A high pressure autocollimating refractometer for determining coexisting liquid and vapor phase densities

Abstract

A high pressure apparatus has been developed for measuring refractive indices and compositions of coexisting phases in vaporliquid equilibrium. The refractive index is determined by measuring the angle of minimum deviation of a 30° prism with an autocollimating telescope mounted on a precision rotary table. The composition is determined by chromatographic analysis. The refractive indices and compositions of the coexisting liquid and vapor phases in the carbon dioxide‐n‐butane system were obtained at 37.7°C and pressures up to 80 atm. The densities of the phases were calculated using the molar average refractivity and these compared favorably with previously published data obtained by direct volumetric measurements.

Vapor-liquid equilibrium of carbon dioxide with isobutane and n-butane: Modified leung-griffiths correlation and data evaluation

“…For carbon dioxide + n -butane, at the beginning of our study the only data available to us and considered to be useful as input were those of Weber [ 15 ] and those of Olds et al [ 16 ]. Some additional data for this mixture had been reported by Robinson and coworkers [ 17 , 18 ] and by Behrens and Sandler [ 19 ], but only over a restricted temperature range. Poettmann and Katz [ 20 ] measured VLE along isopleths up to the critical locus, without densities, for mixtures of carbon dioxide with propane, n -butane, and n -pentane.…”

Equilibrium phase properties of the toluene-hydrogen sulfide and heptane-hydrogen sulfide binary systems

“…The molar volumes of the equilibrium phases reported at the three lower temperatures in Table I were calculated from the measured phase compositions and refractive indices using the Lorentz-Lorenz molar refractivity relationship as explained in the earlier papers by Besserer and Robinson (2,3). The molar refractivity is expressed in terms of the refractive index and molar density as follows: The errors in the vapor molal volumes may be somewhat higher in regions where the refractive index approaches unity.…”

The Measurement of High Pressure Vapour‐Liquid‐Equilibria: Part I: Dynamic Methods

“…Radl and A.L. MWbauer (1) Equilibrium Cell; (2) windows,' (3) sample charging pump; (4) liquid sample; (5) pressure transducer; (6) sampler; (7) magnetic pwnp; (8) magnetic stirrer; (9)jlash tank; (10) temperature controller: (11) vacuum pump: (12) NH, sample cylinder; (13) For recirculation methods in general, vapourization and condensation of the circulating liquid and vapour streams must be avoided. This has been overcome in a number of ways, for example: (a) Having three separately controlled temperature zones, one for the equilibrium cell and another for the vapour recirculation loop in which the temperature was slightly greater than the equilibrium temperature.…”