Computer-Aided Screening of Ionic Liquids as Entrainers for

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Computer-Aided Screening of Ionic Liquids as Entrainers for Separating Methyl Acetate and Methanol via Extractive Distillation Zhaoyou Zhu, Xueli Geng, Wei He, Chao Chen, Yinglong Wang, and Jun Gao Ind. Eng. Chem. Res., Just Accepted Manuscript • DOI: 10.1021/acs.iecr.8b01355 • Publication Date (Web): 05 Jul 2018 Downloaded from http://pubs.acs.org on July 7, 2018

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Industrial & Engineering Chemistry Research

Computer-aided screening of ionic liquids as entrainers for separating methyl acetate and

methanol via extractive distillation

Zhaoyou Zhua, Xueli Genga, Wei Hea, Chao Chena, Yinglong Wanga* and Jun Gaob a

College of Chemical Engineering, Qingdao University of Science and Technology, Qingdao

266042, China b

College of Chemical and Environmental Engineering, Shandong University of Science and

Technology, Qingdao, 266590, China

Corresponding Author

*E-mail: [email protected]

Abstract: In the production of poly(vinyl alcohol), the raw materials methyl acetate (MeOAc) and

methanol (MeOH) exist as a homogeneous azeotropic mixture. Twenty-five kinds of ionic liquids,

composed of five types of cations and five types of anions, were studied using the COSMO-SAC method. The σ-profile data for each component and the selectivity at infinite dilution ( S ∞ ) were calculated and analyzed, respectively. 1-Hexyl-3-methylimidazolium chloride ([HMIM][Cl]) and

1-butyl-3-methylimidazolium chloride ([BMIM][Cl]) were selected as suitable entrainers based on

the COSMO-SAC method. The binary interaction parameters of the NRTL model of the MeOAc

/ionic liquid and MeOH /ionic liquid systems were regressed. The conceptual design for the

separation of MeOAc and MeOH using ionic liquids as entrainers was investigated. The 1

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comparison of two processes using two entrainers was carried out from an economic perspective.

The total annual cost (TAC) of the process using [HMIM][Cl] as an entrainer can be reduced by

16.5% compared with that of the process using [BMIM][Cl]. The results indicated that the

COSMO-SAC method is feasible for screening ionic liquids as optimal entrainers. This work

could provide theoretical instruction for further industrial applications using ionic liquids as

solvents via COSMO-SAC computer-aided screening.

Keywords: COSMO-SAC; Ionic liquids; Methyl acetate; Methanol; Extractive distillation.

1. Introduction In the petrochemical and biopharmaceutical industries, the separation of azeotropic or close-boiling mixtures, particularly for homogeneous mixtures, is attracting increasing attention 1.

MeOAc and MeOH exist as homogeneous azeotropes in the production of ethers, poly(vinyl alcohol) (PVA) and so on2, 3. To deal with the difficulty of azeotropic mixtures separation by

conventional distillation, some uncommon separation methods may be used: azeotropic distillation 4, 5

, pressure-swing distillation

others

6-11

, extractive distillation

12-17

, membrane separation

18, 19

and

20

mixtures

. Extractive distillation is extensively utilized to handle the separation of azeotropic 21

. For extractive distillation, the azeotropic mixture is separated by using an entrainer.

Thus, the selection of entrainer is the vital step in extractive distillation. Some organic solvents

used as entrainers have high volatility and toxicity and are difficult to recycle. These

2


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disadvantages can lead to environmental pollution or high energy consumption. Thus, the

selection of an appropriate entrainer is important for environmental protection and a sustainable

development strategy.

Recently, thanks to their high thermal stability, high solubility, high decomposition

temperature, and so forth

1, 21

, room-temperature ionic liquids (RTILs) have been widely

considered as a new series of benign entrainer for separating azeotropic mixtures in extractive distillation22-24. Díaz et al.25 studied 1-ethyl-3-methylimidazolium dicyanamide as an entrainer for

aromatic–aliphatic and naphtha separation through extractive distillation. Alfonsina et al.

26

investigated the ethanol and ethyl acetate separation using 1-ethyl-3-methylimidazolium

bis(trifluoromethylsulfonyl)imide as an entrainer, and the results showed that this IL can change the relative volatility of ethanol and ethyl acetate. Lei et al. 27 studied the cyclohexane and toluene

separation using 1-butyl-3-methylimidazolium hexafluorophosphate as an entrainer in vapor–

liquid equilibrium (VLE) experiments. These researchers contributed to the further study of the

conceptual design of extractive distillation using ILs as entrainers. Zhu et al.

28

investigated a

separation process of MeOAc and MeOH using ILs as entrainers and the results indicated the process could achieve better resource recovery. Kulajanpeng et al.1 designed and simulated an

extractive distillation column and stripper column for separating water and isopropanol using ILs

as entrainers. Given the great variety of ILs, which include different cations and different anions, a

suitable IL screening method is important.

3



In 1995, a screening method named the COSMO-RS was proposed by Klamt29,30. In 2002, Lin et al. 31 proposed a segment activity coefficient(SAC) model and named as the COSMO-SAC

model based on the COSMO-RS. The COSMO-SAC method addressed the lack of convergence of the chemical potential equation by introducing the Staverman-Guggenheim combinatorial term32, 33

. The model has the advantage of obtaining the activity coefficient of the material only through

the information of the molecular structure. The COSMO-SAC model can also alleviate the

intensity and degree of labor required. To separate the MeOAc and MeOH mixture, many people have studied the VLE using ILs as entrainers. Cai et al. 34 studied the VLE of a ternary system of

MeOAc/MeOH/1-octyl-3-methylimidazolium hexafluorophosphate, and the results showed that this IL can enhance the relative volatility of MeOAc and MeOH. Zhang et al. 35 studied the effects

of ILs (1-butyl-3-methylimidazolium chloride, 1-(2-chloroethyl)-3-methylimidazolium chloride

and 1-butyl-3-methylimidazolium bromide) on the separation of the MeOAc/MeOH azeotrope and

found that the three ILs could break the azeotrope. Cao et al.

21

determined the VLE data for

MeOAc/MeOH /ILs at atmospheric pressure and found that these three dialkyl phosphate ILs can

increase the relative volatility of MeOAc/MeOH.

The COSMO-SAC method was applied to select suitable ILs as entrainers for separating a MeOAc and MeOH azeotropic mixture in this work. Specifically, the selectivity ( S ∞ ) based on ∞

the infinite dilution activity coefficient ( γ ) and the σ-profile ( pτ (σ)) database was computed via the COSMO-SAC 36. [HMIM][Cl] and [BMIM][Cl] were selected as entrainers from twenty-five

4


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kinds of ILs based on the COSMO-SAC method and verified through experimental data. An

extractive distillation process was designed and simulated to separate a MeOAc and MeOH

azeotrope using these two entrainers. The two processes were compared based on their TACs

under the condition of meeting product purity requirements to confirm the feasibility of the

COSMO-SAC method.

2. Selecting suitable ionic liquids as entrainers

2.1 COSMO-SAC screening method COSMO-SAC was developed on the basis of COSMO-RS, which predicts the fluids

thermodynamic properties based on surface charge interactions

37-40

. In the activity coefficients

calculation based on the COSMO-SAC method, the most important step is to get the pτ (σ) data for each component by quantum chemical calculations. The individual IL molecule, consist of

organic cations and organic or inorganic anions, is divided into cations and anions in the

calculation. When the σ-profile data for cations and anions are computed via the quantum

chemical calculation method, the σ-profile data of the whole IL molecule are obtained through the

addition of the σ-profile data of the cations and anions.

Twenty-five kinds of ILs, which were formed randomly from five cations and five anions

(Table S1 and Table S2), were chosen as candidates. The molecular structure of each ion or molecule was made in the DMol3 module of Materials Studio (MS)

36

. The density functional

theory (DFT) functional BVWN-BP was chosen to optimize the molecular structure and energy

5



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with a convergence criterion of 10−6 Hartree, which was based on the principle of minimum energy40,41. Then, COSMO files were generated through geometric optimization and energy optimization. COSMO computed the screening charge density (σ*) 36. The surface charge density

of the standard segment σm was calculated by the following equation.

∑ σ m* σm =

n

∑r

rn2 reff2 rn2 + reff2 rn2 reff2

2 n

n

+ reff2

exp( − f decay（

exp( − f decay（

2 d mn ） ) rn2 + reff2

2 d mn ） ) rn2 + reff2

(1)

where rn, reff, aeff and dmn represent the radius of segment n, the effective radius, the surface area of the standard segment and the distance between segments m and n, respectively. fdecay is a correction factor (fdecay = 3.57). The σ-profile pτ (σ) data of the twenty-five kinds of ILs were obtained based on the above calculation. The pτ (σ) of a pure component indicates the probability of finding a surface segment with screening charge density σ 36. The equation is as follow:

pi =

Ai (σ ) Ai

(2)

The mixed ps (σ) is obtained by a weighted average of the single components pτ (σ). The equation is as follow:

∑ x A p (σ ) p (σ ) = ∑x A i

i

i

i

s

i

(3)

i

i

Based on the pτ (σ) data for the cations and anions, the pτ (σ) data for the molecules were obtained. The activity coefficients were obtained based on the pτ (σ) data using the activity

6


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coefficient equation. The equation is as follows: ln(γ i ) = ni ∑ pi (σ m )[ln(Γ s (σ m )) − ln(Γ i (σ m ))] + ln(γ iSG ) σm

The

(4)

γ ∞ of component i in entrainer could be obtained when the entrainer content

approaches 1. The detailed calculation procedure can be found in previous literature 41-43.

2.2 Effect of the alkyl chain length of cations and anions To analyze the effect of the ILs on the MeOAc and MeOH separation, the imidazolium cations

pτ (σ) are given in Figure 1. Figure 1 shows that the main peaks of the ILs, MeOAc and

MeOH are in a nonpolar region that is located in the −0.0084 e/Å2 < σ < +0.0084 e/Å2 range. Peaks at σ > +0.0084 e/Å2 and σ < - 0.0084 e/Å2 indicate the hydrogen bond donor region and hydrogen bond acceptor region, respectively. The

pτ (σ) were analyzed as follows. MeOAc and

MeOH have remarkabe peaks at +0.012 e/Å2 and -0.014 e/Å2, respectively, which reflect the strong ability of MeOAc to act as a donor and that of MeOH to act as an acceptor. [HMIM]+ has two obvious peaks at +0.014 e/Å2 and -0.014 e/Å2, which also indicates excellent donor and acceptor ability. The outer ranges of the polarization charge density of [HMIM]+ reach -0.017 e/Å2 and +0.017 e/Å2. Thus, [HMIM]+ prefers to form hydrogen bonds with MeOAc and MeOH than are other cations. The ILs similar pτ (σ) with different alkyl chain lengths show that the alkyl chain length has little impact on the MeOAc and MeOH separation. Figure 2 is the pτ (σ) for MeOAc, MeOH and the selected anions ([Cl]−, [DMP]−, [Triflate]−, [PF6]−, and [Tf2N]−). From Figure 2, all of the anions have peaks in the σ > +0.0084 e/Å2 region,

7



Page 8 of 48

which indicates that the five anions have a strong hydrogen bond-acceptor ability. The main peaks of the [Tf2N]− and [Triflate]− anions are in the range -0.001 < σ < 0.0084 e/Å2, which indicates a nonpolar region. The [Tf2N]− anion has partial peaks at 0.0084 e/Å2 < σ < 0.012 e/Å2. The [Triflate]− anion has a peak at 0.0084 e/Å2 < σ < 0.015 e/Å2. The [DMP]− anion has several peaks at 0.0084 e/Å2 < σ < 0.019 e/Å2. Almost all of the [Cl]− anion peaks are at 0.016 e/Å2 < σ < 0.022 e/Å2. A comparison of the above polarization charge densities of the anions shows that the order is as follows: [Cl]- > [DMP]- > [Triflate]- > [PF6]- > [Tf2N]-. The lager the polarization charge density of an anion is, the stronger the hydrogen bond-acceptor ability is

41

. The ILs

pτ (σ) with

different anions are greatly different, which shows that the anions have a significant effect on the

separation of MeOAc and MeOH.

2.3 Selectivity at the infinite-dilution activity coefficient ∞

The selectivity ( S ∞ ) was calculated at the γ , which was obtained by the COSMO-SAC ∞ method. IL selectivity toward MeOAc was compared with that toward MeOH ( SMeOAc , MeOH ) can be

defined as follows. ∞

S

∞ MeOAc , MeOH

γ ，ILs = MeOH ∞ γ MeOAc ，ILs

(5)

In Figure 3, the ionic liquids selectivity at infinite dilution was computed by the COSMO-SAC method. Given imidazolium-based ionic liquids based on the same [Cl]- anion, + + + ∞ SMeOAc ,MeOH increased with the following order of cations: [HMIM] > [BMIM] > [OMIM] >

∞ [EMIM]+ > [MMIM]+. However, for the same [DMP]- anion, SMeOAc ,MeOH increased with the

8


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following order of cations: [EMIM]+ > [MMIM]+ > [BMIM]+ > [HMIM]+ > [OMIM]+. The results ∞ show that the values of SMeOAc increase at first and then decrease with the alkyl chain length , MeOH

of cations. Given ionic liquids composed of the same cations and different anions, the results show ∞ that the trend in SMeOAc is different from that obtained for corresponding alkyl chain lengths ,MeOH

∞ of cations and the degree of the increase in SMeOAc values is relatively small. The results ,MeOH

suggest that the alkyl chain length has a slight influence on the MeOAc and MeOH separation 41.

These conclusions still need more experiments to be proved. [HMIM]+-based ILs paired with the anions [Cl]-, [DMP]-, [Triflate]-, [PF6]- and [Tf2N]- were selected as the case to analyze the effect of anions on the separation of MeOAc and MeOH. The ∞ results are presented in Figure 4. The SMeOAc of the [HMIM]+-based ionic liquids was also ,MeOH

∞ computed by the COSMO-SAC screen model. As shown in Figure 4, SMeOAc increased with ,MeOH

the following order of anions: [Cl]- > [DMP]- > [Triflate]- > [PF6]- > [Tf2N]-. The selectivity of [Cl]- toward MeOAc is better than that of other anions. This selectivity suggests a strong interaction between [Cl]- and MeOH and a weak interaction between [Cl]- and MeOAc.

From Figure 3, the results show that the selectivity of [HMIM][Cl] and [BMIM][Cl] are

higher than those of other ILs. Thus, [HMIM][Cl] and [BMIM][Cl] were selected as suitable

entrainers.

2.4 Comparison of the calculated and experimental results Figure 5 indicates that the COSMO-SAC method could able to predict the MeOAc

9



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vapor-phase composition effectively. The equation of state is used to predicte vapor composition 43.

The equation is as follows:

pyi =γi xi pis (6) where yi and xi are the MeOAc mole fractions in the vapor and liquid phases, s

respectively; P is the system total pressure; pi and

γ i are components corresponding to the

saturated vapor pressure and the activity coefficient, respectively. The activity coefficient

γ i is

obtained by the activity coefficient equation via the COSMO-SAC model 44. Table S3 presents the

Antoine equation parameters for all of the components. The MeOAc mole fractions in the vapor

phase are estimated based on the liquid phase composition in experiments

42, 45

. The compared

results with the experimental data are shown in Figure 5. The results show that the computer-aided

method using the COSMO-SAC is effective for the selection of ILs as entrainers for extractive

distillation.

Therefore, [HMIM][Cl] and [BMIM][Cl] were selected as entrainers through screening based

on the COSMO-SAC method. The process design and economic comparison of the MeOAc and

MeOH separation using ILs as entrainers were further investigated.

3. Process design for separating the MeOAc/MeOH mixture

3.1 Data regression and feasibility analysis The extractive distillation technology with ILs was first proposed by Lei et al

27

. The

thermodynamic model is the key in the process to ensure the accuracy of the design results. The

10


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UNIFAC-Lei model can use a small amount of experimental data to predict the phase behavior of

other systems with ILs. The NRTL model can also be used to predict VLE in ionic-liquid systems.

To select a suitable thermodynamic model, the results predicted by the NRTL model and

UNIFAC-Lei model were compared with the experimental data. The results show the deviation is

small between the data predicted by the NRTL model and the experimental data in Figure 6. Thus,

the NRTL model was selected as the thermodynamic model for the process of extractive

distillation.

Aspen Plus v8.4 was selected as the tool for data regression and the simulation of extractive

distillation with ILs. The ILs were created as user-defined elements in Aspen Plus

component properties (Table S4) were obtained from Valderrama et al.

46

28

. The pure

. The thermophysical

properties of the ILs, such as density (ρ), viscosity (µ) and surface tension (σ), influence the miscibility of the feed and solvent and the energy consumption of the process 45. Thus, these

parameters were considered. These semi-empirical equations and the fitted parameters are listed in

Table S5. The fitted values agreed well with the experimental data are shown in Figure 7. The

results indicate that these fitted parameters can be used to conduct further simulations. The critical properties (Table S5) were taken from the literature 47-49.

The NRTL thermodynamic model was selected to describe the liquid phase nonideality. The

vapor phase was deemed to be an ideal gas. The NRTL binary interaction parameters (Table S6)

were regressed separately with experimental data for the MeOAc/MeOH/IL system

11


35, 45

. The


comparisons of the molar fractions between the model regression results and the experimental

values are shown in Figure 8. For MeOAc and MeOH, the closer each point is to the diagonal line,

the smaller the deviation between the predicted value and the experimental value. For the ILs, the

vapor phase and the liquid phase converge at one point, and the value of the vapor phase is zero.

The results show that all points are located near the diagonal line for MeOAc and MeOH. Among

all the points for ILs, the liquid phase is near a single point and the vapor phase is concentrated at

zero. This distribution indicates that the predicted values of the vapor-liquid fraction of the ternary

system from the NRTL model are consistent with the experimental values. Thus, the use of the

NRTL model as the thermodynamic model is feasible.

Residue curve maps (RCMs) for the MeOAc/MeOH/ILs were used to analyze the feasibility

of this system of separation, and the results are shown in Figure 9. It can be seen that MeOAc and

MeOH were the saddles. The azeotropic mixture was an unstable node. The ILs were the stable

node. The isovolatility curve reaches the binary side of the MeOAc-MeOH mixture, which

suggests that the relative volatility is increased. This relationship indicates that this azeotrope can

be separated with ILs.

3.2 Process design and Economic Analysis The feed condition was set at a flowrate of 100 kmol/h with 50 mol% MeOAc and 50 mol%

MeOH. [HMIM][Cl] and [BMIM][Cl] were selected as entrainers based on the COSMO-SAC

method. The entrainer and the azeotropic mixture are fed to the extractive distillation column

12


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(EDC). In the EDC, the IL entrainer increases the volatility between MeOAc and MeOH, making

separation easier. The MeOAc is separated from the MeOH by the EDC, and the purity of the

MeOAc is designed to be no less than 99.9 mol% by adjusting the reflux mole ratio based on the

design specifications. The bottom stream of the EDC is fed to the flash tank as the entrainer

recovery section. The MeOH is separated from the ILs by the flash tank, and the purity of the

MeOH can reach 99.9 mol%. The ILs are produced in the bottom of the flash tank, and the purity

of the ILs is not less than 99.9 mol%. The ILs are recycled to the EDC.

TAC is one of the important factors used to evaluate process profitability. The TAC,

including the total operating cost and total capital cost, was calculated, and the total capital cost is

assumed to be the capital cost divided by the plant lifetime (Eq. (7))

45

. The plant lifetime is 3

years. The capital cost and utilities is estimated based on the book by Luyben 50. TAC=

total capital cost plant lifetime

+total operating cost

(7)

The EDC operating pressure is fixed at 1 atm. The operating parameters, such as the feed

stage of the azeotrope and entrainer, the number of total stages of the EDC (NEDC), the entrainer flowrate (S), and the temperature and pressure of the flash tank, are optimized based on the

sequential iteration method. Figure 10 shows the optimization procedure for the extractive

distillation process. The basis of the economics of the separation process is shown in Table 7S.

The operating pressure of the flash tank is 10 Pa after optimization. Figure 11 and Figure 12 are

shown in the process flowsheets of optimal parameters.

13



In this work, the economy of two processes for separating MeOAc and MeOH with different

entrainers is compared. The results are shown in Table S7. The comparison shows that the process

using [HMIM[[Cl] as an entrainer for the azeotropic separation is better than the process using

[BMIM[[Cl] as an entrainer.

4. Conclusions The COSMO-SAC method was used to select two suitable entrainers, [HMIM][Cl] and

[BMIM][Cl], from twenty-five ILs through the analysis of the selectivity at infinite dilution and

σ-profiles. A conceptual design process was proposed for separating MeOAc and MeOH

azeotropic mixtures by extractive distillation using IL as an entrainer. The binary interaction

parameters of MeOAc/IL and MeOH/IL were regressed by the NRTL model, and the results

showed that the values predicted by the model agreed with the experimental values. The

thermophysical properties of the ILs were fitted based on the experimental data to conduct an

extractive distillation process. The TACs of two processes using different entrainers were

compared. The results showed that the TAC of the process using [HMIM][Cl] as an entrainer is

16.5% less than that of the process using [BMIM][Cl] as an entrainer. The result agreed with the

result of the COSMO-SAC screening method, from which [HMIM][Cl] was the optimal entrainer.

These observations indicated that the COSMO-SAC method could provide a theoretical

instruction method for further industrial applications using ionic liquid as a entrainer.

14


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Supporting Information Tables S1- S8. This material is available free of charge on the website.

Detailed structures and name for all cations and anions of ILs, antoine equation parameters,

thermodynamic properties and model parameters of methyl acetate, methanol and ILs, equations

and parameters for temperature-dependent property of ILs, basis of economics and optimal

parameters for extractive distillation process can be found in the online version.(PDF)

Note The authors declare no competing financial interest.

ACKNOWLEDGEMENTS This work is supported by the National Natural Science Foundation of China (No. 21776145),

National Natural Science Foundation of China (No. 21676152).

Notation

S ∞ = the selectivity at the infinite dilution NRTL= non-random two liquid

Mw = molecular weight Tc = critical temperature, K Tb = normal boiling point, K Pc = critical pressure, bar Zc = critical compressibility factor

15



Vc = critical volume, m3/kmol ω = acentric factor

µ = viscosity, Pa•s ρ = density, kg/m3

σ = surface tension, N/m

bii, bji, α= binary interaction parameters RCM = residue curve map

NEDC = the total stages for extractive distillation column NIL= the feed stage for entrainer NF= the feed stage for azeotropic mixture IL/F= the ratio of the entrainer to feed

ID1 and ID2= the diameter of the equipment RR= the reflux ratio of extractive distillation column

PEDC = the pressure of extractive distillation column TF = the temperature of flash tank, K PF = the pressure of flash tank, bar QC= the heat duty of condenser QH= the heat duty of flash tank QR= the heat duty of reboiler

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TAC1= the total annual cost of extractive distillation column TAC2= the total annual cost of flash tank TAC = TAC1 + TAC2

References (1) Kulajanpeng, K.; Suriyapraphadilok, U.; Gani, R. Systematic screening methodology and

energy efficient design of ionic liquid-based separation processes. J. Clean Prod. 2016, 111,

93-107.

(2) Tong, L.; Wu, W.; Ye, Y.; Chen, L.;Wozny, G.; Qi, Z. Simulation study on a reactive distillation

process of methyl acetate hydrolysis intensified by reaction of methanol dehydration. Chem. Eng.

Proc: Process Intensif. 2013, 67, 111-119.

(3) Fuchigami, Y. Hydrolysis of Methyl Acetate in Distillation Column Packed with Reactive

Packing of Ion-Exchange Resin. J. Chem. Eng. Jpn. 1990, 23, 354–359.

(4) Kiss, A. A.; Suszwalak, D. J. P. C. Enhanced bioethanol dehydration by extractive and

azeotropic distillation in dividing-wall columns. Sep. Purif. Technol. 2012, 86, 70-78.

(5) Gomis, V.; Pedraza, R.; Saquete, M. D.; Font, A.; García-Cano, J. Ethanol dehydration via

azeotropic distillation with gasoline fraction mixtures as entrainers: A pilot-scale study with

industrially produced bioethanol and naphta. Fuel. Process. Technol. 2015, 140, 198-204.

(6) Zhu, Z.; Xu, D.; Wang, Y.; Geng, X.; Wang, Y. Effect of multi-recycle streams on

triple-column pressure-swing distillation optimization. Chem. Eng. Res. Des. 2017, 127, 215-222.

17



(7) Xia, H.; Ye, Q.; Feng, S.; Li, R.; Suo, X. A novel energy-saving pressure swing distillation

process based on self-heat recuperation technology. Energy. 2017, 141, 770-781.

(8) Shirsat, S. P. Separation of isobutyl alcohol and isobutyl acetate by extractive distillation and

pressure-swing distillation: Simulation and optimization. Sep. Purif. Technol. 2013, 118, 652.

(9) Luyben, W. L. Pressure-Swing Distillation for Minimum- and Maximum-Boiling

Homogeneous Azeotropes. Ind. Eng. Chem. Res. 2012, 51, 10881-10886.

(10) Li, Y.; Xu, C. Pressure-Swing Distillation for Separating Pressure-Insensitive Minimum

Boiling Azeotrope Methanol/Toluene via Introducing a Light Entrainer: Design and Control. Ind.

Eng. Chem. Res. 2017, 56, 4017-4037.

(11) Liang, S.; Cao, Y.; Liu, X.; Li, X.; Zhao, Y.; Wang, Y. Insight into pressure-swing distillation

from azeotropic phenomenon to dynamic control. Chem. Eng. Res. Des. 2017, 117, 318-335.

(12) Aniya, V.; De, D.; Singh, A.; Satyavathi, B. Design and operation of extractive distillation

systems using different class of entrainers for the production of fuel grade tert- butyl Alcohol:A

techno-economic assessment. Energy. 2018, 144, 1013-1025.

(13) Zhao, Y.; Zhao, T.; Jia, H.; Li, X.; Zhu, Z.; Wang, Y. Optimization of the composition of

mixed entrainer for economic extractive distillation process in view of the separation of

tetrahydrofuran/ethanol/water ternary azeotrope. J. Chem. Technol. Biotechnol. 2017, 92,

2433-2444.

(14) Wang, Y.; Cui, P.; Ma, Y.; Zhang, Z. Extractive distillation and pressure-swing distillation for

18


Page 18 of 48

Page 19 of 48 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


THF/ethanol separation. J. Chem. Technol. Biotechnol. 2015, 90, 1463-1472.

(15) Lo, K. M.; Chien, I. L. Efficient separation method for tert -butanol dehydration via

extractive distillation. J Taiwan Inst Chem E. 2017, 73, 27-36.

(16) Li, L.; Tu, Y.; Sun, L.; Hou, Y.; Zhu, M.; Guo, L.; Li, Q.; Tian, Y. Enhanced Efficient

Extractive Distillation by Combining Heat-Integrated Technology and Intermediate Heating. Ind.

Eng. Chem. Res. 2016, 55, 8837-8847.

(17) Zhao, Y.; Ma, K.; Bai, W.; Du, D.; Zhu, Z.; Wang, Y.; Gao, J. Energy-saving thermally

coupled ternary extractive distillation process by combining with mixed entrainer for separating

ternary mixture containing bioethanol. Energy. 2018, 148, 296-308.

(18) Premakshi, H. G.; Ramesh, K.; Kariduraganavar, M. Y. Modification of crosslinked chitosan

membrane using NaY zeolite for pervaporation separation of water–isopropanol mixtures. Chem.

Eng. Res. Des. 2015, 94, 32-43.

(19) Kudasheva, A.; Sorribas, S.; Zornoza, B.; Téllez, C.; Coronas, J. Pervaporation of

water/ethanol mixtures through polyimide based mixed matrix membranes containing ZIF-8,

ordered mesoporous silica and ZIF-8-silica core-shell spheres. J. Chem. Technol. Biotechnol. 2015,

90, 669-677.

(20) Dreimann, J.; Lutze, P.; Zagajewski, M.; Behr, A.; Górak, A.; Vorholt, A. J. Highly integrated

reactor–separator systems for the recycling of homogeneous catalysts. Chem. Eng. Proc: Proc

Intensific. 2016, 99, 124-131.

19



(21) Cao, J.; Yu, G.; Chen, X.; Abdeltawab, A. A.; Al-Enizi, A. M. Determination of Vapor–Liquid

Equilibrium of Methyl Acetate + Methanol + 1-Alkyl-3-methylimidazolium Dialkylphosphates at

101.3 kPa. J. Chem. Eng. Data. 2017, 62, 816-824.

(22) Lei, Z.; Xi, X.; Dai, C.; Zhu, J.; Chen, B. Extractive distillation with the mixture of ionic

liquid and solid inorganic salt as entrainers. AlChE. J. 2014, 60, 2994-3004.

(23) Zhu, Z.; Hu, J.; Geng, X.; Qin, B.; Ma, K.; Wang, Y.; Gao, J. Process design of carbon

dioxide and ethane separation using ionic liquid by extractive distillation. J. Chem. Technol.

Biotechnol. 2018, 93, 887-896.

(24) Lei, Z.; Dai, C.; Wang, W.; Chen, B. UNIFAC model for ionic liquid-CO2systems. AlChE. J.

2014, 60, 716-729. (25) Díaz, I.; Palomar, J.; Rodríguez, M.; de Riva, J.; Ferro, V.; González, E. J. Ionic liquids as

entrainers for the separation of aromatic–aliphatic hydrocarbon mixtures by extractive distillation.

Chem. Eng. Res. Des. 2016, 115, 382-393.

(26) Andreatta, A. E.; Charnley, M. P.; Brennecke, J. F. Using Ionic Liquids To Break the Ethanol–

Ethyl Acetate Azeotrope. ACS Sustain. Chem. Eng. 2015, 3, 3435-3444.

(27) Lei, Z.; Li, C.; Chen, B. Extractive distillation: a review. Sep. Purif. Rev. 2003, 32, 121-213.

(28) Zhu, Z.; Ri, Y.; Jia, H.; Li, X.; Wang, Y.; Wang, Y. Process evaluation on the separation of

ethyl acetate and ethanol using extractive distillation with ionic liquid. Sep. Purif. Technol. 2017,

181, 44-52.

20


Page 20 of 48

Page 21 of 48 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


(29) Coutinho, R. L,; Coutinho, J. A. P. A Group Contribution Method for Heat Capacity

Estimation of Ionic Liquids, Ind. Eng. Chem. Res, 2008, 47. 5751–5757 .

(30) Jose´, O.; Valderrama, a. R. E. R. Critical Properties of Ionic Liquids. Revisited. Ind. Eng.

Chem. Res. 2009, 48, 6890–6900.

(31) Sandler, S-TLaSI. A Priori Phase Equilibrium Prediction from a Segment Contribution

Solvation Model. Ind. Eng. Chem. Res. 2002, 41, 899-918.

(32) Sandler, S-TLaSI. A Priori Phase Equilibrium Prediction from a Segment Contribution

Solvation Model. Ind. Eng. Chem. Res. 2002, 41, 899-913.

(33) Shiang-Tai, Lin J.C,; Shu, Wang,; William, A. Goddard

and Stanley I. Sandler. Prediction of

Vapor Pressures and Enthalpies of Vaporization Using a COSMO Solvation Model. J. Phys. Chem.

A. 2004, 108, 7429-7439.

(34) Cai, J.; Cui, X.; Zhang, Y.; Li, R.; Feng, T. Isobaric Vapor–Liquid Equilibrium for Methanol

+ Methyl Acetate + 1-Octyl-3-methylimidazolium Hexafluorophosphate at 101.3 kPa. J. Chem.

Eng. Data. 2011, 56, 2884-2888.

(35) Zhang, Z.; Hu, A.; Zhang, T.; Zhang, Q.; Sun, M.; Sun, D.; Li, W. Separation of methyl

acetate+methanol azeotropic mixture using ionic liquids as entrainers. Fluid. Phase. Equilib. 2015,

401, 1-8.

(36) Fang, J.; Zhao, R.; Su, W.; Li, C.; Liu, J.; Li, B. A molecular design method based on the

COSMO-SAC model for solvent selection in ionic liquid extractive distillation. AlChE. J. 2016,

21



62, 2853-2869.

(37) Dhanalakshmi, J.; Sai, P. S. T.; Balakrishnan, A. R. Study of Ionic Liquids as Entrainers for

the Separation of Methyl Acetate–Methanol and Ethyl Acetate–Ethanol Systems Using the

COSMO-RS Model. Ind. Eng. Chem. Res. 2013, 52, 16396-16405.

(38) Salleh, Z.; Wazeer, I.; Mulyono, S.; El-blidi, L.; Hashim, M. A.; Hadj-Kali, M. K. Efficient

removal of benzene from cyclohexane-benzene mixtures using deep eutectic solvents –

COSMO-RS screening and experimental validation. J. Chem. Thermodyn. 2017, 104, 33-44.

(39) Li, J.; Yang, X.; Chen, K.; Zheng, Y.; Peng, C.; Liu, H. Sifting Ionic Liquids as Additives for

Separation of Acetonitrile and Water Azeotropic Mixture Using the COSMO-RS Method. Ind. Eng.

Chem. Res. 2012, 51, 9376-9385.

(40) Ma, S.; Yu, Q.; Hou, Y.; Li, J.; Li, Y.; Ma, Z.; Sun, L. Screening Monoethanolamine As

Solvent to Extract Phenols from Alkane. Energ. Fuel. 2017, 31, 12997-13009.

(41) Zhou, Y.; Xu, D.; Zhang, L.; Ma, Y.; Ma, X.; Gao, J. Wang Y. Separation of thioglycolic acid

from its aqueous solution by ionic liquids: Ionic liquids selection by the COSMO-SAC model and

liquid-liquid phase equilibrium. J. Chem. Thermodyn. 2018, 118, 263-273.

(42) Eric, Mullins R.O,; Y. A. Liu,; Shu, Wang,; Stanley, I.; Sandler,; Chau-Chyun, Chen,; Michael,

Zwolak aKCS. Sigma-Profile Database for Using COSMO-Based Thermodynamic Methods. Ind.

Eng. Chem. Res. 2006, 45, 4389-4415.

(43) Yu, G.; Dai, C.; Lei, Z. Modified UNIFAC-Lei Model for Ionic Liquid–CH4 Systems. Ind.

22


Page 22 of 48

Page 23 of 48 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


Eng. Chem. Res. 2018, 57, 7064-7076.

(44) Gutierrez-Sevillano, J. J.; Leonhard, K.; van der Eerden, J. P. J. M.; Vlugt, T. J. H.; Krooshof,

G. J. P. COSMO-3D: Incorporating Three-Dimensional Contact Information into the

COSMO-SAC Model. Ind. Eng. Chem. Res. 2015, 54, 2214-2226.

(45) Zhang, Z.; Hu, A.; Zhang, T.; Zhang, Q.; Yang, Z.; Li, W. Isobaric vapor–liquid equilibrium

for methyl acetate+methanol system containing different ionic liquids at 101.3kPa. Fluid.

Phase .Equilib. 2016, 408, 20-26.

(46) Jose´, O.; Valderrama, aRER. Critical Properties of Ionic Liquids. Revisited. Ind. Eng.

Chem. Res. 2009, 48, 6890–6900.

(47)

Seddon,

K.

R.;

Stark,

A.;

Torres,

M.

J.

Viscosity

and

Density

of

1-Alkyl-3-methylimidazolium Ionic Liquids. Clean Solvents. 2002, 819, 34-49.

(48) Mac, Dowell N.; Llovell, F.; Sun, N.; Hallett, J. P.; George, A.; Hunt, P. A.; Welton, T.;

Simmons, B. A.; Vega, L. F. New experimental density data and soft-SAFT models of

alkylimidazolium ([C(n)C(1)im](+)) chloride (Cl(-)), methylsulfate ([MeSO(4)](-)), and

dimethylphosphate ([Me(2)PO(4)](-)) based ionic liquids. J Phys Chem B. 2014, 118, 6206-6221.

(49) Ghatee MH.Zolghadr AR. Surface tension measurements of imidazolium-based ionic liquids

at liquid–vapor equilibrium. Fluid. Phase. Equilib. 2008, 263, 168-175.

(50) Luyben, W. L. Distillation Design and Control Using Aspen Simulation, JohnWiley & Sons,

2013.

23



Figure 1. σ-profiles for MeOAc, MeOH and cations ([HMIM] +, [EMIM] +, [MMIM] +, [OMIM] +, and [BMIM] +).

24


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Figure 2. σ-profiles for MeOAc, MeOH and anions([Cl]−, [DMP]−, [Triflate]−, [PF6]−, and [Tf2N]−).

25



Figure 3. Selectivity of the imidazolium-based ionic liquids at infinite dilution.

26


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Figure 4. Selectivity of the [HMIM]+-based ionic liquids with anions ([Cl]−, [DMP]−, [Triflate]−, [PF6]−, and [Tf2N] −) at infinite dilution.

27



Figure 5. Comparison of vapor phase values between experiment and calculated data.

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Figure 6. Isobaric VLE diagram for a binary system of MeOAc (1) and MeOH (2). (a) The mole

fraction of [HMIM][Cl] is 0.1; (b) The mole fraction of [BMIM][Cl] is 0.1.

29



Figure 7. Temperature–dependent property of [HMIM][Cl] and [BMIM][Cl]. (a) Density; (b)

Surface tension; (c) Viscosity. Symbols: experimental data. Curve: fitting.

30


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Figure 8. Comparisons of molar fraction between the model regression and the experimental values. (a) and (c) vapor; (b) and (d) liquid.

31



Figure 9. RCM with the isovolatility curve of MeOAc and MeOH using ILs as solvent. (a)

[HMIM][Cl]; (b) [BMIM][Cl].

32


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Figure 10. Optimization procedure for extractive distillation process.

33



Figure 11. Flowsheet for MeOAc and MeOH separation using [HMIM][Cl] as a solvent.

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Figure 12. Flowsheet for MeOAc and MeOH separation using [BMIM][Cl] as a solvent.

35



Figure 1. σ-profiles for MeOAc, MeOH and cations ([HMIM] +, [EMIM] +, [MMIM] +, [OMIM] +, and [BMIM] +). 238x172mm (300 x 300 DPI)


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Figure 2. σ-profiles for MeOAc, MeOH and anions([Cl]−, [DMP]−, [Triflate]−, [PF6]−, and [Tf2N]−). 232x176mm (300 x 300 DPI)



Figure 3. Selectivity of the imidazolium-based ionic liquids at infinite dilution. 229x170mm (300 x 300 DPI)


Page 38 of 48

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Figure 4. Selectivity of the [HMIM]+-based ionic liquids with anion ([Cl]−, [DMP]−, [Triflate]−, [PF6]−, and [Tf2N] −) at infinite dilution. 232x201mm (300 x 300 DPI)



Figure 5. Comparison of vapor phase values between experiment and calculated data. 238x173mm (300 x 300 DPI)


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Figure 6. Isobaric VLE diagram for a binary system of MeOAc (1) and MeOH (2). (a) The mole fraction of [HMIM][Cl] is 0.1; (b) The mole fraction of [BMIM][Cl] is 0.1. 497x191mm (300 x 300 DPI)



Figure 7. Temperature–dependent property of [HMIM][Cl] and [BMIM][Cl]. (a) Density; (b) Surface tension; (c) Viscosity. Symbols: experimental data. Curve: fitting. 501x371mm (300 x 300 DPI)


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Figure 8. Comparisons of molar fraction between the model regression and the experimental values. (a) and (c) vapor; (b) and (d) liquid. 507x399mm (300 x 300 DPI)



Figure 9. RCM with the isovolatility curve of MeOAc and MeOH using ILs as solvent. (a) [HMIM][Cl]; (b) [BMIM][Cl]. 250x360mm (300 x 300 DPI)


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Figure 10. Optimization procedure for extractive distillation process. 24x19mm (300 x 300 DPI)



Figure 11. Flowsheet for MeOAc and MeOH separation using [HMIM][Cl] as a solvent. 27x17mm (300 x 300 DPI)


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Figure 12. Flowsheet for MeOAc and MeOH separation using [BMIM][Cl] as a solvent. 29x19mm (300 x 300 DPI)



166x99mm (300 x 300 DPI)


Page 48 of 48

Computer-Aided Screening of Ionic Liquids as Entrainers for

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