MEASUREMENT OF THE CRITICAL-TEMPERATURES AND CRITICAL PRESSURES OF SOME THERMALLY STABLE OR MILDLY UNSTABLE ESTERS, KETONES, AND ETHERS

A modified Kay-type apparatus has been used for the measurement of the critical temperature Tc and critical pressure Pe of thermally stable or slightly unstable alkanols. Since some oxygen-containing compounds decompose at their critical temperature, thermal decomposition was reduced by heating the sample rapidly to the critical temperature in the present apparatus. The critical temperatures and critical pressures were determined by the standard method of visual observation of the disappearance and reappearance of the meniscus between the liquid and vapour phases. Temperatures and pressures were measured with an accuracy of ±0.1 K and of ±0.001 MPa with a calibrated mineral-coated chromel-to-alumel thermocouple, and a transducer assembly, respectively. The critical temperatures and critical pressures of seven esters, three ketones, and two ethers are reported. The results have been compared with the predicted values using the methods of Ambrose and of Somayajulu. © 1991 Academic Press Limited All rights reserved.