I. An apparatus for the measurement of liquid diffusion coefficients. II. Supersaturation in hydrocarbon systems. 1. N-pentane in the liquid phase. 2. Statistical procedures for supersaturation data. III. Volumetric and phase behavior of hydrocarbon systems. 1. Hydrogen-n-hexane. 2. n-Heptane

Abstract

I. An apparatus was constructed for the measurement of Fick diffusion coefficients in the liquid phase under steady state conditions at pressures up to 10,000 psi. and at temperatures from 40 to 460[degrees]F. The apparatus consists of a device for the feed of a gas at an accurately known rate, a diffusion cell, and a device identical to the feed equipment for the withdrawal of a gas. The details of construction are given and a tentative method of operation is discussed. II. 1. A limited number of measurements were made of the effect of the degree of supersaturation on the rate of bubble formation as shown by the time for the first bubble to form in liquid n-pentane. Data were taken at 160[degrees] and 280[degrees]F. in an isochoric cell and at 160[degrees]F. in an isobaric apparatus which is described. The results show that for a given degree of supersaturation the times of bubble formation are widely distributed and must be considered statistically. II. 2. A procedure for the treatment of supersaturation data is discussed which includes a derivation of a theoretical distribution function for the times of formation of the first bubbles, a regression analysis based on an elementary hypothesis for the dependence of the rate of bubble formation on the degree of supersaturation, and a study of several pertinent confidence intervals. III. 1. The volumetric behavior of four mixtures of different composition in the binary system hydrogen-n-hexane was investigated at pressures up to 10,000 pounds per square inch for eight temperatures in the interval between 40 and 460[degrees]F. The composition of coexisting phases in the heterogeneous region was determined at seven temperatures from 40 to 400[degrees]F. and at pressures up to 10,000 pounds per square inch. The results are presented in tabular and graphical form. III. 2. Prior work on n-heptane by other investigators was extended as a preliminary to the study of the binary system methane-n-heptane. The molal volume of n-heptane is reported in tabular and graphical form as a function of pressure up to 10,000 pounds per square inch at eight temperatures covering the range from 40 to 460[degrees]F.