Solubility Measurement and Thermodynamic Properties of Fluorene in 14 Pure Solvents at Temperatures from 278.15 to 318.15 K

Abstract

In this study, the solubility data of fluorene in 14 pure organic solvents (methanol, ethanol, n-propanol, isopropanol, ethyl formate, methyl acetate, ethyl acetate, n-propyl acetate, isopropyl acetate, n-butyl acetate, isobutyl acetate, propanone, acetonitrile, and tetrahydrofuran) from 278.15 to 318.15 K were measured using a gravimetric method at atmospheric pressure. Four thermodynamic models, including the modified Apelblat model, λh model, van’t Hoff model, and NRTL model, were employed to correlate solubility data and further evaluated by the average relative deviation (ARD). The experimental results revealed a positive correlation between solubility and temperature. ARD values of four models were less than 4%, indicating that all models had good correlations. Among them, the modified Apelblat model had the best correlation. Mixing thermodynamic properties were calculated based on the NRTL model. Results showed that the dissolution process was a spontaneous entropy-driven process. In addition, the solubility of fluorene decreased with increasing solvent polarity, cohesive energy density, and steric hindrance after solvent effect analysis.

Solubility Measurement and Model Calculation of Fluorene in Six Binary Solvents from 288.15 to 328.15 K

“…The PXRD patterns of the raw material of fluorene and the solid residues in the six binary solvents are presented in Figure , which corresponds to the report in the literature . It can be observed that the characteristic peaks of fluorene in the selected solvents had no change compared to that of the raw material, which indicates that no polymorphic transformation of fluorene appeared in the experimental process. , …”

“…The DSC curve of fluorene is shown in Figure . The result indicates that the melting point ( T m ) of fluorene is 387.49 K and the melting enthalpy is ( Δ fus H ) = 17.103 kJ/mol, which is compared to the reported documentation ( T m = 387.92 K and Δ fus H = 16.948 kJ/mol in ref ; T m = 387.943 K and Δ fus H = 19.58 kJ/mol in ref ). Standard uncertainties for the melting point ( T m ) and melting enthalpy ( Δ fus H) are u ( T m ) = 0.5 K and u ( Δ fus H ) = 0.5 kJ/mol, respectively.…”

“…), and Sun et al have reported the solubility data of fluorene in 14 single solvents (isopropyl acetate, n-propyl acetate, propanone, acetonitrile, etc.). For example, the mole fraction solubility of fluorene in isopropyl acetate at 298.15 K is 8.1200 × 10 –2 . − To broaden the selection of crystallization process conditions and to facilitate the exploration of cooling crystallization, evaporation crystallization, and antisolvent crystallization of fluorene, the solubility data of fluorene in various binary solvents is imperatively required. However, there is little available literature on the solubility of fluorene in binary solvents.…”

Solubility Determination and Data Correlation of 4-Methoxybenzoic Acid in 14 Pure Solvents at Temperatures from 283.15 to 328.15 K

“…The solubility of 4-MBA in 14 distinct solvents was ascertained through the application of the gravimetric method within the temperature spectrum of 283.15–328.15 K. − Approximately, 30 mL of the organic solvent was placed in a 50 mL conical flask. Subsequently, an excess of 4-MBA was introduced to ensure the avoidance of complete solid solute dissolution.…”

“…The Modified Apelblat equation is a semiempirical equation that is derived from the Clausius–Clapeyron equation. Due to its simple expression, it is extensively employed in the correlation of solid–liquid equilibrium data. − The Modified Apelblat equation can be represented as follows ln nobreak0em0.25em⁡ x = A + B T + C ln nobreak0em0.25em⁡ T where x signifies the mole fraction of 4-MBA at the absolute temperature “ T ” in Kelvin during the experiment. The equation is defined by three empirical constants, namely, A, B, and C. Parameters A and B are indicative of the nonideality within the solution, accounting for variations in activity coefficients, while parameter C characterizes the influence of temperature on the enthalpy of fusion.…”