Density, viscosity, and excess properties of aqueous solution of diethylenetriamine (DETA)

J. Chem. Thermodynamics 41 (2009) 973–979

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Review

Density, viscosity, and excess properties of aqueous solution of diethylenetriamine (DETA) Ardi Hartono 1, Hallvard F. Svendsen * Department of Chemical Engineering, Norwegian University of Science and Technology, N-7491 Trondheim, Norway

a r t i c l e

i n f o

Article history: Received 19 August 2008 Received in revised form 31 October 2008 Accepted 10 November 2008 Available online 10 December 2008 Keywords: Density Viscosity Diethylenetriamine (DETA) Excess property Redlich–Kister

a b s t r a c t Densities and viscosities of aqueous DETA solutions were measured for the entire concentration range and for the temperature range between (293.15 and 363.15) K. The excess molar volume was determined from the experimental density data whereas the excess Gibbs free energy and the excess entropy of flow were determined from the experimental viscosity data by implementing the theory of rate processes of Eyring. A Redlich–Kister equation was applied to correlate the excess properties such as: the excess molar volume and the excess Gibbs free energy of flow as functions of the DETA mole fraction and temperature. The results showed that the model agree very well with the experimental data. In comparison with AEEA and DEA, the excess properties of DETA are higher than these amines. Ó 2009 Published by Elsevier Ltd.

Contents 1. 2. 3.

4.

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Experimental section . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Results and discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.1. Density and excess molar volume of the {DETA (1) + water (2)} . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.2. Viscosity of {DETA (1) + water (2)}. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Acknowledgment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1. Introduction Absorption of CO2 with amine-based absorbents (i.e., MEA, MDEA) is an established and proven technology, however it still very energy intensive and has high capital cost. The overall challenge is to bring these two factors down with new and environmentally acceptable solvents. A better solvent may have higher capacity, faster absorption rate, lower heat of absorption, and a more benign behavior in the environment. N-(2-aminoethyl)ethane-1,2-diamine(DETA), known as diethylenetriamine with three amine functionalities, can be expected to

* Corresponding author. Tel.: +47 73594100; fax: +47 73594080. E-mail address: [email protected] (H.F. Svendsen). 1 Permanent address: Department of Chemical Engineering, Lambung Mangkurat University, Jl. A. Yani Km 35 Banjarbaru, Kalimantan Selatan, Indonesia. 0021-9614/$ - see front matter Ó 2009 Published by Elsevier Ltd. doi:10.1016/j.jct.2008.11.012

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973 974 975 975 977 978 979 979

have a high loading capacity and faster absorption rate than with a single amine functionality, e.g. MEA. In order to test DETA as a candidate for CO2 capture, a series of studies were undertaken. An NMR study of the (DETA + CO2 + H2O) system shows that the system is very complex and consists of a large number of species [1]. The physical properties of aqueous solutions such as density and viscosity are required for the design of acid gas treatment equipment. The research focusing on the physical properties and the excess property have been reported for the binary mixtures of various amines and water and it is shown in table 1. In this work the physical properties of aqueous DETA solutions were measured at different concentrations and temperatures. The excess properties calculated from the experimental data were correlated with the Redlich–Kister equation and compared with DEA [2] and AEEA [11], in order to see the effect of different groups

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TABLE 1 Physical and excess property data for the binary system of various amines and water. Solvent

Common name

IUPAC name

Reference(s)

MEA DEA TEA MDEA EDEA DMEA DEEA MMEA DIPA IPA AMP AEEA

Ethanolamine Diethanolamine Triethanolamine N-methyldiethanolamine N-ethyldiethanolamine Dimethylethanolamine Diethylethanolamine Methylethanolamine Diisopropanolamine Isopropanolamine Aminomethylpropanol Aminoethylethanolamine

2-Aminoethanol 2-(2-Hydroxyethylamino)ethanol 2-(Bis(2-hydroxyethyl)amino)ethanol 2-(2-Hydroxyethyl-methyl-amino)ethanol 2-(Ethyl-(2-hydroxyethyl)amino)ethanol 2-Dimethyaminoethanol 2-Diethylaminoethanol 2-Methylaminoethanol 1-(2-Hydroxypropylamino)propan-2-ol 1-Aminopropan-2-ol 2-Amino-2-methyl-propan-1-ol 2-(2-Aminoethylamino)ethanol

[2,3,5] [2,5] [2,3,5] [3,5] [4,5] [5,7] [5] [6] [8] [9] [10] [11]

1.02

H N HO

OH

1.00

(ii)

H N

HO

H N

NH2

0.98

NH2

-3

FIGURE 1. Molecular structures of (i) DEA, (ii) AEEA, and (iii) DETA.

-3

(iii) H2N

10 .σ / (kg.m )

(i)

attached to the molecule as the replacement of hydroxyl groups by primary amine groups as shown in figure 1.

0.94 0.92 0.90

2. Experimental section

0.88 0.86 290

310

330

350

370

T / (K) FIGURE 2. Density of water: D, this work; }, [11]; h, [12]; and of pure DETA: s, this work; +, [14]; , [15]; *, [16] at various temperatures.

10.0

-1 -1

10 .η /(kg.m s )

1.0

3

Aqueous solutions of DETA were prepared on the mass basis (balance model Mettler PM1200 with accuracy ±106 kg). DETA (mass fraction P0.99) supplied by Sigma–Aldrich was used without further purification and dissolved with deionized water. Densities and viscosities for the binary system were measured simultaneously with the Anton Paar Stabinger Viscometer SVM 3000. The procedure was done by filling the line and the cell inside the apparatus with ±3  106 m3 of solutions at a specific temperature with accuracy ±0.005 K. The liquid inside the line and the cell should be air-free then the measurement can be started by adding ±1  106 m3 of solution. After reaching equilibrium, the apparatus showed a constant value of the density and the viscosity. The seconds filling of ±1  106 m3 of solution was added to measure the second value. If the different between the two values are in agreement with the accuracy given by manufacturer (viscosity, g, ±0.1% and density, q, ±0.1 kg  m3) then the final results can be obtained. Calibrations were done by measuring the density and the viscosity of water in the temperature range between (293.15 and 363.15) K and displayed in figures 2 and 3. It can be seen that both density and viscosity of water from the measurement agree very well with the literature references [11–13]. The density and viscosity of pure DETA were also measured in the temperature range between (293.15 and 363.15) K and also plotted in the same figures 2 and 3. From figure 2, the measured density values of pure DETA were found to be between the two references value [14,15] whereas at 298.15 K, it seems to agree with the result reported by Rouleau and Thompson [16]. From figure 3, the measured viscosity values were found to be reasonably well with the reported data by Dow [14] whereas at temperature up to 313.15 K, the viscosity seems to be higher than to the reported data by DIPPR [15]. The discrepancy of the data might be attributed to the purity of the chemical.

0.96

0.1 2.7

2.9

3.1

3.3

3.5

3

10 .(K)/ T FIGURE 3. Viscosity of water: 4, this work; }, [11]; h, [13]; and of pure DETA: s, this work; +, [14]; , [15] at various temperatures.

975

A. Hartono, H.F. Svendsen / J. Chem. Thermodynamics 41 (2009) 973–979 TABLE 2 Experimental data of the density of {DETA (1) + water (2)} mixtures at various temperatures. 103  q/(kg  m3)

x1

0.0000 0.0095 0.0299 0.0565 0.0696 0.1043 0.1250 0.1591 0.2076 0.2449 0.3099 0.3438 0.4112 0.4974 0.6111 0.6988 0.8073 0.8954 1.0000

T = 293.15 K

T = 303.15 K

T = 313.15 K

T = 323.15 K

T = 333.15 K

T = 343.15 K

T = 353.15 K

T = 363.15 K

0.9992 1.0015 1.0042 1.0115 1.0145 1.0238 1.0265 1.0307 1.0294 1.0275 1.0191 1.0141 1.0041 0.9928 0.9790 0.9718 0.9634 0.9575 0.9510

0.9965 0.9986 1.0007 1.0071 1.0096 1.0171 1.0198 1.0230 1.0214 1.0186 1.0102 1.0057 0.9950 0.9837 0.9706 0.9627 0.9543 0.9484 0.9423

0.9930 0.9949 0.9967 1.0022 1.0043 1.0107 1.0129 1.0154 1.0132 1.0099 1.0015 0.9971 0.9864 0.9751 0.9621 0.9542 0.9473 0.9398 0.9338

0.9887 0.9905 0.9917 0.9968 0.9986 1.0042 1.0057 1.0079 1.0048 1.0019 0.9931 0.9884 0.9780 0.9668 0.9537 0.9459 0.9391 0.9315 0.9255

0.9837 0.9855 0.9865 0.9910 0.9924 0.9972 0.9982 0.9999 0.9963 0.9931 0.9841 0.9796 0.9692 0.9568 0.9451 0.9373 0.9291 0.9229 0.9170

0.9783 0.9800 0.9808 0.9847 0.9858 0.9901 0.9905 0.9923 0.9876 0.9842 0.9754 0.9707 0.9605 0.9495 0.9365 0.9291 0.9207 0.9146 0.9089

0.9723 0.9738 0.9746 0.9781 0.9789 0.9826 0.9823 0.9829 0.9785 0.9751 0.9663 0.9617 0.9517 0.9408 0.9278 0.9204 0.9122 0.9061 0.9004

0.9659 0.9673 0.9677 0.9709 0.9717 0.9747 0.9742 0.9742 0.9695 0.9661 0.9570 0.9526 0.9427 0.9319 0.9191 0.9118 0.9036 0.8975 0.8919

3. Results and discussion 3.1. Density and excess molar volume of the {DETA (1) + water (2)} The measured density of aqueous DETA solutions over the entire range of mole fractions x1 and temperature range between (293.15 and 363.15) K are listed in table 2 and plotted in figure 4. It can be seen that starting from x1 = 0, the density increases with increasing DETA concentration, reaches a maximum value and then decreases. The effect of the temperature is to decrease the density and to shift the maximum values of the density gradually from approximately x1 = 0.18 for 298.15 K to x1 = 0.11 for 363.15 K. The excess molar volume (VE) calculated form the density data is defined by:

1

V E ðm3  mol Þ ¼ ½ðx1 M 1 þ x2 M2 Þ=qm   x1 M1 =q1  x2 M 2 =q2 ;

ð2Þ

where M1 and M2 represent molar masses of DETA and water, respectively, and qm, q1 and q2 are the densities of the mixtures, of pure DETA and water, respectively. The excess properties (YE) indicate the departure from the ideal condition and can be correlated by the Redlich–Kister [17] equation:

Y E ¼ x 1 x2

X

An ð1  2x2 Þn1 :

ð3Þ

n¼1

1.04

The optimum values for the Redlich–Kister coefficients (An) were determined for each temperature and the temperature dependency of the Redlich–Kister coefficient (An) can be represented by polynomials (equation (4)) with the standard deviation r(YE) corresponding to equation (5)

1.02

An ¼

1.00

" #1=2 X ðY E  Y E Þ2 E calc rðY Þ ¼ ; Nexp  n

1

V E =ðm3  mol Þ ¼ V  x1 V 1  x2 V 2 ;

10-3.ρ / (kg.m-3)

where V represents the volume of a mixture containing one mol of {DETA (1) and water (2)}; V 1 and V 2 are the molar volumes of the corresponding pure liquids. Equation (1) can also be equivalently expressed as:

ð1Þ

X

an T n1 ;

ð4Þ

n¼1

0.98 0.96 0.94 0.92 0.90 0.88 0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

x1 FIGURE 4. Density of {DETA (1) + water (2)} at various temperatures: h, 293.15 K; }, 303.15 K; 4, 313.15 K; , 323.15 K; *, 333.15 K; s, 343.15 K; +, 353.15 K; N, 363.15 K.

ð5Þ

where Nexp and n represent the number of experimental points and the number of coefficients used in fitting the data. The excess molar volumes (VE) for {DETA (1) + water (2)} are shown in figure 5. It can be seen that the values of the excess molar volumes (VE) were found to be negative and a small temperature effect for the whole concentration range was found. The excess molar volume minimum was found to be almost temperature independent at x1 = 0.34. The excess molar volume represents the difference in molar specific value for DETA (1) and water (2). If the value is large, it indicates that there is a volume contraction in the system and also indicates that DETA (1) and water (2) are completely miscible (polar organic solvent + water) system. Similar results were reported for other amines [2–11]. In figure 5, the solid lines indicating the temperature dependency for the excess molar volume (VE) are calculated with equation (3) using the parameter values in table 3 with a standard deviation r(VE) = 3  108 m3  mol1 (equation (5)) for the mixture data.

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A. Hartono, H.F. Svendsen / J. Chem. Thermodynamics 41 (2009) 973–979

Differentiation of equation (3) for the excess molar property (VE) with respect to x2 and combining with equations (7) and (8) leads to the following equations:

-0.1

1

V 1 =ðm3  mol Þ ¼ V 1 þ x2

106. V E/ (m 3.mol -1)

-0.6

X

An ð1  2x2 Þn1

n¼1

 2x2 ð1  x2 Þ

X

An ðn  1Þð1  2x2 Þn2 ;

ð9Þ

n¼1

-1.1

1

V 2 =ðm3  mol Þ ¼ V 2 þ ð1  x2 Þ

X 2

An ð1  2x2 Þn1

n¼1

þ 2x2 ð1  x2 Þ2 -1.6

X

An ðn  1Þð1  2x2 Þn2 :

The partial molar volume of DETA at infinite dilution in water ðV 1 1 Þ can then be calculated by setting x2 = 1 and of water at infinite dilution in DETA ðV 2 1 Þ can be calculated by setting x2 = 0, therefore

-2.1

1

V 1 1 =ðm3  mol Þ ¼ V 1 þ -2.6

X

An ð1Þn1 ;

ð11Þ

An :

ð12Þ

n¼1

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

V 2 1 =ðm3  mol Þ ¼ V 2 þ

1.0

x1

X n¼1

The Redlich–Kister coefficients can be excluded from the determination of the partial molar volumes at infinite dilution by using ‘‘the apparent molar volume” approach. This was proposed based on the Lewis and Randall theory [2]. The apparent molar volume for DETA in water ðV /;1 Þ and of water in DETA ðV /;2 Þ are given as

FIGURE 5. Excess molar volume for {DETA (1) + water (2)} at different temperatures: h, 293.15 K; , 323.15 K; N, 363.15 K: Solid lines, calculated with equation (3) using the parameter values in table 3, are given for (293.15, 323.15, and 363.15) K for comparison.

1

V /;1 =ðm3  mol Þ ¼ V 1 þ ðV E =x1 Þ; 3

A1 A2 A3 A4 A5 A6

a1

a2

9.6982 9.3685 13.8681 2.7973 18.2907 22.5654

0.0038 0.0102 0.0258 0.0133 0.0337 0.0623

1

ð6Þ

Combination of equations (1) and (6) leads to the following equations for the partial molar volumes ðV i Þ [2] 1

V 1 =ðm3  mol Þ ¼ V E þ V 1  x2 ð@V E =@x2 Þp;T ; 1

E

V 2 =ðm  mol Þ ¼ V þ

V 2

ð7Þ

E

þ ð1  x2 Þð@V =@x2 Þp;T :

V 2

ð13Þ

E

þ ðV =x2 Þ:

ð14Þ

At infinite dilution, the apparent molar volume of each species can be determined with a simple analytical extrapolation to infinite dilution. For DETA at infinite dilution in water, it can be done by extrapolating equation (13) at x1 ? 0 leading to the value of V 1 /;1 and for water at infinite dilution in DETA it can also be done by extrapolating equation (14) to x2 ? 0 leading to the value of V 1 /;2 . These two equations (13) and (14) suggest an easy calculation of the apparent molar volume from the excess molar volume (VE) directly. The results from both methods for calculating the partial molar volume of each species ðV i 1 Þ and the apparent molar volume of each species ðV 1 /;i Þ, both at infinite dilution, are shown in table 4 and compared with the molar volume of pure species ðV i Þ. From the values in table 4, it can be seen that both calculation methods agree very well for DETA at infinite dilution in water and for water at infinite dilution in DETA. The partial molar volume ðV i 1 Þ and the apparent molar volumes ðV 1 /;i Þ of species at infinite dilution were found to be smaller than the corresponding molar volumes of pure species ðV i Þ. For DETA this can be explained by the fact that DETA molecules fit (partially) into the open or empty spaces in liquid water. For water, this is consistent with the idea that the molar volume of pure water is the sum of the actual molecular volume plus the ‘‘empty” volumes that arise from the hydrogen-bonded open structure of water [2].

The parameters for the temperature dependency of the Redlich– Kister coefficients (An) for the excess molar volume (VE) are given in table 3. The partial molar volume of each component ðV i Þ is defined by

V i =ðm3  mol Þ ¼ ð@V=@ni ÞT;p;nj :

1

V /;2 =ðm  mol Þ ¼

TABLE 3 Temperature dependency of the Redlich–Kister coefficients for the excess molar volume {106  VE/(m3  mol1)} of {DETA (1) + water (2)}.

3

ð10Þ

n¼1

ð8Þ

TABLE 4 1 Partial molar volume ðV 1 i Þ and apparent molar volume ðV /;i Þ of DETA (1) at infinite dilution in water (2) and of water (2) at infinite dilution in DETA (1) and molar volume of pure species ðV i Þ at various temperatures. T/(K)

3 106  V 1 1 =ðm  mol

293.15 303.15 313.15 323.15 333.15 343.15 353.15 363.15

101.0 101.6 102.2 102.8 103.4 103.9 104.6 105.2

1

Þ

3 106  V 1 /;1 ðm  mol

101.0 101.5 102.1 102.7 103.3 103.9 104.6 105.2

1

Þ

106  V 1 =ðm3  mol 108.5 109.5 110.5 111.5 112.5 113.5 114.6 115.7

1

Þ

3 106  V 1 2 =ðm  mol

12.5 12.9 13.3 13.7 14.2 14.6 15.1 15.6

1

Þ

3 106  V 1 /;2 =ðm  mol

12.7 13.1 13.4 13.8 14.3 14.7 15.1 15.6

1

Þ

106  V 1 =ðm3  mol 18.0 18.1 18.1 18.2 18.3 18.4 18.5 18.7

1

Þ

977

A. Hartono, H.F. Svendsen / J. Chem. Thermodynamics 41 (2009) 973–979 TABLE 5 Experimental data of the viscosity of the {DETA (1) + water (2)} at various temperatures. 103  g/(kg  m1  s1)

x1

0.0000 0.0095 0.0299 0.0565 0.0696 0.1043 0.1250 0.1591 0.2076 0.2449 0.3099 0.3438 0.4112 0.4974 0.6111 0.6988 0.8073 0.8954 1.0000

T = 293.15 K

T = 303.15 K

T = 313.15 K

T = 323.15 K

T = 333.15 K

T = 343.15 K

T = 353.15 K

T = 363.15 K

1.0060 1.3104 2.0762 4.0094 5.4180 11.6320 17.9440 31.0680 50.6800 59.6220 59.4160 55.5210 43.0810 30.1310 19.4580 15.1220 10.6110 8.5152 7.0385

0.7988 1.0168 1.5570 2.8413 3.7357 7.3294 10.5670 16.9400 25.6270 29.4690 29.5490 27.9660 22.6960 16.7690 11.5380 9.1160 6.8988 5.7131 4.8044

0.6546 0.8263 1.2225 2.1010 2.6839 4.8767 6.6899 10.1270 14.3430 16.2030 16.3240 15.6070 12.9900 10.1680 7.3749 5.9439 4.7407 4.0169 3.4001

0.5427 0.6854 0.9871 1.6153 2.0119 3.4233 4.5140 6.5052 8.7333 9.7285 9.8362 9.4918 8.1403 6.6222 5.0319 4.1749 3.4449 2.9763 2.6950

0.4596 0.5792 0.8166 1.2826 1.5616 2.5254 3.2064 4.4301 5.6979 6.2713 6.3664 6.1905 5.4402 4.5721 3.6196 3.0827 2.6180 2.3008 2.1094

0.4271 0.4978 0.6873 1.0437 1.2444 1.9187 2.3764 3.1741 3.9377 4.2929 4.3720 4.2770 3.8458 3.3078 2.7206 2.3660 2.0671 1.8329 1.7034

0.3731 0.4312 0.5864 0.8677 1.0167 1.5072 1.8235 2.3732 2.8520 3.0855 3.1506 3.0999 2.8413 2.5020 2.1181 1.8762 1.6770 1.5040 1.4091

0.2983 0.3693 0.4995 0.7364 0.8452 1.2129 1.4388 1.8396 2.1485 2.3105 2.3646 2.3370 2.1759 1.9554 1.6960 1.5256 1.3871 1.2604 1.1899

The partial molar volume of DETA at infinite dilution varies linearly with temperature and thus the value of the second derivative of the partial molar volume with respect to the temperature at infinite dilution becomes zero. This indicates that DETA would be considered as having no effect on the structure of water [18,19]. 3.2. Viscosity of {DETA (1) + water (2)} The measured viscosity values of aqueous DETA solutions over the entire range of mole fractions and in the temperature range between (293.15 and 363.15) K are listed in table 5 and also shown in figure 6. The measured viscosities increase with increasing DETA concentration, reach a maximum value at about x1 = 0.25 and then decrease. The temperature influences strongly the viscosity but the compositions for the maximum in viscosity were found to be almost constant and independent of temperature.

Applying the theory of rate processes [20] which treats flow as the passage of the flow-unit from one equilibrium position to another position, the vacant equilibrium positions being identified with hole in the liquids. This requires energy which can be either assumed to activate the flow-unit or to produce a hole of requisite size for the translation to occur. The formation of the hole, or of this intermediate activated state, then becomes the rate-determining process which can be treated by the theory of rate processes for viscosity [21,22]. The dynamic viscosity g can be correlated with the activation Gibbs free energy (DG*) of flow by:

gV  =ðkg  m2  s1  mol1 Þ ¼ hNA expðDG =RTÞ:

ð15Þ

For the binary mixture, the activation Gibbs free energy of flow, representing the non ideality of the mixture, can be written as a sum of contributions from the ideal solution (DG*id) and the excess parts (DG*E) 1

DG =ðJ  mol Þ ¼ DGid þ DGE :

100.0

ð16Þ *id

For the ideal activation Gibbs free energy (DG ) of flow, the viscosity of an ideal solution is given by: 1

3

-1 -1

10 .η /(kg.m s )

ðgV  Þid =ðkg  m2  s1  mol Þ ¼ hN A expðDGid =RTÞ:

ð17Þ

For the real binary mixture, the excess Gibbs free energy of flow can then be expressed by equation [3,23]:

10.0

DGE =RT ¼ lnðgm V=hN A Þ  x1 lnðg1 V 1 =hN A Þ  x2  lnðg2 V 2 =hN A Þ;

ð18Þ

where R is the gas constant, T is the absolute temperature; gm, g1, and g2 are the viscosities of mixture, DETA and water, respectively. h is Planck’s constant and NA is Avogadro’s number.

1.0

TABLE 6 Temperature dependency of the Redlich–Kister coefficients for the excess Gibbs free energy 103  DG*E/J  mol1 of {DETA (1) + water (2)} mixtures.

0.1 0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

x1 FIGURE 6. Viscosity of {DETA (1) + water (2)} at various temperatures: h, 293.15 K; }, 303.15 K; 4, 313.15 K; , 323.15 K; *, 333.15 K; s, 343.15 K; +, 353.15 K; N, 363.15 K.

A1 A2 A3 A4 A5 A6

a1

a2

a3

186.35 283.53 381.65 119.04 430.06 247.29

0.8864 1.1434 1.9316 0.4132 2.2414 0.9964

0.0012 0.0015 0.0026 0.0003 0.0029 0.0008

978

A. Hartono, H.F. Svendsen / J. Chem. Thermodynamics 41 (2009) 973–979

The excess Gibbs free energy (DG*E) of flow can also be correlated with the Redlich–Kister equation (equation (3)). The temper-

12

-3

*E

-1

10 .ΔG / (J mol )

10

8

6

4

2

1

DSE =ðJ  mol

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

x1 FIGURE 7. Excess Gibbs free energy of flow ðDGE Þ for {DETA (1) + water (2)} at different temperatures: h, 293.15 K; , 323.15 K; N, 363.15 K: Solid lines, calculated with equation (3) using the parameter values in table 7 are given for (293.15, 323.15, and 363.15) K for comparison.

60

50

40

-1

-1

 K1 Þ ¼ @ðDGE Þ=@T:

ð19Þ *E

0

ΔS /(J mol K )

ature dependency of the Redlich–Kister coefficients (An) obtained from the optimization against data for excess Gibbs free energy (DG*E) (equation (18)) is given in table 6. Figure 7 shows the excess Gibbs free energy of flow for {DETA (1) + water (2)} over the whole range of concentrations and at the different temperatures. It can be seen that at a specific temperature, the excess Gibbs free energy (DG*E) of flow increases with increasing concentration, reaches a maximum value at about x1 = 0.25 and then decreases. Increasing temperature decreases the excess Gibbs free energy (DG*E) but the composition for the maximum value is almost constant. Similar effect was also reported for other amines [3]. In figure 7, the solid lines indicating the temperature dependency for the excess Gibbs free energy (DG*E) were calculated with equation (3) using the parameter values in table 6 with a standard deviation r(GE)=70 J  mol1 (equation (5)) for the mixture data. The excess entropy (DS*E) of flow can be calculated as the slope of the excess Gibbs free energy (DG*E) against (T) at certain mole fraction

*E

30

figure 8 shows the excess entropy (DS ) of flow for {DETA (1) + water (2)} over the whole range of concentrations. The values were determined from equation (19) for a range of temperatures. It can also be seen that the excess entropy (DS*E) of flow follows the same trend as the excess Gibbs free energy; increases with increasing concentration, reaches a maximum value at about x1 = 0.25 and then decreases. Table 7 shows the excess properties {molar volume (VE), Gibbs free energy (DG*E), and entropy (DS*E) of viscous flow} at 298.15 K for different amines. From the values in table 7 it can be seen that the effect of substitution of the hydroxyl group (–OH) by a primary (–NH2) group increases the excess properties. The excess molar volume of DETA was calculated to be higher (1.75 times) than that of AEEA but the excess Gibbs free energy and the excess entropy are comparable. The excess molar volume of AEEA was found to be higher (2 times) compared to that of DEA whereas the excess Gibbs free energy is comparable but the excess entropy was found to be higher (1.6 times) than for DEA. The contribution of the (–NH2) group increases the excess properties and the level of the excess properties can then be classified as DETA > AEEA > DEA.

20

4. Conclusion

10

0 0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

x1 FIGURE 8. Excess entropy of flow ðDSE Þ for {DETA (1) + water (2)} for whole range of mol fractions.

Densities and viscosities of aqueous solutions of DETA were measured for the entire range of molar fractions and for the temperature range between (293.15 and 363.15) K. The measured density increases with increasing DETA concentration, reaches a maximum value and then decreases. The effect of increasing temperature is to decrease the density and the maximum density values were found to be shifted gradually to lower mole fraction values. The excess molar volumes (VE) were found to be negative and a slightly temperature dependent. The negative values of the

TABLE 7 Excess molar volume (VE), excess Gibbs free energy (DG*E) at 298.15 K and excess entropy (DS*E) of flow for different amines. 106  ðV max Þ=m3  mol DEA AEEA DETA a b c

0.65 1.42 2.49c

Recalculated with equation (18). Recalculated with equation (19). Extrapolated to 298.15 K.

1

103  DEmax =ðJ  mol 6.35 8.14a 9.15c

1

Þ

DSE max =ðJ  mol 25.20 40.71b 49.78

1

 K1 Þ

Source(s) [2,3] [11] This work

A. Hartono, H.F. Svendsen / J. Chem. Thermodynamics 41 (2009) 973–979

excess molar volume caused by a more dense molecular packing gives a volume contraction in the system which is a typical characteristic for completely miscible (amine + water) systems. The partial molar volume ðV i Þ and the apparent molar volume (Vu,i) at infinite dilution of each species, DETA (1) and water (2), were found to be smaller than the molar volume of the pure species ðV i Þ. These values were found to vary linearly with the temperature and the second derivative of those properties (partial molar volume/apparent molar volume) with respect to the temperature at infinite dilution becomes zero indicating that DETA would be considered as having no effect on the structure of water. The excess thermodynamic properties were calculated based on the theory of rate processes and shows that the excess Gibbs free energy (DG*E) and entropy (DS*E) of flow exhibit a maximum value. The excess Gibbs free energy (DG*E) decreases with increasing temperature. Acknowledgment This work was supported financially from the Indonesia Ministry of National Education. References [1] A. Hartono, E.F. da Silva, H. Grasdalen, H.F. Svendsen, Ind. Eng. Chem. Res. 46 (2007) 249–254. [2] Y. Maham, T.T. Teng, L.G. Hepler, A.E. Mather, J. Solution Chem. 23 (1994) 195– 205.

979

[3] Y. Maham, C.N. Liew, A.E. Mather, J. Solution Chem. 31 (2002) 743–756. [4] Y. Maham, T.T. Teng, A.E. Mather, L.G. Hepler, Can. J. Chem. 73 (1995) 1514– 1519. [5] B. Hawrylak, S.E. Burke, R. Palepu, J. Solution Chem. 29 (2000) 575–594. [6] L. Li, M. Mundhwa, P. Tontiwachwuthikul, A. Henni, J. Chem. Eng. Data 52 (2007) 560–565. [7] H. Touhara, S. Okezaki, F. Okino, H. Tanaka, K. Ikari, K. Nakanishi, J. Chem. Thermodyn. 14 (1982) 145. [8] A. Henni, J.J. Hromek, P. Tontiwachwuthikul, A. Chakma, J. Chem. Eng. Data 38 (2003) 1062–1067. [9] S. Mokraoui, A. Valtz, C. Coquelet, D. Richon, Thermochim. Acta 440 (2006) 122–128. [10] A. Henni, J.J. Hromek, P. Tontiwachwuthikul, A. Chakma, J. Chem. Eng. Data 48 (2003) 551–556. [11] M. Mundhwa, R. Alam, A. Henni, J. Chem. Eng. Data. 51 (2006) 1268–1273. [12] W. Wagner, A. Pruß, J. Phys. Chem. Chem. Ref. Data 31 (2) (2002) 387–535. [13] J.T.R. Watson, R.S. Basu, J.V. Sengers, J. Phys. Chem. Ref. Data 9 (1980) 1255– 1290. [14] Dow Chemical Company, 2001, Ethyleneamines, the Dow Chemical Company, Midland, Michigan, USA. [15] DIPPR 801, 2004, Information and Data Evaluation Manager for the Design Institute for Physical Properties, Version 4.1.0. [16] D.J. Rouleau, A.R. Thompson, J. Chem. Eng. Data 7 (1962) 356–357. [17] O. Redlich, A.T. Kister, Ind. Eng. Chem. 40 (1948) 345–348. [18] L.G. Hepler, Can. J. Chem. 47 (1969) 4613–4617. [19] J.L. Neal, D.A.I. Goring, J. Phys. Chem. 74 (1970) 658–664. [20] H. Eyring, J. Chem. Phys. 4 (1936) 283–291. [21] W.C. Wake, Trans. Faraday. Soc. 43 (1947) 708–715. [22] W. Kauzmann, H. Eyring, J. Am. Chem. Soc. 62 (1940) 3113–3125. [23] M. Cocchi, A. Marchetti, G. Sanna, L. Tassi, A. Ulrichi, G. Vaccari, Fluid Phase Equilibr. 157 (1999) 317–342.

JCT 08-296