High pressure investigations of (n-alkanes + ether) mixturesElectronic supplementary information (ESI) available: Experimental liquid–solid equilibrium pressures and interpolated solid–liquid equilibrium temperatures for hydrocarbon (1) + MTBE (2). See http://www.rsc.org/suppdata/cp/b2/b200711h/Presented at the ESAT 2000, 18th European Seminar on Applied Thermodynamics, June 8–11 2000, Kutná Hora, Czech Republic.

Abstract

Solid-liquid equilibria, (SLE) of n-alkanes (n-octadecane, or n-eicosane) + methyl 1,1-dimethylethyl ether (methyl tert-butyl ether) at very high pressures up to about 1.0 GPa have been investigated in the temperature range 313 K to 353 K using a new thermostatted apparatus for the measurement of transition pressures from the liquid to the solid state in two-component isothermal solutions. The freezing and melting temperatures at a constant composition increase monotonically with pressure. The high pressure devices used are briefly described and experimental results obtained in isothermic (T ¼ constant) conditions, p-x, are interpolated to well known T-x diagrams. The solid-solid first order transition, characteristic for n-alkanes, shifts to a lower temperature with increasing pressure. In order to describe the pressure-temperature-composition relation of high-pressure SLE, the Nagaoka-Makita polynomial was satisfactorily used.