# Acoustic and Volumetric Properties of Mixture of (N,N-Dimethylacetamide + Ethyl Acrylate) with 1-Butanol or iso-Butanol or t-Butanol at 308.15 K

Authors: M. Kondaiah; K. Sreekanth; D. Sravana Kumar; D. Krishna Rao
Journal: Journal of Thermodynamics
 (2014)

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## Abstract

Densities,ρ, and ultrasonic speeds, u of mixtures of 1-butanol or iso-butanol or t-butanol with equimolar mixture of (N,N-dimethylacetamide + Ethyl acrylate) over the entire composition range have been measured at T=308.15 K. Using the experimental results, deviation in ultrasonic speed, Δu, deviation in isentropic compressibility, Δks, excess molar volume, VmE, excess intermolecular free length, LfE, and excess acoustic impedance, ZE, have been calculated. The variation of these properties with composition of the mixtures has been discussed in terms of molecular interactions in these mixtures. The deviation/excess properties have been fitted to Redlich-Kister type polynomial and the corresponding standard deviations have been calculated. Negative values of VmE, Δks, and LfE and positive values of Δu, and ZE are observed over the entire composition range. The observed negative and positive values of deviation/excess properties are attributed to the strong interactions between the unlike molecules of the mixtures. Further theoretical values of sound velocity in the mixtures have been evaluated using various theories and compared with experimental sound velocities to verify the applicability of such theories to the systems studied. Theoretical ultrasonic velocity data has been used to study molecular interactions in the systems investigated.


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## Body

## 1. Introduction

The measurement of speed of sound in liquids enables for the determination of some useful acoustic and thermodynamic parameters that are found to be very sensitive to molecular interactions. Acrylic esters are important industrial chemicals that are widely used as precursors in the production of technically important special type polymers. Alkanol molecules are polar and self-associated through hydrogen bonding of their hydroxyl groups [1].N,N-dimethylacetamide is commonly used as a solvent for fibres or in the adhesive industry. Ethyl acrylate andN,N-dimethylacetamide molecules are polar having dipole moments 1.96 D [2] and 3.72 D [2] at 298.15 K, respectively. A survey of the literature indicates that Francesconi and Comelli [3], Gonzalez and Ortega [4], and Liau et al. [5] reported density and viscosity data for binary mixtures of esters with alkanols. Recently some researchers have reported the ultrasonic, volumetric, and viscometric studies of esters with alcohols [6–8].N,N-dimethylacetamide as one component and +2-propoxyethanol, +2-isopropoxyethanol [9] and +aliphatic alcohols [10, 11], and +benzene, +toluene, +ethyl benzene [12] as other components.Literature survey indicates that there have been no studies on these equimolar mixtures. As a part of our continuing research on ultrasonic, volumetric, and viscometric properties of binary mixtures/equimolar mixtures of amides/alkanols/acrylic esters [13–17], here, we report densities, ρ, ultrasonic speeds, u of 1-butanol,iso-butanol,t-butanol with equimolar mixture of (N,N-dimethylacetamide + Ethyl acrylate) over the entire composition range at T=308.15 K. From the experimental results, various properties have been calculated and presented as follows: deviation in ultrasonic speed, Δu, deviation in isentropic compressibility, Δks, excess molar volume, VmE, excess intermolecular free length, LfE, and excess acoustic impedance, ZE. The experimental values of u and ρ of pure liquids at T=308.15 K along with their literature [6, 7, 18–24] values are presented in Table 1. These results are in good agreement with the reported data.Table 1
Comparison of experimental values of ultrasonic speed,u, and density, ρ, of pure liquids with the corresponding literature values at 308.15 K.
Compound
u (m·s−1)
ρ (kg·m−3)
Present work
Literature
Present work
Literature
N,N-Dimethylacetamide
1416.23
1417.13 [18]
927.4
927.8 [19]
Ethyl acrylate
1119.12
1118.70 [6]
903.8
904.9 [6]
1-butanol
1207.76
1208.80 [20]
798.0
798.12 [21]
801.91 [22]
iso-butanol
1175.20
1175.20 [7]
789.6
789.7 [23]
t-butanol
1083.60
1084.30 [7]
769.9
770.19 [24]The present work deals with the study of ultrasonic and volumetric properties to investigate the molecular interactions between the unlike molecules of the mixtures of 1-butanol,iso-butanol, andt-butanol with equi molar mixture of (N,N-dimethylacetamide + Ethyl acrylate) over the entire composition range at T=308.15 K (see Table 2 for experimental values).Table 2
Experimental values of ultrasonic speed,u, and density, ρ, of all the systems with mole fraction, x1, or volume fraction, Φ1, of 1-butanol/iso-butanol/t-butanol at 308.15 K.
x
1
Φ
1
u
ρ
x
1
Φ
1
u
ρ
x
1
Φ
1
u
ρ
(m·s−1)
(kg·m−3)
(m·s−1)
(kg·m−3)
(m·s−1)
(kg·m−3)
(DMA + EA) + 1-butanol
(DMA + EA) +iso-butanol
(DMA + EA) +t-butanol
0.0000
0.0000
1260.95
919.62
0.0000
0.0000
1260.95
919.62
0.0000
0.0000
1260.95
919.62
0.1003
0.1005
1255.20
908.95
0.1186
0.1186
1251.60
907.21
0.1429
0.1422
1240.75
903.86
0.2031
0.2028
1249.38
897.99
0.2282
0.2277
1242.93
895.16
0.2647
0.2630
1225.30
889.23
0.3059
0.3066
1244.50
886.79
0.3379
0.3375
1234.37
882.61
0.3867
0.3826
1204.41
873.03
0.4056
0.4055
1239.11
875.39
0.4387
0.4373
1225.81
870.53
0.4924
0.4866
1186.90
857.74
0.5056
0.5067
1233.68
863.68
0.5411
0.5398
1216.98
857.66
0.5965
0.5905
1168.95
841.81
0.6061
0.6072
1228.05
851.53
0.6387
0.6372
1208.24
844.74
0.6857
0.6784
1153.70
827.60
0.7065
0.7092
1222.98
838.80
0.7375
0.7343
1199.64
831.32
0.7752
0.7683
1137.40
812.67
0.8043
0.8059
1217.00
826.11
0.8342
0.8296
1190.30
817.10
0.8498
0.8421
1122.60
799.94
0.9029
0.9038
1211.86
812.52
0.9098
0.9047
1183.30
805.36
0.9306
0.9260
1102.00
784.74
1.0000
1.0000
1207.76
798.00
1.0000
1.0000
1175.20
789.61
1.0000
1.0000
1083.60
769.90


## 2. Experimental Section

Analytical Reagent grade (A.R) of EA (mass fraction purity 0.99) was obtained from KEMPHASOL Company, Mumbai, India.N,N-dimethylacetamide (mass fraction purity 0.99) and isobutyl alcohol (mass fraction purity 0.99) are of Graded Reagent (G.R) and 1-butanol (mass fraction purity 0.99) andt-butanol (mass fraction purity 0.99) of (AR grade) obtained from LOBA Chemicals, Mumbai, India, are used in the present investigation and are further purified by standard methods [25]. Equimolar mixture of DMA and EA is prepared. This solution is in turn used to prepare the liquid mixtures with 1-butanol oriso-butanol ort-butanol so that the entire composition range is covered (i.e., 0–100% of the alkanols). Mixtures are prepared by mass in air tight bottles. The mass measurements are performed with a METTLER TOLEDO (Switzerland make) ABB5-S/FACT digital balance with an accuracy of ±0.01 mg. The uncertainty in the mole fraction is 10−4. The ultrasonic velocity of pure liquids and their mixtures has been measured by using a multifrequency ultrasonic interferometer (M-82 Model) supplied by Mittal enterprise, New Delhi, at a fixed frequency of 2 MHz with an accuracy of ±0.2%. In the present study, the constant temperature water bath (digital electronic) supplied by Concord Instruments Co. Ltd., Chennai (RAAGA type), has been used. The instrument can maintain temperature to ±0.01 K as per its specifications.Densities of pure liquids and their mixtures have been determined by using a 5 cm3 two stem double walled Parker & Parker type pyknometer [26]. This pyknometer is calibrated with triply distilled water. The pyknometer filled with air bubble free experimental liquids was kept in a transparent walled constant temperature bath for 20 to 30 min to attain thermal equilibrium. The positions of the liquid levels in the two arms are recorded with the help of traveling microscope. At least three to four measurements are performed, from which an average value of density of the experimental liquid is determined. The reproducibility in the measured parameter density is 3 in 105 parts.


## 3. Results and Discussion

Using measured data of ultrasonic speed (u) and density (ρ), acoustic parameters such as the isentropic compressibility (ks), acoustic impedance (Z), and the intermolecular free length (Lf) have been determined from the following equations:
(1)ks=1u2ρ,Z=uρ,Lf=Kks1/2,
where K is Jacobson temperature dependent constant and is equal to K=(93.875+0.375T)×10-8, where T is absolute temperature.The deviation in ultrasonic speed in the mixtures has been calculated using the relation(2)Δu=u-(x1u1+x2u2),
where “x” is the mole fraction of the liquid mixture and the subscripts 1 and 2 stand for alkanols and equimolar mixture, respectively. Pertinent to the calculation of deviation and excess parameters, equimolar mixture is considered as one component of the liquid mixture [27].The deviation in isentropic compressibility has been calculated from the following equation [28]:
(3)Δks=ks-(Φ1ks1+Φ2ks2).Sinceks is not additive on mole fraction, it is additive on volume fraction. Hence, such values are calculated using volume fraction Φi=xiVi/∑xiVi.The excess functions such asVmE,  LfE, and ZE have been calculated using
(4)VmE=Vm-(x1Vm1+x2Vm2),LfE=Lf-(x1Lf1+x2Lf2),ZE=Z-(x1Z1+x2Z2).The values of deviation in ultrasonic velocity, excess molar volume, excess free length, and excess acoustic impedance have been fitted to a Redlich-Kister [29] type polynomial equation
(5)YE=x(1-x)∑Ai(1-2x)i-1,
where YE is Δu, VmE,  LfE, and ZE. The subscript “i” in the summation of the above equation takes values from 1 to 5.The values ofΔks have been fitted to Redlich-Kister type polynomial with volume fraction instead of mole fraction in the polynomial:
(6)Δks=Φ(1-Φ)∑Ai(1-2Φ)i-1.The values of coefficientsAi (A1, A2, A3, A4, and A5) in the above equations ((5) and (6)) have been determined using the least square method and are compiled in Table 3 along with the standard deviations σ(YE) calculated using the expression
(7)σ(YE)=[∑(Yexp⁡E-YcalE)2(m-n)]1/2,
where “m” is the total number of experimental points (= 11) and “n” is the number of coefficients (= 5) in (5).Table 3
CoefficientsAi of Redlich-Kister type polynomial Equations (5) and (6) and the corresponding standard deviation, σ, of all the systems.
A
1
A
2
A
3
A
4
A
5
σ
(DMA + EA) + 1-butanol
Δu (m·s−1)
−1.34
1.08
−5.59
4.16
−10.45
0.22
VmE (×10−5) (m3·mol−1)
−0.125
0.052
−0.009
0.064
−0.046
0.0004
Δks (×10−10) (Pa−1)
−0.475
0.110
−0.009
−0.032
0.180
0.0033
LfE (×10−10) (m)
−0.014
0.002
0.003
0.0003
0.003
0.0001
ZE (×106) (kg·m−2·s−1)
0.019
−0.004
0.006
−0.003
−0.019
0.0001
(DMA + EA) +iso-butanol
Δu (m·s−1)
9.9
1.04
0.37
0.08
−11.06
0.14
VmE (×10−5) (m3·mol−1)
−0.255
0.090
−0.067
0.086
−0.048
0.0004
Δks (×10−10) (Pa−1)
−0.890
0.181
−0.068
−0.090
0.255
0.0023
LfE (×10−10) (m)
−0.027
0.005
−0.003
0.002
0.004
0.0001
ZE (×106) (kg·m−2·s−1)
0.038
−0.005
0.002
−0.012
0.003
0.0001
(DMA + EA) +t-butanol
Δu (m·s−1)
51.65
−8.53
86.99
−52.88
−106.74
0.44
VmE (×10−5) (m3·mol−1)
−0.45
0.016
−0.063
0.237
−0.155
0.0005
Δks (×10−10) (Pa−1)
−2.470
0.603
−1.486
0.867
1.522
0.0057
LfE (×10−10) (m)
−0.074
0.016
−0.051
0.039
0.047
0.0002
ZE (×106) (kg·m−2·s−1)
0.073
0.002
0.080
−0.067
−0.086
0.0004The variations of these properties with mole fraction of 1-butanol/iso-butanol/t-butanol with equi molar mixture of (DMA + EA) are presented in Figures 1, 2, 3, 4, and 5. Negative values of VmE, Δks, and  LfE and positive values of Δu  ZE have been observed in the present investigation mixtures. The factors that are mainly responsible for the expansion of molar volume, that is, positive values of VmE, are as follows [30, 31]. (i) Breaking one or both of the components in a solution, that is, loss of dipolar association between the molecules (dispersion forces). (ii) The geometry of molecular structures which does not favor the fitting of molecules of one component into the voids created by the molecules of other component. (iii) Steric hindrance of the molecules. The negative values of VmE [32] are due to strong specific interactions such as (iv) association of molecules through the formation of hydrogen bond (or) association due to dipole-dipole interactions and (v) accommodation of molecules due to considerable differences in molar volumes. The variation of excess molar volume in the present investigation is negative over the entire mole fraction range [33]. As we know, the molecules of alkanols are self-associated through hydrogen bonding in pure state [1]. Mixing of (DMA + EA) with alkanols would induce mutual dissociation of hydrogen bonded structures present in the pure alkanols with subsequent formation of new hydrogen bonds (O⋯H–O–) between carbonyl group (–C=O) of amide/acrylate molecules and hydroxyl group (–OH) of alcohol groups leading to a contraction in volume and decrease in isentropic compressibility of the mixtures. The magnitude of negative VmE, Δks, and LfE values follows the order 1-butanol <iso-butanol <t-butanol which indicates the order of the interactions between the components of the mixtures. In general, the negative values of deviation in isentropic compressibility indicate strong and specific interactions such as H–O and -dipole interactions; on the other hand, the positive values of deviation in isentropic compressibility indicate weak interactions and dispersion forces operating between the molecules of the components of the mixtures [34, 35].Figure 1
Variation of excess molar volumeVmE with mole fraction x1 of (●), 1-butanol/(■),iso-butanol/(▲), andt-butanol with equimolar mixture of (DMA + EA).Figure 2
Variation of deviation in isentropic compressibility,Δks, with volume fraction, x1, of (●), 1-butanol/(■),iso-butanol/(▲), andt-butanol with equimolar mixture of (DMA + EA).Figure 3
Variation of excess free lengthLfE with mole fraction x1 of (●), 1-butanol/(■),iso-butanol/(▲), andt-butanol with equimolar mixture of (DMA + EA).Figure 4
Variation of deviation in ultrasonic velocity,Δu, with mole fraction, x1, of (●), 1-butanol/(■),iso-butanol/(▲), andt-butanol with equimolar mixture of (DMA + EA).Figure 5
Variation of excess acoustic impedance,ZE, with mole fraction, x1, of (●),  1-butanol/(■),iso-butanol/(▲), andt-butanol with equi molar mixture of (DMA + EA).Further, it is interesting to note that interaction is more in (DMA + EA) +t-butanol mixture than in (DMA + EA) +iso-butanol mixture. This is due to the presence of three –CH3 groups at the α-carbon atom oft-butanol, which increase the electron density at oxygen atom to greater extent than that iniso-butanol, which has two –CH3 groups at β-carbon atom, resulting in the strong interaction int-butanol mixture. Hence, the interaction between (DMA + EA) and alkanols increases when the –OH group is attached to more number of –CH3 groups. The variation of Δu and ZE with composition of mixture is displayed in Figures 4 and 5, respectively. From these figures, Δu and ZE values are positive and become more positive with increasing of –CH3 groups attached to –OH group of alkanols. It has been also observed that the strength of interaction in Δu and ZE is the same as that of VmE, Δks, and LfE for all the systems. Furthermore, DMA and alkanol molecules having large dipole moments, causing dipole-dipole and dipole-induced dipole interactions, also exist between the liquid mixtures, which is also favorable to strong interactions between the liquid molecules.In the present study, theoretical sound velocities have been evaluated by considering (DMA + EA) as one component and alkanols as the other component in the mixture. Such an evaluation of theoretical sound velocity is useful to verify the applicability of various postulates of the theories of liquid mixtures and to arrive at some useful inferences regarding the strength of molecular interactions between component liquids in some cases. The theoretical values of ultrasonic velocity obtained using various theories along with the experimental velocity are summarized in Table4.Table 4
Theoretical values of ultrasonic velocity from (8) to (13) and polynomial equation (14) with mole fraction, x1, of 1-butanol/iso-butanol/t-butanol at 308.15 K.
x
1
u
N
u
V
u
Imp
u
Jun
u
J
u
R
f
(
x
)
(m·s−1)
(DMA + EA) + 1-butanol
0.0000
1260.95
1260.95
1260.95
1260.95
1260.95
1260.95
1260.67
0.1003
1255.98
1250.91
1256.26
1253.98
1255.26
1268.06
1255.39
0.2031
1250.80
1241.86
1251.32
1247.20
1249.35
1274.03
1249.90
0.3059
1245.54
1233.97
1246.24
1240.80
1244.53
1277.70
1244.34
0.4056
1240.36
1227.39
1241.18
1234.95
1239.01
1277.67
1238.92
0.5056
1235.09
1221.79
1235.95
1229.44
1233.78
1275.13
1233.48
0.6061
1229.70
1217.13
1230.55
1224.28
1228.09
1269.55
1228.03
0.7065
1224.24
1213.42
1224.99
1219.50
1222.94
1259.95
1222.63
0.8043
1218.83
1210.69
1219.42
1215.21
1217.06
1247.97
1217.44
0.9029
1213.30
1208.79
1213.63
1211.26
1211.82
1230.96
1212.31
1.0000
1207.76
1207.76
1207.76
1207.76
1207.76
1207.76
1207.37
(DMA + EA) +iso butanol
0.0000
1260.95
1260.95
1260.95
1260.95
1260.95
1260.95
1260.80
0.1186
1251.29
1243.76
1252.07
1247.65
1251.71
1270.84
1251.79
0.2282
1242.24
1229.87
1243.58
1236.16
1242.88
1276.04
1243.14
0.3379
1233.07
1217.71
1234.81
1225.39
1234.37
1277.62
1234.19
0.4387
1224.55
1207.97
1226.49
1216.12
1225.73
1275.28
1225.73
0.5411
1215.78
1199.36
1217.78
1207.32
1217.03
1268.83
1216.91
0.6387
1207.33
1192.32
1209.22
1199.49
1208.21
1258.38
1208.31
0.7375
1198.68
1186.27
1200.29
1192.12
1199.62
1244.89
1199.42
0.8342
1190.11
1181.37
1191.27
1185.43
1190.35
1225.46
1190.55
0.9098
1183.35
1178.21
1184.02
1180.58
1183.23
1206.56
1183.51
1.0000
1175.20
1175.20
1175.20
1175.20
1175.20
1175.20
1174.99
(DMA + EA) +t-butanol
0.0000
1260.95
1260.95
1260.95
1260.95
1260.95
1260.95
1261.46
0.1429
1235.74
1219.73
1239.24
1224.71
1240.85
1268.19
1240.77
0.2647
1214.20
1190.14
1219.89
1197.39
1225.26
1267.26
1223.11
0.3867
1192.60
1164.74
1199.70
1172.89
1204.43
1257.64
1204.83
0.4924
1173.86
1145.68
1181.49
1153.72
1186.88
1242.11
1188.10
0.5965
1155.38
1129.25
1162.89
1136.55
1168.95
1221.42
1170.45
0.6857
1139.53
1116.84
1146.38
1123.07
1153.72
1200.01
1154.14
0.7752
1123.62
1105.80
1129.26
1110.60
1137.42
1174.50
1136.45
0.8498
1110.35
1097.59
1114.56
1100.98
1122.62
1151.22
1120.54
0.9306
1095.96
1089.66
1098.15
1091.31
1102.03
1119.18
1101.96
1.0000
1083.60
1083.60
1083.60
1083.60
1083.60
1083.60
1084.75Nomoto [36] established the following relation with sound velocity based on the assumption of the linearity of the molecular sound velocity and the additivity of molar volume:
(8)uN={(∑xiRi)(∑xiVi)}3,
where xi is the mole fraction, Ri=ui1/3Vi is the molar sound velocity, Vi is the molar volume, and ui is the sound velocity of the ith component.Van Dael [37] obtained the ideal mixture relation
(9)∑(xiMiui2)={1∑xiMi}{1uV}2,
where Mi is the molecular weight of ith component in the liquid mixture.Impedance dependence relation used by Baluja and Parsania [38] is given as
(10)uimp=∑xiZi∑xiρi,
where Zi is the acoustic impedance and ρi is the density of the ith component of the mixture.Junjie’s [39] equation is given as
(11)ujun={∑xiVi(∑xiMi)1/2}{∑(xiViρiui2)}-1/2.
Jacobson’s [40] equation is given as
(12)uJ=Kρ-1/2Lf-1,
where K is Jacobson temperature dependent constant and is equal to K=(93.875+0.375T)×10-8, T is absolute temperature, and Lf is the ideal free length of the mixture given by Lf=(x1Lf1+x2Lf2).Rao’s (specific sound velocity) [41] relation is given as
(13)uR=(∑xiriρ)3,
where ri=ui1/3/ρi is the Rao’s specific sound velocity of the ith component of the mixture.The experimental data have been fitted to a polynomial; it describes the ultrasonic velocity data quantitatively as well as qualitatively even in the specific interaction predominant region where nonideal behavior of the system is noticed.The polynomial equation is [42]
(14)f(x)=u(x)=∑akxk,
where k in the summation assumed values from 0 to 3, x is the mole fraction of the 1-butanol/iso-butanol/t-butanol, and ak, is constant coefficient to be determined using numerical methods. The values of sound velocities (after determining the coefficients in the above polynomial equation by applying least squares method) have been compiled in Table 4.The root mean square deviation (RMSD) (σ) corresponding to sound velocity values calculated using the polynomial equation (14) from their experimental values has been evaluated using the relation
(15)σ={∑(uE-uP)2n}1/2,
where uE is the experimental sound velocity, uP is the calculated sound velocity from the polynomial equation f(x), and n is the number of mole fractions at which experimental and theoretical velocities have been determined. These standard deviations which are small and coefficients obtained from (14) are presented in Table 5.Table 5
Parameters and root mean square deviation (RMSD),σ, of ultrasonic velocity; u calculated using polynomial equation f(x).
Name of the System
a
0
a
1
a
2
a
3
σ (m·s−1)
(DMA + EA) + 1-butanol
1260.67
−52.10
−5.54
4.34
0.324
(DMA + EA) +iso-butanol
1260.80
−74.44
−13.50
2.13
0.178
(DMA + EA) +t-butanol
1261.46
−146.66
19.82
−49.87
1.190The percentage of deviations of theoretical velocities from the experimental ultrasonic velocity values are plotted in Figures6, 7, and 8 for all the systems investigated. Data from Table 5 and from Figures 6, 7, and 8 reveal that sound speed computed from Jacobson’s relation exhibits more satisfactory agreement with the experimental values. The interdependence of intermolecular free length and velocity is given by Jacobson relation. The small percentage deviation of Jacobson relation provides the better estimate of the ultrasonic velocity values.Figure 6
Percentage deviations of theoretical ultrasonic velocities with mole fraction,x1, of 1-butanol with equimolar mixture of (DMA + EA); Nomoto (■), van Dael (▲), impedance (●), Junjie (□), Jacobson (△), Rao’s (◯).Figure 7
Percentage deviations of theoretical ultrasonic velocities with mole fraction,x1, ofsec-butanol with equimolar mixture of (DMA + EA); Nomoto (■), van Dael (▲), impedance (●), Junjie (□), Jacobson (△), Rao’s (◯).Figure 8
Percentage deviations of theoretical ultrasonic velocities with mole fraction,x1, oft-butanol with equimolar mixture of (DMA + EA); Nomoto (■), van Dael (▲), impedance (●), Junjie (□), Jacobson (△), Rao’s (◯).


## 4. Conclusions

(i)
Ultrasonic velocities,u, and densities, ρ, of mixtures of 1-butanol oriso-butanol ort-butanol with equi molar mixture of (N,N-dimethylacetamide + Ethyl acrylate) over the entire composition range have been measured at T=308.15 K.
(ii)
Using the experimental results, deviations in ultrasonic velocity, Δu, and isentropic compressibility, Δks, excess molar volume, VmE, excess intermolecular free length, LfE, and excess acoustic impedance, ZE, have been calculated and these properties with composition of the mixtures have been discussed in terms of molecular interactions in these mixtures.
(iii)
The deviation/excess properties have been fitted to Redlich-Kister type polynomial and the corresponding standard deviations have been calculated.
(iv)
Negative values ofVmE, Δks, and  LfE and positive values of Δu and ZE are observed over the entire composition range. The observed negative and positive values of deviation/excess properties are attributed to the strong interactions between the unlike molecules of the mixtures.
(v)
The strength of interaction in the mixtures follow the order (DMA + EA) +t-Butanol >iso-Butanol > 1-Butanol.
(vi)
Further theoretical values of sound velocity in the mixtures have been evaluated using various theories and have been compared with experimental sound velocities to verify the applicability of such theories to the systems studied. Theoretical ultrasonic velocity data has been used to study molecular interactions in the systems investigated.



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*Source: 124012-2014-02-27.xml*