A Force Field for 3,3,3-Fluoro-1-propenes, Including HFO-1234yf

Abstract

The European Union (EU) legislation 2006/40/EC bans from January 2011 the cooperative marketing of new car types that use refrigerants in their heating, ventilation, and air conditioning (HVAC) systems with global warming potentials (GWP) higher than 150. Thus, the phase-out of the presently used tetrafluoroethane refrigerant R134a necessitates the adoption of alternative refrigerants. Fluoropropenes such as 2,3,3,3-tetrafluoro-1-propene (HFO-1234yf) are currently regarded as promising low GWP refrigerants, but the lack of experimental data on their thermophysical properties hampers independent studies on their performance in HVAC systems or in other technical applications. In principle, molecular modeling can be used to predict the relevant properties of refrigerants, but adequate intermolecular potential functions ("force fields") are lacking for fluoropropenes. Thus, we developed a transferable force field for fluoropropenes composed of CF(3)-, -CF=, -CH=, CF(2)=, and CH(2)= groups and applied the force field to study 3,3,3 trifluoro-1-propene (HFO-1243zf), 2,3,3,3-tetrafluoro-1-propene (HFO-1234yf), and hexafluoro-1-propene (HFO-1216). We performed Gibbs ensemble simulations on these three fluoropropenes to compute the vapor pressure, saturated densities, and heats of vaporization. In addition, molecular dynamics simulations were conducted to provide predictions for the density, thermal expansivity, isobaric heat capacity, and transport properties of liquid HFO-1234yf in the temperature range from 263.15 to 310 K and pressures up to 2 MPa. Agreement between simulation results and experimental data and/or correlations (when available) was good, thereby validating the predictive ability of the force field.

Molecular Simulation Studies on the Vapor–Liquid Equilibria of the cis- and trans-HCFO-1233zd and the cis- and trans-HFO-1336mzz

“…More details on the strategy used in the parametrization of the molecular model are given in our earlier work. 9,10 The force field in its original form only comprises different fluoropropene compounds. Supporting Information in ref 10 provides a complete list of the force field parameters for fluoropropenes.…”

“…Simulation studies on the vapor−liquid phase equilibria and liquid phase properties have proven that the new force field yields reliable reproductions and predictions for a wide range of thermophysical properties of fluoropropenes, as the simulated data in general agree well with available experimental data and correlations. 9,10 In this paper, we employ the force field model to molecular simulation studies on the fluorinated butene HFO-1336mzz. Additionally, we present an extension of the molecular model to allow simulation studies on the HCFO compound 1233zd.…”

Evaluation of R-1234ze(Z) as drop-in replacement for R-245fa in Organic Rankine Cycles – From thermophysical properties to cycle performance

“…[22]. Only recently, experimental data for the vapor pressure and saturated densities [15e17] became available that now allow for a comparison of our predictive molecular simulation results and experiment.…”

Sealed Gravitational Capillary Viscometry of Dimethyl Ether and Two Next-Generation Alternative Refrigerants

“…Each data point represents the average value of all four runs at a given temperature. Figure 10 illustrates the viscosity data of the present work compared with those of Hulse et al [ 56 ], those of Raabe and Maginn [ 57 ], and with values calculated with the extended corresponding-states model (ECS) model [ 51 ] implemented in NIST computer program REFPROP Version 9.0 [ 52 ]. The ECS model was adjusted to the data of Hulse et al [ 56 ] because they were the only viscosity measurements of R1234yf in 2009.…”