Showing papers in "Journal of Chemical & Engineering Data in 1972"

Vapor-liquid equilibrium of methane-n-pentane system at low temperatures and high pressures

Abstract: Measurements of the bubble-point compositions are reported and combined with dew-point data to give K-values for the methane--n-butane system at 40/sup 0/, 0/sup 0/, -20/sup 0/, -40/sup 0/, -60/sup 0/, -80/sup 0/, -100/sup 0/, -116.6/sup 0/, -120/sup 0/, -140/sup 0/, -160/sup 0/, -180/sup 0/, and -200/sup 0/F from the vapor pressure of n-butane up to critical point of the vapor pressure of methane. Experimental conditions were selected so that direct isobaric observations were also possible. Results showed significant deviations in the low-temperature range of the NGPSA critical loci as based on the experimental results of J. J. McKetta et al. from +40/sup 0/F to -140/sup 0/F. Data, however, are consistent in the high-temperature range as based on the data of B. H. Sage et al. from 70/sup 0/F to 250/sup 0/F. The 13 isotherms shown are constructed from data obtained from both experimental procedures.

Predicting gas-liquid diffusivities

Abstract: Diffusion in liquids has been studied for many years (14, 16). Available expressions for calculating diffusion coefficients in liquids, however, only partially have been successful. There is no one equation which predicts diffusivities for all systems involving a liquid solvent. The object of this investigation was to compare the existing diffusivity expressions for systems involving a gas solute diffusing through a liquid solvent. Dissolved gases form a special class of molecules of small size and low enthalpy of vaporization in the broad category of liquid diffusion and thus provide a good means of comparing the accuracy of the various equations. The first equation used is the Stokes-Einstein equation developed as early as 1905 (4).

Coefficient of thermal expansion of pentaerythritol tetranitrate and hexahydro-1,3,5-trinitro-s-triazine (RDX)

Abstract: T h e thermal expansion coefficient is a second-order symmetric tensor and hence contains six independent constants for a triclinic crystal. This number is reduced for crystals with higher symmetry. Hexahydro-l,3,5-trinitro-s-triazine (RDX, C3H6N606) crystallizes with orthorhombic symmetry, and its thermal expansion is expressed by three coefficients of linear expansion measured along the principal crystallographic axes. Pentaerythritol tetranitrate (PETN, CSHsK4012) is tetragonal, and two coefficients, one along the unique crystallographic axis and one perpendicular to it, describe the thermal expansion, The direction of measurement of the coefficient of linear thermal expansion is indicated by a subscript giving the crystal face normal to the direction of measurement-e.g., C U ( ~ Z O \ is measured in a direction perpendicular to the (120) crystal face. It happens, for these materials, that a(1oo) is measured parallel to the a crystallographic axis, and similarly ~ ~ ( 0 1 0 ) and