Liquid extraction of thiophene from n-paraffins (C 8 , C 10 or C 12 ) using two ionic solvents [mebupy][BF 4 ] or [emim][CH 3 SO 4 ]

doi:10.21203/rs.3.rs-2504599/v1

Desulfurization of gasoline and diesel models is investigated through liquid-liquid extraction of thiophene (C₄H₄S) from n-paraffin compounds. Ionic solvents of 4-methyl-N-butylpyridinium tetrafluoroborate [mebupy][BF₄] or 1-ethyl-3-methylimidazolium methylsulfate [emim][CH₃SO₄] as selective solvents, have been evaluated at 313.15 K and atmospheric pressure of 101.3 kPa. Experimental liquid–liquid equilibrium (LLE) data for the six ternary systems of n-octane, n-decane or n-dodecane + thiophene + [mebupy][BF₄] or [emim][CH₃SO₄], were used to calculate the values of the thiophene distribution ratio, selectivity and efficiency of ionic solvents. The experimental data were correlated using the UNIQUAC equations, and the binary interaction parameters have been reported. The phase diagrams for the ternary mixtures including both the experimental and calculated tie-lines have been presented.

LLE

ionic liquid

paraffins

thiophene

Fuels containing sulfur compounds generate sulfur oxides (SO_x) in the combustion process, leading to severe environmental threat and serious diseases of human respiratory system [1]. The reduction of sulfur content in real diesel of 80% was achieved in a liquid–liquid extraction with chloroaluminate-containing ionic liquids, but their industrial use is undesirable because of corrosion, environmental concerns, hydrolytic stability and regeneration aspects.

In most petroleum processes, low level of sulfur compounds such as thiophene and disulfides can be considered as the key substance to be extracted from liquid fuel oils. The maximum concentration level of total sulfur compounds content in USA and European gasoline and diesel fuels must be at a of 10 ppm (sulfur-free) [2, 3]. The ionic liquid is partly effective in removing sulfur compounds from real fuels, both diesel and gasoline [4–6].

Hydrodesulphurization (HDS) process is used in the removal of sulfur compounds from petroleum products. Aromatic S-compounds in gasoline and diesel oil are however, difficult to remove completely by HDS. Therefore, alternative methods to HDS have been studied including oxidation, precipitation, extraction, adsorption, distillation and alkylation [7].

Liquid-liquid extraction is an alternative method that can be used for extractive desulfurization and denitrification of liquid fuels. Recent approaches employ different ionic liquids as selective solvents, due to their general immiscibility with gasoline and diesel, negligible vapor pressure, and high selectivity to sulfur- and nitrogen-containing compounds [8].

J.H. Kareem and co-authors evaluated different ionic liquids (ILs) used for the removal of thiophene, benzothiophene and dibenzothiophene by liquid-liquid extraction and polymerization [7].

S.G. Zhang and co-researchers investigated different ionic liquids [C₂mim][BF₄], [C₄mim][BF₄], [C₄mim][PF₆] [9], [C₆mim][PF₆], [C₈mim][BF₄], [Me₃NH]Cl–1.5AlCl₃ and [Me₃NH] Cl–2.0AlCl₃ [10] used to reduce the sulfur content. Anantharaj and Balaji investigated the removal of thiophene or benzothiophene from n-hexadecane using [EMIM][EtSO₄] or [EMIM][MeSO₃] [11]. A.C. Baelhadj and F. Mutelet studied LLE for (dodecane + thiophene + 1-ethyl-3-methylimidazolium methyl) ternary system at 298.15 K and at atmospheric pressure [12].

M. Rogošić et al. tested the liquid extraction of thiophene or pyridine from eight ternary systems involving one hydrocarbon using [bzmim][Tf₂N] as an ionic solvent [13]. L. Alonso and co-authors evaluated [C₂mim][EtSO₄] as green solvent for the separation of thiophene from aliphatic hydrocarbons [14]. Liquid-liquid equilibrium data for [hmmpy][NTf₂] + thiophene + n-hexane or n-dodecane or n-hexadecane ternary systems have been studied by M. Francisco et al. [15]. Marcin Durski et al. considered thiophene as the key substance to be separated from liquid fuel oils. The separation of thiophene from octane or hexadecane using 1-butyl-1-methylpiperidynium dicyanamide or tri-isobutylmethylphosphonium tosylate as a solvent has been evaluated at temperature of 308.15 K and pressure of 101 kPa [16].

R. Anantharaj, T. Banerjee investigated [EMIM][OAc], [EMIM][EtSO₄] and [EMIM][MeSO₃] as solvents for the simultaneous separation of thiophene and pyridine from isooctane [17]. O.V. Oliveira et al. studied the desulfurization process in n-dodecane (a diesel fuel model) using the 1-butyl-3- methylimidazolium tetrafluoroborate and the model sulfur compound thiophene [18]. U. Domaǹska, M. Wlazło reported experimental ternary LLE data for twenty-one ILs on desulfurization of gasoline and diesel models, where the fuel models consisting of three sulfur-aromatic compounds (thiophene, benzothiophene and dibenzothiophene), toluene, tetralin and heptane [19]. K. Kędra-Krόlik et al. investigated liquid-liquid extraction of thiophene or pyridene from heptane using [EMIM][SCN], [TEMA][MeSO4] or [DMIM][MP] ionic liquids [20].

U. Domaǹska et al. studied the removal of thiophene from heptane using [BMPYR][FAP], [BMPYR][TCB] or [BMPYR][TCM] ionic solvents [21]. M. Krόlikowski et al. determined the liquid–liquid phase equilibrium (LLE) data for the ternary systems of [EMIM][TCM] (1) + thiophene or benzothiophene (2) + n-heptane (3) [22]. L. Alonso et al. reported the ability of [C₈mim][BF₄] to act as solvent in the liquid extraction of thiophene from aliphatic hydrocarbons [23]. A.E. Gorji et al. investigated the effect of different cation structures on the thiophene distribution between the ionic liquids containing NTf₂ anion and hydrocarbon phases in the ternary systems [24].

Alonso et al. determined liquid-liquid equilibrium data for ([C₂mim][EtSO₄] + thiophene + 2,2,4-trimethylpentane or toluene) ternary systems [25]. M. Mafi et al. reported LLE data of [Bmim][NO₃] or [Omim][NO₃] + n-decane + thiophene ternary systems [26]. Gorji and Sobati evaluated models for the prediction of thiophene distribution between [C₂MIM][EtSO₄], [C₈MIM][BF₄] or [C₈MIM][NTF₂] ionic solvents and different hydrocarbons [27]. S.K. Cheruku, T. Banerjee performed the experimental data of three liquid–liquid equilibrium ternary systems, namely: [EMIM][OAc] + thiophene + cyclohexane, [EMIM][OAc] + thiophene + isooctane and [EMIM][OAc] + thiophene + toluene [28]. A.A.P. Kumar and T. Banerjee evaluated different types of ionic solvents used to remove aromatic sulphur compounds from diesel oil model by liquid–liquid Extraction [29].

Although quite a few researchers preferred pyridinium based [14] and ammonium based ILs [30] for extractive desulphurization. Some have been noticed to be comparable to imidazolium based ILs if the anions matchup is just appropriate [31].

In this article the determinations of liquid-liquid equilibria of six ternary systems, at temperature of 313.15 K and pressure of 101.3 kPa were carried out. The systems commonly involved n-octane, n-decane or n-dodecane as characteristic compounds of gasoline or diesel models, thiophene and ionic liquids. Two ILs, [mebupy][BF₄] or [emim][CH₃SO₄] were used to evaluate the desulfurization process. The solute distribution ratios, selectivities and efficiencies of IL for the liquid extraction process of thiophene from n-octane, n-decane or n-dodecane are presented.

2.1. Chemicals

While thiophene, n-octane, n-decane and n-dodecane were purchased from Sigma-Aldrich, [mebupy][BF₄] and [emim][CH₃SO₄] were purchased from Iolitec GmbH. A new-generation Mettler Toledo C20 Compact Coulometric Karl Fischer Titrator was used to measure the water contents in [mebupy][BF₄] and [emim][CH₃SO₄]. All chemicals were utilized without any additional purification. Table 1 shows the mass fractions purities and water contents of the pure chemicals that were used in this study.

2.2. Apparatus and procedure

The LLE experimental systems are mixed in six 60 cm³ glass cells heated by a water bath utilizing a Haake DC1 thermostat. The cells temperatures are measured using PT100 platinum resistance thermometer with an accuracy of ± 0.1 K. Initially, 20 g of paraffin compounds are mixed with 20 g of the ionic solvent with different amount of thiophene. All quantities were weighed by a METTLER analytical balance accurate to ± 0.0001 g. Every mixture is stirred vigoursly for one hour using Teflon coated magnetic stirrer before it allowed to settle for four hours to attain equilibrium. All experiments were measured at a temperature of 313.15 K, and atmospheric pressure of 101.3 kPa.

2.3. Measurements of phase compositions

Aliphatic rich and ionic layers were separated and weighed. Then samples from both layers were taken using a syringe and compositions of organic compounds (n-octane, n-decane and n-dodecane) and thiophene were determined using Agilent gas chromatograph 7890B (5977A GC/MSD). The GC details are shown in Table 2. The ionic liquids cannot be analyzed by the GC because they have insignificant vapor pressures. They were collected by a pre-column, to protect the primary column, and to avoid any inaccuracy that can disrupt analysis which could be caused by tainting the GC with ionic liquid. A "three points" calibration method was used reduce systematic errors. Mole fractions of three validation samples were gravimetrically prepared repeatedly analyzed for ten times using the gas chromatograph. All GC analysis were repeated ten times and the average value was recorded to reduce random errors.

The ionic liquids compositions [mebupy][BF₄] or [emim][CH₃SO₄] were determined by measurents of densities of both layers using a density meter (Anton Paar, model DSA 5000 M) with a precision of ± 10^− 5 g·cm³. The standard deviations of mole fraction measurement were calculated and correspond to experimental uncertainty of ± 0.0001.

The influence of [mebupy][BF₄] or [emim][CH₃SO₄] ILs on solute distribution ratio (K) and selectivity (S) values was examined. The values of K and S are also present in Tables 2–4, and they were calculated from the LLE experimental data as follows:

$$K={x}_{2}^{\text{I}\text{I}}/{x}_{2}^{\text{I}}$$

1

$$S={x}_{2}^{\text{I}\text{I}} {x}_{1}^{\text{I}}/{x}_{2}^{\text{I}} {x}_{2}^{\text{I}\text{I}}$$

2

where x is the mole fraction, while subscript 1 and 2 represent n-paraffins and thiophene compounds, superscript I and II represent the n-paraffins-rich phase and the IL-rich phase, respectively.

3.2. Experimental data

Tables 2–4 present the measured equilibrium mole fractions for the n-paraffins-rich phase (raffinate) and the IL-rich phase (extract) of the six ternary mixtures at 313.15 K and 101.3 kPa.

Figure 1 shows the experimental tie lines of the six ternary mixtures at 313.15 K as a ternary diagram. While there was very small amount of ILs found in the n-paraffins-rich phase, more amount of n-paraffins exists in IL-rich phase as shown in the same figure.

3.3. Distribution ratio and selectivity

Tables 2–4, in addition to the LLE data, include the corresponding thiophene distribution ratio and selectivity values for the six ternary systems. These parameters are widely used for evaluating the feasibility of using a solvent in a liquid extraction process.

The solvent power or capacity of an IL, which is evaluated using the distribution ratio of thiophene, was calculated for the six ternary systems. Figure 2 presents the relationship between the calculated distribution ratios and the thiophene mole fractions in the solvent-rich phase (x₂) for the six ternary systems. The distribution ratio values increased with the thiophene mole fraction in the solvent-rich phase. As shown in this figure, the distribution ratio values increase in the following order: n-dodecane < n-decane < n-octane. As shown in the same figure, the thiophene distribution ratio values are higher using [mebupy][BF₄] than [emim][CH₃SO₄] ILs.

The selectivity of the solvent was used to measure the extraction effectiveness of thiophene from n-paraffin compounds using [mebupy][BF₄] or [emim][CH₃SO₄] ILs. The selectivity of the ILs, which is a measure of the ability of the solvent to separate thiophene from paraffin compounds, was calculated.

The relationship between the calculated selectivities and the thiophene mole fractions in the solvent-rich phase (x₂) for the six ternary systems is presented in Fig. 3. The selectivity values decreased as the thiophene mole fraction in the solvent-rich phase (x₂) increased, as shown by the selectivity data presented in same figure. Further, this figure shows that the selectivity values increase in the following order: n-octane < n-decane < n-dodecane. As shown in the same figure, the selectivity values are higher using [mebupy][BF₄] than [emim][CH₃SO₄] ILs.

A comparison of the ternary systems n-octane, n-decane, or n-dodecane + thiophene + [mebupy][BF₄] or [emim][CH₃SO₄] ILs distribution coefficients data at 313.15 K with data from previous studies using other ILs [12, 14, 16, 23, 25, 26] are presented in Figs. 4, 5 and 6 for n-octane, n-decane and n-dodecane respectively.

While Fig. 4 represents a comparison of IL solvents under study ([mebupy][BF₄] and [emim][CH₃SO₄]) with other ILs in previous studies for the ternary systems n-octane + thiophene + ILs ([C₈mim][BF₄], [C₂mim][EtSO₄], [BMPIP][DCA], [Pi₄,i₄,i₄,1][TOS]), Fig. 5 represents a comparison for the ternary systems n-decane + thiophene + ILs ([Bmim][NO₃]), and Fig. 6 represents a comparison for the ternary systems n-dodecane + thiophene + ILs ([C₈mim][BF₄], [C₂mim][EtSO₄]).

3.4. LLE correlation by the UNIQUAC model

The UNIQUAC thermodynamic model was implemented effectively to correlate the experimental (liquid + liquid) equilibrium data in several ILs in which an iterative computer program is utilized, based on flash calculation method as presented in literature.[ 24,25] The parameters, r_i and q_i, of the UNIQUAC model was predicted by Magnussen et al. [26], J.M. Seiten et al [33], Alonso et al. [14]and Santiago et al. [16]as in Table 1. Minimizing the differences between the experimental and calculated mole fractions for each component determined the constituent binary parameters of UNIQUAC model over all the measured LLE data of the ternary systems.

Values of a_ij and a_ji parameters of the UNIQUAC model for the ternary systems at 313.15 K and atmospheric pressure are listed in Table 6 together with the root mean square deviation (RMSD) of the fit calculated as follow:

where x is the mole fraction, n is the number of tie lines and subscripts exp, cal, i, j, and k represent experimental, calculated, components, phases, and tie lines, respectively.

The interaction parameters for the UNIQUAC model were used to calculate the UNIQUAC tie lines for the present systems as shown in Fig. 1. The calculations based on UNIQUAC model gave good representation of the tie line data for those systems and analysis of the mean RMSD.

3.5. Extraction Efficiency Simulation

The extraction efficiency of a 20% by mole thiophene-C₈ mixture, was determined through the simulation of 4 stages extraction process. A molar solvent to feed ratio of 0.5 was selected for this simulation.

The simulation is performed using UNISIM steady-state simulator (R460.1). The ionic solvents were entered as hypothetical components and UNIQUAC interaction parameters were input in the fluid package. The extraction efficiency was calculated as:

%$\epsilon =\left(\frac{{{n}_{F}-n}_{Ri}}{{n}_{F}}\right)\times 100$ (4)

The influence of the number of stages on the extraction efficiency, %ε, of thiophene from n-octane using UNIQUAC model results for [mebupy][BF₄] and [emim][CH₃SO₄] is presented in Fig. 7.

Liquid-liquid equilibria experimental data were studied for the ternary systems n-octane or n-decane or n-dodecane + thiophene + [mebupy][BF₄] or [emim][CH₃SO₄] ILs data at 313.15 K and 101.3 kPa. In addition, to adequately assess the correlation of the experimental LLE data, we utilized the UNIQUAC model. In conclusion, the solute distribution ratios and selectivities of the studied systems indicates that separation of thiophene from mixtures with n-octane or n-decane or n-dodecane is feasible using [mebupy][BF₄] or [emim][CH₃SO₄] ILs. The influence of the number of stages on the extraction efficiency was evaluated.

Acknowledgements

The authors thank the Public Authority for Applied Education and Training (PAAET-TS-06-03) for the financial support of this work.

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Table 1

Details of the chemicals; purities (mass fraction), UNIQUAC structural parameters

Purity (mass fraction)/water

content (mass fraction)

UNIQUAC

structural parameter

Compound

Supplier

r

q

[mebupy][BF₄]	Iolitec GmbH	≥0.99/≤500×10^-6	8.4337	6.5290
[emim][CH₃SO₄]	Iolitec GmbH	≥ 0.99/≤500×10^-6	7.5774	6.0280
n-octane	Sigma-Aldrich	≥ 0.99/≤100×10^-6	5.8486	4.9360
n-decane	Sigma-Aldrich	≥ 0.99/≤90×10^-6	7.1974	6.016
n-dodecane	Sigma-Aldrich	≥ 0.997/≤80×10^-6	8.5462	7.096
thiophene	Sigma-Aldrich	≥ 0.995/≤100×10^-6	2.8569	2.140

Table 2

Experimental data for the ternary system: n-octane (1) + thiophene (2) + {[mebupy][BF₄] or [emim][CH₃SO₄]} (3) at T = 313.15 K and P = 101.3 kPa

Dodecane rich phase			Solventrich phase					K		S
x₁	x₂	x₃	x₁	x₂		x₃
n-octane (1) + thiophene (2) + [emim][CH₃SO₄] (3)
1.000	0.000	0.000	0.009		0.000		0.991
0.859	0.141	0.000	0.009		0.112		0.880		0.79		77.04
0.753	0.247	0.000	0.009		0.201		0.791		0.81		71.65
0.669	0.331	0.000	0.008		0.274		0.718		0.83		67.18
0.603	0.397	0.000	0.008		0.334		0.658		0.84		63.55
0.548	0.452	0.000	0.008		0.384		0.608		0.85		60.59
0.502	0.498	0.000	0.007		0.428		0.565		0.86		58.16
0.463	0.537	0.000	0.007		0.465		0.528		0.87		56.14
0.430	0.570	0.000	0.007		0.497		0.496		0.87		54.47
0.400	0.600	0.000	0.007		0.525		0.469		0.87		53.06
0.374	0.626	0.000	0.006		0.549		0.445		0.88		51.88
0.351	0.649	0.000	0.006		0.570		0.424		0.88		50.88
0.330	0.670	0.000	0.006		0.588		0.406		0.88		49.37
0.312	0.688	0.000	0.006		0.604		0.390		0.88		48.00
0.295	0.705	0.000	0.006		0.618		0.376		0.88		46.72
0.279	0.721	0.000	0.005		0.630		0.365		0.87		45.52
n-octane (1) + thiophene (2) + [mebupy][BF₄] (3)
1.000	0.000	0.000	0.008		0.000		0.993
0.856	0.144	0.000	0.007		0.121		0.871		0.84		98.04
0.748	0.252	0.000	0.007		0.217		0.776		0.86		95.99
0.665	0.335	0.000	0.006		0.295		0.699		0.88		93.94
0.599	0.401	0.000	0.006		0.358		0.636		0.89		91.88
0.544	0.456	0.000	0.005		0.411		0.583		0.90		89.83
0.499	0.501	0.000	0.005		0.456		0.538		0.91		87.78
0.460	0.540	0.000	0.005		0.495		0.500		0.92		85.74
0.427	0.573	0.000	0.005		0.528		0.467		0.92		83.69
0.399	0.601	0.000	0.005		0.557		0.439		0.93		81.64
0.373	0.627	0.000	0.004		0.582		0.414		0.93		79.59
0.351	0.649	0.000	0.004		0.603		0.393		0.93		77.54
0.330	0.670	0.000	0.004		0.622		0.374		0.93		75.49
0.312	0.688	0.000	0.004		0.639		0.357		0.93		73.44
0.295	0.705	0.000	0.004		0.653		0.343		0.93		71.39
0.280	0.720	0.000	0.004		0.665		0.331		0.92		69.34

Table 3

Experimental data for the ternary system: n-decane (1) + thiophene (2) + {[mebupy][BF₄] or [emim][CH₃SO₄]} (3) at T = 313.15 K and P = 101.3 kPa

Dodecane rich phase			Solventrich phase					K		S
x₁	x₂	x₃	x₁	x₂		x₃
n-decane (1) + thiophene (2) + [emim][CH₃SO₄] (3)
1.000	0.000	0.000	0.006		0.000		0.994
0.830	0.170	0.000	0.006		0.104		0.890		0.61		88.59
0.709	0.291	0.000	0.006		0.187		0.807		0.64		82.90
0.618	0.382	0.000	0.005		0.255		0.740		0.67		78.46
0.547	0.453	0.000	0.005		0.311		0.684		0.69		75.04
0.490	0.510	0.000	0.005		0.358		0.637		0.70		72.44
0.444	0.556	0.000	0.005		0.398		0.597		0.72		70.53
0.405	0.595	0.000	0.004		0.433		0.563		0.73		69.20
0.372	0.628	0.000	0.004		0.462		0.534		0.74		68.37
0.344	0.656	0.000	0.004		0.489		0.507		0.74		67.34
0.319	0.681	0.000	0.004		0.512		0.485		0.75		66.66
0.298	0.702	0.000	0.003		0.532		0.465		0.76		66.32
0.279	0.721	0.000	0.003		0.552		0.445		0.77		64.80
0.263	0.737	0.000	0.003		0.569		0.427		0.77		63.47
0.248	0.752	0.000	0.003		0.585		0.412		0.78		62.30
0.235	0.765	0.000	0.003		0.599		0.398		0.78		61.28
n-decane (1) + thiophene (2) + [mebupy][BF₄] (3)
1.000	0.000	0.000	0.005		0.000		0.995
0.830	0.170	0.000	0.005		0.119		0.876		0.70		119.56
0.710	0.290	0.000	0.004		0.212		0.784		0.73		117.41
0.619	0.381	0.000	0.004		0.286		0.710		0.75		114.87
0.549	0.451	0.000	0.004		0.347		0.649		0.77		113.18
0.494	0.506	0.000	0.003		0.400		0.596		0.79		112.09
0.447	0.553	0.000	0.003		0.442		0.555		0.80		109.70
0.409	0.591	0.000	0.003		0.479		0.518		0.81		107.72
0.377	0.623	0.000	0.003		0.511		0.486		0.82		106.14
0.349	0.651	0.000	0.003		0.540		0.457		0.83		104.63
0.326	0.674	0.000	0.003		0.566		0.431		0.84		103.30
0.304	0.696	0.000	0.003		0.585		0.412		0.84		100.60
0.286	0.714	0.000	0.002		0.607		0.390		0.85		99.12
0.270	0.730	0.000	0.002		0.628		0.370		0.86		98.05
0.255	0.745	0.000	0.002		0.641		0.357		0.86		95.16
0.243	0.757	0.000	0.002		0.659		0.339		0.87		94.44

Table 4

Experimental data for the ternary system: n-dodecane (1) + thiophene (2) + {[mebupy][BF₄] or [emim][CH₃SO₄]} (3) at T = 313.15 K and P = 101.3 kPa

Dodecane rich phase			Solventrich phase					K		S
x₁	x₂	x₃	x₁	x₂		x₃
n-dodecane (1) + thiophene (2) + [emim][CH₃SO₄] (3)
1.000	0.000	0.000	0.003		0.000		0.997
0.791	0.209	0.000	0.003		0.079		0.918		0.38		106.76
0.652	0.348	0.000	0.003		0.144		0.853		0.41		104.13
0.554	0.446	0.000	0.002		0.197		0.801		0.44		101.78
0.479	0.521	0.000	0.002		0.239		0.759		0.46		99.78
0.421	0.579	0.000	0.002		0.270		0.728		0.47		98.12
0.373	0.627	0.000	0.002		0.293		0.706		0.47		96.82
0.337	0.663	0.000	0.002		0.319		0.679		0.48		95.30
0.306	0.694	0.000	0.002		0.341		0.657		0.49		94.02
0.280	0.720	0.000	0.002		0.359		0.640		0.50		92.95
0.259	0.741	0.000	0.001		0.381		0.618		0.51		91.74
0.241	0.759	0.000	0.001		0.401		0.598		0.53		90.66
0.225	0.775	0.000	0.001		0.418		0.580		0.54		89.73
0.211	0.789	0.000	0.001		0.440		0.558		0.56		88.65
0.199	0.801	0.000	0.001		0.454		0.544		0.57		87.98
0.188	0.812	0.000	0.001		0.474		0.525		0.58		87.10
n-dodecane (1) + thiophene (2) + [mebupy][BF₄] (3)
1.000	0.000	0.000	0.003		0.000		0.997
0.799	0.201	0.000	0.003		0.104		0.893		0.52		145.49
0.664	0.336	0.000	0.003		0.187		0.811		0.55		143.08
0.566	0.434	0.000	0.002		0.252		0.746		0.58		140.66
0.492	0.508	0.000	0.002		0.304		0.694		0.60		138.31
0.434	0.566	0.000	0.002		0.343		0.655		0.61		136.12
0.386	0.614	0.000	0.002		0.373		0.626		0.61		133.64
0.349	0.651	0.000	0.002		0.405		0.594		0.62		131.37
0.318	0.682	0.000	0.002		0.431		0.567		0.63		129.15
0.291	0.709	0.000	0.001		0.452		0.546		0.64		126.78
0.270	0.730	0.000	0.001		0.478		0.521		0.65		124.53
0.251	0.749	0.000	0.001		0.500		0.498		0.67		122.34
0.235	0.765	0.000	0.001		0.520		0.479		0.68		120.06
0.221	0.779	0.000	0.001		0.544		0.455		0.70		117.74
0.208	0.792	0.000	0.001		0.560		0.439		0.71		115.54
0.198	0.802	0.000	0.001		0.580		0.418		0.72		113.25

Table 5

UNIQUAC interaction parameters and root mean square deviation (RMSD) of the six ternary systems at T = 313.15 K and P = 101.3 kPa.

i	j	a_ij	a_ji	RMSD
n-octane	thiophene	-113.08	547.71	0.1406
n-octane	[mebupy][BF4]	323.89	132.05
thiophene	[mebupy][BF4]	285.73	21.154
n-octane	thiophene	-130.78	571.53	0.0910
n-octane	[emim][CH₃SO₄]	406.43	85.006
thiophene	[emim][CH₃SO₄]	315.50	-2.2630
n-decane	thiophene	-169.36	91.108	0.0730
n-decane	[mebupy][BF4]	425.08	55.590
thiophene	[mebupy][BF4]	402.75	-235.41
n-decane	thiophene	-84.924	35.419	0.0467
n-decane	[emim][CH₃SO₄]	459.83	32.182
thiophene	[emim][CH₃SO₄]	449.19	-200.31
n-dodecane	thiophene	-168.44	165.50	0.3462
n-dodecane	[mebupy][BF4]	418.76	24.781
thiophene	[mebupy][BF4]	339.63	-127.08
n-dodecane	thiophene	-161.77	157.38	0.3707
n-dodecane	[emim][CH₃SO₄]	432.52	16.450
thiophene	[emim][CH₃SO₄]	345.11	-87.186

No competing interests reported.

Liquid extraction of thiophene from n-paraffins (C 8 , C 10 or C 12 ) using two ionic solvents [mebupy][BF 4 ] or [emim][CH 3 SO 4 ]

Status:

Journal Publication

Version 1

Abstract

Figures

1. Introduction

2. Experimental Methods

2.1. Chemicals

2.2. Apparatus and procedure

2.3. Measurements of phase compositions

3. Results And Discussion

3.2. Experimental data

3.3. Distribution ratio and selectivity

3.4. LLE correlation by the UNIQUAC model

3.5. Extraction Efficiency Simulation

4. Conclusions

Declarations

References

Tables

Additional Declarations

Status:

Journal Publication

Version 1