Stereo‐dependent dimerization, boiling points, diffusion coefficients, and dielectric constants of E/Z‐HFO‐1234ze

Abstract

Stereo-dependent properties of E-and Z-HFO-1234ze were investigated by density functional theory, extrapolated complete basis set limit, explicitly correlation, and symmetry-adapted perturbation theory together with molecular dynamics simulations. The enthalpy of isomerization of E-HFO-1234ze to the Z isomer is 9.7 kJ/mol, showing the reverse cis effect. The HFO-1234ze molecules interact predominantly via π-π stacking of the double bonds and hydrogen bonding of CHÁ Á ÁF. Although the E-dimers involve less steric exchange-repulsion, their binding energies are generally smaller by 2-6 kJ/mol than the Z-dimers, in which the Coulombic multipole-multipole-type electrostatic interactions and the long-range dispersions are more profound. Local ordering in liquid occurs primarily via π stacking of the CHF-end. The significant difference in boiling points of E-and Z-HFO-1234ze is clarified in terms of the dimerization free energy. Self-diffusion coefficients and dielectric constants of HFO-1234ze depend strongly on the E-and Z-conformations.

Diffusional Behavior of New Insulating Gas Mixtures as Alternatives to the SF6-Use in Medium Voltage Switchgear

“…The model has made it possible to obtain the diffusion and convection coefficients of the mixtures with a relative standard error lower than 6%. In comparison with the calculation of the diffusion coefficient of HFO3E that Hu et al [57] performed, the estimation shares the same order of magnitude, although it is slightly higher in this work. The convection coefficients of all the mixtures have been significantly low, which could prove that the effect of natural convection is negligible in comparison with molecular diffusion of the order of 10 5 (in the ternary mixture) to 10 8 (in the binary mixtures) times smaller.…”