Accession Number : ADA311531

Title :   Computation of Partial Vapor Pressures of Aqueous Volatile Organic Compound Solutions.

Descriptive Note : Final rept. Jul 93-Dec 95,

Corporate Author : VIRGINIA POLYTECHNIC INST AND STATE UNIV BLACKSBURG

Personal Author(s) : Field, Paul E. ; Combs, Roger J. ; Knapp, Robert B.

PDF Url : ADA311531

Report Date : JUN 1996

Pagination or Media Count : 71

Abstract : A program is described for the evaluation of the partial vapor pressures of solution components dependent on the concentration in solution, total pressure, and temperature. The object of the program is to provide reliable values that represent the best estimate based on the large body of experimental data available in the literature. The basis of the estimate is the evaluation of the Wilson coefficients for calculating the activity coefficients of the components using an iterative least squares algorithm to minimize the excess Gibbs free energy of solution. The computational programs are applied to binary aqueous solutions of volatile organic compounds: methanol, ethanol, iso-propanol, acetone, and methyl ethyl ketone. The statistical evaluation of the results show that where the data base is large, in excess of 20 literature citations, the estimated error is around 1%. Smaller data bases, as in the case of methyl ethyl ketone with five citations, show poorer precision (e.g., around 3%). The results are applied to the evaluation of the vapor concentration dependence of the absorbance of selected peaks in the infrared spectrum of the compounds evaluated.

Descriptors :   *COMPUTATIONS, *SOLUTIONS(MIXTURES), *ORGANIC COMPOUNDS, *VOLATILITY, *VAPOR PRESSURE, *PARTIAL PRESSURE, DATA BASES, ALGORITHMS, ACTIVATION, EXPERIMENTAL DATA, METHYL RADICALS, ESTIMATES, SOLUTIONS(GENERAL), COEFFICIENTS, METHANOLS, ERRORS, LEAST SQUARES METHOD, STATISTICAL ANALYSIS, ITERATIONS, ACETONES, FREE ENERGY, INFRARED SPECTRA, ETHYL RADICALS, KETONES, ETHANOLS.

Subject Categories : Organic Chemistry
      Physical Chemistry
      Atomic and Molecular Physics and Spectroscopy
      Optics

Distribution Statement : APPROVED FOR PUBLIC RELEASE