scholarly journals Influence of Multiple Conformations and Paths on Rate Constants and Product Branching Ratios. Thermal Decomposition of 1-Propanol Radicals

2018 ◽  
Vol 122 (21) ◽  
pp. 4790-4800 ◽  
Author(s):  
David Ferro-Costas ◽  
Emilio Martínez-Núñez ◽  
Jesús Rodríguez-Otero ◽  
Enrique Cabaleiro-Lago ◽  
Carlos M. Estévez ◽  
...  
Keyword(s):  
Thermal Decomposition ◽  
Rate Constants ◽  
Branching Ratios ◽  
Multiple Conformations ◽  
Product Branching

Rate coefficients and product branching ratios for (E)-2-butenal + H reactions

2020 ◽  
Vol 22 (25) ◽  
pp. 14246-14254
Author(s):  
Maiara Oliveira Passos ◽  
Igor Araujo Lins ◽  
Tiago Vinicius Alves
Keyword(s):  
Rate Constants ◽  
Hydrogen Abstraction ◽  
Branching Ratios ◽  
Rate Coefficients ◽  
Variational Theory ◽  
Hydrogen Atoms ◽  
Small Curvature ◽  
Thermal Rate Constants ◽  
First Time ◽  
Product Branching

Thermal rate constants for the hydrogen abstraction reactions of (E)-2-butenal by hydrogen atoms were calculated, for the first time, using the multipath canonical variational theory with small-curvature tunneling (MP-CVT/SCT).

Mechanism and Kinetics of the Oxidation of 1,3-Butadien-1-yl (n-C4H5): A Theoretical Study

2021 ◽  
Author(s):  
Denis P Porfiriev ◽  
Valeriy N. Azyazov ◽  
Alexander Mebel
Keyword(s):  
Potential Energy ◽  
Rate Constants ◽  
Energy Surface ◽  
Theoretical Study ◽  
Branching Ratios ◽  
Dependent Rate ◽  
Mechanism And Kinetics ◽  
Temperature And Pressure ◽  
Product Branching ◽  
Kinetics Of

Ab initio CCSD(T)-F12/cc-pVTZ-f12//B3LYP/6-311G(d,p) calculations of the C4H5O2 potential energy surface have been combined with Rice-Ramsperger-Kassel-Marcus Master Equation (RRKM-ME) calculations of temperature- and pressure-dependent rate constants and product branching ratios to...

scholarly journals Formation Mechanism of a Nonterrestrial C6H Radical: An Ab Initio/RRKM Study on the Reaction of Tetracarbon with Acetylene

2019 ◽  
Author(s):  
Tong Zhu ◽  
Chih-Hao Chin ◽  
John ZH Zhang
Keyword(s):  
Hydrogen Atom ◽  
Ab Initio ◽  
Rate Constants ◽  
Kinetic Equations ◽  
Branching Ratios ◽  
The Other ◽  
Formation Mechanisms ◽  
Hydrogen Elimination ◽  
Carbon Carbon Bond ◽  
Product Branching

This study examined the formation mechanisms of singlet (rhombic) and triplet (linear) C4 with acetylene by using accurate ab initio CCSD(T)/cc-pVTZ/B3LYP/6-311G(d,p) calculations, followed by a kinetic analysis of various reaction pathways and computations of relative product yields in combustion and planetary atmospheres. These calculations were combined with the Rice–Ramsperger–Kassel–Marcus (RRKM) calculations of reaction rate constants for predicting product-branching ratios, which depend on the collision energy under single-collision conditions. The results show that the initial reaction begins with the formation of an intermediate t-i2, with entrance barriers of 3.8 kcal/mol, and an intermediate s-i1 without entrance barriers. On the triplet surface, the t-i2 rearranged the other C6H2 isomers, including t-i3, t-i4, and t-i6, through hydrogen migration; the t-i2, t-i3, t-i4, t-i5, and t-i6 isomers lost a hydrogen atom, and produced the most stable linear isomer of C6H, with an overall reaction exothermicity of 11 kcal/mol. Hydrogen elimination from the t-i10 isomer led to the formation of the annular C6H isomer, HC3C3 + H, at 23.9 kcal/mol above l-C4 + C2H2. On the singlet surfaces, s-i1 rearranged the other C6H2 isomers, including s-i2 and s-i4, through carbon–carbon bond cleavage. The s-i6 and s-i11 isomers also lost a hydrogen atom, and produced the linear C6H radical. Hydrogen elimination from the s-i4 isomer led to the formation of the annular C6H isomer. The s-i5 lost a hydrogen atom, and produced the six-member ring c-C6H isomer, at 2.1 kcal/mol higher than l-C4 + C2H2. The 1,1-H2 loss from the s-i10 isomer produced the linear hexacarbon l-C6 + H2 product, with an endothermicity of 2.3 kcal/mol and a 1,1-H2 loss from the s-i11 isomer, producing in the cyclic hexacarbon c-C6 + H2 product, with an exothermicity of 11.2 kcal/mol. The product-branching ratios obtained by solving kinetic equations with individual rate constants calculated using the RRKM and VTST theories for determining the collision energies between 5 kcal/mol and 25 kcal/mol show that l-C6H + H is the dominant reaction product, whereas HC3C3 + H, l-C6 + H2, c-C6H + H, and c-C6 + H2 are minor products with branching ratios. The s-i6 isomer was calculated to be the most stable C6H2 species, even more favorable than t-i3 (by 76 kcal/mol).

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