Solubilities of Small Hydrocarbons in Tetrabutylphosphonium Bis (2, 4

Subscriber access provided by Wake Forest Univ. Libraries

Article

Solubilities of small hydrocarbons in tetrabutylphosphonium bis(2,4,4-trimethylpentyl) phosphinate and in 1-ethyl-3methylimidazolium bis(trifluoromethylsulfonyl)imide Xiangyang Liu, Waheed Afzal, and John M Prausnitz Ind. Eng. Chem. Res., Just Accepted Manuscript • DOI: 10.1021/ie402196m • Publication Date (Web): 20 Sep 2013 Downloaded from http://pubs.acs.org on September 23, 2013

Just Accepted “Just Accepted” manuscripts have been peer-reviewed and accepted for publication. They are posted online prior to technical editing, formatting for publication and author proofing. The American Chemical Society provides “Just Accepted” as a free service to the research community to expedite the dissemination of scientific material as soon as possible after acceptance. “Just Accepted” manuscripts appear in full in PDF format accompanied by an HTML abstract. “Just Accepted” manuscripts have been fully peer reviewed, but should not be considered the official version of record. They are accessible to all readers and citable by the Digital Object Identifier (DOI®). “Just Accepted” is an optional service offered to authors. Therefore, the “Just Accepted” Web site may not include all articles that will be published in the journal. After a manuscript is technically edited and formatted, it will be removed from the “Just Accepted” Web site and published as an ASAP article. Note that technical editing may introduce minor changes to the manuscript text and/or graphics which could affect content, and all legal disclaimers and ethical guidelines that apply to the journal pertain. ACS cannot be held responsible for errors or consequences arising from the use of information contained in these “Just Accepted” manuscripts.

Industrial & Engineering Chemistry Research is published by the American Chemical Society. 1155 Sixteenth Street N.W., Washington, DC 20036 Published by American Chemical Society. Copyright © American Chemical Society. However, no copyright claim is made to original U.S. Government works, or works produced by employees of any Commonwealth realm Crown government in the course of their duties.

Page 1 of 16

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

Industrial & Engineering Chemistry Research

Solubilities of small hydrocarbons in tetrabutylphosphonium bis(2,4,4-trimethylpentyl) phosphinate and in 1-ethyl-3methylimidazolium bis(trifluoromethylsulfonyl)imide Xiangyang Liu1,3, Waheed Afzal1,2,4, John M. Prausnitz1,2,* 1

Department of Chemical and Biomolecular Engineering, University of California, Berkeley, California 94720-1462, United States 2 Lawrence-Berkeley National Laboratory, Berkeley, California, United States 3 MOE Key Laboratory of Thermo-Fluid Science and Engineering, Xi’an Jiaotong University, Xi'an, Shaanxi, 710049, P.R. China 4 Institute of Chemical Engineering & Technology, University of the Punjab, Lahore, 54590, Pakistan *Corresponding author: John M. Prausnitz; Department of Chemical and Biomolecular Engineering, University of California, Berkeley, CA 94720-1462, United States; Tel: +1 510 642 3592; fax: +1 510 642 4778, E-mail address: [email protected]

1 ACS Paragon Plus Environment


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

ABSTRACT Experimental solubilities are reported for methane, ethane, ethylene and propane in ionic liquid tetrabutylphosphonium bis(2,4,4-trimethylpentyl) phosphinate [P4444][TMPP] from 313 to 353 K up to 5MPa. [P4444][TMPP] shows solubilities for methane, ethane, ethylene and propane that are appreciably larger than those in other typical ionic liquids. However, unlike a hydrocarbon solvent, [P4444][TMPP] is not flammable at ordinary conditions. Unlike other typical ionic liquids, the solubility for ethane is larger than that for ethylene. Because the viscosity of [P4444][TMPP] is high, we consider a low-viscosity diluent. Therefore, experimental solubilities are also reported for the same solutes in 1-ethyl-3methylimidazolium bis(trifluoromethylsulfonyl)imide, [EMIM][Tf2N] from 299 to 354 K up to 4MPa. Comparison between our results and literature data shows good agreement.

Keywords: solubility, ionic liquid, methane, ethane, ethylene, propane


Page 2 of 16

Page 3 of 16

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


INTRODUCTION Ionic liquids are potential substitutes for conventional solvents due to their advantageous physical properties, such as negligible vapor pressure, nonflammability and chemical stability1,2,3. Because ionic liquids can be tuned by altering the cation or anion, they are useful solvents for separation processes, analytical and synthetic chemistry, nanotechnology, and other applications.4,5,6 Recently7, we reported solubilities of lower paraffins and olefins (carbon number=1, 2, 3) in partially hydrophobic ionic liquid trihexyl tetradecylphosphonium bis(2,4,4trimethylpentyl) phosphinate [P(14)666][TMPP]. Solubilities of small paraffins and olefins in [P(14)666][TMPP] are larger than those in other typical ionic liquids.7 Solubilities of paraffins are larger than those of the corresponding olefins. [P(14)666][TMPP] may be useful to enhance the separation factor of olefin and paraffin because the vapor pressure of an olefin is higher than that of its corresponding paraffin at the same temperature. Following our earlier work with tetraalkylphosphonium bis(2,4,4trimethylpentyl) phosphinate, to study the effect of different alkyl groups on the cation on gas solubility, and hoping that the viscosity would decrease, we obtained a similar ionic liquid with tetrabutyl alkyl groups on the cation: tetrabutylphosphonium bis(2,4,4trimethylpentyl) phosphinate [P4444][TMPP]. Regrettably, the viscosity of [P4444][TMPP] is also high as report in a forthcoming publication. We now report solubilities of methane, ethane, ethylene, and propane in [P4444]][TMPP] from 313 to 353 K up to 5 MPa. We compare Henry’s constants for each solute in several ionic liquids with those in [P4444]][TMPP]. Because 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide [EMIM][Tf2N] is a possible diluent (viscosity is about 30 cP at ambient temperature) to reduce viscosity8, we also report solubilities of methane, ethane, ethylene and propane in [EMIM][Tf2N] from 299 to 354 K up to 4MPa; our results are compared with literature data to assure experimental reliability. A 10 or 20 wt. % mixture of [EMIM][Tf2N] may be a useful solvent for separating ethylene from ethane in an absorption process.

EXPERIMENTAL All gases were supplied by Praxair or Matheson with purity ≥ 99.9%. [P4444][TMPP] and [EMIM][Tf2N] were provided by Ionic-Liquid-Technologies (Io-Li-Tech) with purity > 97%. The ionic liquids were dried in a vacuum oven at about 373 K for 24 hours to remove water and other volatile impurities. We used an Anton Paar vibrating-tube densimeter (model DMA 5000M) for measuring the density of [P4444][TMPP]. Previous publications give experimental details.9 The isochoric saturation method was used to measure the solubilities of gases in [P4444][TMPP] and [EMIM][Tf2N], as described in previous publications7, 10. This method requires density data. 3 ACS Paragon Plus Environment


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

Page 4 of 16

CORRELATION Experimental solubilities are fitted to the Krichevsky-Kasarnovsky (KK) equation11: For gas 1 in solvent 2,

ln

f1 V ∞ ( p − p2S ) = ln H + 1 x1 RT

(1)

where f1 is the fugacity of gas 1 calculated using the REFPROP computer program12; x1 is the mole fraction of solute 1 in solvent 2; H is Henry’s constant when total pressure p equals solvent vapor pressure p2S ; V1∞ is the partial molar volume of solute in the solvent at infinite dilution and R is the gas constant. For an ionic liquid at normal temperature, p2S is essentially zero. Eq.(1) becomes

ln

f1 V∞p = ln H + 1 x1 RT

(2)

Where H and f are in MPa, and T is in kelvins. At a fixed temperature and for a particular solute in a particular solvent, Henry’s constant and V1∞ are obtained from the intercept and slope of a plot of ln(f1/x1) vs p. RESULTS AND DISCUSSION Densities of [EMIM][Tf2N] were reported earlier9; Table S1 (Supporting Information) presents experimental densities of [P4444][TMPP] from 303 to 363 K at atmospheric pressure(Mass density is necessary for calculating solubility). The mass densities of [P4444][TMPP] and [EMIM][Tf2N] are represented by Eq.(3) and Eq.(4), respectively.

ρ = − 5.9896 ⋅10−4T +1.0954

(3)

ρ = − 9.9430 ⋅10−4T +1.8148

(4)

where ρ is in g·cm-3 and T is in kelvins. Tables S2, S3 (Supporting Information) present experimental solubilities for methane, ethane, ethylene, and propane in [P4444][TMPP] and in [EMIM][Tf2N] from 299 to 354 K up to 5MPa. We repeated each experiment three times. The relative uncertainty in mole fraction is less than 5%. Figures 1, 2 present the solubilities for methane, ethane, ethylene and propane in [P4444][TMPP] and in [EMIM][Tf2N] at 333K. Figures 1 and 2 show that the solubilities of the four gases in [P4444][TMPP] and in [EMIM][Tf2N] rise with pressure and with the carbon number of the solute. [EMIM][Tf2N] shows that the solubility for ethylene is higher than that for ethane, but [P4444][TMPP] shows that the solubility for ethane is higher than that for ethylene, as in [P(14)666][TMPP]. Table S4 (Supporting Information) and Figures 3 and 4 show Henry’s constants for the four gases in [P4444][TMPP] and in [EMIM][Tf2N] as a function of temperature. Henry’s constants fall as temperature increases. They can be represented by: 4 ACS Paragon Plus Environment

Page 5 of 16

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


A +B (5) T where H is in MPa and T is in kelvins. Coefficients A and B are listed in Table 1, together with the absolute average deviation between experiment and Eqs.(2 and 5) for each solute in [P4444][TMPP] and in [EMIM][Tf2N]. Table 1 shows that Eq.(5) agrees well with experiment. ln H =

Figure 3 shows that our experimental Henry’s constants for gases in [EMIM][Tf2N] agree well with those reported by Camper et al.13, 14, 15. Figures 1 and 2 and Table 1 show that the KK equation gives a good representation of the experimental data. Table 2 compares Henry’s constants for four solutes in [P4444][TMPP] with those in other phosphonium-based ionic liquids7, 16, 17. Table 2 gives abbreviations for the names of ionic liquids; solubilities for the four solutes in other ionic liquids were given earlier7. Phosphonium-based ionic liquids show that solubilities for methane, ethane, ethylene and propane are larger than those in ammonium-based and imidazolium-based ionic liquids. Table 2 shows that the four solutes have high solubility in [P4444][TMPP]. Figure 5 shows that the solubility of methane in [P4444][TMPP] is much higher than those in imidazolium-based ionic liquids. Solubilities of the four solutes in [P(14)666][TMPP] are higher than those in ionic liquids with the same cation. [P4444][TMPP] shows solubilities for the four solutes slightly lower than those in [P(14)666][TMPP] because the cation is smaller. For [P4444][TMPP], solubilities for ethylene are larger than those in [P(14)666][Cl] and in [P(14)666]DCA], indicating that the anion is more important in the dissolution of light hydrocarbons in ionic liquids than the cation. SUPPORTING INFORMATION The supporting information gives details concerning solubilities and Henry’s constants for methane, ethane, ethylene and propane in [P4444][TMPP] and [EMIM][Tf2N]. Density data are given for [P4444][TMPP]. This information is available free of charge via the Internet at http://pubs.acs.org/. CONCLUSIONS The solubilities of methane, ethane, propane, and ethylene in [P4444][TMPP] and in [EMIM][Tf2N] have been measured from 299 to 354K up to 5MPa. [P4444][TMPP] shows high solubilities for methane, ethane, propane and ethylene. Ethylene is less soluble than ethane in [P4444][TMPP], indicating that [P4444][TMPP] may be useful to enhance the relative volatility for ethane and ethylene. When we compare [P4444][TMPP] with other tetraalkylphosphonium-based ionic liquids, we find that the anion plays a leading role in the dissolution of light hydrocarbons in an ionic liquid. Our experimental solubilities for methane, ethane, propane and ethylene in [EMIM][Tf2N] show good agreement with the literature. The experimental solubilities of methane, ethane, ethylene and propane in [P4444][TMPP] and in [EMIM][Tf2N] are described well by the Krichevsky-Kasarnovsky(KK) equation. The data given here suggest that 5 ACS Paragon Plus Environment


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

[P4444][TMPP] diluted with [EMIM][Tf2N] may be a useful solvent for separation of light hydrocarbons by absorption.

ACKNOWLEDGMENTS The authors are grateful to the Environmental Energy Technologies Division of the Lawrence Berkeley National Laboratory for financial support, and to Prof. Scott Lynn, to Dr. Amit Gokhale and to Prof. Alexis Bell and co-workers for general assistance. We are grateful to Prof. Michael Manga (Dept. of Earth and Planetary Sciences, University of California, Berkeley) for providing his density meter.


Page 6 of 16

Page 7 of 16

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


REFERENCE (1) Anderson, J. L.; Dixon, J. K.; Brennecke, J. F. Solubility of CO2, CH4, C2H6, C2H4, O2, and N2 in 1-hexyl-3-methylpyridinium bis(trifluoromethylsulfonyl)imide: Comparison to other ionic liquids. Acc. Chem. Res. 2007, 40, 1208-1216. (2) Mokrushin, V.; Mokrushina, L.; Arlt, W.; Assenbaum, D.; Wasserscheid, P.; Petri, M.; Wewers, W. Ionic Liquids for Chloromethane/Isobutane Distillative Separation: Express Screening. Chem. Eng. Technol. 2010, 33, 993-997. (3) Cull, S. G.; Holbrey, J. D.; Vargas Mora, V.; Seddon, K. R.; Lye, G. J. Roomtemperature ionic liquids as replacements for organic solvents in multiphase bioprocess operations. Biotechnol. Bioeng. 2000, 69, 227-233. (4) Swatloski, R. P.; Spear, S. K.; Holbrey, J. D.; Rogers, R. D. Dissolution of cellose with ionic liquids. J. Am. Chem. Soc. 2002, 124, 4974-4975. (5) Anthony, J. L.; Maginn, E. J. Brennecke, J. F. Solubilities and thermodynamic properties of gases in the ionic liquid 1-n-butyl-3-methylimidazolium hexafluorophosphate. J. Phys. Chem. B. 2002, 106, 7315-7320; (6) Weingaertner, H. Understanding ionic liquids at the molecular level: Facts, problems, and controversies. Angew. Chem. Int. Edit. 2008, 47, 654-670. (7) Liu, X. Y.; Afzal, W.; Prausnitz, J. M. High solubilities of small hydrocarbons in trihexyl tetradecylphosphonium bis(2,4,4-trimethylpentyl) phosphinate. J. Phy. Chem. B. 2013, accepted. (8) Yu, G. R.; Zhao, D. C.; Wen, L.; Yang, S. D.; Chen, X. C. Viscosity of ionic liquids: Database, observation, and quantitative structure-property relationship analysis. Aiche J. 2012, 58, 2885-2899. (9) Yoo, B.; Afzal, W. Prausnitz, J. M. Effect of Water on the Densities and Viscosities of Some Ionic Liquids Containing a Phosphonium Cation. Z. Phys. Chem. 2013, 227, 157-165. (10) Afzal, W.; Liu, X. Y.; Prausnitz, J. M. Solubilities of some gases in four immidazolium-based ionic liquids. J. Chem. Thermodyn. 2013, 63, 88-94. (11) Krichevsky, I. R.; Kasarnovsky, J. S. Thermodynamical calculations of solubilities of nitrogen and hydrogen in water at high pressures. J. Am. Chem. Soc. 1935, 57, 2168-2171. (12) Lemmon, E. W.; McLinden, M. O.; Huber, M. L. NIST Reference Fluid Thermodynamic and Transport Properties Database-REFPROP, version 8.0; National Institute of Standards and Technology: Gaithersburg, MD, 2006. (13) Camper, D.; Bara, J.; Koval, C.; Noble, R. Bulk-fluid solubility and membrane feasibility of Rmim-based room-temperature ionic liquids. Ind. Eng. Chem. Res. 2006, 45, 6279-6283. (14) Camper, D.; Becker, C.; Koval, C. Noble, R. Low pressure hydrocarbon solubility in room temperature ionic liquids containing imidazolium rings interpreted using regular solution theory. Ind. Eng. Chem. Res. 2005, 44, 1928-1933. (15) Camper, D.; Becker, C.; Koval, C.; Noble, R. Diffusion and solubility measurements in room temperature ionic liquids. Ind. Eng. Chem. Res. 2006, 45, 445-450.



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

(16) Blath, J.; Christ, M.; Deubler, N.; Hirth, T.; Schiestel, T. Gas solubilities in room temperature ionic liquids - Correlation between RTiL-molar mass and Henry's law constant. Chem. Eng. J. 2011, 172, 167-176. (17) Ferguson, L.; Scovazzo, P. Solubility, diffusivity, and permeability of gases in phosphonium-based room temperature ionic liquids: Data and correlations. Ind. Eng. Chem. Res. 2007, 46, 1369-1374.


Page 8 of 16

Page 9 of 16

5 methane

4.5

ethane ethylene

4

propane

3.5

KK equation

3 p / MPa

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


2.5 2 1.5 1 0.5 0 0

0.15

0.3 x / mole fraction

0.45

Figure 1. Solubilities for four gases in [P4444][TMPP] at 333K. Points are experimental data. Lines show the Krichevsky-Kasarnovsky equation.



methane

4

ethane

3.5

ethylene propane

3

KK equation

2.5 p / MPa

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

Page 10 of 16

2 1.5 1 0.5 0 0

0.025

0.05

0.075 0.1 0.125 x / mole fraction

0.15

0.175

Figure 2. Solubilities for four gases in [EMIM][Tf2N] at 333K. Points are experimental data. Lines show the Krichevsky-Kasarnovsky equation.


Page 11 of 16

70 methane ethane

60

ethylene propane Camper et al

50

Eq.(5)

H / MPa

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


40

30

20

10

0 290

310

T/K

330

350

Figure 3. Henry constants for four gases in [EMIM][Tf2N]. Points are experimental data. Lines show Eq.(5).



16 methane

14

ethane ethylene propane

12

Eq.(5)

10 H / MPa

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

Page 12 of 16

8 6 4 2 0 310

320

330

T/K

340

350

Figure 4. Henry constants for four gases in [P4444][TMPP]. Points are experimental data. Lines show Eq.(5).


Page 13 of 16

1000

100 H/MPa

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


10

1 1

2

3

4

5

6

7 Solvent

8

9

10

11

12

Figure 5. Henry’s constants for methane in several ionic liquids at 313K. 1: [MIMM][MeSO4]7; 2: [EMIM][BF4]7;3: [EMIM][dca]7; 4: [EMIM][CF3SO3]7; 5: [BMIM][PF6]7; 6: [EMIM][Tf2N]; 7: [BMIM][Tf2N]7; 8: [C1COOC5MIM][Tf2N]7; 9: [HMPY][Tf2N]7; 10: [P(14)666][FAP] (333 K)16; 11: [P4444][TMPP]; 12: [P(14)666][TMPP]7. Solubility is highest in solvent 12.



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

Page 14 of 16

Table 1. Coefficients in Eq.(5) for four gases in [EMIM][Tf2N] and in [P4444][TMPP] [EMIM][Tf2N]

A/K B a

|∆H| /% b

|∆xKK| /%

[P4444][TMPP]

methane

ethane

ethylene

propane

methane

ethane

ethylene

propane

-425.57

-1020.4

-1255.9

-1433.2

-533.07

-1119.5

-860.98

-1705.4

5.3591

6.0878

6.4767

6.7134

4.2223

4.6341

4.0792

5.4259

0.37

0.02

0.82

2.14

0.12

0.01

1.46

0.72

0.48

0.83

0.89

1.20

0.41

0.81

0.98

0.71

a

|∆H| is the absolute average deviation between experiment and calculation from Eq.(5). |∆xKK| is the absolute average deviation between experiment and calculation from the KrichevskyKasarnovsky equation.

b


Page 15 of 16

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


Table 2. Henry’s constants for four gases in a variety of ionic liquids ionic liquid

H/MPa 303K

313K

333K

methane [EMIM][Tf2N]a

52.2

[P(14)666][FAP]

[P(14)666][TMPP] [P4444][TMPP]

54.6

16

59.2 9.1

7

a

7.5

7.8

8.5

11.8

12.4

13.8

ethane [EMIM][Tf2N]

a

[P(14)666][TMPP] [P4444][TMPP]

7

a

15.2

16.9

20.6

1.6

1.9

2.4

2.6

2.9

3.6

ethylene a

10.0

17

3.6

[EMIM][Tf2N] [P(14)666][Cl]

11.6

15.4

2.3

2.6

3.3

3.5

3.8

4.5

[P(14)666]DCA]17

3.7

[P(14)666][Tf2N]17

2.5

[P2444][DEP]

17

8.3

[P(14)444][DBS]

17

2.7

[P(14)666][TMPP]7 [P4444][TMPP]

a

propane [EMIM][Tf2N]

a

[P(14)666][TMPP] [P4444][TMPP]a a

7

7.3

8.5

11.1

0.51

0.64

0.95

0.82

1.0

1.4

: Henry’s constants at different temperatures calculated from Eq. (5).



Graphic

Solubilities of small hydrocarbons in tetrabutylphosphonium bis(2,4,4-trimethylpentyl) phosphinate and in 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide Xiangyang Liu1,3, Waheed Afzal1,2,4, John M. Prausnitz1,2,* 1 Department of Chemical and Biomolecular Engineering, University of California, Berkeley, California 94720-1462 2 Division of Lawrence-Berkeley National Laboratory, Berkeley, California 94720 3 MOE Key Laboratory of Thermo-Fluid Science and Engineering, Xi’an Jiaotong University, Xi'an, Shaanxi, 710049, P.R. China 4 Institute of Chemical Engineering & Technology, University of the Punjab, Lahore, 54590, Pakistan 5 4.5 methane

4

ethane ethylene

3.5

propane KK equation

3 p / MPa

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

2.5 2

1.5 1 0.5 0 0

0.15

0.3 x / mole fraction

0.45

Solubilities for four gases in [P4444][TMPP] at 333K. Points are experimental data. Lines show the Krichevsky-Kasarnovsky equation.

ACS Paragon Plus Environment

Page 16 of 16

Solubilities of Small Hydrocarbons in Tetrabutylphosphonium Bis (2, 4

Recommend Documents