Aminoethers of boric acid, which are organoboron ionic liquids, were synthesized by using boric acid, triethanolamine, and triethylene glycol/diethylene glycol. Due to the formation of intermolecular complexes of borates, the structure of aminoethers of boric acid contains ion pairs separated in space, giving these compounds the properties inherent to ionic liquids. It is established that the thermal stability of aminoethers under normal atmospheric conditions increases with an increase in the size of the glycol. According to measurements of fast scanning calorimetry, density, dynamic viscosity, and electrical conductivity, water is involved in the structural organization of aminoethers of boric acid. The impact of the most thermostable organoboron ionic liquids on the phase equilibrium conditions of the vapor–liquid azeotropic ethanol–water mixture is studied. It is shown that the presence of these substances leads to increase in the relative volatility of ethanol. In general, the magnitude of this effect is at the level shown by imidazole ionic liquids, which provide high selectivity in the separation of aqueous alcohol solutions. A large separation factor, high resistance to thermal oxidative degradation processes, accompanied by low cost start reagents, make aminoethers of boric acid on the basis of triethylene glycol a potentially effective extractant for the extractive distillation of water–alcohol mixtures.

Aminoethers of boric acid (AEBA) were studied as potential extractants for the separation of aqueous–alcoholic azeotropic mixtures by extractive distillation. The conditions of vapor–liquid equilibrium in aqueous solutions of ethanol and isopropanol in the presence of AEBA were studied. The division of AEBA molecules into group components was proposed, and previously unknown geometric parameters of the boron group and the energetic pair parameters of the boron group with the alkane group, ether group, amine-3d group, and alcohol group were determined within the framework of the Universal Functional Group Activity Coefficient (UNIFAC) model. The modeling of the extractive rectification process of an ethanol–water mixture with AEBA as extractant has been carried out. The dependences of the cost function on the extractant flow rate, the residual water content in it and the number of theoretical trays were obtained. A technological scheme for ethanol dehydration has been proposed, and its technological characteristics have been calculated.

The effect of amino esters of boric acid (AEBA) on the conditions of vapor–liquid equilibrium in binary mixtures of acetonitrile–water, ethanol–acetonitrile and a three-component mixture of ethanol-acetonitrile-water was investigated. Residual curves and vapor–liquid phase equilibrium conditions (TPXY data) were experimentally measured at atmospheric pressure for a binary mixture of acetonitrile-AEBA and a triple mixture of acetonitrile-water-AEBA. Previously unknown energy binary parameters of groups B, CH₂N with group CH₃CN were determined for the UNIFAC model. The correction of the value of the binary parameter water—acetonitrile was carried out. On the basis of thermodynamic modeling, the degree of influence of AEBA on the relative volatility of acetonitrile in binary and ternary mixtures was analyzed. It is shown that the use of AEBA removes all azeotropic points in the studied mixtures. In this case, acetonitrile turns out to be a volatile component, and water is a non-volatile component in the entire concentration range.

Objectives. To study the effect of a deep eutectic solvent (DES) based on glucose and citric acid on the vapor–liquid equilibrium of an aqueous solution of ethanol.Methods. A qualitative and quantitative analysis of the conditions of vapor–liquid equilibrium in an ethanol–water–DES ternary mixture was performed based on the open evaporation method and the measurement of TPxy data using a Świętosławski ebulliometer. Since the volatility of the DES is negligible in comparison with that of water and ethanol, the composition of the vapor phase was measured by means of Karl Fischer titration. The conditions of vapor–liquid phase equilibrium were modeled using the UNIFAC model.Results. The open evaporation method was used to determine the curves of residual concentrations for the ethanol–water–DES mixture at various DES concentrations and compositions (glucose–citric acid ratios). TPxy data was obtained for the mixture produced by adding 30 wt % DES to an aqueous solution of ethanol at atmospheric pressure. Studies show that DES based on glucose and citric acid has a significant effect on the relative volatility of ethanol in aqueous solution, leading to the disappearance of the azeotropic point. This effect is due to only the presence of glucose. Citric acid does not change the composition of the equilibrium phases, but rather increases the solubility of glucose in aqueous ethanol solutions. This is especially important at high ethanol concentrations, since glucose is poorly soluble in ethanol.Conclusions. Addition of DES based on glucose and citric acid to an aqueous solution of ethanol leads to the disappearance of the azeotropic point. DES can thus be considered as a promising entrainer for extracting ethanol from aqueous solutions using extractive distillation. Modeling of the conditions of vapor–liquid equilibrium in the ethanol–water–DES system using the UNIFAC model showed a satisfactory level of accuracy. The error in the calculated data increases with increasing the glucose concentration, while remaining acceptable for practical use.

Amino ethers of ortho-phosphoric acid prepared using triethanolamine; ortho-phosphoric acid; polyoxyethylene glycol, diethylene glycol, triethylene glycol and glycerol (AEPA-DEG/TEG/Gl) were investigated as extractants for the separation of aqueous ethanol solutions by extractive distillation. Using the method of open evaporation, the influence of the molecular structure of AEPA-DEG/TEG/Gl on the conditions of vapor–liquid equilibrium in ethanol–water solutions was studied. It has been shown that the addition of AEPA-DEG/TEG/Gl removes the azeotropic point. At the same time, the observed effect turned out to be significantly higher in comparison with the use of pure glycerol or glycols for these purposes. The UNIFAC model was used to calculate the activity coefficients in a three-component ethanol–water–AEPA-DEG/TEG/Gl mixture. Within the framework of this model, a division of AEPA-DEG/TEG/Gl molecules into group components is proposed. Previously unknown parameters of the groups PO–CH, PO–CH₂, PO–OCH₂, PO–NHCH₂, PO–OH, and PO–H₂O were determined from our own and published experimental data. The concentration dependences of the density and dynamic viscosity of AEPA-Gl aqueous solutions have been experimentally measured. Experimental studies of the extractive distillation of ethanol–water using AEPA-Gl as an extractant have been carried out in a column with bubble cap plates and a packing, and its high efficiency has been established.