Measurement of critical temperatures of thermally unstable n-Alkanes

✍ Scribed by R. L. Smith Jr.; A. S. Teja; W. B. Kay

• Publisher: American Institute of Chemical Engineers
• Year: 1987
• Tongue: English
• Weight: 637 KB
• Volume: 33
• Category: Article
• ISSN: 0001-1541
• DOI: 10.1002/aic.690330209

✦ Synopsis

A modified sealed-tube apparatus has been developed for the measurement of the critical temperatures of thermally unstable fluids. The apparatus has been used to measure the critical temperatures of the normal alkanes from n-octane to n-hexadecane. Since the higher alkanes (with more than 10 carbon atoms) decompose at temperatures well below their critical temperatures, a new method of analysis of the apparent critical temperature vs. time data has been developed. This method employs reaction kinetics based on an irreversible first-order reaction and is used to linearize the data and to perform an unambiguous extrapolation to the critical temperature of the undecomposed substance. The method is successful because the temperature history of the substance is recorded by computer, and ampoule contents are analyzed at the completion of the experiment. The critical temperatures of the n-alkanes reported in this paper have been compared with values found in previous studies.