Phase equilibria of (water + butyric acid + butyl acetate) ternary systems at different temperatures

doi:10.1016/j.fluid.2014.07.023

Fluid Phase Equilibria

Volume 379, 15 October 2014, Pages 185-190

https://doi.org/10.1016/j.fluid.2014.07.023 Get rights and content

Abstract

Phase equilibrium (LLE) data of the solubility (binodal) curves and tie-line end compositions were examined for mixtures of {(water (1) + butyric acid + butyl acetate (2)} at T = 298.2 K, 308.2 K, and 318.2 K and 101.3 ± 0.7 kPa. The relative mutual solubility of butyric acid is higher in the butyl acetate than water layers at the all temperatures used in this study. The consistency of the experimental tie-lines was determined through the Othmer–Tobias correlation equation. The LLE data were correlated with UNIQUAC and NRTL model, indicating the reliability of the NRTL and UNIQUAC equations for these ternary systems. The best results were achieved with the UNIQUAC equation for the correlations. Distribution coefficients and separation factors were measured to evaluate the extracting capability of the solvent.

Introduction

Butyric acid is one of the most widely used carboxylic acids which has many applications in pharmaceutical and chemical industries. Recently there is a great interest of using butyric acid as a precursor of biofuels like biobutanol. Biobutanol is a promising biofuel replacement for gasoline in the future. As an industrial solvent biobutanol has a couple of advantages over ethanol. For example butanol provides more energy when burned, and it is less volatile when comparing the ethanol. The best way to produce butanol is making butyric acid from fermented biomass then converting downstream to butanol. Another important biofuels that can be produced from butyric acid are ethyl butyrate and butyl butyrate [1].

Recovery of carboxylic acid from aqueous solutions is generally an important matter for industry because it affects directly the cost of production. Liquid extraction is an alternative way for recovery of butyric acid because of low energy cost.

Researchers still continue on studying different solvents that higher the gain for recovery of butyric acid from aqueous solutions [2], [3], [4], [5], [6], [7], [8], [9], [10], [11], [12], [13], [14], [15], [16], [17], [18].

In our study butyl acetate chosen as a solvent. Butyl acetate is an important solvent for chemical industry and is used in the paint and coatings manufacture for the lacquer industry. Generally it is used in paint and coating manufacture for the lacquer industry. Because it is an environmentally friendly solvent it is a good alternative for liquid extraction [19].

In LLE, if a liquid mixture separated in two phase both phase mole fraction can be calculated from activity coefficients using the following equation: $γ_{i}^{E} x_{i}^{E} = γ_{i}^{R} x_{i}^{R},$ where $x_{i}^{E}$ and $x_{i}^{R}$ mole fraction of component i on extract and raffinate phases. Likewise $γ_{i}^{E}$ and $γ_{i}^{R}$ are the corresponding activity coefficients of component i in extract and raffinate phases. The liquid phase activity coefficient is represented as follows: $\ln γ_{i} = \ln γ_{i} (combinatorial) + \ln γ_{i} (residual)$

The combinatorial and residual parts of the activity coefficient are due to the difference in shape and energy of the molecules, respectively [20].

In this study, the LLE results for the ternary system, (water + butyric acid + butyl acetate) at different temperatures (T = 298.2, 308.2, 318.2 K) were reported. The tie-line data were correlated using the non-random two-liquid (NRTL) and Universal quasi chemical model (UNIQUAC) for which no such data were available.

Section snippets

Materials

Butyric acid, and butyl acetate were purchased from Merck Co. and were of >99%, and >99% (w/w) purities, respectively. The chemicals were used without further purification. Deionised water was further distilled before use. The suppliers and mass fraction of the chemical reagents were given in Table 1.

Apparatus and procedure

Refractive indices were measured with Anton Paar refractometer (RXA 170 model) with stated accuracy of ±5 × 10⁻⁵. Densities have been measured, using a DMA 4500 Anton Paar densimeter. The estimated

LLE measurements

The experimental values for the ternary system at each temperature are listed in Table 3. At the same time, Table 3 presents the compositions of mixtures on the binodal curve, as well as the mutual binary solubilities of water and butyl acetate at T = 298.2 K, 308.2 K and 318.2 K. w_i denotes the mass fraction of the ith component.

Table 4 shows the experimental tie-line compositions of the equilibrium phases, for which w_i1 and w_i3 refer to the mass fractions of the ith component in the aqueous and

Conclusion

The LLE data for the ternary systems of (water + butyric acid + butyl acetate) at T = 298.2 K, T = 308.2 and T = 318.2 K are reported. The UNIQUAC and NRTL models were used to correlate the experimental LLE results and to calculate the phase compositions of the mixtures studied. The UNIQUAC model was satisfactorily used to correlate the experimental data and to calculate the phase compositions of the mixtures studied. The corresponding optimized binary interaction parameters were also calculated. It is

References (25)

H. Ghanadzadeh et al.
Thermochim. Acta
(2011)
M. Bilgin et al.
J. Chem. Thermodyn.
(2005)
Ş.İ. Kırbaşlar et al.
J. Chem. Thermodyn.
(2007)
Ş.İ. Kırbaşlar et al.
J. Chem. Thermodyn.
(2007)
Ş.İ. Kırbaşlar et al.
J. Chem. Thermodyn.
(2007)
Ş.İ. Kırbaşlar et al.
J. Chem. Thermodyn.
(2007)
Ş.İ. Kırbaşlar et al.
J. Chem. Thermodyn.
(2007)
T. Banerjee et al.
Fluid Phase Equilib.
(2005)
M. Dwidar et al.
Sci. World J.
(2012)
G.H. Gilani et al.
J. Chem. Eng. Data
(2014)

H.G. Gilani et al.

J. Chem. Thermodyn.

(2013)

J. Zigová et al.

Sep. Sci. Technol.

(1996)

Cited by (12)

Techno-economic modeling and optimization of catalytic reactive distillation for the esterification reactions in bio-oil upgradation
2019, Chemical Engineering Research and Design
Citation Excerpt :
To understand the economics of the process, capital and operating costs were evaluated by Aspen Economic Analyzer and effects of different parameters on costs were evaluated to design a cost-minimized RD unit. Property analysis and process simulation were performed using Aspen Properties V10 and Aspen Plus V10, respectively (AspenTech, 2017), with UNIQUAC property method to combat the non-ideality and Aspen RADFRAC module to satisfactorily correlate vapor–liquid-equilibrium (VLE) during esterification (Bayazıt et al., 2014; Liu and Tan, 2001). Thermodynamic parameters for all components were present and selected from the Aspen databanks already incorporated in the Aspen PLUS software.
Equilibrium reactive distillation (RD) process simulation and economic evaluation were carried out for the esterification of complex mixtures of several fatty acids and water (representative of crude bio-oils) with n-butanol using Aspen PLUS process simulator and economic analyzer. Complete design and optimization were carried out using evolutionary techniques from simplest system to the most rigorous one with introduction of intermittent progressive complexity. Prior to distillation design, esterification reaction kinetics and binary/ternary interactions were analyzed using Aspen RGibbs reactor module and Property PLUS, respectively. Simple distillation column was designed and optimized to obtain the initial trial parameters to be used in RD simulation. UNIQUAC is used as base property method and reaction equilibria estimated by minimization of Gibbs free energy. Near atmospheric column pressure, reflux ratio of 0.95, distillate to feed ratio of 0.505 and total 18 stages were found to be optimum based on attainable reaction conversion, ester separation, heat duties, and capital and operating costs. The effects of n-butanol:acid feeding ratio and water percent in bio-oil and their relationship were also analyzed to predict n-butanol requirement. The results of this study, including the optimized parameters, could serve as design platforms for pyrolysis bio-oil upgradation to transportation fuels.
Liquid-liquid equilibria for (volatile fatty acids + water + alcohol ethoxylates): Experimental measurement of pseudo-ternary systems
2019, Journal of Chemical Thermodynamics
Citation Excerpt :
Although it is not the main requirement for an effective extraction, higher values of D1 are desired to minimize the amount of solvent needed for extraction [32]. The effectiveness of VFA extraction by N23E2 can also be evaluated by the selectivity or separation factor, S, which is an indication of the ability of the surfactant to separate VFA from water [33]. For all the ternary systems studied, separation factors were found to be greater than 1, suggesting that separation is possible.
Experiments were conducted to establish the phase diagrams for ternary systems containing (acetic acid or propionic acid or butyric acid + water + alcohol ethoxylate surfactant) at 308.15 K and ambient pressure. Results indicated that the systems belong to Type 1 Treybal classification with water–surfactant binary pair exhibiting partial miscibility. The liquid–liquid equilibrium data were used to determine the ability of the surfactant to extract the acids from aqueous solutions. The calculated distribution coefficients and separation factors indicated that the effectiveness of the surfactant to extract acids follow the trend: butyric acid > propionic acid > acetic acid. The effectiveness of the surfactant to extract butyric acid from aqueous solutions is similar to previously studied environmentally-friendly solvents with added benefit of being non-inhibitory to microbial growth and metabolism. These characteristics of the alcohol ethoxylate used in this study could be exploited for the development of an extractive butyric acid fermentation process.
Ternary liquid–liquid equilibrium of an azeotropic mixture (hexane + methanol) with different imidazolium-based ionic liquids at T = 298.15 K and 101.325 kPa
2018, Fluid Phase Equilibria
Citation Excerpt :
Due to the close boiling point and formation of azeotropes, ordinary distillation encounters difficulty in separating the mixtures. Liquid-liquid extraction is an effective method for the separation of azeotropes [9] and is an energy-saving process [10]. Liquid–liquid equilibrium (LLE) data of ternary systems are the primary consideration for the design of a separation process [11], in which a large number of LLE data are required for the separation of alcohol from its mixture.
The recovery and purification of methanol from its mixtures is of great importance; to this end, liquid-liquid extraction is an effective method for the separation of azeotropes. In this work, three imidazolium-based ionic liquids were used to separate a hexane-methanol azeotropic mixture, and the ternary liquid-liquid equilibria (LLE) data for the systems of hexane + methanol + [MIM][HSO₄] (1-methylmidazole hydrogen sulfate), [BMIM][HSO₄] (1-Butyl-3-methylimidazolium hydrogen sulfate), [BMIM][OTf] (1-Butyl-3-methylimidazolium trifluoromethansulfonate) were measured at 298.15 K and atmospheric pressure. The separation factor and distribution coefficient were calculated from the experimental LLE data to evaluate the separation performance. The influence of the anions and mono-/di-substituted hydrocarbon chains on the imidazolium cation ring of the LLE was investigated. The experimental LLE data were successfully correlated by non-random two liquid (NRTL) and universal quasi-chemical (UNIQUAC) models, and the binary interaction parameters were obtained.
Phase equilibria of (water+propionic acid or butyric acid+2-methoxy-2-methylpropane) ternary systems at 298.2K and 323.2K
2015, Fluid Phase Equilibria
Citation Excerpt :
Table 4 lists these distribution coefficients and separation factor for propionic acid and butyric acid at different temperatures, indicating 2-methoxy-2-methylpropane is an excellent solvent to extract propionic acid and butyric acid, especially for butyric acid. Other solvents’ distribution coefficients are usually lower than 2-methoxy-2-methylpropane [3,16,17,21]. Methyl butyl ketone, methyl isopropyl ketone [22] and cyclohexanone’s [23] distribution coefficients are slightly higher, but their boiling points are much higher, which may lead to difficulties in recovery.
In this work, Liquid–liquid equilibrium (LLE) data for ternary system, (water + propionic acid + 2-methoxy-2-methylpropane) and (water + butyric acid + 2-methoxy-2-methylpropane), were experimentally measured at atmospheric pressure and temperatures of 298.2 K and 323.2 K. The reliability of the experimental tie-line data was verified by the Othmer–Tobias and Hand equations. Distribution coefficients and separation factor values were evaluated for the immiscibility region. The consistency of experimental tie-line data was confirmed by the NRTL and UNIQUAC models. Both models describe the phase behavior of the studied systems accurately with very small average deviations.
Liquid-Liquid Equilibrium Study of the Ternary Systems (Water + Propionic or Butyric Acids + Kerosene) at T = (293.2, 303.2, and 313.2) K and Ambient Pressure
2023, Journal of Chemical and Engineering Data
Phase equilibria modeling of biorefinery-related systems: A systematic review
2022, Chemical Product and Process Modeling

View all citing articles on Scopus

View full text

Phase equilibria of (water + butyric acid + butyl acetate) ternary systems at different temperatures

Abstract

Introduction

Section snippets

Materials

Apparatus and procedure

LLE measurements

Conclusion

Thermochim. Acta

J. Chem. Thermodyn.

J. Chem. Thermodyn.

J. Chem. Thermodyn.

J. Chem. Thermodyn.

J. Chem. Thermodyn.

J. Chem. Thermodyn.

Fluid Phase Equilib.

Sci. World J.

J. Chem. Eng. Data

J. Chem. Thermodyn.

Sep. Sci. Technol.