Showing papers in "Journal of Physical and Chemical Reference Data in 2003"

Enthalpies of Vaporization of Organic and Organometallic Compounds, 1880-2002

Abstract: A compendium of vaporization enthalpies published within the period 1910–2002 is reported. A brief review of temperature adjustments of vaporization enthalpies from temperature of measurement to the standard reference temperature, 298.15 K, is included as are recently suggested reference materials. Vaporization enthalpies are included for organic, organo-metallic, and a few inorganic compounds. This compendium is the third in a series focusing on phase change enthalpies. Previous compendia focused on fusion and sublimation enthalpies. Sufficient data are presently available for many compounds that thermodynamic cycles can be constructed to evaluate the reliability of the measurements. A protocol for doing so is described.

A Comprehensive and Critical Compilation, Evaluation, and Selection of Physical–Chemical Property Data for Selected Polychlorinated Biphenyls

Abstract: Accurate physical–chemical properties (aqueous solubility SW, octanol–water partition coefficient KOW, vapor pressure P, Henry’s law constant H, octanol–air partition coefficient KOA, octanol solubility SO) are of fundamental importance for modeling the transport and fate of organic pollutants in the environment. Energies of phase transfer are used to describe the temperature dependence of these properties. When trying to quantify the behavior of contaminant mixtures such as the polychlorinated biphenyls, consistent physical–chemical properties are required for each individual congener. A complete set of temperature dependent property data for sixteen polychlorinated biphenyls (PCB-3, 8, 15, 28, 29, 31, 52, 61, 101, 105, 118, 138, 153, 155, 180, 194) was derived, based on all experimentally obtained values reported for these congeners in the literature. Log mean values derived from the experimental data were adjusted to yield an internally consistent set of data for each congener. These adjusted data also...

Henry’s Constants and Vapor–Liquid Distribution Constants for Gaseous Solutes in H2O and D2O at High Temperatures

Abstract: We have developed correlations for the Henry’s constant kH and the vapor–liquid distribution constant KD for 14 solutes in H2O and seven solutes in D2O. The solutes considered are common gases that might be encountered in geochemistry or the power industry. Solubility data from the literature were critically assessed and reduced to the appropriate thermodynamic quantities, making use of corrections for nonideality in the vapor and liquid phases as best they could be computed. While the correlations presented here cover the entire range of temperatures from near the freezing point of the solvent to high temperatures approaching its critical point, the main emphasis is on representation of the high-temperature behavior, making use of asymptotic relationships that constrain the temperature dependence of kH and KD near the critical point of the solvent.

Vibrational Spectroscopic Database on Acetylene, X̃ 1Σg+ (12C2H2, 12C2D2, and 13C2H2)

Abstract: Information on the vibrational energy states in acetylene (12C2H2, 12C2D2, and 13C2H2) is gathered: spectroscopic constants (vibrational frequencies and anharmonicities, vibration-rotation interaction parameters), observed vibrational energy states and complete sets of predicted vibrational energies and predicted principal rotational constants Bv for states of 12C2H2, 12C2D2, and 13C2H2 up to 15000, 10000, and 12000 cm−1, respectively. Statistical parameters (partition functions and integrated number of states) deduced from these predicted spectroscopic data are provided for the three isotopomers. The equilibrium geometrical structure is determined to be re(CH)=106.138(35) pm and re(CC)=120.292(13) pm from constants available for 12C2H2, 12C2D2, 13C2H2, and 12C2HD.

NIST-JANAF Thermochemical Tables. II. Three Molecules Related to Atmospheric Chemistry: HNO3, H2SO4, and H2O2

Abstract: The structural, spectroscopic, and thermochemical properties of three polyatomic molecules with internal rotation—HNO3(g), H2SO4(g), and H2O2(g)—have been reviewed Three revised ideal gas thermodynamic tables result from this critical examination The revisions involved the consideration of new spectroscopic information and the use of theoretical results to model the internal rotation in the H2SO4 molecule Compared to previous calculations, the entropies at 29815 K are unchanged for HNO3 and H2O2, but the high temperature values (T>4000 K) are significantly different As for H2SO4, its thermodynamic functions differ significantly from values calculated earlier

A Fundamental Equation for Trifluoromethane (R-23)

Abstract: A new formulation for the thermodynamic properties of trifluoromethane (R-23) is presented. The formulation is valid for single-phase and saturation states for temperatures from the triple point (118.02 K) to 475 K, pressures up to 120 MPa, and densities up to 24.31 mol/dm3. The formulation includes a fundamental equation and ancillary functions for the estimation of saturation properties. The experimental data used to determine the fundamental equation included pressure–density–temperature (p–ρ–T), isobaric heat capacity (cp–p–T), isochoric heat capacity (cν–ρ–T), saturation heat capacity (cσ), speed of sound (w–p–T), and vapor pressure. A nonlinear regression algorithm was used to determine the constants and exponents of various functions within the formulation. Experimental data and values computed using the formulation are compared to verify the uncertainties in the calculated properties. The formulation presented may be used to compute densities to within ±0.1%, heat capacities to within ±0.5%, speed...

Correlations for Vapor Nucleating Critical Embryo Parameters

Abstract: Condensation nucleation light scattering detection in principle works by converting the effluent of the chromatographic separation into an aerosol and then selectively evaporating the mobile phase, leaving less volatile analytes and nonvolatile impurities as dry aerosol particles. The dry particles produced are then exposed to an environment that is saturated with the vapors of an organic solvent (commonly n-butanol). The blend of aerosol particles and organic vapor is then cooled so that conditions of vapor supersaturation are achieved. In principle, the vapor then condenses onto the dry particles, growing each particle (ideally) from as small as a few nanometers in diameter into a droplet with a diameter up to about 10 μm. The grown droplets are then passed through a beam of light, and the light scattered by the droplets is detected and used as the detector response. This growth and detection step is generally carried out using commercial continuous-flow condensation nucleus counters. In the present research, the possibility of using other fluids than the commonly used n-butanol is investigated. The Kelvin equation and the Nucleation theorem [Anisimov et al. (1978)] are used to evaluate a range of fluids for efficacy of growing small particles by condensation nucleation. Using the available experimental data on vapor nucleation, the correlations of Kelvin diameters (the critical embryo sizes) and the bulk surface tension with dielectric constants of working liquids are found. A simple method for choosing the most efficient fluid, within a class of fluids, for growth of small particles is suggested.

Ultrasonic Parameters as a Function of Absolute Hydrostatic Pressure. I. A Review of the Data for Organic Liquids

Abstract: This review provides an overview of experimental results involving ultrasonic parameters as a function of absolute hydrostatic pressure in organic liquids. Major topics of discussion include the pioneering work of Litovitz and Carnevale involving deduction of the chemical and structural properties of liquids from acoustical properties as a function of pressure; modern general ultrasonic studies of a broad range of organic liquids; work accomplished by Russians and others from the former Soviet block countries, particularly the work headed by Otpuschennikov at the Kursk Pedagogical Institute; the studies involving refrigerants published by Takagi at the Kyoto Institute of Technology; tribological and petroleum industry studies related to oils; Brillouin scattering experiments; and thermodynamic methods of B/A measurement. The importance of ultrasonic parameters as a function of pressure to the understanding of a variety of processes is highlighted. A table of 325 liquids and liquid mixtures with a total of...

Ultrasonic Parameters as a Function of Absolute Hydrostatic Pressure. II. Mathematical Models of the Speed of Sound in Organic Liquids

Abstract: Polynomial expressions for the speed of sound as a function of pressure for 68 different organic liquids are presented in tabular form. (The liquids form a subset of those discussed in the companion paper: Ultrasonic parameters as a function of absolute hydrostatic pressure. I. A review of the data for organic liquids.) The polynomial expressions are based upon the experimental results reported by many different researchers. For some common liquids, such as benzene, hexane, ethanol, and carbon tetrachloride, the results of as many as five different researchers are reported. These results sometimes vary widely—far more than would be expected from calculated experimental uncertainties. An analysis is presented of how well pressure-dependent polynomials fit the experimental data when the number of coefficients is increased. The error in the polynomial fit is also explored when both pressure and temperature dependencies are present. Finally, differences between ultrasonic and Brillouin scattering experimental...

Recommended Critical Temperatures. Part I. Aliphatic Hydrocarbons

Abstract: This work deals with the critical temperature (Tc) for saturated and unsaturated aliphatic hydrocarbons. For 175 hydrocarbons (branched alkanes, branched and unbranched alkenes, and alkynes), an existing lack of critical temperature values have been complemented. Prediction methods have been used, the usefulness of which for specific groups and subgroups of the above mentioned hydrocarbons had been previously critically evaluated. The evaluation of accuracy of the relevant aspects of these methods is given in this study. An additional result of this work is the creation of a set of recommended experimental data on critical temperatures and normal boiling points for aliphatic hydrocarbons. Such a set has been created mainly for the purpose of evaluation of prediction methods applied in this study.

Thermochemical Properties, ΔfH°(298.15 K),S°(298.15 K), and Cp°(T), of 1,4-Dioxin, 2,3-Benzodioxin, Furan, 2,3-Benzofuran, and Twelve Monochloro and Dichloro Dibenzo-p-dioxins and Dibenzofurans

Abstract: Values for ΔfH°(298.15 K), S°(298.15 K), and Cp°(T) (5⩽T/K⩽6000) are computed by density functional B3LYP/6-31G(d,p) and B3LYP/6-311+G(3df,2p) calculation methods for 12 monochloro and dichloro dibenzo-p-dioxins and dibenzofurans: 1-chloro dibenzo-p-dioxin, 2-chloro dibenzo-p-dioxin, 1,6-dichloro dibenzo-p-dioxin, 1,8-dichloro dibenzo-p-dioxin, 1,9-dichloro dibenzo-p-dioxin, 2,8-dichloro dibenzo-p-dioxin, 3-chloro dibenzofuran, 4-chloro dibenzofuran, 1,6-dichloro dibenzofuran, 3,6-dichloro dibenzofuran, 3,7-dichloro dibenzofuran, and 4,6-dichloro dibenzofuran. Molecular structures and vibration frequencies are determined at the B3LYP/6-31G(d,p) level of theory. Isodesmic reactions are utilized at each calculation level to determine the enthalpy of formation of each species. Contributions to the entropy and the heat capacity from translation, vibration, and external rotations are calculated using the rigid-rotor-harmonic-oscillator approximation based on the B3LYP/6-31G(d,p) structures. The enthalpies of f...

Thermodynamics of Chlorinated Phenols, Polychlorinated Dibenzo- p -Dioxins, Polychlorinated Dibenzofurans, Derived Radicals, and Intermediate Species

Abstract: The thermodynamics of 31 chlorinated phenols, polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans, and some chlorinated cyclo–C5 compounds have been calculated. Twelve of these species are radicals. Additionally the thermodynamic properties of temperature dependent tables (T=0 K–6000 K) of the ideal gas phase thermodynamic properties are listed, together with recommended values for the structure, vibrational frequencies, and enthalpy of formation either found in the literature or calculated.

Viscosity and pVT–Second Virial Coefficient of Binary Noble–Globular Gas and Globular–Globular Gas Mixtures Calculated by Means of an Isotropic Temperature-Dependent Potential

Abstract: This work presents results of an extension of our earlier studies of the transport and equilibrium properties of pure heavy globular gases. It demonstrates a simple and reliable procedure for estimating the equilibrium and transport properties of their mixtures using the pure gas potentials of interaction when there are no available experimental data. Here we consider binary gas mixtures of globular gases between themselves and with the noble gases as well. The gases involved are: BF3, CH4, CF4, SiF4, SiCl4, CCl4, SF6, MoF6, WF6, UF6, C(CH3)4, Si(CH3)4, Ar, Kr, and Xe. The calculations were performed by means of the so called isotropic temperature–dependent potential (ITDP) introduced by us earlier and applied to some binary mixtures (CH4–CF4, CH4–SF6, CF4–SF6). The CH4–CH4 and noble gases potentials of interactions have been determined in a (n−6) Lennard-Jones shape in the temperature range 200–1000 K by fitting a large number of viscosity and pVT–second virial coefficient data measured by different auth...

Atomic Spectral Tables for the Chandra X-Ray Observatory. Part I S VIII–S XIV

Abstract: Tables of critically compiled wavelengths, energy levels, line classifications, and transition probabilities are given for spectra of ionized sulfur (S VIII–S XIV) in the region 21–170 A. These tables provide data of interest for the Emission Line Project in support of the analysis of astronomical data from the Chandra X-Ray Observatory. They will also be useful for the diagnostics of plasmas encountered in fusion energy research. The transition probabilities were obtained mainly from recent sophisticated calculations carried out with complex computer codes.

Vapor Pressure and Critical Point of Tritium Oxide

Abstract: A simple general corresponding-states principle has been developed to represent the vapor pressure of tritium oxide from its triple point to its critical point, to describe the available experimental data, and to extrapolate beyond their range. This work takes advantage of the adoptions of the ITS-90 temperature scale and of the new critical parameters obtained from the extended corresponding-states principle. The vapor pressure data are described within their scatter in the entire temperature range. Comparisons with the available experimental data show that the extended corresponding-states principle for vapor pressure can calculate values with good accuracy. The substance-dependent characteristic parameters are given, such as critical temperature, critical density, critical pressure, and acentric factor. The values of the pressures, along with their first and second derivatives, as a function of temperature over the entire region from the triple point to the critical point are tabulated and recommended for scientific and practical uses.