Thermochemistry of vinyl alcohol and vinyl ether radical and kinetic analysis of neopentyl radical reaction with molecular oxygen
Biomedical Engineering Committee
Master of Science
Bozzelli, Joseph W.
Knox, Dana E.
Huang, Michael Chien-Yueh
Vinyl Alcohol And Ethers
Vinyl alcohols and ethers are important intermediates in low-temperature combustion processes, such as in the initial stages of combustion and in the atmospheric photochemical oxidation of hydrocarbons. Knowledge of the thermodynamic parameters for these species is central to understanding and predicting their reaction pathways, rate constants, and equilibrium constants. The rapid interconversion of conformers and the instability of vinyl alcohols and ethers lead to complexities in studies of these species.
In this work, enthalpy,ΔH°f 298, entropy, S°298, and heat capacities, Cp(T), are determined for vinyl alcohol and vinyl methyl ether and the radicals corresponding to loss of a H atom from these two parent molecules by using density functional and ab initio calculation methods. The enthalpies of formation are evaluated at four calculation levels using three different working reactions. Entropies (S'°298) and heat capacities (Cp(T), 300 <= T/K <= 5000) are calculated using the rigid-rotor-harmonic-oscillator approximation based on frequencies and moments of inertia of the optimized B3LYP/6-31g(d,p) structures. Contributions to entropy and heat capacity from internal rotation are estimated with the B3LYP/6-31g(d,p) level calculations for rotation barrier estimations. Hydrogen Bond Increment groups (HBI) is derived from data obtaining data.
Thermodynamic properties on reactants, intermediates, products and important transition states are calculated and a thermochemical kinetic analysis performed for reaction of neopentyl radical with 02. 'The reaction forms a chemically C3CC=O+OH activated C3CCOO* adduct, which can be stabilized, dissociate back to reactants to or isomerize to a hydroperoxide alkyl radical. The isomer can dissociate to CH3 + C=C(C)COOH, to a cyclic ether (C2CYCCOC) + OH, and to OH + CH2O + C=C(C2), isomerize back to the peroxy, or further react with O2. Kinetics are analyzed with Quantum RRK theory for k(E) coupled with modified strong collision analysis of Gilbert et al for fall-off.
njit-etd2002-006 (128 pages ~ 9,185 KB pdf)
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Created March 4, 2003