Ostwald Concentration Coefficients of Acetonitrile in Aqueous Mixed Solvents: A New, Rapid Method for Measuring the Solubilities of Volatile Solutes (original) (raw)
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Solubility of sulfamethazine (SMT) in acetonitrile (MeCN) + methanol (MeOH) cosolvents was determined at nine temperatures between 278.15 and 318.15 K. From the solubility data expressed in molar fraction, the thermodynamic functions of solution, transfer and mixing were calculated using the Gibbs and van ’t Hoff equations; on the other hand, the solubility data were modeled according to the Wilson models and NRTL. The solubility of SMT is thermo-dependent and is influenced by the solubility parameter of the cosolvent mixtures. In this case, the maximum solubility was achieved in the cosolvent mixture w0.40 at 318.15 K and the minimum in pure MeOH at 278.15 K. According to the thermodynamic functions, the SMT solution process is endothermic in addition to being favored by the entropic factor, and as for the preferential solvation parameter, SMT tends to be preferentially solvated by MeOH in all cosolvent systems; however, δx3,1<0.01, so the results are not conclusive. Finally, ac...
2014
The solubility of sodium acetate in ternary solvent mixtures of water + methanol (MeOH) + acetonitrile (ACN), water + MeOH + 1-propanol (PrOH), water + PrOH + ACN, and MeOH + PrOH + ACN at 298.2 K is reported and mathematically represented using two numerical analyses (based on measured solubility data in 54 ternary mixtures containing the particular solvents in the mass fraction ranges between 0.08 and 0.84). In the first analysis, the solubility is predicted using the Jouyban−Acree model constants for the binary mixtures of the respective solvent pairs that were used to prepare the ternary mixtures. By this approach, the overall mean percentage deviation (OMPD) of the predicted data in ternary solvents is 57 %. The largest OMPD for this model was up to 80 % for a mixture of water, PrOH, and ACN. To improve the model, an additional term (with ternary constants J i ∥) was included, reflecting the combined effect of all three solvents in a mixture. By this numerical analysis, the experimental ternary solubility data is used to calculate the additional ternary constants. After employing the calculated constants, the prediction of the solubility in the ternary mixtures was improved significantly by a factor of 2 with an OMPD of 25 %. As an additional ability of the Jouyban−Acree model, the density of the solute saturated solutions in the solvent mixtures is predicted using three numerical methods; i.e., (i) data of solute saturated solutions in the binary solvent mixtures, (ii) ternary mixtures, and (iii) density data of solute free binary solvent mixtures with predicting errors (OMPD) of 1.2 %, 3.0 %, and 2.8 %, respectively.
Acetanilide (ACN) and phenacetin (PNC) are compounds structurally related with acetaminophen widely used as model drugs in pharmaceutical chemistry. Based on published thermodynamic quantities for dissolution, partitioning and sublimation of ACN and PNC, at 25.0 °C, thermodynamic quantities for drugs solvation in cyclohexane-saturated water (W (CH)) and water-saturated cyclohexane (CH (W)), chloroform-saturated water (W (CLF)) and water-saturated chloroform (CLF (W)), and isopropyl myristatesaturated water (W (IPM)) and water-saturated isopropyl myristate (IPM (W)), as well as the drugs dilution in the organic solvents were calculated. The Gibbs energies of solvation were favourable in all cases. Respective enthalpies and entropies were negative indicating an enthalpy-driving for the solvation process in all cases. Otherwise, the Gibbs energies of dilution were favourable for ACN and PNC in IPM (W) but unfavourable in the other organic solvents, whereas the respective enthalpies and entropies were negative for both drugs in all the organic solvents, except for PNC in CH (W) indicating enthalpy-driving for the dilution process in the former cases and entropy-driving for the later. From obtained values for the transfer From obtained values for the transfer processes, an interpretation based on solute-solute and solute-solvent interactions was developed.
Volumetric Properties of Acetonitrile with 1,2-Alkanediols (C2–C6) at 20°C
Journal of Solution Chemistry, 2001
Dilatometric measurements of excess molar volumes, VE and excess partial molar volumes, \overline V _{\text{i}}^{\text{E}}$$ have been made for binary mixtures of acetonitrile with 1,2-ethanediol, 1,2-propanediol, 1,2-butanediol, 1,2-pentanediol, and 1,2-hexanediol at 20°C over the entire composition range. VE for acetonitrile + 1,2-ethanediol and 1,2-propanediol mixtures are negative over the entire range of mole fractions and positive values are obtained for
Structural characterization of the ternary solvent mixture methanol-acetonitrile-1-propanol
Journal of Physical Organic Chemistry, 2002
Refractive indices and E T values were measured for the ternary mixture methanol-acetonitrile-1propanol at 25.0°C for 13 mole fractions, and also for the corresponding binary mixtures, methanol-1-propanol, methanol-acetonitrile and 1-propanol-acetonitrile, at 25.0 and 50.0°C, at 10 different compositions. Solvent exchange equilibrium models were applied to the transition energy of the Dimroth-Reichardt E T (30) solvatochromic indicator in the binary systems and the Redlich-Kister polynomial was used to correlate excess E T N and n D values for the binary solvent mixtures data. The results allowed the analysis of synergetic behaviours, polarizability effects and preferential solvation trends both in the binary and in the ternary mixtures. Our results point towards the prevalence of specific solute-solvent-solvent interactions mainly due to hydrogen bonding by the hydroxylic components of the ternary mixture.
Solubility of acid gases in chemical and mixed solvents
Gas Separation & Purification, 1991
A mixed solvent containing chemical and physical solvents can be used to remove acid gases from gas streams. The solubility data for mixtures of the acid gases, CO2 and H25, in a mixed solvent at 4O" and 1 OO"C for partial pressures ranging f rom 1 9 to 3669 kPa and 55 to 4240 kPa respectively, have been obtained. The mixed solvent consists of an aqueous solution of a sterically hindered amine, 2-amino-2methyl-1 -propanol (AM P), and a physical solvent, sulfolane. The effect of the presence of one gas on the solubility of the other in the mixed solvent was studied. A mathematical model has been used to correlate the data for the individual gases in the mixed solvent. The model consists of chemical equilibria in the liquid phase, mass balance, electroneutrality, activity coefficient and vapour-liquid equilibrium equations for water. Parameters obtained for the individual gases in the solvent mixture have been used to predict the partial pressures of both CO2 and H2S in the gas mixtures. The predicted and measured values were in good agreement.
Gas chromatography used to calculate the specific retention volume of several hydrocarbons in different chromatographic liquid phases (Squalane, Carbowax-400, Carbowax-1500, Carbowax-4000, Amine-220, Dinonyl phthalate, Tributyl phosphate and Trixylenyl phosphate). Some thermodynamic parameters, such as enthalpy of sorption and Flory-Huggins parameters relating the interaction between liquid phases and solutes, were also calculated from the determined retention volumes. Liquid phase solubility parameters of Squalane, Carbowax-400, Carbowax-1500 and Carbowax-4000 at 80 ºC as well as the polar and apolar components were calculated too. A new model was proposed to correlate polar contribution to the solubility parameter of a liquid phase with the specific retention volume of a solute in this liquid phase.
Fluid Phase Equilibria, 2003
Densities of {(1 − x)CH 3 (CH 2 ) n−1 OH + xCH 3 CN} for n = 1, 2, 3 or 4 have been determined as a function of composition at 288.15, 293.15, 298.15 and 303.15 K at atmospheric pressure using a vibrating-tube densimeter (Anton Paar DMA 4500, resolution 1 × 10 −5 g cm −3 ). Excess molar volumes were calculated. The V E m values were negative for acetonitrile-methanol mixtures and sigmoid for acetonitrile-alkanols (C 2 -C 4 ) mixtures over the complete mole fraction range. V E m values increase in a positive direction with increase in chain length of the alkanols and with the temperature. The Extended Real Associated Solution Model (ERAS-Model) calculations allowing for self-association for the alkanols and complex formation between acetonitrile and alkanols have been used to correlate experimental data. The model is able to reproduce the asymmetrical V E m behavior of the studied systems, although agreement between theoretical and experimental values is less satisfactory for some concentration ranges.