Article pubs.acs.org/jced
Viscosities of Glycine, L‑Alanine, and L‑Valine in (0.2, 0.4, 0.6, and 0.8) mol·kg−1 Aqueous Trisodium Citrate Solutions at Different Temperatures Harsh Kumar,* Meenu Singla, and Rajeev Jindal Department of Chemistry, Dr B R Ambedkar National Institute of Technology, Jalandhar, 144 011 Punjab, India ABSTRACT: The viscosities, η of glycine, L-alanine, and L-valine with trisodium citrate (TSC) have been measured as a function of temperature at T = (288.15, 298.15, 308.15 and 318.15) K. The change in viscosity of amino acids with increase in TSC concentration and temperature is attributed to amino acids−TSC interactions. The viscosity B coefficients and viscosity interaction parameters obtained from Jones−Dole equation and transition state theory, respectively, have been discussed to interpret interactions between ions of amino acids and TSC.
1. INTRODUCTION
2. EXPERIMENTAL SECTION Glycine, L-alanine, and L-valine with mass fraction purities > 0.99 procured from Merck, Germany, and trisodium citrate with mass fraction purity > 0.99 purchased from SD Fine Chem. Ltd., India, were used as supplied. However, these were vacuum-dried before use and then were kept over P2O5 in a desiccator for 48 h. All the aqueous solutions were prepared afresh in double distilled and degassed water having specific conductance < 10−6 S·cm−1. The specifications of the chemicals used have also been given in Table 1. All the weighings were
The interactional behavior of large biomolecules like hormones, enzymes, and especially proteins are difficult to understand because of many specific interactions. Amino acids are the low molar mass model compounds or building blocks of proteins which can be used for studies which are expected to impact the solvation and conformation of proteins.1,2 In general the electrolytes present in our body influence the properties of biological molecules like proteins which are the vital part of our body. Electrolytes like tripotassium citrate, potassium dihydrogen phosphate, and dipotassium hydrogen phosphate which are of valuable importance in industries like medicines, biosensors, optics, and cosmetics, also play a significant role in various metabolic processes.3−5 The B coefficients obtained from viscosity values and calculated using the Jones−Dole equation are a very good parameter to describe the kosmotropic and chaotropic nature of solute in different solvents. Much work has been done on the determination of the B coefficient of amino acid and peptides in aqueous6−11 and aqueous electrolyte solutions12−16, but there has been less focus on the interactions of amino acids with the salts which are involved in the biochemical process of the body17,18 such as citrates and phosphates. In a continuation of our research program on thermodynamics studies19−21 of amino acids with salts of citrates, here, the viscosities η of glycine, L-alanine, and −1 L-valine in (0.2, 0.4, 0.6 and 0.8) mol·kg aqueous trisodium citrate (TSC) solutions at T = (288.15, 298.15, 308.15 and 318.15) K have been reported. Our main aim here is to study the interactional behavior of amino acids with these salts, which will further help us to better understand these classes of compounds. © 2014 American Chemical Society
Table 1. Specification of Chemical Samples chemical name glycine L-alanine L-valine
trisodium citrate
source Merck, Germany Merck, Germany Merck, Germany S D Fine Chem. Ltd., India
initial mass fraction purity > > > >
0.99 0.99 0.99 0.99
purification method used used used used
as as as as
such such such such
made on a Sartorius CPA225D balance having precision of ± 0.00001 g. Uncertainty in the solution concentration was estimated to be ± 2·10−5 mol·kg−1 in calculations. The AntonPaar Automated MicroViscometer (AMVn) was used to determine dynamic viscosities η of the solutions. The temperature was controlled to ± 0.01.K by a built in Peltier thermostat. The measurement of viscosities with AMVn is based on the falling ball principle. A calibrated glass capillary Received: October 7, 2013 Accepted: January 15, 2014 Published: January 24, 2014 419
dx.doi.org/10.1021/je400894j | J. Chem. Eng. Data 2014, 59, 419−425
Journal of Chemical & Engineering Data
Article
Table 2. Dynamic Viscosities η of Glycine, L-Alanine, and L-Valine in Aqueous Solutions of TSC at Different Temperatures and Experimental Pressure, p = 0.1 MPa−1a
Table 2. continued η/mPa·s m/mol·kg
η/mPa·s m/mol·kg
T = 288.15 K
0.00000 0.01207 0.0523 0.1 0374 0.20373 0.30678 0.41239 0.50277 0.60576 0.68289 0.82001
1.119 1.123 1.133 1.152 1.168 1.1 72 1.177 1.201 1.229 1.241 1.250
0.00000 0.01954 0.05491 0.09665 0.20869 0.3083 0.40064 0.50838 0.59657 0.69776 0.80295
1.343 1.370 1.372 1.374 1.389 1.404 1.421 1.456 1.467 1.493 1.502
0.00000 0.01087 0.04829 0.10 580 0.19845 0.29836 0.41666 0.49305 0.60292 0.71664 0.79774
1.661 1.663 1.669 1.675 1.715 1.74 3 1.782 1.793 1.840 1.872 1.882
0.00000 0.01403 0.05256 0.09928 0.20412 0.30230 0.39812 0.49961 0.58908 0.69413 0.78825 0.86392
2.072 2.117 2.127 2.144 2.155 2.175 2.220 2.255 2.308 2.339 2.366 2.399
0.00000 0.01133 0.05094 0.10 775 0.20440 0.30559 0.40682
2.633 2.660 2.667 2.689 2.735 2.78 8 2.869
T = 298.15 K
T = 308.15 K
Glycine + Water 0.883 0.894 0.911 0.928 0.932 0.932 0.951 0.975 0.976 0.985 0.986 Glycine + 0.2 mol·kg−1 1.056 1.079 1.079 1.082 1.096 1.106 1.121 1.147 1.157 1.175 1.197 Glycine + 0.4 mol·kg−1 1.296 1.296 1.300 1.308 1.335 1.360 1.390 1.398 1.434 1.461 1.483 Glycine + 0.6 mol·kg−1 1.592 1.627 1.633 1.655 1.662 1.671 1.711 1.739 1.787 1.803 1.836 1.861 Glycine + 0.8 mol·kg−1 2.002 2.023 2.027 2.048 2.080 2.121 2.177
0.722 0.729 0.730 0.740 0.761 0.766 0.777 0.804 0.806 0.806 0.809 TSC 0.858 0.876 0.880 0.883 0.887 0.911 0.921 0.932 0.942 0.955 0.966 TSC 1.047 1.047 1.047 1.048 1.058 1.071 1.098 1.128 1.156 1.178 1.205 TSC 1.277 1.300 1.309 1.324 1.331 1.336 1.367 1.389 1.424 1.442 1.463 1.482 TSC 1.581 1.597 1.603 1.621 1.643 1.675 1.714
T = 318.15 K 0.611 0.616 0.618 0.632 0.640 0.642 0.658 0.673 0.676 0.676 0.682 0.719 0.733 0.735 0.739 0.750 0.752 0.765 0.778 0.789 0.822 0.839 0.868 0.872 0.877 0.879 0.880 0.912 0.929 0.956 0.959 0.978 0.990 1.049 1.065 1.078 1.089 1.092 1.099 1.123 1.142 1.164 1.184 1.198 1.213 1.287 1.294 1.305 1.323 1.338 1.363 1.389 420
T = 288.15 K
0.46139 0.59657 0.69469 0.79205
2.898 2.956 3.007 3.067
0.00000 0.00939 0.04689 0.09896 0.20034 0.29792 0.39972 0.49412 0.60987 0.69727 0.79784
1.119 1.189 1.198 1.218 1.242 1.255 1.264 1.288 1.324 1.342 1.351
0.00000 0.01095 0.04907 0.10 134 0.20243 0.29922 0.39624 0.48854 0.59241 0.70653 0.79536
1.343 1.391 1.409 1.426 1.465 1.48 5 1.512 1.561 1.602 1.661 1.693
0.00000 0.01027 0.05007 0.10029 0.20084 0.30259 0.39825 0.51024 0.59764 0.70069 0.80668
1.661 1.670 1.700 1.714 1.772 1.820 1.893 1.941 1.992 2.054 2.123
0.00000 0.01000 0.05102 0.09 796 0.20125 0.29538 0.40326 0.48309 0.59335 0.70955 0.79773
2.072 2.080 2.096 2.142 2.204 2.28 3 2.362 2.419 2.504 2.546 2.575
0.00000 0.01206 0.05011 0.10 740 0.20719
2.633 2.661 2.681 2.735 2.822
T = 298.15 K
T = 308.15 K
Glycine + 0.8 mol·kg−1 2.199 2.242 2.279 2.322 Alanine + Water 0.883 0.949 0.957 0.968 0.976 0.987 1.000 1.001 1.039 1.046 1.055 Alanine + 0.2 mol·kg−1 1.056 1.105 1.120 1.135 1.154 1.176 1.190 1.219 1.250 1.292 1.319 Alanine + 0.4 mol·kg−1 1.296 1.297 1.327 1.340 1.376 1.412 1.469 1.501 1.555 1.585 1.631 Alanine + 0.6 mol·kg−1 1.592 1.620 1.635 1.649 1.693 1.751 1.804 1.848 1.918 1.966 1.999 Alanine + 0.8 mol·kg−1 2.002 2.029 2.038 2.075 2.135
TSC 1.734 1.764 1.794 1.826 0.722 0.757 0.768 0.776 0.799 0.804 0.813 0.820 0.837 0.843 0.861 TSC 0.858 0.880 0.888 0.906 0.937 0.958 0.971 0.984 1.020 1.041 1.068 TSC 1.047 1. 047 1.068 1.080 1.106 1.137 1.176 1.204 1.229 1.267 1.298 TSC 1.277 1.281 1.308 1.316 1.349 1.394 1.430 1.463 1.531 1.549 1.596 TSC 1.581 1.599 1.610 1.633 1.680
T = 318.15 K 1.409 1.429 1.451 1.478 0.611 0.635 0.645 0.659 0.673 0.675 0.677 0.699 0.701 0.715 0.735 0.719 0.735 0.739 0.746 0.750 0.781 0.798 0.816 0.822 0.838 0.870 0.868 0.879 0.896 0.90 3 0.918 0.940 0.966 1.005 1.019 1.044 1.062 1.049 1.055 1.060 1.079 1.107 1.141 1.167 1.192 1.228 1.247 1.296 1.287 1.298 1.311 1.324 1.363
dx.doi.org/10.1021/je400894j | J. Chem. Eng. Data 2014, 59, 419−425
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Table 2. continued
Table 2. continued
η/mPa·s
η/mPa·s m/mol·kg
T = 288.15 K
T = 298.15 K
T = 308.15 K −1
0.29908 0.40011 0.50861 0.59248 0.69231 0.83880
2.90 7 3.009 3.167 3.222 3.338 3.502
0.00000 0.00555 0.02398 0.03504 0.05824 0.07873 0.09938 0.20678 0.29923 0.40172
1.119 1.172 1.188 1.194 1.204 1.214 1.231 1.290 1.335 1.362
0.00000 0.00219 0.00492 0.00982 0.03003 0.05839 0.07898 0.09797 0.19960 0.29588 0.39873
1.343 1.347 1.357 1.369 1.374 1.395 1.406 1.427 1.489 1.563 1.640
0.00000 0.00310 0.00676 0.00 993 0.03119 0.06018 0.07509 0.09961 0.20333 0.28514 0.31777 0.35139
1.661 1.663 1.670 1.672 1.685 1.71 7 1.724 1.751 1.839 1.930 1.957 2.009
0.00000 0.00236 0.00543 0.01 005 0.03017 0.05981 0.07695 0.10096 0.20016 0.25160 0.30713
2.072 2.076 2.077 2.081 2.098 2.13 2 2.165 2.189 2.304 2.379 2.451
0.00000 0.00285 0.00523
2.633 2.650 2.654
Alanine + 0.8 mol·kg 2.194 2.268 2.378 2.416 2.496 2.613 Valine + Water 0.883 0.919 0.922 0.934 0.949 0.960 0.969 0.99 7 1.027 1.050 Valine + 0.2 mol·kg−1 1.056 1.059 1.068 1.075 1.079 1.094 1.103 1.118 1.162 1.215 1.270 Valine + 0.4 mol·kg−1 1.296 1.297 1.301 1.303 1.312 1.335 1.342 1.360 1.422 1.487 1.506 1.547 Valine + 0.6 mol·kg−1 1.592 1.600 1.603 1.610 1.625 1.636 1.664 1.690 1.760 1.813 1.863 Valine + 0.8 mol·kg−1 2.002 2.015 2.017
TSC 1.723 1.779 1.856 1.883 1.951 2.030 0.722 0.789 0.798 0.805 0.815 0.825 0.839 0.875 0.900 0.921 TSC 0.858 0.861 0.874 0.878 0.881 0.888 0.896 0.906 0.939 0.977 1.035 TSC 1.047 1.052 1.058 1.061 1.077 1.084 1.098 1.109 1.149 1.185 1.203 1.237 TSC 1.277 1.290 1.293 1.299 1.317 1.344 1.359 1.397 1.437 1.468 1.495 TSC 1.581 1. 589 1.590
m/mol·kg
T = 318.15 K
0.01375 0.02871 0.06205 0.07723 0.09908 0.14972 0.19869 0.23400
1.397 1.440 1.494 1.515 1.573 1.634 0.611 0.682 0.699 0.701 0.713 0.731 0.742 0.774 0.800 0.811
T = 288.15 K 2.669 2.684 2.764 2.789 2.817 2.870 2.977 3.062
T = 298.15 K
Valine + 0.8 mol·kg 2.029 2.037 2.094 2.112 2.132 2.170 2.239 2.298
T = 308.15 K −1
TSC 1.600 1.605 1.648 1.656 1.672 1.703 1.755 1.792
T = 318.15 K 1.30 0 1.303 1.333 1.339 1.351 1.379 1.419 1.441
a
m is the molality of amino acid in aqueous TSC solution. Standard uncertainty: in molality u(m) = ± 2·10−5 mol·kg−1, in temperature u(T) = ± 0.01 K, in viscosity u(η) = ± 1.5·10−2 mPa·s. The combined expanded uncertainty (k = 2) for viscosity Uc(η) = ± 3.0·10−2 mPa·s.
with a steel ball as supplied by manufacturer with AMVn was filled with the sample to measure the ball falling time. The ball falling time and densities were used to estimate kinematic as well as dynamic viscosities. The calibration of capillary was performed by the manufacturer using viscosity standard fluids. The experimental uncertainty in viscosity measurement was estimated to be less than ± 1.5·10−2 mPa·s and the combined expanded uncertainties (k = 2) for viscosity is ± 3·10−2 mPa·s. The densities used in the calculations were taken from our earlier reported results.21
0.719 0.728 0.730 0.731 0.734 0.741 0.750 0.762 0.781 0.818 0.842
3. RESULTS AND DISCUSSION The values of dynamic viscosities η for glycine, L-alanine, and −1 L-valine in (0.2, 0.4, 0.6, and 0.8) mol·kg aqueous trisodium citrate solutions at temperatures T = (288.15, 298.15, 308.15, and 318.15) K are given in Table 2. The plots of viscosities against molalities of amino acids are given in Figures 1 and 2. Figure 1 shows the experimental viscosities for glycine and L-alanine in different TSC solutions at T = 288.15 K and T = 298.15 K, respectively. Figure 2 shows the experimental viscosities for L-valine in (0.2 and 0.4) mol·kg−1 solution of TSC at different temperatures. The viscosity values show an increase with increase in amino acids concentration. This may be due to an increase in the number of cations and anions like NH3+, COO−, Na+, Cit3− of amino acids and TSC in solutions which may in turn lead to an increase in the interactions between them and therefore increase in frictional resistance in the solutions for their flow. The elevated temperatures of the solutions decrease the viscosities of the solutions. The viscosity A and B coefficients which describes ion−ion and ion−solvent interactions were determined using JonesDole equation.22 The special behavior at low concentrations made Jones and Dole to conclude that there must be some effect which is of relatively greater importance and which is responsible for the curvature found in dilute end of η vs C plots. Furthermore, this effect always tends to increase whether the overall effect of the addition of the salt is to increase or decrease the viscosity. The increase in viscosity was attributed to the interionic forces. Inspired by the results of Debye and Huckel, who had earlier shown that the effect of interionic forces in opposing the motion of ions is proportional to the square root of concentration in very dilute solutions, Jones and Dole gave the equation
0.868 0.869 0.870 0.879 0.885 0.888 0.895 0.902 0.939 0.971 0.990 1.017 1.049 1.050 1.053 1.060 1.064 1.065 1.085 1.096 1.141 1.173 1.192 1.287 1.289 1.291
(ηr − 1)/C1/2 = A + BC1/2 421
(1)
dx.doi.org/10.1021/je400894j | J. Chem. Eng. Data 2014, 59, 419−425
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Figure 2. Experimental viscosities η for (a) L-valine in 0.2 mol·kg−1 TSC solutions and (b) L-valine in 0.4 mol·kg−1 TSC solutions at different temperatures. [○, 288.15 K; △, 298.15 K; □, 308.15 K; ◇, 318.15 K].
Figure 1. Experimental viscosities η for (a) glycine in aqueous TSC solutions [○, 0.0 mol·kg−1; △, 0.2 mol·kg−1 ; □, 0.4 mol·kg−1 ; ◇, 0.6 mol·kg−1; ×, 0.8 mol·kg−1] at T = 288.15 K and (b) L-alanine in aqueous TSC solutions [○, 0.0 mol·kg−1; △, 0.2 mol·kg−1 ; □, 0.4 mol·kg−1 ; ◇, 0.6 mol·kg−1; ×, 0.8 mol·kg−1] at T = 298.15 K.
hydrophilic and hydrophobic groups on the solvent. The observed values of B coefficient are positive for glycine, L-alanine, and L-valine in aqueous TSC solutions except for (L-alanine + water) at (298.15 and 308.15) K, for (L-valine + water) at higher temperatures and for L-valine in 0.4 mol·kg−1 TSC at 308.15 K. The positive and large values of B coefficient as compared to A coefficient suggest the presence of strong solute−solvent interactions. This indicates that the amino acid−TSC−water interactions are dominant over amino acid−amino acid interactions23 and also the structure-making tendency of amino acids with TSC. It is also observed from Table 3 that higher values of B coefficients are obtained for L-valine than L-alanine than glycine which means L-valine has greater kosmotropic effect than glycine in TSC solutions which reinforces that solute−solvent interactions follow the order: L-valine > L-alanine > glycine. This is because in L-valine, the ion-hydrophilic group interactions between the (COO−/NH3+) zwitterionic centers of L-valine and ions of TSC are higher in comparison to L-alanine and glycine. The sign of the derivative of the B coefficient, that is, dB/dT predicts the ability of solute to act as structure maker or structure breaker in a particular solvent.24,25 From Table 3, it is also observed that the magnitude of B coefficient for amino acids decreases with an increase in temperature. The positive values of dB/dT for amino acids indicate structure breaker characteristics while negative dB/dT values indicate structure-maker characteristics for amino acids. The dB/dT values for amino acids change signs from positive to negative, but overall negative values of dB/dT predict amino acids to be the structure-maker in TSC−water mixtures. The analysis of viscosity data of amino acids was done with the help of transition state treatment by Feakins et al.26 for relative viscosities. According to transition state theory,27,28
where ηr (= η/η0) is the relative viscosity, η is the viscosity of (amino acid + TSC + water) solution, and η0 is the viscosity of solvent (TSC + water). A and B are the constants which are characteristics of ion−ion and ion−solvent interactions, respectively. C (mol·m−3) is the concentration in moles per unit volume (molarity). The conversion of molality “m” to molarity “C” was done by using our density values.21 The experimental viscosity data were fitted to Jones−Dole using least-squares method to obtain A and B coefficients. The A coefficient is characteristic of amino acid−amino acid interactions, that is, solute−solute interactions associated with the size and shape of solute, whereas the B coefficient is a measure of structural modification of solutions induced by solute−solvent interactions, that is, it is characteristic of amino acid−TSC−water interactions. The values of A and B coefficients as obtained are reported in Table 3. The values of A coefficients as reported in Table 3 are positive for glycine in all concentrations of TSC at all temperatures except at higher temperature in 0.2 mol·kg−1 and at all temperatures in 0.4 mol·kg−1 TSC. The values are positive for L-alanine in all concentrations except at lower temperatures in 0.4 mol·kg−1 TSC, at higher temperatures in 0.6 mol·kg−1 TSC, and at all temperatures in 0.8 mol·kg−1 TSC. Also, the values are positive for L-valine at all concentrations except at lower and higher temperatures in 0.4 mol·kg−1 and 0.6 mol·kg−1 TSC solutions. The small negative or positive values of A coefficient in aqueous TSC solutions indicate the weak amino acid−amino acid interactions. The B coefficient is a valuable tool and provides information concerning the solvation of solutes and their effects on the structure of solvent in the vicinity of the solute molecules. It reflects the net structural effects of the charged end groups, 422
dx.doi.org/10.1021/je400894j | J. Chem. Eng. Data 2014, 59, 419−425
Journal of Chemical & Engineering Data
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Table 3. Values of A and B Parameters of Jones−Dole Equation for Glycine, L-Alanine, and L-Valine in Aqueous TSC Solutions at Different Temperatures ma mol·kg
A·103/2
T −1
−1/2
m ·mol 3/2
K
ma
B·103 −1
m ·mol 3
mol·kg
K
Glycine 0
0.2
0.4
0.6
0.8
0
0.2
0.4 a
288.15 298.15 308.15 318.15 288.15 298.15 308.15 318.15 288.15 298.15 308.15 318.15 288.15 298.15 308.15 318.15 288.15 298.15 308.15 318.15 288.15 298.15 308.15 318.15 288.15 298.15 308.15 318.15 288.15 298.15
0.0296 0.1216 0.0681 0.0685 0.0320 0.0318 0.0616 −0.0026 −0.0216 −0.0351 −0.1118 −0.0293 0.0372 0.0349 0.0300 0.0373 0.0022 0.0090 0.0179 0.0250 L-Alanine 0.2109 0.2501 0.2198 0.1965 0.1046 0.1638 0.1171 0.0485 −0.0084 −0.0017
A·103/2
T −1
−1/2
m ·mol 3/2
B·103 m3·mol−1
L-Alanine
0.1149 0.0162 0.0900 0.0775 0.1198 0.1304 0.0914 0.2004 0.2150 0.2369 0.3295 0.2286 0.1567 0.1711 0.1666 0.1522 0.2358 0.2200 0.2200 0.1801
0.6
0.8
308.15 318.15 288.15 298.15 308.15 318.15 288.15 298.15 308.15 318.15
−0.0011 0.0381 0.0253 0.0246 −0.0046 −0.0048 −0.0274 −0.0252 −0.0252 −0.0282
0.3216 0.2571 0.3307 0.3334 0.3506 0.3185 0.4435 0.4119 0.4119 0.3925
0.3305 0.3206 0.6449 0.8984 0.0447 0.0535 0.0517 0.0823 −0.0304 −0.0310 0.3548 −0.0191 −0.0581 0.0192 0.1779 −0.0155 0.0385 0.0452 0.0296 0.0061
0.0218 −0.0417 −0.3540 −0.6220 0.4947 0.4322 0.4223 0.3103 0.6723 0.6210 −0.1784 0.5134 0.7705 0.5650 0.2816 0.5233 0.6716 0.5858 0.5595 0.5571
L-Valine
0
0.2
0.4
0.0274 −0.0407 −0.0229 0.0192 0.2107 0.1195 0.1744 0.2036 0.3786 0.3501
0.6
0.8
288.15 298.15 308.15 318.15 288.15 298.15 308.15 318.15 288.15 298.15 308.15 318.15 288.15 298.15 308.15 318.15 288.15 298.15 308.15 318.15
m is the molality of aqueous TSC solution.
where η0 is the viscosity of the solvent, R is the gas constant, h is Planck’s constant, and N is Avogadro’s number. The calculated values of V̅ 01, V̅ 02, Δμ01*, and Δμ02* at all the temperatures are given in Table 4. The data reported in Table 4 shows that values of Δμ01* and Δμ02* are positive. Further, the values of Δμ02* are much larger thanΔμ01* values for amino acids in aqueous TSC solutions except for L-valine in water at (308.15 and 318.15) K and −1 L-valine in 0.4 mol kg TSC at 308.15 K. The large values of 0 Δμ2* as compared to Δμ01* indicate that interionic interactions between the solute (glycine, L-alanine, and L-valine) and solvent (TSC + water) molecules are stronger in the ground state than in the transition state. Thus, the solvation of the solutes in the transition state is less favored in terms of free energy. This further suggests that the formation of the transition state is less favored because of the breaking of intermolecular bonding in solvent molecules in the presence of solute molecules, such as amino acids. Feakins et al.26 in their transition state treatment also suggest that solute molecules having large values of Δμ02* will have more tendency to act as structure maker. The large values of Δμ02* obtained in the present study predicts the amino acids as structure maker in the (amino acids + TSC + water) mixtures.
every solvent molecule in one mole of solution must pass through the transition state and interact more or less strongly with solute molecules. Hence, the Gibbs free energy of transfer of a solute from the ground state to the transition state solvents is the first contribution and Gibbs free energy of solute through its own viscous transition state is the second contribution to Δμ02* which is equal to Δμ01*. The B coefficient as per transition state treatment is given by following relationship B = (V1̅ 0 − V2̅ 0)/1000 + V1̅ 0(Δμ20 * − Δμ10 *)/1000RT (2)
where V̅ 01 and V̅ 02 are the mean volume of the solvent and partial molar volume of the solute at infinite dilution. Δμ01* and Δμ02* are the free energy of activation per mole of the solvent and per mole of the solute respectively. The free energy of activation per mole of the solvent and solute can further be calculated as follows:29 Δμ10 * = RT ln(η0V1̅ 0/hN )
(3)
Δμ20 * = Δμ10 * + RT[1000B − (V1̅ 0 − V2̅ 0)]/V1̅ 0
(4) 423
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Table 4. Values of V̅ 01, V̅ 02, Δμ01*, and Δμ02* for Glycine, L-Alanine, and L-Valine in Aqueous TSC Solutions at Different Temperatures m/(mol·kg−1)a
T = 288.15 K
T = 298.15 K
T = 308.15 K
T = 318.15 K
Glycine 0.0
0.2
0.4
0.6
0.8
V̅ 01·106 (m3 mol−1) V̅ 02·106 (m3 mol−1) Δμ01* (kJ mol−1) Δμ02* (kJ mol−1) V̅ 01·106 (m3 mol−1) V̅ 02·106 (m3 mol−1) Δμ01* (kJ mol−1) Δμ02*/(kJ mol−1) V̅ 01·106 (m3 mol−1) V̅ 02·106 (m3 mol−1) Δμ01* (kJ mol−1) Δμ02* (kJ mol−1) V̅ 01·106 (m3 mol−1) V̅ 02·106 (m3 mol−1) Δμ01* (kJ mol−1) Δμ02*(kJ mol−1) V̅ 01·106 (m3 mol−1) V̅ 02·106 (m3 mol−1) Δμ01* (kJ mol−1) Δμ02* (kJ mol−1)
18.02 41.92 25.95 44.41 18.35 43.61 26.43 45.36 18.64 46.23 26.46 57.63 18.79 49.12 26.48 50.32 21.62 52.11 26.82 56.33
V̅ 01·106 (m3 mol−1) V̅ 02·106 (m3 mol−1) Δμ01* (kJ mol−1) Δμ02* (kJ mol−1) V̅ 01·106 (m3 mol−1) V̅ 02·106 (m3 mol−1) Δμ01* (kJ mol−1) Δμ02* (kJ mol−1) V̅ 01·106 (m3 mol−1) V̅ 02·106 (m3 mol−1) Δμ01* (kJ mol−1) Δμ02* (kJ mol−1) V̅ 01·106 (m3 mol−1) V̅ 02·106 (m3 mol−1) Δμ01* (kJ mol−1) Δμ02* (kJ mol−1) V̅ 01·106 (m3 mol−1) V̅ 02·106 (m3 mol−1) Δμ01* (kJ mol−1) Δμ02* (kJ mol−1)
18.02 56.96 25.95 34.78 18.35 59.05 26.43 59.24 18.64 62.03 26.97 81.19 18.79 65.18 27.52 75.59 21.62 68.11 28.43 82.72
V̅ 01·106 (m3 mol−1) V̅ 02·106 (m3 mol−1) Δμ01* (kJ mol−1) Δμ02* (kJ mol−1) V̅ 01·106 (m3 mol−1) V̅ 02·106 (m3 mol−1) Δμ01* (kJ mol−1) Δμ02* (kJ mol−1) V̅ 01·106 (m3 mol−1) V̅ 02·106 (m3 mol−1) Δμ01* (kJ mol−1) Δμ02* (kJ mol−1) V̅ 01·106 (m3 mol−1) V̅ 02·106 (m3 mol−1) Δμ01* (kJ mol−1) Δμ02* (kJ mol−1) V̅ 01·106 (m3 mol−1)
18.02 89.47 25.95 38.35 18.35 90.55 26.43 100.42 18.64 94.46 26.97 123.09 18.79 96.24 27.52 135.59 21.62
18.05 42.62 26.27 31.87 18.40 44.62 26.75 47.84 18.70 47.54 27.30 62.52 18.86 50.45 27.83 54.47 19.32 53.23 28.46 61.02
18.11 43.56 26.64 42.98 18.46 45.42 27.13 43.56 18.77 48.34 27.68 76.69 18.92 51.21 28.21 55.14 19.40 54.11 28.82 59.82
18.18 44.38 27.07 42.16 18.53 46.43 27.55 60.13 18.85 49.32 28.09 64.43 19.00 52.12 28.62 54.41 19.49 55.02 29.22 58.49
18.052 59.98 26.27 26.43 18.40 59.34 26.75 48.36 18.70 62.74 27.30 79.54 18.86 66.66 27.83 77.93 19.32 70.35 28.46 87.82
18.11 61.27 26.64 29.51 18.46 61.32 27.13 57.28 18.77 64.44 27.68 77.82 18.92 67.17 28.21 82.20 19.40 70.3 28.82 89.92
18.18 62.39 27.07 36.30 18.53 62.42 27.55 62.86 18.85 65.62 28.09 70.72 19.00 68.15 28.62 79.79 19.49 71.22 29.22 89.51
18.05 90.68 26.27 30.51 18.40 91.66 26.75 94.83 18.70 94.46 27.30 119.64 18.86 97.23 27.83 112.38 19.329
18.11 91.69 26.64 −13.03 18.46 90.63 27.13 95.74 18.77 94.13 27.68 13.62 18.92 97.46 28.21 76.97 19.40
18.18 92.78 27.07 −52.57 18.53 93.91 27.55 82.58 18.85 97.1 28.09 111.09 19.00 99.98 28.62 112.72 19.49
L-Alanine
0.0
0.2
0.4
0.6
0.8
L-Valine
0.0
0.2
0.4
0.6
0.8
424
dx.doi.org/10.1021/je400894j | J. Chem. Eng. Data 2014, 59, 419−425
Journal of Chemical & Engineering Data
Article
Table 4. continued m/(mol·kg−1)a
T = 288.15 K
T = 298.15 K
T = 308.15 K
T = 318.15 K
100.03 28.46 113.93
100.84 28.82 113.44
102.79 29.22 116.13
L-Valine
V̅ 02·106 (m3 mol−1) Δμ01* (kJ mol−1) Δμ02* (kJ mol−1) a
99.01 28.43 111.43
m is the molality of aqueous TSC solution.
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AUTHOR INFORMATION
Corresponding Author
*E-mail:
[email protected];
[email protected]. Funding
M.S. is thankful to The Director and Head, Department of Chemistry, Dr B R Ambedkar National Institute of Technology, Jalandhar, for providing an MHRD fellowship. Notes
The authors declare no competing financial interest.
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dx.doi.org/10.1021/je400894j | J. Chem. Eng. Data 2014, 59, 419−425
