Thermodynamic Properties of Butane

Temperature Pressure Density Volume Int. energy Enthalpy Entropy C, CF Sound speed Joule-Thomson Therm, cond. Viscosity 

The uncertainties in density are 0.02% at temperatures below 340 K and pressures below 12 MPa (both liquid and vapor states), 0.1% at temperatures below 270 K and pressures above 12 MPa, 0.2% between 340 and 515 K at pressures less than 0.6 MPa, and 0.4% elsewhere. In the critical region, deviations in pressure are 0.5%. At temperatures above 500 K, the uncertainties in density increase up to 1%. Uncertainties in heat capacities are typically 1%, rising to 5% in the critical region and at pressures above 30 MPa. Uncertainties in the speed of sound are typically 0.5%, rising to 1% at temperatures below 200 K and to 4% in a large area around the critical point. 

The uncertainty in viscosity varies from 0.4% in the dilute gas between room temperature and 600 K, to 3.0% over the rest of the fluid surface. 

Uncertainty in thermal conductivity is 3%, except in the critical region and dilute gas which have an uncertainty of 5%. 

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The properties of butane and isobutane have been summarized ia Table 5 and iaclude physical, chemical, and thermodynamic constants, and temperature-dependent parameters. Graphs of several physical properties as functions of temperature have been pubUshed (17) and thermodynamic properties have been tabulated as functions of temperature (12). 

Heintz, A., Lehman, J.K., and Wertz, Ch., Thermodynamic properties of mixtures containing ionic liquids. 3. Liquid-liquid equilibria of binary mixtures of l-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide with propan-l-ol, butan-l-ol, and pentan-l-ol, /. Chem. Eng. Data, 48, 472, 2003. 

Benedict, M., Webb, G.B., and Rubin, L.C. An Empirical Equation for Thermodynamic Properties of Light Hydrocarbons and Their Mixtures, I. Methane, Ethane, Propane and n-Butane, J. Chem. Phys. (April 1940) 8, 334-345. 

TABLE 2-235 Thermodynamic Properties of 2-Methyl Butane (Isopentane)... 

The values in these tables were generated from the NIST REFPROP software (Lemmon, E. W., McLinden, M. O., and Huber, M. L., NIST Standard Reference Database 23 Reference Fluid Thermodynamic and Transport Properties—REFPROP, National Institute of Standards and Technology, Standard Reference Data Program, Gaithersburg, Md., 2002, Version 7.1). The primary source for the thermodynamic properties is Buecker, D., and Wagner, W, Reference Equations of State for the Thermodynamic Properties of Fluid Phase n-Butane and Isobutane, /. Phys. Chem. Ref Data 35(2) 929-1019, 2006. The source for viscosity is Vogel, E., Kuechenmeister, C., Bich, E., and Laesecke, A., Reference Correlation of the Viscosity of Propane, /. Phys. Chem. Ref Data 27(5) 947-970, 1998. The source for thermal conductivity is Marsh, K., Perkins, R., and Ramires, M. L. V, Measurement and Correlation of the Thermal Conductivity of Propane from 86 to 600 K at Pressures to 70 MPa, /. Chem. Eng. Data 47(4) 932-940, 2002. 

Substances considered in a compilation of the thermodynamic properties of refrigerants include hydrogen, parahydrogen, helium, neon, nitrogen, air, oxygen, argon, carbon dioxide, hydrocarbons (e.g. methane, ethane, propane, butane, isobutane, ethylene, and propene), and fluoro-and fluoro-chloro-hydrocarbons. Properties listed include those for the liquid and saturated vapour, superheated vapour, and unsaturated vapour. In addition, pressure-enthalpy, and in some instances pressure-entropy, diagrams are provided. 

Many applications of Kilpatrick and Pitzer s procedure for calculating thermodynamic properties of molecules with compound rotation have been reported. In all cases possible potential energy cross-terms between rotating tops have been neglected. Contributions from internal rotation of symmetric tops have been calculated using the appropriate tables." These tables have also been used in calculations for the internal rotation of asymmetric tops hindered by a simple -fold cosine potential. 3-Fold potential barriers have been assumed in calculations for the —OH rotations in propanol and 1-methylpropanol, the —SH rotations in propane-1-thiol, butane-2-thiol, 2-methylpropane-l-thiol, and 2-methylbutane-2-thiol, the C—S skeletal rotations in ethyl methyl sulphide, diethyl sulphide, isopropyl methyl sulphide, and t-butyl methyl sulphide, and the C—C skeletal rotations in 2,3-dimethylbutane, and 2-methylpropane-l-thiol. 2-Fold cosine potential barriers have been assumed in calculations in the S—S skeletal rotations in dimethyl disulphide and diethyl disulphide. ... 

Biicker, D., and Wagner, W, Reference Equations of State for the Thermodynamic Properties of Fluid Phase n-Butane and Isobutane, J. Phys. Chem. Ref. Data 35, 929, 2006. 

Vogel, E., Kuechenmeister, C., and Bich, E., Viscosity Correlation for n-Butane in the Fluid Region, High Temp.-High Press. 31,173,1999. Richter, M., McLinden, M. O., and Lemmon, E. W, Thermodynamic Properties of 2,3,3,3-Tetrafluoroprop-l-ene (R1234yf) p-p-T Measurements and an Equation of State, submitted to /. Chem. Eng. Data, 2011. 

At Berkeley, Kenneth Pitzer and Samuel Ruben recommended use of nontoxic butane instead of highly toxic phosgene for the field studies of gas cloud dissipation. Phosgene is poisonous, dangerous to handle, and difficult to analyze in the field. Butane has similar thermodynamic properties and would be transported by air in the same way as phosgene. Sam Ruben and Bill Gwinn had developed a simple, ingenious, practical way to measure and record trace amounts of butane in air. In the late summer and early... 

H. Luo and C. Hoheisel, Phys. Rev. E, 47, 3956 (1993). Thermodynamics and Transport Properties of n-Butane Computed by Molecular Dynamics and a Rigid Interaction Model. 

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