Ideal Gas Thermodynamic Properties of Six Chloroethanes

Abstract

The thermodynamic properties: $C_p^{\mathrm{o}}{\mathrm{,\hspace{0.17em}S}}^{\mathrm{o}}{\mathrm{,\hspace{0.17em}H}}^{\mathrm{o}}{\mathrm{-H}}_0^{\mathrm{o}}{\mathrm{,-(G}}^{\mathrm{o}}{\mathrm{-H}}_0^{\mathrm{o}}{\mathrm{)/T,\hspace{0.17em}\Delta Hf}}^{\mathrm{o}}{\mathrm{,\hspace{0.17em}\Delta Gf}}^{\mathrm{o}}$ , and log K_f for chloroethane, 1,1‐dichloroethane, 1,1,1‐trichloroethane, 1,1,1,2‐tetrachloroethane, pentachloroethane, and hexachloroethane in the ideal gaseous state in the temperature range from 0 to 1500 K and at 1 atm were evaluated by statistical thermodynamic methods based on a rigid‐rotor harmonic‐oscillator model. The internal rotation contributions to thermodynamic functions were calculated by using a partition function formed by summation of internal rotation energy levels. The internal rotation barrier heights (in kcal mol^‐1) employed for generation of the energy levels for each of the above six chloroethanes are: 3.69, 3.54, 5.08, 10.38, 14.43, and 14.7, respectively. The calculated heat capacities and entropies are compared with available experimental data. The derived values of $C_p^{\mathrm{o}}{\mathrm{,\hspace{0.17em}S}}^{\mathrm{o}}\mathrm{,\hspace{0.17em}}\mathrm{and}{\mathrm{\hspace{0.17em}\Delta Hf}}^{\mathrm{o}}$ at 298.15 and 700 K are compared with those reported in the other major compilations.