Pressure‐Jump Experiments for the Study of the Kinetics of Phase Separation in the Binary System Ethene/Hexane. II. Measurements of Pressure‐Induced Temperature Changes

Abstract

AbstractIn order to study the process of demixing of the binary gas/liquid system ethene/hexane we used a pressure‐jump technique that makes possible to generate differential pressure jumps from 0.05 up to 1 MPa into the miscibility gap. For relating the time‐dependent appearance of a new phase by means of light scattering to the respective maximum supersaturation of the system under test (see Part I), the knowledge of the corresponding adiabatic temperature changes induced by the pressure jumps was necessary. In this paper we report transient temperature measurements at pressures up to 8 MPa and temperatures from 293 to 323 K that were made with a thermocouple in contact with the binary liquid phase. An empirical formula is presented and discussed which relates the adiabatic thermal pressure coefficient to the critical temperatures and the critical pressures of the binary system over pressures and temperatures ranging from 2 MPa and 20 K respectively away from the vicinity of the critical line.