We report a systematic chemical kinetics study of the H atom abstractions from ethyl formate (EF) by H, O(3P), CH3, OH, and HO2 radicals. The geometry optimization and frequency calculation of all the species were conducted using the M06 method and the cc-pVTZ basis set. The one-dimensional hindered rotor treatment of the reactants and transition states and the intrinsic reaction coordinate analysis were also performed at the M06/cc-pVTZ level of theory. The relative electronic energies were calculated at the CCSD(T)/cc-pVXZ (where X = D, T) level of theory and further extrapolated to the complete basis set limit. Rate constants for the tittle reactions were calculated over the temperature range 500–2500 K by the transition state theory (TST) in conjunction with the asymmetric Eckart tunneling effect. In addition, the rate constants of H-abstraction by hydroxyl radical were measured in shock tube experiments at 900–1321 K and 1.4–2.0 atm. Our theoretical rate constants of OH + EF → products agree well wit...

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Theoretical and Shock Tube Study of the Rate Constants for Hydrogen Abstraction Reactions of Ethyl Formate.

A computational study on the kinetics of pyrolysis of isopropyl propionate as a biodiesel model: DFT and ab initio investigation

Publisher Summary Gas phase offers significant advantages for the investigation of substituent effects on the reactivity of organic molecules. Gas-phase studies can also provide insights about the problem of salvation. In the gas-phase, it is possible to investigate the behavior of a single molecule, uninfluenced by the presence of the remainder of the system. The effect of substitution in a parent molecule upon the rate of a given reaction can thus be effectively studied without the complications arising from the co-operative effects of the solvent, as can occur in reactions in solution. This chapter describes the several investigations of homogeneous, molecular gas-phase elimination reactions. The reactions considered are essentially homogeneous and unimolecular. Three types of homogeneous mechanisms are considered that include radical nonchain, radical chain, and unimolecular mechanisms. The first two of these are multistep processes, having a common initial step; the homolytic splitting of the C–X bond. However, the third type of mechanism is one-step unimolecular decomposition, proceeding through a four-centered transition state.

Gas-Phase Heterolysis

Publisher Summary This chapter discusses substituent effects, linear free energy relations, kinetic isotope studies, and conformation analysis of products. Existing interpretations of such data have been summarized, and in some instances, new interpretations have also been presented. It discusses relative rate and kinetic isotope studies, which are conceded reliable, and to contribute significantly to the elucidation of the kinetics. Photochemical and irradiation induced reactions do not produce unimolecular reactions, which can be studied quantitatively; therefore, the vast majority of the reactions reviewed here are those induced thermally. To facilitate the presentation of the data, organic group class, for example, alcohols, anhydrides, ethers, esters, acids, and peroxides have grouped reactions, and have all been reviewed in detail. This provides a convenient data reference source, but has the distinct disadvantage of not emphasizing the similarities in mechanism, which exist among molecules of the various organic group classes. It examines that kinetic results for gas phase and for solution and other condensed phases are presented separately.

R. F. Makens

Papers

Kinetics of the Thermal Decomposition of Ethyl Formate