Investigation of vapor pressures and heats of vaporization of condensed aromatic compounds at elevated temperatures

Abstract

A hlgh-temperature static apparatus Is used to Investigate vapor pressures In the range 1-2780 ironHg over the temperature range 425-840 K for three aromatic compounds similar to those which are often found In coal liquide: fluorene, dlbenzofuran, and dibenzothlophene. The experimental vapor pressure data of fluorene and Its homomorphs cited above have been fitted to Chebyshev polynomials. The values of dp/dT calculated from the Chebyshev polynomials, the compressibility factors of saturated vapor and liquid estimated from three-parameter corresponding states correlation, and the acentric factors determined from their experimental vapor pressure data presented In this paper were used to evaluate the heats of vaporization of the aromatic compounds mentioned above from the Clapeyron equation.

Revisiting dibenzothiophene thermochemical data: Experimental and computational studies

“…Edwards and Prausnitz [18] performed vapour and sublimationpressure measurements at moderate temperatures for dibenzothiophene and, although they did not report the value of the enthalpy of sublimation, from the results presented in their work we derived the following value (91.7 kJ Á mol À1 ). Sivaraman and Kobayashi [19] used a high-temperature static apparatus to measure vapour pressures of dibenzothiophene; again, from the results presented in that work, we derived the value for the enthalpy of sublimation obtaining 91.0 kJ Á mol À1 . Mraw and Keweshan [20] used a ballistic Calvet calorimetry for the determination of the enthalpy of vaporization of dibenzothiophene and calculated the value of the enthalpy of sublimation using the heat capacities recommended by Stein and Barton [17] for the gas and by O'Rourke and Mraw [12] for the condensed phases reaching the value (93.8 ± 3.6) kJ Á mol À1 .…”

“…Dibenzothiophene is considered as a S-containing polyaromatic ''key" compound, and probably this is one of the reasons for the considerable number of thermochemical and thermophysical studies published in the literature for this compound since the 1970s [12][13][14][15][16][17][18][19][20][21][22][23][24][25]. Table 1 contains a compilation of data available in the literature for dibenzothiophene, namely values of the enthalpy of sublimation, D g cr H m , and values of the enthalpies of formation, in the crystalline, D f H m ðcrÞ, and gaseous, D f H m ðgÞ, phases, at T = 298.15 K. Despite the strong efforts done for the fulfillment of the gaps on the thermodynamic properties of dibenzothiophene, the analysis of the values shown in table 1 allows one to detect that some results are of questionable reliability, as can be discerned by the large disagreement among the results determined by different groups.…”

Critical point measurement of some polycyclic aromatic hydrocarbons

“…c The average of the values given in reference [29][30][31][32] and calculated from Ref. [33]. d The average of the values given in reference [29,[34][35][36][37].…”

Glass transitions in the stable crystalline states of dibenzofuran and fluorene

“…(4) The experimental molar heat capacities C s, m at saturated vapor pressure of dibenzofuran are tabulated in table 1 and shown in figure 3 together with the results of Chirico et al (3) The correction for vaporization was made using the vapor pressure. (3,(12)(13)(14) The temperature dependence of the vapor pressures was expressed by the Antoine equation:…”

“…are collected in table 2. The correction for vaporization was made using vapor pressures: (13,16,17) lg(p/p°)=3.61−1530/{(T/K)−142} (6) where p°=101.325 kPa. The correction was evaluated to be negligible: only 0.008 per cent even at T=400 K. Good agreement was obtained between the present and literature results.…”