Volume 35, Issue 2, June 2006
Index of content:
IUPAC-NIST Solubility Data Series. 81. Hydrocarbons with Water and Seawater—Revised and Updated. Part 11. Hydrocarbons with Water35(2006); http://dx.doi.org/10.1063/1.2132315View Description Hide Description
The mutual solubilities and related liquid–liquid equilibria of hydrocarbons with water are exhaustively and critically reviewed. Reports of experimental determination of solubility in 56 chemically distinct binary systems that appeared in the primary literature prior to end of 2002 are compiled. For 17 systems sufficient data are available to allow critical evaluation. All data are expressed as mass percent and mole fraction as well as the originally reported units. In addition to the standard evaluation criteria used throughout the Solubility Data Series, a new method based on the evaluation of all the experimental data for a given homologous series of aliphatic and aromatic hydrocarbons was used.
IUPAC-NIST Solubility Data Series. 81. Hydrocarbons with Water and Seawater—Revised and Updated Part 12. Hydrocarbons with Seawater35(2006); http://dx.doi.org/10.1063/1.2132316View Description Hide Description
The mutual solubility of hydrocarbons with seawater is exhaustively and critically reviewed. Reports of experimental determination of solubility in 46 chemically distinct binary systems that appeared in the primary literature prior to end of 2002 are compiled. For 15 of these systems sufficient data are available to allow critical evaluation. All data are expressed as mass percent and mole fraction as well as the originally reported units.
35(2006); http://dx.doi.org/10.1063/1.2141635View Description Hide Description
An optimization technique was applied to develop a functional form for a multiparameter viscosityequation for R134a. The results obtained are very promising, with an average absolute deviation of 0.55% for the currently available 549 primary data points. Compared to viscosityequations available in the literature, this is a significant improvement. Advantages become evident especially at gaseous states. As usual, both the development and the use of the viscosityequation require a highly accurate equation of state in order to convert the independent variables used for the experimental data and in most applications, into the independent variables of the viscosityequation, Though the equation was developed directly using the available data, the zero-density viscosity and the reduced second viscosity virial coefficient are correctly reproduced in the data range. The technique used to develop the equation, which is heuristic and not theoretically founded, is capable of selecting consistent data sets and thus is a powerful tool for screening the available experimental data. For the viscosity surface representation of a pure fluid this study shows that the limit in the achievement of a better accuracy is much more due to the present experimental uncertainty level for this property rather than to the effectiveness of the proposed modeling method.
35(2006); http://dx.doi.org/10.1063/1.2137724View Description Hide Description
The experimental data on elementary processes (collisional deactivation, chemical reactions,photodissociation) involving spin-orbitally excited atoms published up to the middle of 2005 are summarized in the present compilation. Critical evaluation of the data and limited comparison to theoretical calculations are also presented.
35(2006); http://dx.doi.org/10.1063/1.1901687View Description Hide Description
New formulations for the thermodynamic properties of fluid phase -butane and isobutane in the form of fundamental equations explicit in the Helmholtz energy are presented. The functional form of the correlation equations for the residual parts was developed simultaneously for both substances considering data for the thermodynamic properties of ethane, propane,-butane, and isobutane. Each contains 25 coefficients which were fitted to selected data for the thermal and caloric properties of the respective fluid both in the single-phase region and on the vapor–liquid phase boundary. This work provides information on the available experimental data for the thermodynamic properties of and isobutane, and presents all details of the new formulations. The new equations of state describe the surfaces with uncertainties in density of 0.02% (coverage factor corresponding to a confidence level of about 95%) from the melting line up to temperatures of 340 K and pressures of 12 MPa. The available reliable data sets in other regions are represented within their experimental uncertainties. The primary data, to which the equation for -butane was fitted, cover the fluid region from the melting line to temperatures of 575 K and pressures of 69 MPa. The equation for isobutane was fitted to primary data that cover the fluid region from the melting line to temperatures of 575 K and pressures of 35 MPa. Beyond the range described by experimental data, the equations yield reasonable extrapolation behavior up to very high temperatures and pressures. In addition to the equations of state, independent equations for the vapor pressures, the saturated-liquid and saturated-vapor densities, and the meltingpressures are given. Tables of thermodynamic properties calculated from the new formulations are listed in Appendix 2. Additionally, a preliminary equation of state for propane is presented that was developed in the course of the simultaneous optimization. This equation has the same functional form as the equations of state for and isobutane.
35(2006); http://dx.doi.org/10.1063/1.2183324View Description Hide Description
Various thermodynamic equilibrium properties of naturally abundant, hexagonal ice(ice Ih) of water have been used to develop a Gibbs energy function of temperature and pressure, covering the ranges 0–273.16 K and 0 Pa–210 MPa, expressed in the temperature scale ITS-90. It serves as a fundamental equation from which additional properties are obtained as partial derivatives by thermodynamic rules. Extending previously developed Gibbs functions, it covers the entire existence region of ice Ih in the diagram. Close to zero temperature, it obeys the theoretical cubic limiting law of Debye for heat capacity and Pauling’s residual entropy. It is based on a significantly enlarged experimental data set compared to its predecessors. Due to the inherent thermodynamic cross relations, the formulas for particular quantities like density, thermal expansion, or compressibility are thus fully consistent with each other, are more reliable now, and extended in their ranges of validity. In conjunction with the IAPWS-95 formulation for the fluid phases of water, the new chemical potential of ice allows an alternative computation of the melting and sublimation curves, being improved especially near the triple point, and valid down to 130 K sublimation temperature. It provides an absolute entropy reference value for liquid water at the triple point.