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Indian Journal of Pure & Applied Physics Yol.37. August 1999. pp. 59 1 - 594
Ultrasonic velocities and isentropic compressibilities of N,N-dimethylformamide + cyclopentanone + I-alkanols at 303.15 K
P Venkatesu & M V Prabhakara Rao·
Department of Chemistry. Sri Yenkateswara University. Tirupati 517 502
Rece ivcd I June 1998: rev ised 10 September 1998: accepted 18 January 1999
The ultrasonic ve loci ties in ternary mixtures of N.N- dimethyl form am ide + cyc lopentanone + I-propanol. I-butanol. 1-pentanol and I-hexanol have been measured at 303 .15 K. Isentropic compressibilities. Ks' were calculated from ultrasonic
ve locity and density data. Excess isentropic compress ib ilities. K .:'. were also computed. Negative values of K:' were obtaincd
fo r all the systems throughout the range of volume fractions. The results are interpreted on the bas is of mo lecular inte ractions between unlike molecul es.
1 Introduction In recent years the measurement of ultrasonic veloc
ity has been adequate ly employed in understanding the nature of molecular in teractions in pure liquids and liquid mixtures. These studies are of importance because of their extensive use in text i Ie industry, leather industry, pharmaceutica l ind ustry and in many others. The ultrasonic studies for the binary mi xtures of N, Ndimethylformamide with substi tuted benzenes 1 , wi th ketones2
, with alcohols3,4 with branched alcohols5, with
aliphati c esters6, with tetrahydrofuran7
, with chl oroethanes and chloroethenes8 and with vinylpyrrolidine9
are already reported in the li terature. An exhaustive survey of literature has shown that a few attempts have been made for the isentropi c compress ibility data of
. 10-17 H fe h ternary mi xtures . owever, no e lort appears to ave been made to collect the isentropic compressibili ty data fo r the ternary mixtures of N,N-dimethylformamide, cyclopentanone with I-a lkanols. Hence, these experimental data are reported fo r isentropi c compress ibility of N, N-di methylformami de + cyclopentanone -+- 1-propanol, -+- I-butano l, -+- I-pen tano l and -+- 1- hexanol at 303. 15 K. The main purpose of this paper is to characterize the molecular interactions in these systems and to subsequently evaluate the effect of chain length of I-alcohols on the ultrasonic velocity va lues of these mixtures.
2 Experimental Details Analytical grade N,N-d imethylfo rmamide was puri
fied as described by Corrad ini et 01. 18 Cyclopentanone was purified by the method described by Venkateswarl u
and Raman 19. The I-alkanols were further purified by the method described by Rao and Naidu20 The purity of each sample was confirmed by GLC where single sharp peaks. The measured density and ultrasonic veloc ity data of these compounds and those reported in the literature are listed in Table I and are in agreement.
Isentropic compress ibilities were computed from the measured ul trasonic veloc iti es and densities, eva luated from the measured excess vo lumes. Ultrasonic veloc ities were measured by a si ngle-crystal ultrasonic interferometer (Mittal Company, New Delhi , Model o. M 8 1) at 4 MHz frequency at 303 .15 K. These were acc urate to ± 0.02%. Densiti es of the I iquids were determ ined with a bicap illary type pycnometer, of capac ity 12 cm3
,
Tab le I. - Ultrasonic ve loc ity (U) and density (p) of pure components at 303 .15 K
Componenl
N.N-diJIlcthy I formamick
Cyclopentanonc
l-propanol
1-butanol
I-pcn tanol
I-hexanol
pig cm-3
Exptl Lit3.t9.21 Exptl
1462
1371
11 89
1226
1258
1284
1462
1373
11 9 1
1224
1256
1287
0.94 1 18
0.939 01
0.796 0 1
0.802 03
0.807 61
0.8 12 03
Lit3. 19.2 1
0.94 1 20
0.939 02
0.796 00
0.802 06
0.807 64
0.812 0 1
592 INDIAN J PURE APPL PHYS. VOL 37, AUGUST 1999
which offers an accuracy of 2 parts in 105. The tempera
tu re was maintained us ing electronica ll y contro lled
thermostat havi ng an accuracy of ± 0.0 I K .
3 Results and Discussion The isentropic compressibility (KsJ23 ) of ternary mix
tures was calculated from the expression: v [) -2 - I "' 5123 = 123 P l21 .. . ( I )
\-"here U 12.1 , P 123 denotes ultrason ic ve locity and density of ternary mi xture , respective ly.
Excess isentropic com press ibility K::;n was esti
mated using the relation:
K :'m- Ksl23 - ~IKs l - ~2Js2 - ~JKs.l .. . (2)
where ~I, ~2 , ~ 1, and Ksi. Ks2 , Ks.1 are vo lum e fractions an d isentropic compress ibilities of the three pure com-
pounds. The quant ity dK ~2.1 the di fference between the , E
measllred va lue o t K "23 and that of computed from
F' binary data f( .i13 have been ca lculated using the rela-
tion: dK 1 = K I: - K I ' (3 .1~1 .121 .• 12.1 ... )
The latter quant ity was computed using the relation:
K F' = K I: + K I :" + K I:" , I 2.1 • I 2 " 3 ,~.l
... (4)
'1 ab le 2 - Volu mc fraction ( ~ I ) of N. N-<limcthy lform amidc. d~n,ity (r») . ultrasonic v.: loci ty (lJ ). isent ropi c compressibi li ly (Ks).
cxcess isentrop ic comp rcs~ ib il i[y ( /\ ::" ) fo r ~'N- di rm:thylfo r-
mCll11 ide ( I ) + c\ c lopenlano lH: (2) a t 03 . 15 K
~I pi g cm -3 1m s -I " 'sr rPa -I ".1 r rp -I , a
0.1134 0 .93903 1385 555 -4
0 191 1 0.93991 1393 549 -S
0.266 1 0.938 8 1 1402 542 -6
0.3373 0.93975 1408 537 -6
0.3872 0.93 8 7] 14 15 532 -7
0.4980 0.93887 1423 526 -6
0.5877 0.939 17 1431 52 1 -6
070 11 0. 93972 1440 5 13 - 5
() 8024 0.94027 1448 507 -4
0.8948 09-1075 14 -6 501 ,
- .'
h K E K E d K E d .. were " 2' .,1 3 an x23 enote excess IsentropIc
compress ibil it ies for the three binary mixtures and the e are estimated using the smoothing eq uation:
K:~/- ~j ~j [bo + bl (~, - ~j ) + b2 (~i - ~j )2J . ..(5)
where, bo, b l and b2 are constants obtained by the methods of least squares. The binary parameters of excess isentropic compressibil ity fo r the binary mixtures of . N-dimethylformamide wi th l-alcohols3 and cyc lopentanone with l-alcohols2 1 were taken from literature. Further, the excess isentropic compressibi I ities for the system N, N-d imethylfonn am ide with cyc lopentanone, whi ch are not availab le in li terature have been determined experimenta ll y in th e present investigat ions.
K r: fo r thi s binary system exhi bi ts negati ve deviati on
from idea l behav iour of the entire range of the composit ion. The data are presented in Table 2 and graphical ly
represented in Fig. I . The negat ive K: values indicate
that the contri bution made by dipolar interact ions between unli ke molecul es of the components are predominant. The binary parameters for a ll the binary systems are presented in Table 3. The experimental data for four ternary mi xtures are listed in Tab le 4.
Tnble 3 - Values of paramcters ho. in. b2 and standa rcl devia tion
cr(/\ : ') for binary systems a l :03 . 15 K
Systcm s"
.N-<Iimclily lfo rmam id.: - 25 .2 ( I ) , C) clop.:nlanonc (2)
6 .0
N. r-<lirlll;lhy lfo rrna mid.: - 225. 6 35.6 ( 1) + l-propnno l (3)
I .N-<li methy lform.llnid.: - 92 .3 (I) ~ I-bll tano l (3)
N. - d imcthy lfo rlllam ick 37.2 ( 1 ) ~ I-pcnlanol n)
-1 6.5
8.8
N.N-d illlc lhy lfo rillamid.: -1 07.20 26.9 1 ( I ) + I- hexanol (3)
Cyc lop<.: nlan onc (2 ) 1- -69 .9 1 2996 hutanol (3)
Cyc lopcr llanon.: (2) + 1- - 32 X9 25 .66 pentanol (3)
- IS.D
89.5
69. 1
- 5.9
12 . .1 I
2200
-972
a (K :: )
T Pa-1
2
2
3
.1 k:' data for Ih .: mi :\ turcs uf cyclop.:nlanonc \\ ith l-h<':X3I1ol Jr~
.:Ios.: 10 <.:xp<:r il11cntal error" I and an: not s ho\~n in the Tabk.
VENKA TESU et al.: ULTRASONIC VELOCITIES OF TERNARY MIXTURES Table 4 - The values of density (p), ultrasonic velocity (U), isentropic compressibility (Ksl 23) and its related properties for
N, N-dimetylformamide (I) + cyclopentanone (2) + l -alkanols (3) at 303. 1 4 K
0. 1 1 24
0.2380
0.3 1 42
0/3355
0.4 1 32
0.5267
0.6225
0.7227
0.7886
0.895 1
0. 1 067
0. 1 906
0.2793
0.3 1 05
0.3853
0.48 1 6
0. 5954
0.69 1 6
0.7845
0.8902
0.0630
0. 1 084
0 . 1 837
0.2453
0.33 1 7
0.4609
0.5599
0.6695
0.7846
0.88 1 7
0,0554
0 . 1089
0. 1 638
0.228 1
0.3 1 1 1
0.4379
0.5384
0,655 1
0,7548
0.8683
0.7432
0.5987
0.5655
0,4768
0,4460
0.3 1 98
0.2253
0. 1 253
0.0698
0.0452
Ksl 23 E K ,,123
N,N-dimethylformamide ( I) + cyclopentanone (2) + l-propanol (3)
0.832 86 1 248 771 -27
0,853 62 1 287 707 -36
0,858 66
0.871 I I
0,875 82
0.893 99
0.907 73
0,922 29
0,930 48
0.934 47
1 298
1 3 1 6
1 33 1
1 363
1 388
1 4 1 6
1 433
1 443 -
69 1
663
--- 644
602
572
541
523
5 1 4
-36
-34
-38
-3 1
-24
-16
-I I
-5
E ' K ,,1 23
-3 1
-45
-49
-48
-50
-44
-34
-2 1
-1 3
-7
N,N-dimethylformamide ( I) + cyclopentanone C2) - I �utanol (3)
0,7909 0,830 55 1 269 748 -'20 - 1 3
0.6736
0.6 1 46
0.5 1 73
0.4848
0.3807
0.2926
0, 1 5 1 1
0.0873
0.0493
0.8387
0.7737
0.7032
0.6203
0,5448
0.4256
0.3 123
0.2089
0.0888
0,058 1
0_8804
0.7896
0.7266
0,6655
0.5704
0,4520
0.3620
0.226 1
0. 1 1 26
0.07 1 6
0,846 50
0,854 74
0.867 83
0.87� 62
0,887 1 0
0,899 67
0,9 1 9 29
0,928 42
0,934 I I
1 293
- 1 3 1 0
l 31l
1 342
1 366
1 388
- 14 1 7
1 433
1 446
707
682
� 650
636
604
577
542
)25
5 1 2
-24
-27
-3 1
-32
-29
-25
-16
- 1 0
-6 N,N-dimethylformamide ( I ) + cyclopentanone (2) + I -pentanol (3)* *
0,828 50 1 286 730 -1 3
0,836 9 1
0.846 1 0
0_856 99
0.866 59
0.882 72
0,897 97
0_9 1 2 07
0.928 26
0.933 0 1
1 297
1 3 1 2
1 327
1 342
1 368
1 390
1 4 1 1
1 436
,1 446
7 1 0
687
663
64 1
605
576
5 5 1
522
5 1 3
- 16
-1 8
-20
-20
-2 1
-19
-14
-9
-5
-1 8
-20
-22
-23
-23
-20
- 1 3
-7
-4
-4
-3
-I
o 2
4
4
3
o o
N,N-dimethylformamide ( I) + cyclopentanone (2) + l -hexanol (3)
0 ,826 68 1 303 712 -10 -3
0.837 87 l 3 1 8 687 - 1 5 -4
0.845 74 1 330 " 668 -18 -3
0,853 34 1 340 653 -1 8 -2
0,865 27"--"
1 3 54 630 - 1 8
0.880 43 1 3 7 1 604 -14 6
0,892 1 4 1 385 �� -10 1 0
0_909 95
0.925 1 2
0.93 1 05
1 4 1 6
1 434
1 442
548
526
5 1 7
-14
-8 -2
1 0
6
6
·Within the combined experimental errors
· · The values of K �1�3 • calculated from binary data indicates ideal behaviour
E dK ,, 1 23
4*
9
1 3
1 4
1 2
1 3
IO
5
2-
2·
-7
-6
-9
-9
-6 -5
-3 -
-3 -
-2*
-9
-1 3
-1 7
-20
-22
-25
-23
-1 7
-9
-5
-7
-I I
-1 5
- 1 6 -19
-20
-20
-24
-14
-8
593
594 INDIAN J PURE APPL PHYS. VOL 37, AUGUST 1999
Table 5 - Values of parameters A, 8 , C and the standard deviation
(dK:12J
) of ternary systems at 303 .15 K
N,N-dimethylfor- A B C (J
mamide (I) + cy- F
c1opentanone (2) + (dK;123 )
TPa-1
+ I- propanol (3) 456 ~40 - 3481
+ i-hutanol (3 ) -483 2107 25765 3
+ l-pentanol (3)- 1436 7053 82096 2
+ l-hexanol (3) -163 1 6768 86673 3
:=:;] 0·6 "0
'/>.
Fig. 1- Excess isentrop ic compressibil ity ( K s E) for N.N-d imethyl fomlamide ( 1) + cyclopentanone (2) at 303 .15 K.
The dK ~23 have been fitted into smooth ing equa
ion .
dK ;123 - ~1~2(h(A + B~J (~L - ~3) + 01>1 1 (~2 - ~3)2 ). .. (6)
Th adju:;table parameters A , Band C are obtained
from th least- squares analysis and are g iven in Table
5 along with standard dev ia tion.
A close examinat ion of reo ults included in Tab le 4
shows that K ~:;13 values a re negative at a ll vo lume frac
tion compos it ions stud ied in a ll fo ur ternary mixtures.
The resul ts ind icate that there is a strong interaction in
the liquid mixtures . Due to polar natu re of DMF. cy
clopentanone and alcohols, d ipole-d ipo le interactions
prevail in these mixtures.
Acknowledgement One of the authors (PY) is highly thankfu l to Council
of Scientific & Industrial Research (CSIR), New Delhi
fo r the award of a Research Assoc iateship .
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r