The Products of the Reactions of o-Benzyne with Ethene, Propene, and Acetylene: A Combined Mass Spectrometric and Quantum Chemical Study
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Abstract
The primary products of the bimolecular reactions of ortho-benzyne, o-C6H4 (1,2-dehydrobenzene), with ethene, propene, and acetylene have been detected by molecular beam mass spectrometry at a combustion relevant temperature of T = 1475 K. o-Benzyne was produced by flash pyrolysis of phthalic anhydride in the absence and presence of the respective reactant. Potential reaction pathways of the addition reactions were investigated by quantum chemical calculations. Channels with biradical intermediates were found to be energetically more favorable than alternative quasi-concerted [2+1] cycloaddition and concerted H-transfer pathways. Bicyclic benzocyclobutene and benzocyclobutadiene were identified as the main products of the reactions with C2H4 and C2H2, respectively. At combustion temperatures, however, these cyclic products are likely to undergo sequential ring opening. In the case of propene, the presence of an allylic H atom initiates a favorable ene-type reaction sequence yielding the open-chain product allylbenzene. Overall, hydrocarbon reactivity was found to increase in the order C2H2, C2H4 to 3H8. The range of the estimated bimolecular rate constants is comparable to the rate constants of the corresponding phenyl radical reactions and hence point out a potentially important role of o-C6H4 reactions in flame and soot formation chemistry.
© by Oldenbourg Wissenschaftsverlag, München, Germany
Artikel in diesem Heft
- Preface
- Towards Simplified Thermal and Specific Rigidity Factors for Ion-Molecule Reactions and Ion Fragmentations
- Chemistry and Microphysics of Atmospheric Aerosol Surfaces: Laboratory Techniques and Applications
- The Products of the Reactions of o-Benzyne with Ethene, Propene, and Acetylene: A Combined Mass Spectrometric and Quantum Chemical Study
- CH2Cl and CHCl2 Radical Chemistry: The Formation by the Reactions CH3Cl + F and CH2Cl2 + F and The Destruction by the Reactions CH2Cl + O and CHCl2 + O
- Formation of H-atoms in the Pyrolysis of 1,3-butadiene and 2-butyne: A Shock Tube and Modelling Study
- High-level Ab-initio Calculations for Astrochemically Relevant Polyynes (HC2nH), their Isomers (C2nH2) and their Anions (C2nH−)
- Investigation of the Hierarchical Structure of Kinetic Models in Ignition Problems
- Laser Diagnostics for the Model Development in Turbulent Premixed Flames
- Sampling Probe Influences on Temperature and Species Concentrations in Molecular Beam Mass Spectroscopic Investigations of Flat Premixed Low-pressure Flames
- Shock-Tube Study of the Reactions of Hydrogen Atoms with Benzene and Phenyl Radicals
- The Generation of a Compact n-Heptane / Toluene Reaction Mechanism Using the Chemistry Guided Reduction (CGR) Technique
- Modeling of Rich Premixed C2H4/O2/Ar and C2H4/Dimethoxymethane/O2/Ar Flames
- Conformation and Aggregation of Proline Esters and Their Aromatic Homologs: Pyramidal vs. Planar RR´N-H in Hydrogen Bonds
- A Two-equation Model to Simulate Soot Formation under Shock-tube Conditions
- CO Formation in the 254 nm Gas Phase Photolysis of Nitrosobenzene-Oxygen Mixtures at Room Temperature
- Experimental and Numerical Investigation of Fe(CO)5 Addition to a Laminar Premixed Hydrogen/Oxygen/Argon Flame
- Structures of Laminar Methane/Nitrogen/Oxygen, Methane/Oxygen and Methane/Liquid Oxygen Counterflow Flames for Cryogenic Conditions and Elevated Pressures
Artikel in diesem Heft
- Preface
- Towards Simplified Thermal and Specific Rigidity Factors for Ion-Molecule Reactions and Ion Fragmentations
- Chemistry and Microphysics of Atmospheric Aerosol Surfaces: Laboratory Techniques and Applications
- The Products of the Reactions of o-Benzyne with Ethene, Propene, and Acetylene: A Combined Mass Spectrometric and Quantum Chemical Study
- CH2Cl and CHCl2 Radical Chemistry: The Formation by the Reactions CH3Cl + F and CH2Cl2 + F and The Destruction by the Reactions CH2Cl + O and CHCl2 + O
- Formation of H-atoms in the Pyrolysis of 1,3-butadiene and 2-butyne: A Shock Tube and Modelling Study
- High-level Ab-initio Calculations for Astrochemically Relevant Polyynes (HC2nH), their Isomers (C2nH2) and their Anions (C2nH−)
- Investigation of the Hierarchical Structure of Kinetic Models in Ignition Problems
- Laser Diagnostics for the Model Development in Turbulent Premixed Flames
- Sampling Probe Influences on Temperature and Species Concentrations in Molecular Beam Mass Spectroscopic Investigations of Flat Premixed Low-pressure Flames
- Shock-Tube Study of the Reactions of Hydrogen Atoms with Benzene and Phenyl Radicals
- The Generation of a Compact n-Heptane / Toluene Reaction Mechanism Using the Chemistry Guided Reduction (CGR) Technique
- Modeling of Rich Premixed C2H4/O2/Ar and C2H4/Dimethoxymethane/O2/Ar Flames
- Conformation and Aggregation of Proline Esters and Their Aromatic Homologs: Pyramidal vs. Planar RR´N-H in Hydrogen Bonds
- A Two-equation Model to Simulate Soot Formation under Shock-tube Conditions
- CO Formation in the 254 nm Gas Phase Photolysis of Nitrosobenzene-Oxygen Mixtures at Room Temperature
- Experimental and Numerical Investigation of Fe(CO)5 Addition to a Laminar Premixed Hydrogen/Oxygen/Argon Flame
- Structures of Laminar Methane/Nitrogen/Oxygen, Methane/Oxygen and Methane/Liquid Oxygen Counterflow Flames for Cryogenic Conditions and Elevated Pressures
