Density, Speed of Sound, and Viscosity of Monoethanolamine +

Article pubs.acs.org/jced

Density, Speed of Sound, and Viscosity of Monoethanolamine + Water + N‑Ethyl-2-pyrrolidone from T = (293.15 to 323.15) K Alicia García-Abuín,* Diego Gómez-Díaz, and José M. Navaza Department of Chemical Engineering, ETSE, University of Santiago de Compostela, Rúa Lope Gómez de Marzoa s/n, Santiago de Compostela E-15706, Spain S Supporting Information *

ABSTRACT: The influence of the addition of N-ethyl-2-pyrrolidone to the system monoethanolamine + water upon several physical properties has been studied in the present work. Density, speed of sound, and viscosity were determined for the tertiary mixture monoethanolamine (MEA) + water + N-ethyl-2-pyrrolidone (NEP), for NEP mass fraction lower than 0.3. These properties were obtained at different temperatures from (293.15 to 323.15) K and at atmospheric pressure. The excess molar volumes and isentropic compressibility were also calculated.

formulations, for instance due to the importance of flow properties in the production process or application procedures. On the other hand, speed of sound values can contribute useful information about molecules interactions and aggregation procedures in this kind of mixtures.

1. INTRODUCTION Nowadays the best available technique to capture carbon dioxide is the chemical absorption with aqueous alkanolamine solutions.1 However, recently different researchers2−4 have proposed blends of two amines (such as mixtures of monoethanolamine and methyldiethanolamine or mixtures of monoethanolamine + triethanolamine) as suitable solvents to capture this acid gas. Another option to remove carbon dioxide is using physical solvents, these substances do not react with carbon dioxide but capture it by a physical absorption process,5 for instance N-methyl-2-pyrrolidone or N-ethyl-2-pyrrolidone (NEP). For this reason, the addition of small amounts of physical solvent, including NEP, to an aqueous solution of alkanolamine could be a promising alternative to conventional processes for carbon dioxide capture.6 On the other hand, both N-ethyl-2-pyrrolidone and monoethanolamine (MEA) are used in the formulation of cosmetic products. The first one is a permeation enhancer for transdermal drug delivery,7 and the second one helps to form emulsions by reducing the surface tension of the substances to be emulsified so that water-soluble and oil-soluble ingredients can be blended together. At the same time, it is also used to control the pH of cosmetic and personal care products. Taking into account the current and potential uses of these blends, several physical properties (density, speed of sound, and viscosity) are measured in the present work at different temperatures from (293.15 to 323.15) K, at atmospheric pressure, and for different compositions. These physical properties can show a high influence upon mass transfer processes and hydrodynamics8 during the carbon dioxide absorption, and also the knowledge of these properties could help to improve the quality and acceptance of cosmetic © 2013 American Chemical Society

2. EXPERIMENTAL SECTION 2.1. Materials. Information about the reagents employed in the present work is included in Table 1. The samples preparation procedures (by mass) has shown an uncertainty in mole fraction of ± 0.0008. Bidistilled water was used to prepare the binary and ternary mixtures. Table 1. Sample Description Table chemical name a

NEP MEAb a

source

initial mole fraction purity

Alfa Aesar Sigma-Aldrich

0.98 ≥ 0.99

N-ethyl-2-pyrrolidone. bMonoethanolamine.

2.2. Methods. Density and Speed of Sound. The density and speed of sound of pure components and the mixtures of different compounds were measured with an Anton Paar DSA 5000 vibrating tube densimeter and sound analyzer.8 2.3. Viscosity. The kinematic viscosity (ν) was determined from the efflux time of the liquid meniscus through capillary Ubbelohde viscosimeters supplied by Schott.8 In the present work the capillaries used were numbers I, Ic, and Ia. They were Received: June 21, 2013 Accepted: November 13, 2013 Published: November 22, 2013 3387

dx.doi.org/10.1021/je4005883 | J. Chem. Eng. Data 2013, 58, 3387−3391

Journal of Chemical & Engineering Data

Article

Table 2. Comparison between Density ρ, Speed of Sound c, and Viscosity η, Experimental and Literature Data for Pure Components at T = 298.15 K at p = 101325 Pac ρ/g·cm‑3

T/K exptl.

c/m·s‑1 lit.

298.15

1.01198

1.011809 1.0118010 1.0123911

298.15

0.99706

0.9970410 0.9970411 0.9970514

exptl. MEA 1719.2

Water 1496.7

η/mPa·s lit.

exptl.

lit.

1717.79 1719.212 1798.1811

18.740

18.98013

1496.79 1498.6711 1497.015

0.891

0.89014

c Standard uncertainties u are u(T) = 0.01 K, u(p) = 20 Pa, and the combined expanded uncertainties Uc (level of confidence = 0.95, k = 2) are Uc(ρ) = 2·10−4 g·cm−3, Uc(c) = 1.2 m·s−1 and Uc(η) = 0.0026 mPa·s.

Table 3. Density ρ/g·cm−3, of MEA (1) + H2O (2) + NEP (3) from T = (293.15 to 323.15) K for Mass Fractions C at Atmospheric Pressurec

connected to a Schott-Geräte AVS 350 Ubbelohde viscosimeter, and eq 1 was employed for viscosity calculations on the basis of transit time

ν = K · (t − θ )

(1)

where t is the efflux time; K is the characteristic constant of the capillary viscosimeter; and θ is a correction value to correct end effects. These parameters (K and θ) were obtained from the supplier (Schott), specifically the values of constants of viscosimeters are (0.01013, 0.03006, and 0.05047) mm2·s−2, respectively. To measure efflux times, an electronic stopwatch, with an accuracy of ± 0.01 s, was used. A Schott-Geräte AVS 350 Ubbelohde viscosimeter was employed to carry out this kind of measurements. Dynamic viscosity (η) was calculated (see eq 2) from the product of kinematic viscosity (ν) and density (ρ).8 η = ν·ρ (2)

3. RESULTS AND DISCUSSION First, a comparison between experimental density, dynamic viscosity, and speed of sound of pure components and bibliographic data obtained by other researchers at 293.15 K was performed. This comparison allowed us to check the purity of chemical reagents as well as test the experimental procedures and the different equipments used. Data are listed in Table 2 and they show a good agreement except for some speed of sound value for MEA, with low deviation between experimental and literature data. Information about density, speed of sound, and viscosity for NEP contributed by other authors has not been found in the literature. Tables 3 to 5 show experimental data of density, dynamic viscosity. and speed of sound, respectively, for the tertiary mixtures studied in the present work, that is, monoethanolamine (MEA) + water + NEP. These physical properties have been obtained at several temperatures, from (293.15 to 323.15) K and for different mass concentrations. The maximum mass fraction value for NEP was 0.3 because this compound was considered as an additive. Figure 1 shows the influence of tertiary mixture composition upon the value of density for a constant temperature.16−18 Several solid lines, corresponding to density isolines, are represented in this triangular diagram. It is possible to observe that the maximum value for this physical property is located at the binary system MEA + H2O, for a MEA mass fraction of 0.7, approximately in agreement with a previous work.16 Therefore, a variation in the mixture composition produces a decrease in

w2/w1

T/K = 293.15

0.9/0 0.8/0.1 0.7/0.2 0.6/0.3 0.5/0.4 0.4/0.5 0.3/0.6 0.2/0.7 0.1/0.8 0/0.9

1.00208 1.00741 1.01308 1.01898 1.02411 1.02780 1.02908 1.02738 1.02237 1.01900

0.8/0 0.7/0.1 0.6/0.2 0.5/0.3 0.4/0.4 0.3/0.5 0.2/0.6 0.1/0.7 0/0.8

1.00767 1.01369 1.01941 1.02443 1.02780 1.02846 1.02654 1.02115 1.01763

0.7/0 0.6/0.1 0.5/0.2 0.4/0.3 0.3/0.4 0.2/0.5 0.1/0.6 0/0.7

1.01382 1.01888 1.02388 1.02754 1.02800 1.02482 1.01840 1.01586

T/K = 303.15 w3 = 0.1 0.99833 1.00337 1.00828 1.01340 1.01783 1.02076 1.02141 1.01954 1.01449 1.00889 w3 = 0.2 1.00322 1.00844 1.01334 1.01773 1.01966 1.01964 1.01871 1.01314 1.00741 w3 = 0.3 1.00812 1.00931 1.01429 1.01991 1.02008 1.01605 1.00976 1.00553

T/K = 313.15

T/K = 323.15

0.99460 0.99868 1.00298 1.00745 1.01128 1.01324 1.01338 1.01130 1.00656 0.99876

0.98974 0.99340 0.99720 1.00112 1.00443 1.00487 1.00532 1.00281 0.99855 0.99062

0.99811 1.00269 1.00678 1.01076 1.01218 1.01262 1.01076 1.00504 0.99716

0.99241 0.99647 0.99975 1.00351 1.00542 1.00542 1.00267 0.99684 0.98887

1.00190 0.99742 1.00310 1.01208 1.01200 1.00783 1.00130 0.99516

0.99512 0.98280 0.98943 1.00405 1.00376 0.99885 0.99282 0.98674

c

Standard uncertainties u are u(T) = 0.01 K, u(p) = 20 Pa, u(w) = 0.002, and the combined expanded uncertainty Uc (level of confidence = 0.95, k = 2) is Uc(ρ) = 2·10−4 g·cm−3.

the value of this physical property, in all cases. Figure 2 shows the dependence of tertiary mixture density with regard to MEA concentration at different temperatures. The observed behavior shows some changes in relation to the system in the absence of NEP, especially when temperature and NEP concentration increase. For the MEA + H2O system the density increases with the concentration of amine up to a maximum value, however the presence of NEP causes a displacement in the maximum 3388



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Table 4. Speed of Sound c/m·s−1, of MEA (1) + H2O (2) + NEP (3) from T = (293.15 to 323.15) K for Mass Fractions C at Atmospheric Pressurec w2/w1

T/K = 293.15

0.9/0 0.8/0.1 0.7/0.2 0.6/0.3 0.5/0.4 0.4/0.5 0.3/0.6 0.2/0.7 0.1/0.8 0/0.9

1555.7 1617.3 1676.5 1731.2 1772.4 1795.6 1798.4 1784.7 1748.7 1706.9

0.8/0 0.7/0.1 0.6/0.2 0.5/0.3 0.4/0.4 0.3/0.5 0.2/0.6 0.1/0.7 0/0.8

1620.0 1677.1 1726.3 1763.8 1786.2 1787.6 1760.3 1727.4 1679.7

0.7/0 0.6/0.1 0.5/0.2 0.4/0.3 0.3/0.4 0.2/0.5 0.1/0.6 0/0.7

1671.7 1720.5 1753.2 1769.3 1765.0 1739.9 1701.4 1653.3

T/K = 303.15 w3 = 0.1 1568.9 1621.1 1671.1 1717.2 1751.6 1770.3 1770.3 1754.9 1717.3 1674.0 w3 = 0.2 1620.0 1667.5 1708.9 1740.1 1757.8 1755.8 1728.8 1695.2 1645.9 w3 = 0.3 1658.9 1701.0 1726.9 1739.0 1732.8 1706.4 1666.6 1618.6

Table 5. Viscosity η/mPa·s, of MEA (1) + H2O (2) + NEP (3) from T = (293.15 to 323.15) K for Mass Fractions at Atmospheric Pressurec

T/K = 313.15

T/K = 323.15

w2/w1

T/K = 293.15

1576.8 1621.0 1663.3 1701.8 1729.8 1744.1 1741.0 1722.8 1686.2 1641.2

1580.3 1617.0 1652.6 1684.4 1707.1 1717.1 1711.5 1691.2 1654.5 1608.0

0.9/0 0.8/0.1 0.7/0.2 0.6/0.3 0.5/0.4 0.4/0.5 0.3/0.6 0.2/0.7 0.1/0.8 0/0.9

1.474 2.047 2.938 4.413 6.654 10.025 14.786 19.259 21.866 19.950

1616.3 1655.7 1690.3 1715.3 1727.2 1723.2 1697.1 1662.9 1611.7

1608.9 1641.4 1669.8 1689.7 1697.4 1690.1 1665.1 1630.1 1578.2

0.8/0 0.7/0.1 0.6/0.2 0.5/0.3 0.4/0.4 0.3/0.5 0.2/0.6 0.1/0.7 0/0.8

2.068 2.938 4.294 6.283 9.436 13.433 17.212 18.630 16.011

1644.0 1677.6 1698.9 1707.8 1700.3 1673.3 1632.7 1584.0

1627.1 1653.2 1670.7 1676.6 1666.9 1639.6 1598.5 1549.5

0.7/0 0.6/0.1 0.5/0.2 0.4/0.3 0.3/0.4 0.2/0.5 0.1/0.6 0/0.7

2.857 4.063 5.942 8.682 11.595 14.587 15.030 12.250

c

T/K = 303.15 w3 = 0.1 1.123 1.533 2.119 3.077 4.432 6.537 9.241 11.928 13.525 12.483 w3 = 0.2 1.520 2.112 2.984 4.206 6.141 8.492 10.737 11.525 10.269 w3 = 0.3 2.030 2.812 3.939 5.644 7.493 9.181 9.590 8.104

T/K = 313.15

T/K = 323.15

0.891 1.184 1.610 2.258 3.151 4.437 6.148 7.829 8.835 8.350

0.730 0.954 1.263 1.735 2.353 3.226 4.338 5.414 6.105 5.863

1.176 1.583 2.168 2.987 4.201 5.647 7.082 7.730 6.967

0.942 1.239 1.655 2.223 3.028 3.984 4.952 5.382 5.017

1.522 2.031 2.788 3.866 5.089 6.179 6.465 5.666

1.196 1.539 2.057 2.791 3.612 4.351 4.577 4.173

c

Standard uncertainties u are u(T) = 0.01 K, u(p) = 20 Pa, u(w) = 0.002, and the combined expanded uncertainty Uc (level of confidence =0.95, k = 2) is Uc(c) = 1.2 m·s−1.

Standard uncertainties u are u(T) = 0.01 K, u(p) = 20 Pa, u(w) = 0.002, and the combined expanded uncertainty Uc (level of confidence =0.95, k = 2) is Uc(η) = 0.0026 mPa·s.

density value for the system. Then this maximum is obtained at lower concentrations of MEA. Another difference takes place at an NEP mass fraction of 0.3, in this case a decrease in the density value is produced at low concentrations of MEA. This behavior is due to a high expansion that is produced when the temperature increases, and it is completely consistent with the density data previously obtained for the binary systems NEP + MEA18 and MEA + H2O.16 In relation to the temperature effect upon density, the behavior is similar to that of other systems: a decrease in this property is observed with temperature. With regard to speed of sound, experimental data are listed in Table 4, and Figure 3 shows the influence of mixture composition upon the values of this physical property at a temperature of 293.15 K, as well as speed of sound for the binary system MEA + H2O at 298.15 K.9 On the one hand, it is possible to observe that an increase in MEA concentration produces an increase in the speed of sound value until a maximum is reached and followed by a subsequent decrease. This behavior shows great similarity to previously discussed data for the density. In this case, as NEP concentration increases the location of the maximum is moved toward the MEA-poor region. This behavior is due to the presence of NEP, since this substance modifies the interactions between water

Figure 1. Density ρ, for the system MEA (1) + H2O (2) + NEP (3) at T = 303.15 K. Solid lines are density isolines.

and MEA. On the other hand, an increase in temperature causes a decrease in the value of speed of sound. 3389



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decrease is higher when MEA concentration increases in the mixture due to the magnitude of the viscosity value for pure MEA is greater than for water. At the same time, an increase in the MEA concentration produces an increase in the viscosity value till a maximum is reached and, as in the case of speed of sound, when NEP concentration increases the location of maximum is moved toward the MEA-poor region. From experimental data of density the excess molar volume, VE, has been calculated using eq 3. 3

VE =

∑ xiMi(ρ−1 − ρi−1) i=1

(3)

where xi, Mi, and ρi are the mole fractions, molecular weights, and densities of pure components, respectively. These data are shown in Table S1, which is included in the Supporting Information. The results show, almost entirely, negative values for the molar excess volume, which is in agreement with previous studies.16,17 This behavior indicates a deviation with regard to ideality and also a possible interaction between different molecules causing a contraction in the mixture volume. Taking into account experimental data obtained for speed of sound and density, the isentropic compressibility, ks, has been calculated using the Laplace equation (eq 4).

Figure 2. Influence of composition upon density for the tertiary system. w3 = 30 %: ○, T = 293.15 K; ●, T = 303.15 K; □, T = 313.15 K; ■, T = 323.15 K. For the binary system MEA (1) + H2O (2):14 Δ, T = 323.15 K.

ks =

1 ρc 2

(4)

where ρ and c are the density and speed of sound of the ternary mixture, respectively. As for the excess molar volume, isentropic compressibility data are listed in Table S2 included in the Supporting Information section.

4. CONCLUSIONS Density, speed of sound, and viscosity were measured for the tertiary system monoethanolamine (MEA) + water + N-ethyl2-pyrrolidone (NEP), for NEP mass fractions lower than 0.3. The influence of temperature over these physical properties was also analyzed. Some changes with regard to the density of system in the absence of NEP were detected, especially when temperature and NEP concentration increased; for instance, at a wNEP = 0.3 a decrease in the density value is produced at low concentrations of MEA due to a high expansion produced when temperature increases. With regard to speed of sound an increase in MEA concentration produces an increase in this physical property until a maximum is reached and as NEP concentration increases the location of maximum is moved toward MEA-poor region because the presence of NEP modifies the interactions between water and MEA. Temperature causes an important decrease in the viscosity value, and this decrease is higher as MEA concentration increases. The excess molar volume shows, almost entirely, negative values which indicates a deviation with regard to ideality and also a possible interaction between different molecules

Figure 3. Influence of composition upon the speed of sound. T = 293.15 K: ○, w3 = 10 %; ●, w3 = 20 % ; □, w3 = 30 %. T = 298.15 K: ■ w3 = 0 %.9

Figure 4 shows the influence of temperature upon tertiary mixture viscosity for a constant concentration of NEP but changing the ratio H2O/MEA. When temperature increases an important decrease in the viscosity value is observed and this

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ASSOCIATED CONTENT

S Supporting Information *

Additional data tables as described in the text. This material is available free of charge via the Internet at http://pubs.acs.org.

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Figure 4. Influence of temperature and water/MEA ratio upon viscosity. w3 = 10 %. ○, w1 = 0 %; ●, w1 = 20 %; □, w1 = 40 %; ■, w1 = 60 %; Δ, w1 = 80 %.

AUTHOR INFORMATION

Corresponding Author

*E-mail: [email protected]. 3390



Article

Notes

(18) Blanco, A.; García-Abuín, A.; Gómez-Díaz, D.; Navaza, J. M.; L. Villaverde, O. Density, speed of sound, viscosity, surface tension, and excess volume of N-ethyl-2-pyrrolidone + ethanolamine (or diethanolamine or triethanolamine) from T = (293.15 to 323.15) K. J. Chem. Eng. Data 2013, 58, 653−659.

The authors declare no competing financial interest.

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REFERENCES

(1) Bounaceur, R.; Lape, N.; Roizard, D.; Vallieres, C.; Favre, E. Membrane processes for post-combustion carbon dioxide capture: A parametric study. Energy 2006, 31, 2556−2570. (2) Liao, C. H.; Li, M. Kinetics of absorption of carbon dioxide into aqueous solutions of monoethanolamine + N-methyldiethanolamine. Chem. Eng. Sci. 2002, 57, 4569−4582. (3) Horng, S. Y.; Li, M. Kinetics of absorption of carbon dioxide into aqueous solutions of monoethanolamine + triethanolamine. Ind. Eng. Chem. Res. 2002, 41, 257−266. (4) Mandal, B. P.; Guha, M.; Biswas, A. K.; Bandyopadhyay, S. S. Removal of carbon dioxide by absorption in mixed amines: Modeling of absorption in aqueous MDEA/MEA and AMP/MEA solutions. Chem. Eng. Sci. 2001, 56, 6217−6224. (5) Kohl, A.; Nielsen, R. Gas Purification, 5th ed.; Gulf Publishing Company: Houston, Tx, 1997. (6) Schütz, M.; Daun, M.; Weinspach, P.-M.; Krumbeck, M.; Hein, K. R. G. Study on the CO2-Recovery from an ICGCC-Plant. Energy Convers. Manage. 1992, 33, 357−363. (7) Yoneto, K.; Ghanem, A. H.; Higuchi, W. I.; Peck, K. D.; Li, S. K. Mechanistic studies of the 1-alkyl-2-pyrrolidones as skin permeation enhancers. J. Pharm. Sci. 1995, 84, 312−317. (8) García-Abuín, A.; Gómez-Díaz, D.; La Rubia, M. D.; López, A. B.; Navaza, J. M. Density, speed of sound, refractive index, viscosity, surface tension, and excess volume of N-methyl-2-pyrrolidone + 1amino-2-propanol{or bis(2-hydroxypropyl)amine} from T = (293.15 to 323.15) K. J. Chem. Eng. Data 2011, 56, 2904−2908. (9) Hawrylak, B.; Burke, S. E.; Palepu, R. Partial Molar and Excess Volumes and Adiabatic Compressibilities of Binary Mixtures of Ethanolamines with Water. J. Solution Chem. 2000, 29, 575−594. (10) Maham, Y.; Teng, T. T.; Hepler, L. G.; Mather, A. E. Densities, excess molar volumes, partial molar volumes for binary mixtures of water with monoethanolamine, diethanolamine, and triethanolamine from 25 to 80°C. J. Sol Chem. 1994, 23, 195−205. (11) Pagé, M.; Huot, J.-Y.; Jolicoeur, C. A comprehensive thermodynamic investigation of water−ethanolamine mixtures at 10, 25, and 40°C. Can. J. Chem. 1993, 71, 1064−1072. (12) Á lvarez, E.; Cerdeira, F.; Gómez-Diaz, D.; Navaza, J. M. Density, speed of sound, isentropic compressibility, and excess volume of (monoethanolamine + 2-amino-2-methyl-1-propanol), (monoethanolamine + triethanolamine), and (monoethanolamine + N-methyldiethanolamine) at temperatures from (293.15 to 323.15) K. J. Chem. Eng. Data 2010, 55, 994−999. (13) Mandal, B. P.; Kundu, M.; Bandyopadhyay, S. S. Density and viscosity of aqueous solutions of (N-methyldiethanolamine + monoethanolamine), (N-methyldiethanolamine + diethanolamine), (2-amino-2-methyl-1-propanol + monoethanolamine), and (2-amino2-methyl-1-propanol + diethanolamine). J. Chem. Eng. Data 2003, 48, 703−707. (14) González, B.; Calvar, N.; Gomez, E.; Domínguez, A. Density, dynamic viscosity, and derived properties of binary mixtures of methanol or ethanol with water, ethyl acetate, and methyl acetate at T = (293.15, 298.15, and 303.15) K. J. Chem. Thermodyn. 2007, 39, 1578−1588. (15) González, B.; Domínguez, A.; Tojo, J. Dynamic viscosities, densities, and speed of sound and derived properties of the binary systems acetic acid with water, methanol, ethanol, ethyl acetate and methyl acetate at T = (293.15, 298.15, and 303.15) K at atmospheric pressure. J. Chem. Eng. Data 2004, 49, 1590−1596. (16) Lee, M. J.; Lin, T. K. Density and viscosity for monoethanolamine + water, + ethanol, and + 2-propanol. J. Chem. Eng. Data 1995, 40, 336−339. (17) Blanco, A.; García-Abuín, A.; Gómez-Díaz, D.; Navaza, J. M.; Vidal-Tato, I. Influence of temperature and composition upon density, viscosity, speed of sound, and refractive index of aqueous solutions of 1-ethyl-2-pyrrolidinone. J. Chem. Eng. Data 2010, 55, 962−965. 3391


Density, Speed of Sound, and Viscosity of Monoethanolamine +

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