Density and Adsorption Studies in the Region of the Critical Temperature: System Dimethyl-Ether–alumina

An apparatus and an experimental procedure for simultaneously determining the density and adsorption of liquids, vapors and gases in the region of the critical temperature are described. Measurements of adsorption and density of dimethyl ether through the temperature range 124–135 °C. are given for the liquid, vapor and gas. Adsorption of the liquid does not occur below 124 °C. but beginning at this temperature, it rapidly increases to a maximum, beyond which the adsorption curve resembles a normal isobar. It is shown that the apparent adsorption cannot be ascribed to a lag in the critical temperature of liquid held in the pores, and further that an absurd value for the density of such liquid must exist to account for the total adsorption observed. Hysteresis effects of a complex nature are noticed, and these are discussed from the point of view of the hypothesis that: "there is an essential difference, other than concentration, between a liquid and a highly compressed gas."