ids 135 (2007) 32–37www.elsevier.com/locate/molliq

Journal of Molecular Liqu

Densities, viscosities and ultrasonic velocity studies of binarymixtures of toluene with heptan-1-ol, octan-1-ol

and decan-1-ol at 298.15 and 308.15 K

Mehdi Hasan⁎, Dinesh F. Shirude 1, Apoorva P. Hiray, Ujjan P. Kadam2, Arun B. Sawant

P.G. Department of Physical Chemistry, M. S.G. College, Malegaon Camp, Pin 423 105, India

Received 28 August 2006; accepted 15 October 2006Available online 23 March 2007

Abstract

Densities, viscosities and ultrasonic velocities of binary mixtures of toluene with heptan-1-ol, octan-1-ol and decan-1-ol have been measuredover the entire range of composition at (298.15, and 308.15) K and at atmospheric pressure. From the experimental values of density, viscosity andultrasonic velocity, the excess molar volumes (VE), deviations in viscosity (Δη) and deviations in isentropic compressibility (Δκs) have beencalculated. The excess molar volumes, deviations in viscosity and deviations in isentropic compressibility have been fitted to the Redlich–Kisterpolynomial equation.© 2007 Elsevier B.V. All rights reserved.

Keywords: Excess molar volumes; Deviations in viscosity; Deviations in isentropic compressibility; Toluene; Heptan-1-ol; Octan-1-ol; Decan-1-ol

1. Introduction

Studies on thermodynamic and transport properties of binaryliquid mixtures provide information on the nature of interac-tions in the constituent binaries. Literature provides extensivedata on the density of liquid mixtures, less for density andviscosity of liquid mixtures but a combined study of density,viscosity and ultrasonic velocity is quite scarce. In our previousstudies we have reported [1–8] the effect of molecular size,shape, chain length and degree of molecular association ofnormal and branched alkanols, on the volumetric, viscometricand acoustic properties of binary mixtures containing acetoni-trile, dimethylsulfoxide, ethyl acetate, chloroform and benzoni-

⁎ Corresponding author. Fax: +91 2554 251705.E-mail address: mihasan@rediffmail.com (M. Hasan).

1 Arts, Science and Commerce College, Nampur. Pin 423 204, India.2 Present address: Arts, Science and Commerce College, Manmad. Pin

423104, India.

0167-7322/$ - see front matter © 2007 Elsevier B.V. All rights reserved.doi:10.1016/j.molliq.2006.10.012

trile. In continuation with our earlier study of intermolecularinteractions in toluene–alkanol binary mixtures [9,10] we nowreport the density, viscosity and ultrasonic velocity data for thebinary mixtures of toluene with heptan-1-ol, octan-1-ol anddecan-1-ol at 298.15 and 308.15 K.

2. Experimental

Toluene, heptan-1-ol, octan-1-ol and decan-1-ol (QualigensFine Chemicals, purity N99.5 mass %) were used after singledistillation. The densities, viscosities and ultrasonic velocitiesof the pure components were compared with the correspondingliterature values at 298.15 and 308.15 K (Table 1).

Binary mixtures were prepared by mass in airtight-stopperedglass bottles. The masses were recorded on an Adairdutt balanceto an accuracy of ±1×10−4 g. Care was taken to avoid evapo-ration and contamination during mixing. The estimated uncer-tainty in mole fraction was b1×10−4.

Densities were determined by using a 15 cm3 bicapillarypycnometer as described earlier [11,12]. The pycnometer wascalibrated using conductivity water with 0.99705 g cm−3 as itsdensity [13] at 298.15 K. The pycnometer filled with air bubble

Table 1Comparison of experimental density, viscosity and ultrasonic velocity of pure liquids with literature values at 298.15 K

Pure liquid ρ 10−3/(kg m−3) η/(mPa s) u/(m s−1)

Experimental Literature Experimental Literature Experimental Literature

Toluene 0.86218 0.8621 a 0.554 0.552 a 1306 1304 b

Heptan-1-ol 0.81873 0.8187 c 5.726 5.758 d 1331 1330 e

Octan-1-ol 0.82162 0.82157 a 7.365 7.363 a 1351 –Decan-1-ol 0.82632 0.82623 e 11.792 11.790 f 1388 –a [17].b [18].c [19].d [20].e [21].f [22].

33M. Hasan et al. / Journal of Molecular Liquids 135 (2007) 32–37

free experimental liquids was kept in a transparent walledwater bath (maintained constant to ±0.01 K) for 10 to 15 minto attain thermal equilibrium. The positions of the liquid levelsin the two arms were recorded with the help of a travellingmicroscope, which could read to 0.01 mm. The estimateduncertainty of density measurements of solvent and binarymixtures was 0.00005 g cm− 3. At least three to fourmeasurements were made which had an average deviation of±0.00005 g cm−3.

The viscosities were measured using an Ubbelohde sus-pended level viscometer [6–8] calibrated with conductivitywater. An electronic digital stopwatch with readability of±0.01 s was used for the flow time measurements. At least threerepetitions of each data reproducible to ±0.05 s were obtainedand the results were averaged. The uncertainties in dynamicviscosities are of the order of ±0.003 mPa s.

The ultrasonic velocities (u) were measured at a frequencyof 2 MHz in these solutions through interferometric method(using Mittal's F-81 model) at 298.15, and 308.15 K (±0.05 K).The error in velocity measurements is ±0.1%. The otherexperimental details are the same as reported earlier [2–4].

3. Results and discussion

Experimental values of densities, ρ, viscosities, η, and ul-trasonic velocities, u, of mixtures at 298.15 and 308.15 K arelisted as a function of mole fraction in Table 2.

The density values have been used to calculate excess molarvolumes (VE) using the following equation

VE ¼ ðx1M1 þ x2M2Þ=q12−ðx1M1=q1Þ−ðx2M2=q2Þ ð1Þ

where ρ12 is the density of the mixture and x1, M1, ρ1, and x2,M2, ρ2 are the mole fraction, the molecular weight, and thedensity of pure components 1 and 2, respectively.

The viscosity deviations (Δη) were calculated using

Dg ¼ g12−x1g1−x2g2 ð2Þ

where η12 is the viscosity of the mixture and x1, x2 and η1, η2are the mole fraction and the viscosity of pure components 1 and2, respectively.

The ultrasonic velocity u was used to calculate the isentropiccompressibility κs by the equation

js ¼ 1=ðu2 � qÞ: ð3Þ

The deviation from isentropic compressibility, (Δκs), wasobtained using the relation,

Djs ¼ js;mix−x1js1−x2js2 ð4Þ

where κs,mix is the experimental isentropic compressibility ofthe mixture, x1, x2 and κs1, κs2 are the mole fraction andisentropic compressibility of the pure components.

The excess molar volumes and deviations in viscosity andisentropic compressibility were fitted to Redlich–Kister [14]equation of the type

Y ¼ x1x2Xni¼0

aiðx1−x2Þi ð5Þ

where Y is either VE, or Δη, or Δκs, and n is the degree ofpolynomial. Coefficients ai were obtained by fitting Eq. (5) toexperimental results using a least-squares regression method. Ineach case, the optimum number of coefficients is ascertainedfrom an examination of the variation in standard deviation (σ).

σ was calculated using the relation

rðY Þ ¼PðYexpt−YcalcÞ2

N−n

" #1=2

ð6Þ

where N is the number of data points and n is the number ofcoefficients. The calculated values of the coefficients ai alongwith the standard deviations (σ) are given in Table 3.

The variation of VE with the mole fraction x1 of toluene forheptan-1-ol, octan-1-ol and decan-1-ol at 298.15 K is rep-resented in Fig. 1. It is seen that the VE values are positive for

Table 2Density (ρ), viscosity (η), ultrasonic velocity (u), isentropic compressibility (κs),excess molar volume (VE ), deviation in viscosity (Δη) and deviation inisentropic compressibility (Δκs) for toluene (1)+1−alkanols (2) at 298.15 and308.15 K

x1 ρ 10−3 VE 106 η Δη u κs Δκs

kg m−3 m3 mol−1 mPa s mPa s m s−1 TPa−1 TPa−1

Toluene (1)+heptan-1-ol (2)

298.15 K

0.0000 0.81873 0.000 5.726 0.000 1331 689 00.0525 0.82045 0.003 4.969 −0.485 1329 690 10.1014 0.82207 0.010 4.357 −0.845 1327 691 30.1518 0.82374 0.024 3.776 −1.165 1324 693 50.1859 0.82489 0.034 3.412 −1.353 1321 695 70.2489 0.82707 0.053 2.873 −1.566 1317 697 100.3011 0.82894 0.067 2.473 −1.696 1312 701 140.3504 0.83072 0.085 2.153 −1.761 1307 705 190.4006 0.83260 0.101 1.843 −1.811 1303 707 210.4494 0.83448 0.117 1.630 −1.772 1299 710 240.5003 0.83649 0.134 1.435 −1.703 1295 713 280.5486 0.83850 0.143 1.245 −1.644 1292 714 290.5903 0.84030 0.148 1.120 −1.553 1290 715 310.6493 0.84292 0.155 0.965 −1.403 1287 716 320.7011 0.84535 0.154 0.893 −1.207 1287 714 310.7520 0.84787 0.145 0.768 −1.069 1288 711 280.8041 0.85057 0.130 0.676 −0.891 1291 705 230.8495 0.85303 0.113 0.645 −0.687 1293 701 190.9009 0.85596 0.087 0.600 −0.467 1297 694 130.9487 0.85888 0.049 0.572 −0.247 1302 687 61.0000 0.86218 0.000 0.554 0.000 1306 680 0

Toluene (1)+heptan-1-ol (2)

308.15 K

0.0000 0.81252 0.000 4.329 0.000 1294 735 00.0525 0.81407 0.011 3.846 −0.282 1290 738 30.1014 0.81552 0.027 3.429 −0.511 1287 740 60.1518 0.81705 0.044 3.068 −0.679 1283 744 100.1859 0.81814 0.050 2.862 −0.754 1279 747 130.2489 0.82011 0.076 2.456 −0.919 1274 751 180.3011 0.82180 0.096 2.202 −0.973 1269 756 230.3504 0.82343 0.117 1.942 −1.044 1264 760 270.4006 0.82510 0.143 1.719 −1.075 1260 763 310.4494 0.82686 0.155 1.542 −1.064 1255 768 360.5003 0.82869 0.175 1.357 −1.054 1251 771 390.5486 0.83054 0.185 1.223 −1.003 1248 773 420.5903 0.83219 0.191 1.094 −0.972 1245 775 440.6493 0.83460 0.200 0.967 −0.873 1243 775 450.7011 0.83686 0.196 0.874 −0.768 1242 775 450.7520 0.83918 0.189 0.766 −0.681 1243 771 420.8041 0.84169 0.173 0.664 −0.583 1245 766 370.8495 0.84402 0.149 0.624 −0.449 1250 758 290.9009 0.84680 0.114 0.575 −0.301 1255 750 220.9487 0.84960 0.064 0.527 −0.166 1260 741 131.0000 0.85279 0.000 0.496 0.000 1270 727 0

Toluene(1)+octan-1-ol (2)

298.15 K

0.0000 0.82162 0.000 7.365 0.000 1351 666.835 00.0495 0.82297 0.005 6.430 −0.598 1347 669.701 20.1104 0.82467 0.014 5.450 −1.163 1342 673.31 50.1513 0.82581 0.028 4.841 −1.493 1339 675.396 70.1999 0.82721 0.045 4.200 −1.803 1335 678.3 100.2517 0.82874 0.065 3.646 −2.005 1329 683.175 14

Table 2 (continued)

x1 ρ 10−3 VE 106 η Δη u κs Δκs

kg m−3 m3 mol−1 mPa s mPa s m s−1 TPa−1 TPa−1

Toluene(1)+octan-1-ol (2)

298.15 K

0.2997 0.83020 0.085 3.252 −2.072 1323 688.173 180.3560 0.83198 0.108 2.717 −2.223 1316 694.025 240.3998 0.83340 0.128 2.395 −2.247 1312 697.074 260.4506 0.83516 0.144 2.092 −2.204 1307 700.937 290.5001 0.83695 0.157 1.840 −2.119 1302 704.821 330.5513 0.83887 0.172 1.598 −2.012 1298 707.548 350.6014 0.84085 0.183 1.404 −1.865 1294 710.253 370.6495 0.84290 0.183 1.244 −1.697 1292 710.721 370.6997 0.84515 0.179 1.098 −1.501 1290 711.028 360.7569 0.84788 0.169 0.960 −1.250 1289 709.839 340.8012 0.85011 0.158 0.859 −1.049 1289 707.977 320.8527 0.85295 0.127 0.769 −0.788 1293 701.261 240.9000 0.85570 0.096 0.674 −0.561 1295 696.849 190.9540 0.85908 0.049 0.612 −0.255 1300 688.779 101.0000 0.86218 0.000 0.554 0.000 1306 680.011 0

Toluene(1)+octan-1-ol (2)

308.15 K

0.0000 0.81457 0.000 5.522 0.000 1314 711.018 00.0495 0.81577 0.019 4.918 −0.355 1310 714.315 30.1104 0.81732 0.038 4.280 −0.687 1303 720.641 80.1513 0.81835 0.060 3.853 −0.909 1299 724.174 110.1999 0.81965 0.079 3.402 −1.115 1294 728.623 150.2517 0.82106 0.104 3.009 −1.248 1288 734.165 200.2997 0.82241 0.127 2.674 −1.342 1281 740.992 260.3560 0.82408 0.150 2.317 −1.416 1274 747.639 320.3998 0.82536 0.179 2.048 −1.465 1268 753.56 380.4506 0.82704 0.189 1.825 −1.432 1263 757.996 410.5001 0.82864 0.215 1.637 −1.371 1259 761.347 440.5513 0.83048 0.223 1.420 −1.331 1254 765.73 470.6014 0.83233 0.235 1.272 −1.227 1250 768.926 500.6495 0.83422 0.240 1.119 −1.139 1248 769.645 500.6997 0.83639 0.228 1.015 −0.990 1246 770.114 490.7569 0.83888 0.228 0.870 −0.848 1246 767.828 460.8012 0.84103 0.209 0.779 −0.716 1245 767.096 440.8527 0.84369 0.179 0.699 −0.537 1247 762.227 380.9000 0.84632 0.142 0.610 −0.389 1251 755.007 300.9540 0.84969 0.072 0.554 −0.173 1259 742.486 171.0000 0.85279 0.000 0.496 0.000 1270 727.027 0

Toluene(1)+decan-1-ol (2)

298.15 K

0.0000 0.82632 0.000 11.792 0.000 1388 628.164 00.0507 0.82729 0.015 10.296 −0.927 1383 631.972 20.1015 0.82833 0.025 9.101 −1.550 1377 636.691 50.1473 0.82927 0.043 8.207 −1.930 1371 641.548 90.2091 0.83066 0.055 7.146 −2.297 1362 648.967 140.2577 0.83176 0.076 6.303 −2.593 1355 654.822 180.3006 0.83277 0.095 5.584 −2.830 1348 660.838 230.3496 0.83396 0.121 4.913 −2.950 1340 667.798 280.4028 0.83533 0.148 4.195 −3.070 1332 674.735 320.4516 0.83668 0.168 3.678 −3.039 1324 681.812 370.4989 0.83808 0.184 3.222 −2.964 1317 687.928 410.5497 0.83969 0.198 2.797 −2.818 1311 692.908 440.6009 0.84146 0.203 2.439 −2.600 1305 697.823 460.6498 0.84325 0.210 2.130 −2.360 1300 701.709 470.7065 0.84556 0.203 1.819 −2.034 1295 705.206 470.7524 0.84760 0.190 1.537 −1.800 1293 705.687 45

34 M. Hasan et al. / Journal of Molecular Liquids 135 (2007) 32–37

Table 2 (continued)

x1 ρ 10−3 VE 106 η Δη u κs Δκs

kg m−3 m3 mol−1 mPa s mPa s m s−1 TPa−1 TPa−1

Toluene(1)+decan-1-ol (2)

298.15 K

0.8069 0.85020 0.174 1.308 −1.416 1291 705.71 410.8472 0.85235 0.149 1.071 −1.200 1293 701.754 340.9063 0.85584 0.097 0.807 −0.800 1296 695.661 240.9530 0.85857 0.058 0.608 −0.520 1299 690.249 151.0030 0.86218 0.000 0.554 0.000 1306 680.011 0

Toluene(1)+decan-1-ol (2)

308.15 K

0.0000 0.81942 0.000 8.114 0.000 1352 667.637 00.0507 0.82028 0.025 7.108 −0.620 1346 672.896 40.1015 0.82122 0.041 6.203 −1.138 1338 680.187 90.1473 0.82205 0.067 5.499 −1.493 1332 685.636 130.2091 0.82327 0.094 4.673 −1.849 1323 693.966 190.2577 0.82426 0.120 4.079 −2.072 1316 700.526 230.3006 0.82519 0.140 3.647 −2.177 1310 706.161 270.3496 0.82626 0.171 3.173 −2.278 1301 715.037 340.4028 0.82753 0.196 2.786 −2.259 1294 721.685 380.4516 0.82875 0.221 2.398 −2.276 1286 729.616 430.4989 0.83005 0.235 2.122 −2.192 1279 736.469 480.5497 0.83153 0.250 1.832 −2.094 1273 742.105 500.6009 0.83315 0.258 1.569 −1.967 1266 748.875 540.6498 0.83480 0.264 1.393 −1.771 1262 752.14 540.7065 0.83694 0.257 1.159 −1.573 1256 757.402 560.7524 0.83886 0.240 1.047 −1.335 1256 755.668 510.8069 0.84128 0.222 0.858 −1.109 1254 755.9 470.8472 0.84332 0.190 0.798 −0.862 1255 752.87 400.9063 0.84661 0.132 0.687 −0.522 1259 745.187 270.9530 0.84921 0.085 0.585 −0.300 1263 738.207 161.0030 0.85279 0.000 0.496 0.000 1270 727.027 0

Table 3Parameters and standard deviationsσ of Eqs. (4) and (5) for toluene+1−alkanols

Temp/K

a0 a1 a2 a3 σ

Toluene+heptan-1-olVE 106/(m3 mol−1)

298.15 0.5256 0.4864 0.0149 0.0552 0.0017308.15 0.6870 0.5956 0.1172 0.0204 0.0024

Δη/(mPa s) 298.15 −6.8885 2.7389 −0.6637 −0.2150 0.0137308.15 −4.1678 1.1559 −0.4628 0.1883 0.0125

Δκs/(TPa−1) 298.15 112.3415 108.0644 −43.0770 −61.6244 0.6720

308.15 157.9421 129.1486 1.9743 −22.6955 0.7229

Toluene+ Octan-1-olVE 106/(m3 mol−1)

298.15 0.6395 0.5713 −0.0454 0.0017308.15 0.8338 0.6502 0.2203 0.0737 0.0042

Δη/(mPa s) 298.15 −8.4963 3.7560 −0.9580 0.0184308.15 −5.5724 2.0782 −0.2232 −0.235 0.0137

Δκs/(TPa−1) 298.15 129.8756 109.8213 0.6395 −10.957 0.7147

308.15 172.9760 125.7085 51.6991 61.0571 1.2147

Toluene+decan-1-olVE 106/(m3 mol−1)

298.15 0.7226 0.6988 0.0126 −0.2456 0.0039308.15 0.9276 0.6862 0.1848 0.0038

Δη/(mPa s) 298.15 −11.2932 4.5142 −3.2829 0.0992308.15 −8.8164 3.4712 −0.8900 0.4410 0.0164

Δκs/(TPa−1) 298.15 163.8639 147.1372 13.4654 −8.5540 0.4732

308.15 191.2929 161.8168 25.1440 −23.4600 0.7732

35M. Hasan et al. / Journal of Molecular Liquids 135 (2007) 32–37

binary mixtures of toluene with heptan-1-ol, octan-1-ol anddecan-1-ol over the entire composition range at both the tem-peratures. It is a well known fact that alkanols are self asso-ciated through hydrogen bonding. The mixing of toluene withalkanols is expected to induce changes in hydrogen bondingequilibrium and electrostatic interactions with different resul-tant contributions to the volumes of mixtures. Weakening ofinteractions between molecules of toluene tend to result in anincrease in volume. Similarly, the disruption of alkanol multi-mers through breaking of hydrogen bonds makes a positivecontribution to VE. The VE values of binary mixtures of tol-uene with alkanols follow the order heptan-1-olboctan-1-olbdecan-1-ol. This may be due to the fact that the extent ofhydrogen bonding and self association decreases with increas-ing chain length of alkanols.

Fig. 2 depicts the variation of Δη with the mole fraction x1of toluene. Δη values are negative for binary mixtures oftoluene with heptan-1-ol, octan-1-ol and decan-1-ol over theentire composition range at both temperatures. As the chainlength in alkanols increases the Δη values become morenegative.

The variation of Δκs with the composition of mixture (x1 oftoluene) is represented in Fig. 3. Kiyohara and Benson [15]have suggested that Δκs is the resultant of several opposingeffects. A strong molecular interaction through charge transfer,dipole induced dipole and dipole–dipole [16] interactions,interstitial accommodation and orientational ordering leading toa more compact structure makes Δκs negative and break up ofthe alkanol structures tends to make Δκs positive. The Δκsvalues are positive for mixtures of toluene with heptan-1-ol,octan-1-ol and decan-1-ol. These values are given in Table 2.The positive values of Δκs for mixtures of toluene with heptan-1-ol, octan-1-ol and decan-1-ol signify decreasing dipole–dipole interactions due to decreasing proton donating abilitywith increasing chain length of alkan-1-ols. De-clustering ofalkan-1-ols in the presence of chloroform may also lead topositive Δκs values.

4. Conclusion

There are specific interactions present in the mixtures studiedand the strength of interaction varies as the chain length ofalkanols increases.

Acknowledgment

Authors thank Principal M.S.G. College for the facilitiesprovided.

Fig. 1. Excess molar volumes (VE) at 298.15 K for x1 toluene+(1−x1) alkanols: (▪) heptan-1-ol, (▴) octan-1-ol, (●) decan-1-ol.

Fig. 2. Deviations in viscosity (Δη) at 298.15 K for x1 toluene+(1−x1) alkanols: (▪) heptan-1-ol, (▴) octan-1-ol, (●) decan-1-ol.

Fig. 3. Deviations in isentropic compressibility (Δκs) at 298.15 K for x1 toluene+(1−x1) alkanols: (▪) heptan-1-ol, (▴) octan-1-ol, (●) decan-1-ol.

36 M. Hasan et al. / Journal of Molecular Liquids 135 (2007) 32–37

37M. Hasan et al. / Journal of Molecular Liquids 135 (2007) 32–37

References

[1] P.S. Nikam, L.N. Shirsat, M. Hasan, J. Chem. Eng. Data 43 (1998) 732.[2] P.S. Nikam, M.C. Jadhav, M. Hasan, J. Mol. Liq. 76 (1998) 1.[3] P.S. Nikam, M.C. Jadhav, M. Hasan, Acta Acustica 83 (1997) 86.[4] P.S. Nikam, T.R. Mahale, M. Hasan, Acta Acustica 84 (1998) 579.[5] P.S. Nikam, B.S. Jagdale, A.B. Sawant, M. Hasan, Acoust. Lett. 22 (1999)

199.[6] U.B. Kadam, A.P. Hiray, A.B. Sawant, Mehdi Hasan, J. Chem. Eng. Data

51 (2006) 60.[7] Mehdi Hasan, U.B. Kadam, A.P. Hiray, A.B. Sawant, J. Chem. Eng. Data

51 (2006) 671.[8] U.B. Kadam, A.P. Hiray, A.B. Sawant, Mehdi Hasan, J. Chem. Thermo-

dyn. (2006), doi:10.1016/jct.2006.03.010.[9] P.S. Nikam, B.S. Jagdale, A.B. Sawant, M. Hasan, J. Chem. Eng. Data 45

(2000) 559.[10] P.S. Nikam, B.S. Jagdale, A.B. Sawant, M. Hasan, J. Pure Appl. Ultrason.

22 (2000) 115.[11] P.S. Nikam, M. Hasan, R.P. Shewale, A.B. Sawant, J. Solution Chem. 32

(2003) 987.

[12] P.S. Nikam, R.P. Shewale, A.B. Sawant, M. Hasan, J. Chem. Eng. Data 50(2005) 487.

[13] K.N. Marsh, Recommended Reference Materials for the Realisation ofPhysicochemical Properties, Blackwell Scientific Publications, Oxford,1987.

[14] O. Redlich, A.T. Kister, Ind. Eng. Chem. 40 (1948) 345.[15] O. Kiyohara, G.C. Benson, J. Chem.Thermodyn. 11 (1979) 861.[16] R.D. Rai, R.K. Shukla, A.K. Shukla, J.D. Pandey, J. Chem.Thermodyn. 21

(1989) 125.[17] J.A. Riddick, W.B. Bunger, T.K. Sakano, 4th ed., Organic Solvents,

Physical Properties and Methods of Purification, Techniques of Chemistry,vol. II, Wiley Interscience, New York, 1986.

[18] J.D. Pandey, A.K. Shukla, N. Tripathi, J.P. Dubey, Pramana J. Physics 2(1993) 81.

[19] R.C. Wilhoit, B. Zwolinski, J. Phys. Chem. Ref. Data 2 (Suppl. 1) (1973).[20] T.M. Aminabhavi, S.K. Raikar, J. Chem. Eng. Data 38 (1993) 310.[21] M. Diaz Pena, G. Tardojose, J. Chem.Thermodyn. 11 (1979) 441.[22] N.V. Sastry, M.K. Valand, J. Chem. Eng. Data 41 (1996) 1426.