The critical temperatures of forty organic compounds

Abstract

Precise measurements have been made of the critical temperatures of pure specimens of forty compounds drawn from the paraffin, olefine, cyclopentane, cyclohexane, benzene, pyridine and naphthalene series. The visual method of determining the critical point was employed, and observed critical temperatures are believed accurate to within 0.1" in most instances. The results for compounds of the paraffin, olefine and benzene series have been combined with earlier measurements on other compounds of these series to yield correlating equations, which should prove useful for predicting the critical temperatures of compounds for which experimental data do not exist. Fluorobenzene was included in the present study in order to check the accuracy of our experimental method, since a very accurate value for the critical temperature of this substance is available from P-V-T studies. The experimental value obtained by our visual method proved to be identical with the value from P-V-T studies.

Phase behavior in binary and multicomponent systems at elevated pressures :

“…The vapor pressure of re-pentane has been studied by numerous investigators [8][9][10][11][12][13] and the critical properties have been measured many times [8,9,12,14,15] [12] and Ambrose [14]. Likewise [12] from direct volumetric measurement and that selected by the American Petroleum Institute Project 44 [16] resulted in a somewhat smaller estimate of uncertainty than otherwise would haive been the case.…”

“…Ambrose [14] 385 41 Partington [15] 385 5 API 44 [16] Young [9] Sage [11] Beattie [12] Li [13] Kozicki [17] 3. The Methane-n-Pentane System…”

“…Likewise, the vapor pressure of n-pentane was studied by Young and others [8,9,12,13], and the critical properties determined [9,12,14,16].…”

Vapor pressures, high-temperature heat capacities, critical properties, derived thermodynamic functions, and barriers to methyl-group rotation, for the six dimethylpyridines

“…The dimethylpyridines have been the subject of many thermodynamic and physical-property investigations including the determination of heat capacities, (6) enthalpies of combustion, (7) vapor pressures, (8)(9)(10)(11)(12) densities, (8,(13)(14)(15)(16)(17) enthalpies of vaporization, (18) second virial coefficients, (19,20) critical temperatures, (21,22) and vibrational analyses. (23,24) However, excluding the critical-temperature determinations, none of the measurements was made at temperatures exceeding the normal-boiling temperature.…”

Maxima of the Specific Heat at Constant Pressure of the n-Alkanes C7-C9 in the Supercritical Region

“…The above requirements for the measurement of T c of individual substances are virtually satisfied by a setup proposed by Ambrose et al [9]. Their data for T c are given in the table.…”