The study of activity coefficients at infinite dilution for organic solutes and water in 1-butyl-4-methylpyridinium dicyanamide, [B4MPy][DCA] using GLC

doi:10.1016/j.jct.2013.09.007

The Journal of Chemical Thermodynamics

Volume 68, January 2014, Pages 138-144

https://doi.org/10.1016/j.jct.2013.09.007 Get rights and content

Highlights

•
The $γ_{13}^{\infty}$ for organic solutes and water in [B⁴MPy][DCA] have been determined.
•
The basic thermodynamic functions were determined.
•
Selectivity for heptane/thiophene, or heptane/nitropropane separation process was calculated.

Abstract

The main aim of this paper is to investigate the possibility of using ionic liquid as a solvent for the separation processes, especially for extraction of azeotropic mixtures i.e. aliphatic from aromatic hydrocarbons. The first step in assessing the ability of selective extraction is to determine the selectivity based on measurements of activity coefficients at infinite dilution. In this work new data of the activity coefficients at infinite dilution for 53 solutes including: alkanes, alk-1-enes, alk-1-ynes, cycloalkanes, aromatic hydrocarbons, alcohols, thiophene, ethers, ketones, acetonitrile, pyridine, 1-nitropropane and water in the ionic liquid: 1-butyl-4-methylpyridinium dicyanamide, [B⁴MPy][DCA] were determined using GLC technique at wide temperature range from (308.15 to 368.15) K. From the temperature dependence of $γ_{13}^{\infty}$ the partial molar excess Gibbs free energies, $Δ G_{1}^{E, \infty}$ , enthalpies $Δ H_{1}^{E, \infty}$ and entropies $T_{ref} Δ S_{1}^{E, \infty}$ at infinite dilution were calculated. Additionally the (gas + liquid) partition coefficients, K_L were determined. The selectivities for the many separation problems were calculated and compared to the values from the recent literature for other ionic liquids. The densities of pure ionic liquid were determined over a wide temperature range from (308.15 to 368.15) K.

Introduction

During the past decade, ionic liquids (ILs) have gained tremendous attention in separation processes. As solvents with low vapour pressure, IL can be an alternative for conventional volatile organic compounds (VOCs) [1], [2]. For exploration and design of such applications, the knowledge of interaction of IL with common organic compounds is required. The measurements of the activity coefficients at infinite dilution by inverse (gas + liquid) chromatography provides an especially convenient and widely accepted technique. Activity coefficients at infinite dilution, $γ_{13}^{\infty}$ are an important parameters, which provide an information about the intermolecular energy between solvent and solute and are used particularly for the selection of solvents for (liquid + liquid) extraction, extractive distillation and separation of the azeotropic mixtures [3], [4]. Since ILs have a negligible vapour pressure, (gas + liquid) chromatography (GLC) is a suitable method for measuring the activity coefficients at infinite dilution. From a technological point of view the most important factors are the selectivity and capacity, that can be calculated directly from experimental values of $γ_{13}^{\infty}$ . Apart from that, from GLC technique it is possible to determine the basic thermodynamic functions at infinite dilution such as: partial molar excess Gibbs free energy, enthalpy and entropy and (gas + liquid) partition coefficients. In this work, which is a continuation of our systematic investigation on the measurements of activity coefficients at infinite dilution [5], [6], [7], [8], [9], [10], the ionic liquid: 1-butyl-4-methylpyridinium dicyanamide, [B⁴MPy][DCA] was considered for possible use in extraction of aliphatic from aromatic hydrocarbons, denitrification or desulphurisation of fuels. The experimental results for the tested ionic liquid have been compared to literature values for ionic liquids based on pyridinium cation [5], [6], [7], [8], [4], [11] and sulfolane [12], which is commonly use in the real technological process on the industrial scale.

Section snippets

Materials

The ionic liquid used in this work, 1-butyl-4-methylpyridinium dicyanamide, [B⁴MPy][DCA] had a purity of >0.970 mass fraction and was supplied by Io-li-tec. The volatile chemicals and water were reduced to negligible values by subjecting ionic liquid to a pressure about 5 ⋅ 10⁻³ Pa at a temperature about 353 K for 24 h. The basic thermophysical properties that is: glass transition temperature, (T_g,1) heat capacity at glass transition temperature, (ΔC_p(g),1) temperature, (T_fus) and enthalpy of

Result and discussion

The activity coefficients at infinite dilution, determined for 53 organic solutes and water in ionic liquid [B⁴MPy][DCA] at T = (308.15, 318.15, 328.15, 338.15, 348.15, 358.15 and 368.15) K by inverse gas chromatography are presented in table 2. FIGURE 1, FIGURE 2, FIGURE 3, FIGURE 4, FIGURE 5, FIGURE 6 show the natural logarithm of the experimental activity coefficients at infinite dilution as a function of the inverse absolute temperature for all investigated solutes in [B⁴MPy][DCA].

It can be

Conclusions

In this paper, activity coefficients at infinite dilution for organic solvents and water in 1-butyl-4-methylpyridinium dicyanamide, [B⁴MPy][DCA] were determined at wide temperature range from (308.15 to 368.15) K. High values of selectivity for the tested separation processes were found. It was found that the tested ionic liquid shows lower selectivity than [B⁴MPy][SCN] but much higher than other pyridinium-based ionic liquids with [NTf₂], [BF₄], or [CF₃SO₃] anions.

Acknowledgments

Funding for this research was provided by the National Science Centre in years 2011–2014 (Grant No. 2011/01/B/ST5/00800). Author Marek Królikowski would like to thank START Program of the Foundation for Polish Science.

References (14)

A.B. Pereiro et al.
J. Chem. Thermodyn.
(2012)
U. Domańska et al.
J. Chem. Thermodyn.
(2009)
M. Królikowska et al.
J. Chem. Thermodyn.
(2013)
A. Marciniak
J. Chem. Thermodyn.
(2011)
M. Królikowska et al.
Fluid Phase Equilib.
(2013)
U. Domańska et al.
J. Chem. Thermodyn.
(2008)
M. Seiler et al.
AIChE J.
(2004)

There are more references available in the full text version of this article.

Cited by (42)

Ionic liquid screening for desulfurization of coke oven gas based on COSMO-SAC model and process simulation
2021, Chemical Engineering Research and Design
1305 ionic liquids (ILs) involving 45 cations and 29 anions were computationally screened to search the optimal solvents for deep desulfurization of coke oven gas (COG) based on the combination of the COSMO-SAC model and process simulations. Firstly, the molecular structures, including those of independent ions and solutes, were constructed and geometrically optimized using density functional theory (DFT) calculation with the VWN-BP functional of generalized gradient approximation (GGA) and DNP basis set (v4.0) in DMol3 software. The σ-profiles of ion pairs for COSMO-SAC model were calculated through summation of σ-profiles of cations and anions. Secondly, Henry’s constant of various gas solutes such as H₂S, COS, TS, CH₄ in each ion pair was estimated by COSMO-SAC model. In order to balance the trade-off between the solubility and selectivity of various sulfides in ionic liquids, the mass-based Absorption-Selectivity-Desorption index (ASDI) combined with physical properties was employed as the evaluation metrics. Four ILs with high values of ASDI and appropriate melting point and viscosity were screened out for further process simulation. Finally, sensitivity analysis and central composite experimental design were performed to optimize the input parameters of process simulations on COG desulfurization, while total annual cost and specific energy consumption of the desulfurization processes were used to evaluate the economic and energy efficiency of various ILs. It is indicated that [C1mpyr][Oac] exhibits the high total sulfur removal ratio of 99.05% and the CH₄ recovery ratio of 94.65%. In addition, its specific energy consumption and total annual cost were 5 kWh/kg Sulfides and $9 million/year, respectively. In short, we proposed the combined COSMO-SAC and process simulation method that provide a comprehensive perspective of large-scale IL design for COG or similar gas mixture desulfurization.
The investigation of the infinite dilution activity coefficients for molecular compounds in 1-(3-hydroxypropyl)-3-methyl-imidazolium thiocyanate
2021, Journal of Chemical Thermodynamics
Measurements of infinite dilution activity coefficients of 46 organic solutes including alkanes, alkenes, alkynes, aromatic hydrocarbons, alcohols, ethers, ketones, pyridine, thiophene, acetonitrile, and 1-nitropropane in ionic liquids (IL), 1-(3-hydroxypropyl)-3-methyl-imidazolium thiocyanate (abbreviated as [C₁C_3OHIM][SCN]) are reported in the temperature range from T = (318.15 to 358.15) K. Based on the experimental data, the infinite dilution capacity and selectivity of the studied IL are presented to evaluate the effectiveness of using it as an extractant in the separation of aliphatic from aromatic hydrocarbons and sulfur compounds from alkanes. Obtained selectivity and capacity values for different separation processes are compared with the literature data for other ionic liquids. From the temperature – dependence of the infinite dilution activity coefficient, the partial molar excess Gibbs energy, $Δ G_{1}^{E, \infty}$ , enthalpy $Δ H_{1}^{E, \infty}$ and entropy term $T_{r e f} Δ S_{1}^{E, \infty}$ at infinite dilution were calculated and discussed.
trends in solvent impact on infinite dilution activity coefficients of solutes reviewed and visualized using an algorithm to support selection of solvents for greener fluid separations
2021, Separation and Purification Technology
The infinite dilution activity coefficient, ${γ_{i}}_{}^{\infty}$ , is a frequently used molecular descriptor to pre-select a solvent for various kinds of fluid separations. Unfortunately, information related to these coefficients is scattered through-out the open literature. Therefore, an open-source ${γ_{i}}_{}^{\infty}$ -database containing 77.173 $γ_{i}^{\infty}$ data points over the temperature interval 243 K < T < 555.6 K for 268 solutes and 692 solvents is provided in the electronic supporting information of this work. Additionally, we performed an inter- and extrapolation data analysis algorithm using the Van ‘t Hoff equation to extend the $γ_{i}^{\infty}$ data points at 298.15 K. The ${γ_{i}}_{}^{\infty}$ for five solutes (n-hexane, benzene, chloroform, acetone and ethanol) in a wide range of molecular solvents and ionic liquids (ILs) were compared. Various trends between the molecular solvent structure and the ${γ_{i}}_{}^{\infty}$ are visualized, which allows for not only a pre-selection of solvents for targeted ${γ_{i}}_{}^{\infty}$ but also visualizes the effect molecular modification of the solvent will have on the ${γ_{i}}_{}^{\infty}$ . Overall, the presented methodology is complementary to approaches using simulation software, and helps acquiring a detailed understanding of the effect of the solvent structure on the ${γ_{i}}_{}^{\infty}$ , which will facilitate solvent pre-selection in an early process design stage towards greener fluid separations.
Determination of physicochemical properties of ionic liquids by gas chromatography
2021, Journal of Chromatography A
Over the years room temperature ionic liquids have gained attention as solvents with favorable environmental and technical features. Both chromatographic and conventional methods afford suitable tools for the study of their physicochemical properties. Use of gas chromatography compared to conventional methods for the measurement of physicochemical properties of ionic liquids have several advantages; very low sample concentrations, high accuracy, faster measurements, use of wider temperature range and the possibility to determine physicochemical properties of impure samples. Also, general purpose gas chromatography instruments are widely available in most laboratories thus alleviating the need to purchase more specific instruments for less common physiochemical measurements. Some of the main types of physicochemical properties of ionic liquids accessible using gas chromatography include gas-liquid partition constants, infinite dilution activity coefficients, partial molar quantities, solubility parameters, system constants of the solvation parameter model, thermal stability, transport properties, and catalytic and other surface properties.
Application of dicyanamide-based ionic liquid in separation of binary mixtures based on gamma infinity data measurements
2020, Journal of Molecular Liquids
Citation Excerpt :
Moreover, from comparison with the available literature data, the influence of the cation structure in the IL is also investigated. The comparison with previously-published data for the [DCA]-based ILs is presented to show the ability of a new solvents in the discussed separation processes of sulfur and nitrogen compounds from fuels, especially in the separation of the three chosen problems: heptane/thiophene, heptane/pyridine and heptane/1-nitropropane [18,61–74]. The linear free energy relationship (LFER) system constants as a function of temperature were determined from obtained values of KL.
In this research, the activity coefficients (γ₁₃^∞) at infinite dilution of 61 solutes were experimentally determined in the 1-(4-methoxy-4-oxobutyl)-3-methylimidazolium dicyanamide, [(C₃COOMe)MIM][DCA]. The data were obtained using the gas-liquid chromatography technique (GLC). The experiment was carried out at a wide temperature range of (318.15 to 368.15) K, in 10 K intervals. The studied solutes included polar and non-polar compounds, as alkanes, alkenes, and alkynes, as well as aromatic hydrocarbons, alcohols, water, ethers, ketones, acetonitrile, pyridine, 1-nitropropane, thiophene, and esters. Density, ρ, measurements for a range of temperatures (298.15–368.15) K, in 10 K intervals, for the chosen ionic liquid (IL) were undertaken at pressure, p = 101 kPa. Values of the gas-liquid partition coefficients, K_L at infinite dilution, as well as the basic thermodynamic functions, such as partial molar excess Gibbs energy, enthalpy and entropy at infinite dilution were calculated from the experimental data measurements. The values of selectivity and capacity for the three chosen separation problems as heptane/thiophene, heptane/pyridine and heptane/1-nitropropane were calculated from γ₁₃^∞ values and compared to literature data for dicyanamide-based, ILs. The results from the study indicate that [(C₃COOMe)MIM][DCA] has attractive capacity for all of the studied separation cases. These measurements allow to verify the possibility of use of investigated ionic liquid as an entrainer in liquid-liquid extraction.
Evaluation of an imidazolium-based ionic liquid as a separation solvent for binary mixtures based on limiting activity coefficient data
2020, South African Journal of Chemical Engineering
The separation of volatile organic solvents (herewith, solutes) were tested in an imidazolium-based ionic liquid (1,3-dimethylimidazolium dimethylphosphate), [MMIM] [DMP] as a solvent at four different temperatures, T = (313 .15 to 343.15) K and at atmospheric pressure. The solutes include alcohols, aromatic hydrocarbons, thiophene, ketones, alkanes, alkynes, alkenes, acetonitrile, THF, as well as water. The separation potential of the investigated ionic liquid was based on the activity coefficients at infinite dilution, $γ_{13}^{\infty}$ , of organic solutes. This was based on the retention data acquired by gas liquid chromatography. Excess thermodynamic parameters at infinite dilution such as Gibbs free energy, $Δ G_{1}^{E, \infty}$ , entropy term, T_ref $Δ S_{1}^{E, \infty}$ and partial molar enthalpy, $Δ H_{1}^{E, \infty}$ were determined from the $γ_{13}^{\infty}$ data. The results are discussed in terms of intermolecular interactions occurring between the solutes under investigation and the ionic liquid. The effectiveness of 1,3-dimethylimidazolium dimethylphosphate to separate some of the separation problems discussed in this work is determined from the selectivity and capacity values calculated from the limiting activity coefficients at infinite dilution. These thermodynamic functions can be used to develop, design or optimise industrial extraction processes.

View all citing articles on Scopus

View full text

The study of activity coefficients at infinite dilution for organic solutes and water in 1-butyl-4-methylpyridinium dicyanamide, [B4MPy][DCA] using GLC

Highlights

Abstract

Introduction

Section snippets

Materials

Result and discussion

Conclusions

Acknowledgments

J. Chem. Thermodyn.

J. Chem. Thermodyn.

J. Chem. Thermodyn.

J. Chem. Thermodyn.

Fluid Phase Equilib.

J. Chem. Thermodyn.

AIChE J.

The study of activity coefficients at infinite dilution for organic solutes and water in 1-butyl-4-methylpyridinium dicyanamide, [B⁴MPy][DCA] using GLC