts

Kinetics of the Reaction of OH with Isoprene over a Wide Range of Temperature and Pressure Including Direct Observation of Equilibrium with the OH Adducts

Isomeric Product Detection in the Heterogeneous Reaction of Hydroxyl Radicals with Aerosol Composed of Branched and Linear Unsaturated Organic Molecules

Supplementary material to "Derivation of Atmospheric Reaction Mechanisms for Volatile Organic Compounds by the SAPRC Mechanism Generation System (MechGen)"

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