Antoine Constants Research Articles

A weighted least squares computation of the Antoine constants from vapor pressure data using a microcomputer

The purpose of this work was to develop an accurate, rapid method for determining the constants A, B, and C of the Antoine equation, log p = A - B/( C + t) which relates the vapor pressure of a liquid to temperature. The procedure makes use of a weighted least squares curve fit with an iterative computation. The computation has been programmed in BASIC for use on a microcomputer, and the details of the program and its use are presented. A comparison of the results of the present method with published values for several compounds indicates that the constants are determined more accurately by the present method than by other methods.

Cohesion energies and solubility parameters for tetra- n-alkylgermanes

Previously published vapor pressure and density data for tetra- n-alkylgermanes (C 1 to C 5) have been used to calculate cohesion energies and solubility parameters in the range 273–400 K. Antoine constants are also reported for these compounds. The van der Waals constants ( a) and the effective molecular radii have been determined for these molecules. These parameters show normal ranges and relationships for liquids interacting only by London dispersion forces.

Vapour pressure of α-iodonaphthalene

Using three different techniques, the vapour pressure of α-iodonaphthalene was measured in the temperature range 322–422 K. The pressure equation log P(kPa) = 8.82 ± 0.29 − (3719 ± 300) / T, was determined. The enthalpy of vaporization change, Δ H 0 298 = 69.4 ± 4.0 kJ mole −1, was determined as the average of the results obtained by second-and third-law treatment of the experimental data. Antoine's constants, A = 6.258, B = 2010 and C = 171, were also derived.

Vapor pressures and boiling points of selected halomethanes

This critical review is a study of the vapor pressure–boiling point data from the triple point to the critical point for CH4–a Xa (X=Br, I) and CH4−(a+b+c+d) FaClbBrcId halomethanes. The available data are carefully analyzed and the ’’best’’ data selected. The selection procedure is discussed. Uncertainties in the selected temperatures and pressures are reported. The selected data were fitted to the Antoine equation for data up to 1500 mm Hg pressure and the Wagner equation for data up to the critical point. Antoine constants for nineteen compounds and the Wagner constants for five compounds are reported. The enthalpy of vaporization at 298.15 K and at the normal boiling point have been computed.