Solid-Liquid Equilibrium in the Systems with an Ionic Liquid

2008 ◽  
Vol 73 (5) ◽  
pp. 657-664 ◽  
Author(s):  
Zuzana Sedláková ◽  
Hélène Sauton ◽  
Vladimír Hynek ◽  
Ivona Malijevská

An active interest in ionic liquids has grown over the last years. This relatively new class of solvents appears to be potentially useful as a "greener" alternative to volatile organic compounds. This work was aimed at studying the effect of addition of the ionic liquid 1-butyl-3-methylimidazolium chloride to two systems (acetic acid (1)-formamide (2) and propionic acid (1)-formamide (2)) on formation of a compound in the solid phase. In previous work, the presence of a solid compound with a formula (CH3COOH)2·HCONH2 was investigated in the binary system acetic acid (1)-formamide (2) and a stable solid compound with a different formula CH3CH2COOH·(HCONH2)2 was found in the binary system propionic acid (1)-formamide (2). In both cases the compound formation is attributed to a strong cross-association (O···H···N). Solid-liquid equilibrium of the systems measured in this work was determined from time-temperature warming curves. In both measured ternary systems with a small addition of the ionic liquid 1-butyl-3-methylimidazolium chloride (i.e. the systems acetic acid (1)-formamide (2)-1-butyl-3-methylimidazolium chloride (3) and propionic acid (1)-formamide (2)-1-butyl-3-methylimidazolium chloride (3)) the above mentioned stable solid compounds are formed and the corresponding melting temperature of these compounds decreased. Dissociation parameters were modelled thermodynamically for solid adducts.

2015 ◽  
Vol 87 (5) ◽  
pp. 453-460 ◽  
Author(s):  
Jan Rotrekl ◽  
Pavel Vrbka ◽  
Zuzana Sedláková ◽  
Zdeněk Wagner ◽  
Johan Jacquemin ◽  
...  

AbstractIn the present work, the solid–liquid–liquid equilibrium in the binary system of diethylamine (1) and ionic liquid (2) 1-methyl-3-ethylimidazolium bis(trifluoromethylsulfonyl)imide and solid–liquid equilibrium in system 1-methyl-3-butylimidazolium bis(trifluoromethylsulfonyl)imide was studied. Phase equilibrium was determined experimentally by means of a polythermic method. These data were then used to determine the activity coefficients for both ionic liquids. For the pure diethylamine the enthalpy of fusion was determined by differential scanning calorimetry, because to the best of our knowledge, this data is not yet reported in the open literature, a contrario of pure ionic liquids tested during this work.


2020 ◽  
Vol 10 (3) ◽  
pp. 149-156
Author(s):  
Nuvaid Ahad ◽  
Arno de Klerk

Abstract About half of the product from iron-based high-temperature Fischer–Tropsch synthesis is an aqueous product containing dissolved oxygenates. Volatile oxygenates can be recovered by distillation, but the bulk of the carboxylic acids remain in the water, which is called acid water. Fractional freezing was explored as a process for producing a more concentrated carboxylic acid solution from which the carboxylic acids could be recovered as petrochemical products, while concomitantly producing a cleaner wastewater. Solid–liquid equilibrium data were collected for aqueous solutions of acetic acid, propionic acid, and butyric acid. A synthetic Fischer–Tropsch acid water mixture (0.70 wt% acetic acid, 0.15 wt% propionic acid, and 0.15 wt% butyric acid) was prepared and the liquid phase concentrations of the acid species at solid–liquid equilibrium were determined. Control experiments with material balance closure on each of the carboxylic acid species were performed at selected conditions. Having more than one carboxylic acid species present in the mixture meaningfully changed the solid–liquid equilibrium versus temperature of the system. The carboxylic acids partitioned between the solid phase and the liquid phase and a practical design would require multiple duty-controlled solid–liquid equilibrium stages, with most of the separation taking place in the temperature range 0 to − 5 °C.


1989 ◽  
Vol 54 (11) ◽  
pp. 2840-2847 ◽  
Author(s):  
Ivona Malijevská ◽  
Alena Maštalková ◽  
Marie Sýsová

Isobaric equilibrium data (P = 101.3 kPa) for the system cyclohexane-acetic acid-propionic acid have been measured by two different analytical techniques. Activity coefficients calculated by simultaneous solving of equations for the chemical and phase equilibria were subjected to a consistency test based on inaccuracies determined from the error propagation law, and were correlated by Wilson’s equation. The activity coefficients measured were compared with those calculated from binary vapour-liquid equilibrium data and with values predicted by the UNIFAC method.


2021 ◽  
Vol 530 ◽  
pp. 112874
Author(s):  
María Dolores Robustillo ◽  
Larissa Castello Branco Almeida Bessa ◽  
Pedro de Alcântara Pessôa Filho

Author(s):  
Ernesto A Martínez ◽  
Marco Giulietti ◽  
Mauricio Uematsu ◽  
Silas Derenzo ◽  
João B Almeida e Silva

This work deals with the study of thermodynamical models for the solid-liquid equilibrium (SLE) and comparing its performance with experimental data. The xylose solubility in the xylose-water and xylose-water-ethanol systems has been measured using a variant of the isothermal method. A total of 12 experiments were performed in a 100 mL glass jacketed crystallizer with helix-type agitator by changing the temperature from 0 to 60°C. The solution was mixed during 72 h with an IKA Labortechnic, RW 20.n agitator at 450 rpm. Later, the experimental and reported results were fitted using the prediction models based on the vapor-liquid-equilibrium (UNIFAC (Universal Functional Activity Coefficient), ASOG (Analytical Solutions of Groups) and GSP (Group Solubility Parameter); semi-empirical models based on the vapor-liquid-equilibrium (VLE) (UNIQUAC (Universal Quasi Chemical), Wilson and NRTL (Non Randon Two Liquid)) on the solid-liquid-equilibrium, and empirical model with fitted parameters (Nývlt, λh, Margules with 1 and 2 parameters). The results showed that the UNIQUAC model with fitted parameters can describe the SLE with reasonable accuracy (1.28 and 3.36% for binary and ternary systems, respectively). The average deviation was the arithmetic mean of the deviations. On the other hand, the other methods resulted in poor agreement with the system’s behavior presenting systematic deviations from the experimental data.


Sign in / Sign up

Export Citation Format

Share Document