Homogeneity of the water+ethanol+toluene azeotrope at 101.3kPa

Abstract

7An all-glass, dynamic recirculating still equipped with an ultrasonic homogenizer has been used in the determination of the vapour-liquid equilibrium (VLE) and vapour-liquid-liquid equilibrium (VLLE). Consistent data for the ternary water + ethanol + toluene system are reported at 101.3 kPa at temperatures in the range of 347-357 K. These data have been compared with previously published VLLE data. The experimental data indicates that a ternary azeotrope is present at 347.60 K. It has been determined experimentally that the ternary azeotrope is homogeneous and not heterogeneous as is claimed in some of the studied references. The experimental results have been used to check the accuracy of the UNIFAC, UNIQUAC and NRTL models, proving that these models predict a bigger heterogeneous region than the experimental one.

Spectroscopic characterisation of hydroxyapatite and nanocrystalline apatite with grafted aminopropyltriethoxysilane: nature of silane–surface interaction

“…The spectroscopic data show a decrease of water content and hydrogen bonding for all blank samples relative to the initial powders. Indeed, toluene is widely used as a carrier for the dehydration of alcohol by azeotropic distillation [33] and thus could extract water from the apatitic samples. This behavior favors the formation of a silane layer by covalent grafting instead of polycondensation.…”

“…Moreover, for the HAP0 and NCA0 samples, a strong decrease of the intensity of vibration bands attributed to the carbonate species was observed relative to the HAP and NCA samples, probably attributable to the increase of the apatitic environment [18]. At the same time, the decrease of the free water vibration bands could be attributed either to the effect of the temperature or to the influence of toluene, which is known to make an azeotrope with water [33]. For all blank samples, a significant narrowing of the OH -vibration bands at 630 and 3560 cm -1 (or appearance in the case of NCA0) was observed and attributed to OH group formation by drying.…”

Vapor–Liquid–Liquid Equilibria Measurements for the Dehydration of Ethanol, Isopropanol, and n-Propanol via Azeotropic Distillation Using DIPE and Isooctane as Entrainers

“…1 Generally the models predict larger heterogeneous regions than experimentally observed, and for example for the water/toluene/ethanol system, the models may even predict a heterogeneous azeotrope where the azeotrope is in fact homogeneous or not present at all. 6 Such insufficient predictive behavior of these models may lead to erroneous simulations of the processes, 6 and even small deviations of a model from the experimental measurements could lead to significant deviations between simulation and reality. 6 It follows that accurate and reliable vapor−liquid−liquid (VLLE) equilibria data are required to further develop thermodynamic models and simulate heterogeneous azeotropic processes.…”

Separation of the Mixture 2-Propanol + Water by Heterogeneous Azeotropic Distillation with Isooctane as an Entrainer

“…It is also important to highlight that the use of isooctane as an entrainer can be extremely beneficial in the case of 2-propanol dehydration: traces of such an entrainer do not pose a problem within the recovered dehydrated alcoholic product with a view to its subsequent use as a fuel. [27] New simulation method for three-phase distillation using a modified phase-stability analysis Luyben [24] Process simulation Pienaar [30] Process simulation cyclohexane Gomis et al [45] VLE and VLLE data toluene Gomis et al [62] VLE and VLLE data Zhao et al [31] Process simulation isooctane or 2,2,4-trimethylpentane Cairns and Furzer [27] New simulation method for three-phase distillation using a modified phase-stability analysis Font et al [28] VLE and VLLE data Simulation method 1 Wang et al [26] Experiment using a laboratory-scale sieve plate distillation column; dynamic simulation Chien et al [21] Dynamics and control of a HAD column…”