# REFPROP

REFPROP is a software program for the prediction of thermophysical properties of fluids, developed by the National Institute of Standards and Technology (NIST).
The primary component of REFPROP is an equation of state for each implemented fluid. For most pure fluids, the equation of state is obtained by fitting an expression for the Helmholtz free energy to experimental data. This formulation allows the computation of all equilibrium properties of the fluid, such as density, temperature, pressure, sound speed, heat capacity, second virial coefficients, vapor pressures, saturated liquid and vapor densities, enthalpy of vaporization, entropy, and the Joule-Thomson coefficient.
REFPROP also predicts surface tension, viscosity, and thermal conductivity for many fluids, either using extended corresponding states formulations or fluid-specific equations fit directly to experimental data.
Various methods are used to compute the analogous properties of fluid mixtures.
The full list of fluids properties implemented in REFPROP v10.0 can be found in Table 2 of Huber, et al. (2022).

## List of implemented fluids

REFPROP v10.0 implements equation of state models for 147 pure fluids, listed in Table 1. Except for F$_3$N, R-13, R-123, and R-152a, all of these are Helmholtz free energy formulations.
REFPROP v10.0 also predicts surface tension, viscosity, and thermal conductivity for most of the listed fluids.
Table 1: List of pure fluids implemented in REFPROP v10.0 :
| Short name | Full name | Short formula | CAS number |
| 1,3-Butadiene | Buta-1,3-diene | C$_4$H$_6$ | 106-99-0 |
| 1-Butyne | But-1-yne | C$_4$H$_6$ | 107-00-6 |
| 1-Pentene | Pent-1-ene | C$_5$H$_{10}$ | 109-67-1 |
| 2,2-Dimethylbutane | 2,2-Dimethylbutane | C$_6$H$_{14}$ | 75-83-2 |
| 2,3-Dimethylbutane | 2,3-Dimethylbutane | C$_6$H$_{14}$ | 79-29-8 |
| 3-Methylpentane | 3-Methylpentane | C$_6$H$_{14}$ | 96-14-0 |
| Acetone | Propanone | C$_3$H$_6$O | 67-64-1 |
| Acetylene | Ethyne | C$_2$H$_2$ | 74-86-2 |
| Ammonia | Ammonia | NH$_3$ | 7664-41-7 |
| Argon | Argon | Ar | 7440-37-1 |
| Benzene | Benzene | C$_6$H$_6$ | 71-43-2 |
| Butane | n-Butane | C$_4$H$_{10}$ | 106-97-8 |
| Butene | 1-Butene | C$_4$H$_8$ | 106-98-9 |
| Carbon dioxide | Carbon dioxide | CO$_2$ | 124-38-9 |
| Carbon monoxide | Carbon monoxide | CO | 630-08-0 |
| Carbonyl sulfide | Carbon oxide sulfide | COS | 463-58-1 |
| Chlorine | Chlorine | Cl$_2$ | 7782-50-5 |
| Chlorobenzene | Chlorobenzene | C$_6$H$_5$Cl | 108-90-7 |
| cis-Butene | cis-2-Butene | C$_4$H$_8$ | 590-18-1 |
| Cyclobutene | 1-Cyclobutene | C$_4$H$_6$ | 822-35-5 |
| Cyclohexane | Cyclohexane | C$_6$H$_{12}$ | 110-82-7 |
| Cyclopentane | Cyclopentane | C$_5$H$_{10}$ | 287-92-3 |
| Cyclopropane | Cyclopropane | C$_3$H$_6$ | 75-19-4 |
| D4 | Octamethylcyclotetrasiloxane | C$_8$H$_{24}$O$_4$Si$_4$ | 556-67-2 |
| D5 | Decamethylcyclopentasiloxane | C$_{10}$H$_{30}$O$_5$Si$_5$ | 541-02-6 |
| D6 | Dodecamethylcyclohexasiloxane | C$_{12}$H$_{36}$O$_6$Si$_6$ | 540-97-6 |
| DEA | 2,2'-Iminodiethanol | C$_4$H$_{11}$NO$_2$ | 111-42-2 |
| Decane | Decane | C$_{10}$H$_{22}$ | 124-18-5 |
| Deuterium | Deuterium | D$_2$ | 7782-39-0 |
| Dichloroethane | 1,2-Dichloroethane | C$_2$H$_4$Cl$_2$ | 107-06-2 |
| Diethyl ether | Diethyl ether | C$_4$H$_{10}$O | 60-29-7 |
| Dimethyl carbonate | Dimethyl ester carbonic acid | C$_3$H$_6$O$_3$ | 616-38-6 |
| Dimethylether | Methoxymethane | C$_2$H$_6$O | 115-10-6 |
| Docosane | Docosane | C$_{22}$H$_{46}$ | 629-97-0 |
| Dodecane | Dodecane | C$_{12}$H$_{26}$ | 112-40-3 |
| Ethane | Ethane | C$_2$H$_6$ | 74-84-0 |
| Ethanol | Ethyl alcohol | C$_2$H$_6$O | 64-17-5 |
| Ethylene glycol | 1,2-Ethandiol | C$_2$H$_6$O$_2$ | 107-21-1 |
| Ethyl benzene | Phenylethane | C$_8$H$_{10}$ | 100-41-4 |
| Ethylene | Ethene | C$_2$H$_4$ | 74-85-1 |
| Ethylene oxide | Ethylene oxide | C$_2$H$_4$O | 75-21-8 |
| Fluorine | Fluorine | F$_2$ | 7782-41-4 |
| Heavy water | Deuterium oxide | D$_2$O | 7789-20-0 |
| Helium | Helium-4 | He | 7440-59-7 |
| Heptane | Heptane | C$_7$H$_{16}$ | 142-82-5 |
| Hexadecane | Hexadecane | C$_{16}$H$_{34}$ | 544-76-3 |
| Hexane | Hexane | C$_6$H$_{14}$ | 110-54-3 |
| Hydrogen | Hydrogen | H$_2$ | 1333-74-0 |
| Hydrogen chloride | Hydrogen chloride | HCl | 7647-01-0 |
| Hydrogen sulfide | Hydrogen sulfide | H$_2$S | 7783-06-4 |
| Isobutane | 2-Methylpropane | C$_4$H$_{10}$ | 75-28-5 |
| Isobutene | 2-Methyl-1-propene | C$_4$H$_8$ | 115-11-7 |
| Isohexane | 2-Methylpentane | C$_6$H$_{14}$ | 107-83-5 |
| Isooctane | 2,2,4-Trimethylpentane | C$_8$H$_{18}$ | 540-84-1 |
| Isopentane | 2-Methylbutane | C$_5$H$_{12}$ | 78-78-4 |
| Krypton | Krypton | Kr | 7439-90-9 |
| MD2M | Decamethyltetrasiloxane | C$_{10}$H$_{30}$O$_3$Si$_4$ | 141-62-8 |
| MD3M | Dodecamethylpentasiloxane | C$_{12}$H$_{36}$O$_4$Si$_5$ | 141-63-9 |
| MD4M | Tetradecamethylhexasiloxane | C$_{14}$H$_{42}$O$_5$Si$_6$ | 107-52-8 |
| MDM | Octamethyltrisiloxane | C$_8$H$_{24}$O$_2$Si$_3$ | 107-51-7 |
| MEA | Ethanolamine | C$_2$H$_7$NO | 141-43-5 |
| Methane | Methane | CH$_4$ | 74-82-8 |
| Methanol | Methanol | CH$_4$O | 67-56-1 |
| Methyl linoleate | Methyl(Z,Z)-9,12-octadecadienate | C$_{19}$H$_{34}$O$_2$ | 112-63-0 |
| Methyl linolenate | Methyl(Z,Z,Z)-9,12,15-octadecatrienoate | C$_{19}$H$_{32}$O$_2$ | 301-00-8 |
| Methyl oleate | Methylcis-9-octadecenoate | C$_{19}$H$_{36}$O$_2$ | 112-62-9 |
| Methyl palmitate | Methyl hexadecanoate | C$_{17}$H$_{34}$O$_2$ | 112-39-0 |
| Methyl stearate | Methyl octadecanoate | C$_{19}$H$_{38}$O$_2$ | 112-61-8 |
| Methyl cyclohexane | Methylcyclohexane | C$_7$H$_{14}$ | 108-87-2 |
| MM | Hexamethyldisiloxane | C$_6$H$_{18}$OSi$_2$ | 107-46-0 |
| m-Xylene | 1,3-Dimethylbenzene | C$_8$H$_{10}$ | 108-38-3 |
| Neon | Neon | Ne | 7440-01-9 |
| Neopentane | 2,2-Dimethylpropane | C$_5$H$_{12}$ | 463-82-1 |
| Nitrogen | Nitrogen | N$_2$ | 7727-37-9 |
| Nitrogen trifluoride | Nitrogen trifluoride | F$_3$N | 7783-54-2 |
| Nitrous oxide | Dinitrogen monoxide | N$_2$O | 10024-97-2 |
| Nonane | Nonane | C$_9$H$_{20}$ | 111-84-2 |
| Novec649,1230 | 1,1,1,2,2,4,5,5,5-Nonafluoro-4-(trifluoromethyl)-3-pentanone | C$_6$F$_{12}$O | 756-13-8 |
| Octane | Octane | C$_8$H$_{18}$ | 111-65-9 |
| Orthohydrogen | Orthohydrogen | H$_2$ | - |
| Oxygen | Oxygen | O$_2$ | 7782-44-7 |
| o-Xylene | 1,2-Dimethylbenzene | C$_8$H$_{10}$ | 95-47-6 |
| Parahydrogen | Parahydrogen | H$_2$ | - |
| Pentane | Pentane | C$_5$H$_{12}$ | 109-66-0 |
| Perfluorobutane | Decafluorobutane | C$_4$F$_{10}$ | 355-25-9 |
| Perfluorohexane | Tetradecafluorohexane | C$_6$F$_{14}$ | 355-42-0 |
| Perfluoropentane | Dodecafluoropentane | C$_5$F$_{12}$ | 678-26-2 |
| Propadiene | 1,2-Propadiene | C$_3$H$_4$ | 463-49-0 |
| Propane | Propane | C$_3$H$_8$ | 74-98-6 |
| Propyl cyclohexane | n-Propyl cyclohexane | C$_9$H$_{18}$ | 1678-92-8 |
| Propylene | Propene | C$_3$H$_6$ | 115-07-1 |
| Propylene oxide | 1,2-Epoxy propane | C$_3$H$_6$O | 75-56-9 |
| Propyne | Propyne | C$_3$H$_4$ | 74-99-7 |
| p-Xylene | 1,4-Dimethylbenzene | C$_8$H$_{10}$ | 106-42-3 |
| R11 | Trichlorofluoromethane | CCl$_3$F | 75-69-4 |
| R1123 | Trifluoroethylene | C$_2$HF$_3$ | 359-11-5 |
| R113 | 1,1,2-Trichloro-1,2,2-trifluoroethane | C$_2$Cl$_3$F$_3$ | 76-13-1 |
| R114 | 1,2-Dichlorotetrafluoroethane | C$_2$Cl$_2$F$_4$ | 76-14-2 |
| R115 | Chloropentafluoroethane | C$_2$ClF$_5$ | 76-15-3 |
| R116 | Hexafluoroethane | C$_2$F$_6$ | 76-16-4 |
| R12 | Dichlorodifluoromethane | CCl$_2$F$_2$ | 75-71-8 |
| R1216 | Hexafluoropropene | C$_3$F$_6$ | 116-15-4 |
| R1224yd(Z) | (Z)-1-Chloro-2,3,3,3-tetrafluoropropene | C$_3$HClF$_4$ | 111512-60-8 |
| R123 | 2,2-Dichloro-1,1,1-trifluoroethane | C$_2$HCl$_2$F$_3$ | 306-83-2 |
| R1233zd(E) | trans-1-Chloro-3,3,3-trifluoro-1-propene | C$_3$H$_2$ClF$_3$ | 102687-65-0 |
| R1234yf | 2,3,3,3-Tetrafluoroprop-1-ene | C$_3$F$_4$H$_2$ | 754-12-1 |
| R1234ze(E) | trans-1,3,3,3-Tetrafluoropropene | C$_3$F$_4$H$_2$ | 29118-24-9 |
| R1234ze(Z) | cis-1,3,3,3-Tetrafluoropropene | C$_3$F$_4$H$_2$ | 29118-25-0 |
| R124 | 1-Chloro-1,2,2,2-tetrafluoroethane | C$_2$HClF$_4$ | 2837-89-0 |
| R1243zf | 3,3,3-Trifluoropropene | C$_3$H$_3$F$_3$ | 677-21-4 |
| R125 | Pentafluoroethane | C$_2$HF$_5$ | 354-33-6 |
| R13 | Chlorotrifluoromethane | CClF$_3$ | 75-72-9 |
| R1336mzz(Z) | (Z)-1,1,1,4,4,4-Hexafluoro-2-butene | C$_4$H$_2$F$_6$ | 692-49-9 |
| R134a | 1,1,1,2-Tetrafluoroethane | C$_2$H$_2$F$_4$ | 811-97-2 |
| R13I1 | Trifluoroiodomethane | CF$_3$I | 2314-97-8 |
| R14 | Tetrafluoromethane | CF$_4$ | 75-73-0 |
| R141b | 1,1-Dichloro-1-fluoroethane | C$_2$H$_3$Cl$_2$F | 1717-00-6 |
| R142b | 1-Chloro-1,1-difluoroethane | C$_2$H$_3$ClF$_2$ | 75-68-3 |
| R143a | 1,1,1-Trifluoroethane | C$_2$H$_3$F$_3$ | 420-46-2 |
| R152a | 1,1-Difluoroethane | C$_2$H$_4$F$_2$ | 75-37-6 |
| R161 | Fluoroethane | C$_2$H$_5$F | 353-36-6 |
| R21 | Dichlorofluoromethane | CHClF | 75-43-4 |
| R218 | Octafluoropropane | C$_3$F$_8$ | 76-19-7 |
| R22 | Chlorodifluoromethane | CHClF$_2$ | 75-45-6 |
| R227ea | 1,1,1,2,3,3,3-Heptafluoropropane | C$_3$HF$_7$ | 431-89-0 |
| R23 | Trifluoromethane | CHF$_3$ | 75-46-7 |
| R236ea | 1,1,1,2,3,3-Hexafluoropropane | C$_3$H$_2$F$_6$ | 431-63-0 |
| R236fa | 1,1,1,3,3,3-Hexafluoropropane | C$_3$H$_2$F$_6$ | 690-39-1 |
| R245ca | 1,1,2,2,3-Pentafluoropropane | C$_3$H$_3$F$_5$ | 679-86-7 |
| R245fa | 1,1,1,3,3-Pentafluoropropane | C$_3$H$_3$F$_5$ | 460-73-1 |
| R32 | Difluoromethane | CH$_2$F$_2$ | 75-10-5 |
| R365mfc | 1,1,1,3,3-Pentafluorobutane | C$_4$H$_5$F$_5$ | 406-58-6 |
| R40 | Methyl chloride | CH$_3$Cl | 74-87-3 |
| R41 | Fluoromethane | CH$_3$F | 593-53-3 |
| RC318 | Octafluorocyclobutane | C$_4$F$_8$ | 115-25-3 |
| RE143a | Methyl trifluoromethyl ether | C$_2$H$_3$F$_3$O | 421-14-7 |
| RE245cb2 | Methyl pentafluoroethyl ether | C$_3$H$_3$F$_5$O | 22410-44-2 |
| RE245fa2 | 2,2,2-Trifluoroethyl-difluoromethyl-ether | C$_3$H$_3$F$_5$O | 1885-48-9 |
| RE347mcc(HFE7000) | 1,1,1,2,2,3,3-Heptafluoro-3methoxypropane | C$_4$H$_3$F$_7$O | 375-03-1 |
| Sulfur dioxide | Sulfur dioxide | O$_2$S | 7446-09-5 |
| Sulfur hexafluoride | Sulfur hexafluoride | SF$_6$ | 2551-62-4 |
| Toluene | Methylbenzene | C$_7$H$_8$ | 108-88-3 |
| trans-Butene | trans-2-Butene | C$_4$H$_8$ | 624-64-6 |
| Undecane | Undecane | C$_{11}$H$_{24}$ | 1120-21-4 |
| Vinyl chloride | Chloroethylene | C$_2$H$_3$Cl | 75-01-4 |
| Water | Water | H$_2$O | 7732-18-5 |
| Xenon | Xenon | Xe | 7440-63-3 |