Molecular Interaction Study of Multicomponent System of Benzonitrile + Decane + l-alkanols from Acoustic and Thermodynamic Properties at 298K

International Journal of Pure and Applied Physics ISSN 973-1776 Volume 6, Number 3 (21), pp. 311 326 Research India Publications http://www.ripublication.com/ijpap.htm Molecular Interaction Study of Multicomponent System of Benzonitrile + Decane + l-alkanols from Acoustic and Thermodynamic Properties at 298K Rita Mehra*, Brij Bihari Malav and Ashish Gupta Acoustic and Environmental Laboratory, Department of Pure and Applied Chemistry, Maharshi Dayanand Saraswati University, Ajmer 359, Rajasthan (India) *E-mail: mehra_rita@rediffmail.com Abstract Densities (ρ), viscosities (η) and ultrasonic velocities (u) of ternary mixtures of benzonitrile, decane and 1-alkanol were determined using bicapillary pyknometer, Ostwald's viscometer and ultrasonic interferometer respectively at 298K. Derived parameters such as molar volume, isentropic compressibility, specific acoustic impedance, free length and excess properties viz. excess molar volume (V E ), deviation in viscosity (Δη), deviation in isentropic compressibility (ΔK s ), excess free length (L f E ) and excess specific impedance have been calculated from the experimental values of ρ, η and u. The results are discussed to explain the strength of interactions between component molecules in the ternary mixtures taken for study. Redlich-Kister polynomial equation is used to calculate standard deviation from excess properties. The sign and magnitude of these properties are used to illustrate the nature of interactions between component molecules. Key words: Ternary liquid mixture, Redlich kister equation, Thermoacoustic parameter, Alkanol, Decane and Benzonitrile. Introduction Molecular interaction study of multicomponent systems has wide application in various industrial fields like automobiles, refineries, Pharmaceuticals. As an extension of our earlier work present study are used to understand possible association between benzonitrile 1 + decane + 1-alkanol 2,3 (C 3 to C 7 ) from various acoustic and transport properties. The experimental values of density (ρ), viscosity (η) and ultrasonic velocity (u) measured at 298K have been used to compute derived parameters viz.

312 Rita Mehra et al molar volume (V), isentropic compressibility (K s ), specific acoustic impedance (Z) and free length (L f ) along with excess properties like excess molar volume (V E ), deviation in Viscosity (Δη), deviation in isentropic compressibility (ΔK s ), excess free length (L f E ) and excess specific impedance (Z E ) at temperature 298K. The properties of ternary mixtures based on ultrasonic measurements have been proved to be of significance in studying the physico-chemical behaviour of liquid mixtures. These properties throw light on specific molecular interaction between component molecules 4. Similar studies have been done by many researchers but exhaustive literature survey reveals that no attempt has been made to study the properties of ternary systems of benzonitrile + decane + 1-alkanols 5,1. Due to the presence of l-alkanols (C 3 to C 7 ) in the system H-bonded interactions are expected leading to self-association. Thus this study will shed more light on the formation of mixed species and their influence on the excess properties of the mixtures. Experimental The chemicals used for this study were of Anala R grade. 1- propanol and 1-butanol (Ranbaxy), l-pentanol, 1-hexanol and 1-heptanol (Sd Fine), decane (Fluka) and benzonitrile (Merck) with purities better than 99 % were used. The purities of liquid were checked by comparing the density and boiling point values at 298K with those reported in literature. All mixtures were prepared by mixing the known volumes of pure liquids weighed on an electronic balance in airtight round-stoppered bottles with narrow mouth to minimize the evaporation losses and to avoid possible chances of error. The densities of pure components as well as mixtures were determined using precalibrated bicapillary pyknometer, the uncertainty of density data being ±.24 %. Ultrasonic velocity is determined by using single crystal ultrasonic interferometer model F-81 at 2 MHz frequency. The ultrasonic velocity data are accurate upto ±.3%. Viscosity measurements have been made using precalibrated Ostwald's Viscometer. Uncertainty of viscosity data is within ±.9 %. Temperature of experimental liquids and their mixtures were maintained to an accuracy of ±.1 C in an electronically controlled thermostatic water bath with circulation medium. Theoretical The experimental values of density, ultrasonic velocity and viscosity are used to evaluate various derived parameters like molar volume (V mix ), acoustic impedance (Z), isentropic compressibility (κ S ) and free length (L f ) of ternary liquid mixture using the following relations. V mix =(x 1 M 1 +x 2 M 2 + x 3 M 3 )/ ρ mix (1) where x 1, M 1, x 2, M 2, x 3, and M 3 are the mole fraction and Molecular weight of benzonitrile, decane and alkanols respectively. Z =uρ (2) κ S =1/u 2 ρ (3) L f =K/u ρ 1/2 (4)

Molecular Interaction Study of Multicomponent 313 where u is sound speed, ρ is density and K is Jacobson constant which is temperature dependent but independent from the nature of liquids. K =(93.875+.375xT) x1-8 The excess molar volumes (V E ) 14 were calculated from the molar masses and the densities of pure liquids and mixture as follows. V E = x i M i (l/ρ - l/ρ i ) properties like excess acoustic impedance, excess free length, deviation in isentropic compressibility and deviation in viscosity were calculated by using the following equation. Y E = Y m (x 1 Y 1 + x 2 Y 2 + x 3 Y 3 ) Suffix 1, 2, 3 and m represents 1-alkanols, benzonitrile, decane and mixture, x is mole fraction of alkanols and Y E represent or Z E or L E f or ΔK S or Δη. The values of Z E, V E, ΔK s, Δη, and L E f obtained were fitted to Redlich-Kister polynomial equation 15-17. Y E =x 1 x 2 A i (1-2x i ) I where Y E is V E or Δη or Z E or ΔK s or L E f. The values of the coefficient A, of these fitting equations together with the standard deviation σ (Y E ) can be calculated as σ (Y E ) = [(Y E ob-y E cal) 2 / n-p] 1/2 where n is the total number of data points and p is the number of coefficients A i considered (p =2 in the present case). Results and Discussion Experimental and literature values for density and boiling point of pure liquid components have been reported in Table I. Experimentally determined values of density, viscosity and ultrasonic velocity and other derived parameters such molar volume (V), isentropic compressibility (K s ), specific acoustic impedance (Z) and free length (L f ) at 298 K are given in Table 2 (a,b,c,d and e) and excess properties like deviation in viscosity (Δη), excess molar volume (V E ), excess free length (L f E ) and excess specific impedence (Z E ), deviation in isentropic compressibility (ΔK s ) at temperature 298 K for benzonitrile + decane + l-alkanol (C 3 to C 7 ) are plotted in Fig.1 to 5 (a, b, c, d and e). The excess parameters have been fitted in the Redlich Kister equation and adjustable parameters have been evaluated by least square analysis and are listed in tables-3 for benzonitrile + decane + l-alkanol (C 3 to C 7 ) at 298 K. Negative values of viscosity (Fig-1) indicate existence of low dispersion forces indicating weak interactions due to difference in shape and size of the component molecules present in liquid mixtures. The negative deviation as observed from the graph increases regularly as the chain length of alkanols is increased. This 18, 19 reveals that the strength of intermolecular H-bonding is not the only factor influencing the viscosity deviations in liquid mixtures but the molecular sizes and shape of the components are also equally important, this suggest that larger the chain length of the alkanols greater is the decrease in degree of association resulting in more dissociation as the chain length of alkanol increases. molar volume may be attributed to the structure making and structure breaking effects which include i) depolymerisation of alcohols aggregation by electron withdrawing group attached aromatic hydrocarbon and ii) loss of dipolar

314 Rita Mehra et al association of the three components upon mixing while structure breaking effect contributes to expansion in volume, and the structure making effects lead to contraction in volume. The excess molar volume becomes more negative with decreasing π-electron density. This is consistent with our ternary excess molar volurne (V E ) data for the mixture taken for study, which are negative over the entire range of composition of alkanols due to the nitrile (-CN) group, an electron-withdrawing group being attached to benzene. Similar observation was suggested by Ramachandran et al 2 for n-butylacetate +nitrobenzene + 1-butanol. Thus the negative values indicate that attractive interactions present between the components of the system under study. The plot for excess acoustic impedance (Fig.3) is found to be negative for entire mole fraction range of alkanols. Negative values reveal weak interactions between component molecules. free length values (Fig. 4) are negative; it suggests weak interactions in the ternary mixtures under study. The reverse is observed by Ali et al 21 who reports loosely packed structure for positive values of excess free length, supporting our above discussion for negative values of L E E f. As observed from the graph the L f decreases negatively with the increase in chain length i.e. an increase in L E f is understood which is due to increase in size of alkanol molecules resulting in decrease in interaction between component molecules. Fig. 5 reports negative values for deviation in isentropic compressibility (ΔK s ) at all concentrations of alkanols. The curve obtained is half parabolic. Negative values of ΔK s though suggest interactions but they are of weak nature due to interstitial accommodation, dipole - induced dipole 22, 23 and dipole-dipole 24, 25, as generally for ternary mixtures fewer interactions have been reported because addition of third component weakens the energy of interaction and the ternary mixture tends to approach ideal behaviour. This view is also supported by Pandey et al. 26 Table 1: Density and boiling point of pure component at 298 K. Compound Density (ρ) kg m -3 Boiling Point ( o C) Observed (Literature) (17) Observed (Literature) (17) n-decane 1-Propanol 1-Butanol 1-Pentanol 1-Hexanol 1-Heptanol Benzonitrile 729.5 (726.3) 799.5 (799.6) 87.8 (89.5) 89.9 (81.8) 814.7 (816.) 817.2 (818.5) 18.8 (1.6) 173.8 (174.1) 97.5 (97.1) 117.4 (117.7) 138.3 (138) 156.7 (157.) 174.6 (175.) 19.6 (191.1)

Molecular Interaction Study of Multicomponent 315 Table 2: Experimental data (ρ, u, η), derived parameters (K, Z, V and L f ) of Multicomponent System of Benzonitrile + Decane + l-alkanols at 298 K. X (1-Pro) X (Benzo) ρ kg m -3 u η 1-1 m s -1 mpas V (1-3 ) m 3 mol -1 K s 1-1 m 2 N -1 Z (1 5 ) Rayl L f (A o ) (a) Benzonitrile + Decane + 1 Propanol..6531 91.6 1466.1 1.1384.1282 5.1 91 13.353.4649.1962.528 888.1 1421.9 1.293.1188 5.5693 12.6279.4854.2591.4848 882.1 147.5 1.331.1156 5.7224 12.4158.492.3551.4228 872.1 1386.1 1.47.117 5.9682 12.882.525.4442.3643 86.5 1366.1 1.476.163 6.2271 11.7553.5133.5432.2994 851.2 1344. 1.541.19 6.538 11.441.5245.637.2395 84.1 1324.1-1.618.965 6.7893 11.1238.5359.7688.149 825. 1292.8 1.736.888 7.2524 1.6656.5539.8743.842 814.4 127.3 1.839.824 7.694 1.3453.5674.9773.149 83.1 1246.7 1.924.764 8.114 1.122.5822 1.. 799.5 124.5 1.9427.752 8.1281 9.9178.5864 (b) Benzonitrile + Decane + 1 Butanol..6531 91.6 1466.1 1.1384.1282 5.191 13.353.4649.1865.5566 898.1 1435.7 1.356.12 5.419 12.894.478.2564.4769 884.2 149.9 1.434.12 5.6895 12.4663.496.344.4351 878.2 1396.7 1.551.1159 5.8371 12.2658.4969.4546.3522 863.5 137.8 1.74.1129 6.163 11.8369.516.5479.343 855.7 1357.1 1.877.187 6.3453 11.6127.5181.633.2424 845.9 1336.6 1.991.162 6.6173 11.363.5291.7735.1549 834.1 139.2 2.24.11 6.9947 1.92.544.8763.89 823.1 1286.2 2.351.964 7.344 1.5867.5574.9774.152 811.3 1264.2 2.54.925 7.7124 1.2565.5712 1.. 87.8 126. 2.5448.918 7.7975 1.1783.5743 (c) Benzonitrile + Decane + 1 Pentanol..6531 91.6 1466.1 1.1384.1282 5.191 13.353.4649.1745.5723 91.9 1461.2 1.534.1224 5.193 13.1786.4687.233.5236 89.9 1431.3 1.561.1243 5.4791 12.7515.4814.3289.4477 878.2 1411.2 1.844.1218 5.7178 12.3932.4918.423.3894 868.8 1393.5 2.26.1212 5.9274 12.167.58.597.3247 857.1 1376.4 2.283.119 6.1586 11.7971.514.651.2662 851.9 136.6 2.527.1163 6.349 11.591.5179.736.191 838.3 1341.3 2.854.1133 6.635 11.2441.5296.8631.972 823.6 1314.8 3.161.1114 7.237 1.8287.5451.9694.23 813.1 1293.6 3.437.195 7.3495 1.5183.5576 1.. 89.9 1286.9 3.5112.188 7.4555 1.4226.5616

316 Rita Mehra et al (d) Benzonitrile + Decane + 1 Hexanol..6531 91.6 1466.1 1.1384.1282 5.191 13.353.4649.1215.69 99.1 146.2 1.4818.1249 5.159 13.2747.4672.2643.498 889.1 1428.1 1. 913.1265 5.5148 12.6972.483.3417.43 877.9 1412.2 2.1425.1273 5.7117 12.3977.4916.4583.3587 868.1 1394.4 2.5272.1265 5.9246 12.148.56.5352.3133 863.2 1384.3 2.8114.1258 6.454 11.9493.557.6616.2171 846.4 1358.5 3.2637.1267 6.418 11.4983.524.7198.245 846.8 1358.6 3.5113.1245 6.3979 11.546.523.887.1256 833.7 1337.3 3.8345.1259 6.771 11.1491.5327.9632.244 819.2 1311.9 4.4423.1254 7.927 1.7471.5478 1.. 814.7 135.7 4.5875.1254 7.1997 1.6375.5519 (e) Benzonitrile + Decane + 1 Heptanol..6531 91.6 1466.1 1.1384.1282 5.191 13.353.4649.1664.5496 897.2 1443.9 1.935.1298 5.3461 12.9547.4756.2852.4866 89.2 1434.1 2.498.131 5.462 12.7664.487.3377.4324 879.1 1418.7 2.733.1326 5.6517 12.4718.489.4762.3476 867.2 142.5 3.381.1341 5.8624 12.1625.498.5855.2873 861.3 1392.4 3.895.1344 5.9885 11.9927.533.6555.2265 851.2 1377.9 4.23.1366 6.1878 11.7287.5116.7436.1987 849.1 1375.2 4.663.1356 6.2274 11.6768.5133.867.1314 837.3 1356.4 4.961.1387 6.4~15 11.3571.524.9656.221 82.3 1334.2 5.724.1417 6.8483 1.9444.5383 1.. 817.2 1328.5 5.898.1422 6.9334 1.8565.5416 Table 3: Coefficient A i and standard deviation σ (Y E ) of ternary mixture at 298 K. properties A A 1 A 2 σ (Y E ) (a) Benzonitrile + Decane + 1-Propanol Δηx1-1 (Pa s).138 -.35 -.3426.265 V E x1-3 (m 3 mol -1 ) -.599 -.132.1312.533 ΔK s x1-11 (m 2 N -1 ).283 -.3891.839.53 L E f (A o ).218.812.8931.837 Z E x1 5 Rayl) 1.938 2.921.9831.931 (b) Benzonitrile + Decane + 1-Butanol Δηx1-1 (Pa s).2931 -.3422 -.431.213 V E x1-3 (m 3 mol -1 ) -.873 -.312.1321.521 ΔK s x1-11 (m 2 N -1 ).839.131.8389.981 L E f (A o ) -.521 -.9831.7831 -.93 Z E x1 5 (Rayl).9381.7638.5317.893 (c) Benzonitrile + Decane + 1-Pentanol Δηx1-1 (Pa s).1289.4533 -.582.947 V E x1-3 (m 3 mol -1 ).4831.9483.4892.32

Molecular Interaction Study of Multicomponent 317 ΔK s x1-11 (m 2 N -1 ).9381.381.831.293 L E f (A o ).3916.4617.3412.938 Z E x1 5 (Rayl).3916.4617.3412.938 (d) Benzonitrile + Decane + 1-Hexanol Δηx1-1 (Pa s).3482.8348.9381.238 V E x1-3 (m 3 mol -1 ).9635 -.9882.8737.582 ΔK s x1-11 (m 2 N -1 ).939.7615.6351.338 L E f (A o ) -.291.8923.9723.38 Z E x1 5 (Rayl).421.8719.3345.132 (e) Benzonitrile + Decane + 1-Heptanol Δηx1-1 (Pa s).4231.381.4131.241 V E x1-3 (m 3 mol -1 ) -.131 -.821.3811.781 ΔK s x1-11 (m 2 N -1 ).3938 -.8837.3781 -.183 L E f (A o ).3341.8311.7823.923 Z E x1 5 (Rayl).8832.9838.6371.6614 x 1-Propanol.2.4.6.8 1 1.2 -.5 ℵx1-1 (Pas) -.1 -.15 -.2 -.25 Deviation in Viscocity -.3 -.35 -.4 Figure 1(a): Variation of Deviation in Viscocity with mole fraction of 1-Propanol in Benzonitrile+n-Decane+ 1-Propanol System at 298K. x1-1 (Pas) x 1-Butanol -.1.2.4.6.8 1 1.2 -.2 -.3 -.4 -.5 -.6 -.7 -.8 -.9 Deviation in Viscocity Figure 1(b): Variation of Deviation in Viscocity with mole fraction of 1-Butanol in Benzonitrile+n-Decane+ 1-Butanol System at 298K.

318 Rita Mehra et al x 1-Pentanol.2.4.6.8 1 1.2 -.1 -.2 x1-1 (Pas) -.3 -.4 -.5 -.6 Deviation in Viscocity -.7 -.8 -.9 Figure 1(c): Variation of Deviation in Viscocity with mole fraction of 1-Penanol in Benzonitrile+n-Decane+ 1-Pentanol System at 298K. x1-1 (Pas) x 1-Hexanol.2.4.6.8 1 1.2 -.5 -.1 -.15 -.2 Deviation in Viscocity -.25 Figure 1(d): Variation of Deviation in Viscocity with mole fraction of 1-Hexanol in Benzonitrile+n-Decane+ 1-Hexanol System at 298K. x 1-Heptanol -.5.2.4.6.8 1 1.2 -.1 ℵxℵ4 ℵ4 ℵ4Pasℵ -.15 -.2 -.25 -.3 -.35 -.4 Deviation in Viscocity Figure 1(e): Variation of Deviation in Viscocity with mole fraction of 1-Heptanol in Benzonitrile+n-Decane+ 1-Heptanol System at 298K. x 1-Propanol.2.4.6.8 1 1.2 -.1 V E x1-3 (m 3 mol -1 ) -.2 -.3 -.4 -.5 Molar Volume -.6 -.7 Figure 2(a): Variation of Molar Volume with mole fraction of 1-Propanol in Benzonitrile+n-Decane+ 1-Propanol System at 298K.

Molar Volume Molecular Interaction Study of Multicomponent 319 x1-butanol.2.4.6.8 1 1.2 -.1 V E x1-3 (m 3 mol -1 ) -.2 -.3 -.4 -.5 Molar Volume -.6 -.7 Figure 2(b): Variation of Molar Volume with mole fraction of 1-Butanol in Benzonitrile+n-Decane+ 1-Butanol System at 298K. x 1-Pentanol -.1.2.4.6.8 1 1.2 V E x1-3 (m 3 mol -1 ) -.2 -.3 -.4 -.5 E xces s M olar Volum e -.6 -.7 Figure 2(c): Variation of Molar Volume with mole fraction of 1-Pentanol in Benzonitrile+n-Decane+ 1-Pentanol System at 298K. x 1-Hexanol.2.4.6.8 1 1.2 -.1 V E x1-3 (m 3 mol -1 ) -.2 -.3 -.4 -.5 Molar Volume -.6 -.7 Figure 2(d): Variation of Molar Volume with mole fraction of 1-Hexanol in Benzonitrile+n-Decane+ 1-Hexanol System at 298K. x 1-Heptanol.2.4.6.8 1 1.2 -.1 -.2 V E x1-3 (m 3 mol -1 ) -.3 -.4 -.5 -.6 -.7 Figure 2(e): Variation of Molar Volume with mole fraction of 1-heptanol in Benzonitrile+n-Decane+ 1-Heptanol System at 298K.

32 Rita Mehra et al x 1-Propanol.2.4.6.8 1 1.2 -.5 -.1 Z E x1 5 (Rayl) -.15 -.2 Acoustic Impedance -.25 -.3 Figure 3(a): Variation of Acoustic Impedance with mole fraction of 1- Propanol in Benzonitrile+n-Decane+ 1-Propanol System at 298K. x 1-Butanol.2.4.6.8 1 1.2 -.5 Z E x1 5 (Rayl) -.1 -.15 -.2 Acoustic Impedance -.25 Figure 3 (b): Variation of Acoustic Impedance with mole fraction of 1- Butanol in Benzonitrile+n-Decane+ 1-Butanol System at 298K. -. 5 x 1-P entanol.2.4.6.8 1 1.2 Z E x1 5 (Rayl) -.1 -.1 5 Acoustic Im pedance -.2 -.2 5 Figure 3 (c): Variation of Acoustic Impedance with mole fraction of 1- Pentanol in Benzonitrile+n-Decane+ 1-Pentanol System at 298K x 1-Hexanol.2.4.6.8 1 1.2 -.5 Z E x1 5 (Rayl) -.1 -.15 Acoustic Impedance -.2 -.25 Figure 3(d): Variation of Acoustic Impedance with mole fraction of 1- Hexanol in Benzonitrile+n-Decane+ 1-Hexanol System at 298K

Molecular Interaction Study of Multicomponent 321 x 1-Heptanol.2.4.6.8 1 1.2 -.5 Z E x1 5 (Rayl) -.1 -.15 Acoustic Impedanc e -.2 -.25 Figure 3(e): Variation of Acoustic Impedance with mole fraction of 1- Heptanol in Benzonitrile+n-Decane+ 1-Heptanol System at 298K. x 1-Propanol.2.4.6.8 1 1.2 -.2 -.4 -.6 L f E (A o ) -.8 -.1 Free Length -.12 -.14 -.16 -.18 Figure 4(a): Variation of Free Length with mole fraction of 1-Propanol in Benzonitrile+n-Decane+ 1-Propanol System at 298K. L f E (A o ) x 1-Butanol -.2.2.4.6.8 1 1.2 -.4 -.6 -.8 -.1 -.12 -.14 -.16 -.18 Free Length Figure 4(b): Variation of Free Length with mole fraction of 1-Butanol in Benzonitrile+n-Decane+ 1-Butanol System at 298K. x 1-Pentanol.2.4.6.8 1 1.2 -.5 L f E (A o ) -.1 -.15 Free Length -.2 -.25 Figure 4(c): Variation of Free Length with mole fraction of 1-Pentanol in Benzonitrile+n-Decane+ 1-Pentanol System at 298K.

322 Rita Mehra et al x 1-Hexanol.2.4.6.8 1 1.2 -.2 -.4 -.6 L f E (A o ) -.8 -.1 -.12 Free Length -.14 -.16 -.18 Figure 4(d): Variation of Free Length with mole fraction of 1-Hexanol in Benzonitrile+n-Decane+ 1-Hexanol System at 298K. L f E (A o ) x 1-Heptanol -.2.2.4.6.8 1 1.2 -.4 -.6 -.8 -.1 -.12 -.14 -.16 -.18 Free Length Figure 4(e): Variation of Free Lengthwith mole fraction of 1-Heptanol in Benzonitrile+n-Decane+ 1-Heptanol System at 298K. x 1-Propanol.2.4.6.8 1 1.2-1 s x1-11 (m 2 N -1 ) -2-3 -4-5 Deviation in Isentropic C om pressibility -6-7 Figure 5(a): Variation of Deviation in Isentropic Compressibility with mole fraction of 1-Propanol in Benzonitrile+n-Decane+ 1-Propanol System at 298K. ℵ s x1-11 (m 2 N -1 ) -1.2.4 x 1-Butanol.6.8 1 1.2-2 -3-4 -5-6 -7 Deviation in Isentropic Compressibility Figure 5(b): Variation of Deviation in Isentropic Compressibility with mole fraction of 1-Butanol in Benzonitrile+n-Decane+ 1-Butanol System at 298K.

Molecular Interaction Study of Multicomponent 323 x 1-Pentanol.2.4.6.8 1 1.2-1 ℵ s x1-11 (m 2 N -1 ) -2-3 -4-5 D eviation in Isentropic C om pressibility -6-7 Figure 5(c): Variation of Deviation in Isentropic Compressibility with mole fraction of 1-Pentanol in Benzonitrile+n-Decane+ 1-Pentanol System at 298K..2.4.6.8 1 1.2-1 x 1-Hexanol -2 ℵsx1-11 (m 2 N -1 ) -3-4 -5 Deviation in Isentropic Compressibility -6-7 Figure 5(d): Variation of Deviation in Isentropic Compressibility with mole fraction of 1-Hexanol in Benzonitrile+n-Decane+ 1-Hexanol System at 298K. ℵ s x1-11 (m 2 N -1 ) x 1-Heptanol -1.2.4.6.8 1 1.2-2 -3-4 -5-6 -7 Deviation in Isentropic Com pressibility Figure 5(e): Variation of Deviation in Isentropic Compressibility with mole fraction of 1-Heptanol in Benzonitrile+n-Decane+ 1-Heptanol System at 298K. Conclusion Values of thermo acoustic parameters and excess properties suggest that, dipole - induced dipole and dipole-dipole interactions are present among the components of ternary mixture. Such study also reveals that as size of alkanol molecule increases interactions between component molecules decreases.

324 Rita Mehra et al List of symbols Symbols Properties ρ Density η Viscosity u Ultrasonic velocity V Molar volume K s Isentropic compressibility L f Free length Z Specific impedance V Molar volume K/ C Temperature V E molar volume η E viscosities E K s isentropic compressibility E L f free length Z E specific impedance V E Molar volume K Jacobson constant References [1] Jyostna, T. S. and Satyanarayana, N. Densities and viscosities of binary liquid systems of actonitrile with aromatic ketones at 38.15 K Ind. J. Chem. 44A, 25, pp. 1365-1371. [2] Mehra, R. and Gaur, A. K. Study of a binary liquid mixture of diethylamine and 1-decanol and validation of theoretical approaches of sound speed at different temperatures J. Chem. Eng. Data, 53, 28, pp. 863-866. [3] Mehra, R. and Pancholi, M. Acoustic, thermodynamic, viscometric and volumetric studies in multicomponent system of hexane+ 1-dodecanol+ cyclohexane with respect to temperature Z. Phys. Chem., 221, 27, pp.847-866. [4] Oswal, S. L., Gardas, R. L. and Phalak, R. P. Densities, speeds of sound, isentropic compressibilities, refractive indices and viscosities of binary mixtures of tetrahydrofuran with hydrocarbons at 33.15 K, J. Mol. Liq. 116, 25, pp. 19-118. [5] Ali. A., Pandey, J. D., Soni, N. K., Nain, A. K., Lal, B., Chand, D. Densities, ultrasonic speeds, viscosities and refractive indices of binary mixtures of benzene with benzyl alcohal, benzonitrile, benzoyl chloride and chlorobenzene at 33.15 K, Chinese J. Chem 23, 25, pp. 1-1. [6] Prabhavathi, C. L., Sivakumar, K., Venkateswarlu, P., Raman, G. K. Volumetric and ultrasonic study of binary liquid mixtures of m-xylene with 1- alkanols at 33.15 K, Ind. J. Chem. 43A, 24, pp. 294-298.

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