Volume 44, Issue 1, March 2015
Index of content:
- REGULAR ARTICLES
Critical Evaluation of Thermochemical Properties of C1–C4 Species: Updated Group-Contributions to Estimate Thermochemical Properties44(2015); http://dx.doi.org/10.1063/1.4902535View Description Hide Description
A review of literature on enthalpies of formation and molar entropies for alkanes, alkenes, alcohols, hydroperoxides, and their associated radicals has been compiled and critically evaluated. By comparing literature values, the overall uncertainty in thermochemical properties of small hydrocarbons and oxygenated hydrocarbons can be highlighted. In general, there is good agreement between heat of formation values in the literature for stable species; however, there is greater uncertainty in the values for radical species and for molar entropy values. Updated values for a group-additivity method for the estimation of thermochemical properties based on the evaluated literature data are proposed. The new values can be used to estimate thermochemical data for larger, combustion-relevant species for which no calculations or measurements currently exist, with increased confidence.
IUPAC-NIST Solubility Data Series. 100. Rare Earth Metal Fluorides in Water and Aqueous Systems. Part 2. Light Lanthanides (Ce–Eu)44(2015); http://dx.doi.org/10.1063/1.4903362View Description Hide Description
This is the second part of the volume devoted to the evaluation of experimental solubility data for rare earth metal (REM) fluorides in water as well as in aqueous ternary and multicomponent systems. Fluorides of Ce, Pr, Nd, Pm, Sm, and Eu (so-called light lanthanides), as the main solutes, are covered in the present part, which has thorough coverage of the experimental literature through the end of 2012. The experimentally unknown solubility value for PmF3 in water was predicted by an interpolation of the solubility values for NdF3 and SmF3 at 298 K. General features of the systems, such as the nature of the equilibrium solid phases, solubility as a function of temperature, influence of ionic strength, pH, mixed solvent medium on the solubility, quality of the solubility results, and solubility as a function of REM atomic number, have already been presented in Part 1 of the volume.
Reference Correlation of the Viscosity of para-Xylene from the Triple Point to 673 K and up to 110 MPa44(2015); http://dx.doi.org/10.1063/1.4908048View Description Hide Description
A new correlation for the viscosity of para-xylene (p-xylene) is presented. The correlation is based upon a body of experimental data that has been critically assessed for internal consistency and for agreement with theory. It is applicable in the temperature range from the triple point to 673 K at pressures up to 110 MPa. The overall uncertainty of the proposed correlation, estimated as the combined expanded uncertainty with a coverage factor of 2, varies from 0.5% for the viscosity of the dilute gas to 5% for the highest temperatures and pressures of interest. Tables of the viscosity generated by the relevant equations, at selected temperatures and pressures and along the saturation line, are provided.
44(2015); http://dx.doi.org/10.1063/1.4913493View Description Hide Description
A new fundamental equation of state explicit in the Helmholtz energy is presented for 1,1,1,3,3-pentafluoropropane (R-245fa), based on recent experimental data for vapor pressures, densities, and sound speeds. The functional form uses Gaussian bell-shaped terms, according to recent trends in the development of accurate equations of state. The independent variables of the equation of state are temperature and density. The equation is valid for temperatures between the triple point (170.0 K) and 440 K, and for pressures up to 200 MPa. Estimated uncertainties in this range are 0.1% for vapor pressures, 0.1% for saturated liquid densities, 0.1% for liquid densities below 70 MPa, 0.2% for densities at higher pressures, 0.3% for vapor densities, 0.3% for liquid sound speeds, and 0.1% for vapor sound speeds. The uncertainties in the critical region are higher for all properties except vapor pressures. The equation shows reasonable extrapolation behavior at extremely low and high temperatures, and at high pressures.
44(2015); http://dx.doi.org/10.1063/1.4913926View Description Hide Description
Cross section data are collected and reviewed for electron collisions with carbon monoxide. Collision processes included are total scattering, elastic scattering, momentum transfer, excitations of rotational, vibrational and electronic states, ionization, and dissociation. For each process, recommended values of the cross sections are presented, when possible. The literature has been surveyed through to the end of 2013.