Some Thermochemical Properties of Fluorinated Ethanol’s and its Radicals : CH3-xCH2FxOH,CH3CH2, Heat Capacity and Bond Dissociation Energy using Gaussian Calculations

The objective of this research is to use gaussian M-062x/6-31 + g (d, p) Ab initio and density functional theory method to calculate enthalpies of formation values in Kcal/mol, entropy and heat capacity values in cal/mol.K, and also include internal rotor contribution of each molecule to the calculated values of entropy and heat capacity to obtain more accurate calculated values. The Optimized structures and thermochemical properties of these species were determined by the Gaussian M-062x/6-31+g (d,p) calculation. Contributions of entropy, S°298 and heat capacities, Cp(T) due to vibration, translation, and external rotation of the molecules were calculated based on the vibration frequencies and structures obtained from the M-062x/6-31+g (d,p) density functional method. Potential barriers are calculated using M-062x/6-31+g (d,p) density functional method and are used to calculate rotor contributions to entropy and heat capacity using integration over energy levels of rotational potential . Enthalpies of formation for 19 fluorinated ethanol and some radicals were calculated with a popular ab initio and density functional theory methods: the Gaussian M-062x/6-31+g (d,p) via several series of isodesmic reactions. Entropies were estimated using the M-062x/6-31+g (d,p) computed frequencies and geometries. Rotational barriers were determined and hindered internal rotational contributions for S298 °- 1500°, and Cp(T) were calculated using the rigid rotor harmonic oscillator approximation, with direct integration over energy levels of the intramolecular rotation potential energy curves. The thermochemical properties of fluorinated alcohols are needed for understanding their stability and reactions in the environment and in thermal process.