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Journal of Molecular Liquids, 50 (1991) 39-,52 39 E l sev i e r Sc i ence P u b l i s h e r s B.V., ~ , r n
Thermodynamic Studies on the Binary Liquid Hixtures Containing
Furan Derivatives: Furfural t Allphatic Ketches
Homendra Naorem and Sushll K. Suri ~ Department of Chemistry,
Indian Institute of Chemistry, Delhi Hau~ Khas. New Delhi - 110016. (India)
( R e c e i v e d 22 O c t o b e r 1 9 9 0 )
ABSTRACT
The excess molar volumes,V E . isentroplc compressibillties,
K E , and viscositles, R E , of mixing for the binary liquid mixtures
of fu~fural with acetone, 2-butanone, and 2-penta.one
over the entire composition range have been determined and
reported. The V E and K E for all the mixtures studied were found
to be negative and the E for the mixtures containing acetone and
2-butanone were positive over the entire composition range while
it was negative for the 2-pentanone mixtures. The results have
been discussed in the light of the specific intermolecular
interactions between the component molecules in the mixtures_
INTRODUCTION
Thermodynamic studies on ~he solution behavlour of binary
liquid mixtures of tetr~hydrofuran (THF) with various
hydrocarbons have reveal~d the presence of strong unlike speelflc
interactions between the component molecules (I-ii). These
interactions were found to be stronger than those expected from
dlsper~lon or induced dlpole-dlpole forces. The binary mixtures
of furan with aromatic hydrocarbons exhibited a similar behavlour
expect for the weakening of the unlike 5-~ interactions in the
0167-7322 /91 /$03 .D0 O 1991 m E l sev i e r S c i e n c e P u b l i s h e m B.V. Al l r i g h t s r e se rved
furan mixtures due to the presence of fl-alctron cloud In the
furan molecule (12). The introduction of a functional group in
the furan ring was found to bring about a significant change ln
the s01uti0a behavfour. In binary mixtures containing a
substituted furan viz. furfural or furfural aloohol the overall
solution behaviour of the mixtures was determined by the
struoture breaking effect of the dipolar associatea of the
furfural or furfuryl alcohol molecules (11-15). The strength of
unlike interaotions in binary mixtures of furfural with self
associated aliphatic alcohola were observed to be relatively
stronger than those of the hydrocarbon mixtures (14.16). These
were attributed to the presence of hydrogen bond interactions
between the carbonyl group of furfural and the -08 group of the
alcohol and the stre,ngth of the interaotion waa found to decrease
as the chain length of the alkyl group of the alcohol increases_
In continuation to our investigations on aolution behaviour of
binary liquid mixtures containing a substittited furan. we have
determined the molar excess volumes, BXC6SS isentropic
compresaibilitias. and excess visoosities for the mixtures of
furfural wfth three aliphatlc ketones namely, acetone, 2-
butanona. and 2-pentanone over the entire composition range. The
purpose of these investigations is to provide more informations
Oil the solution behavior of binary mixtures of furfural with
organic solvents of varying polarities in order to have a better
understanding of the type and the nature of the unlike
interactions present in these mixtures.
EXPEEIMMTAL
The laboratory reagent grade samples of X-butanone and 2-
pentanone supplied by E Merck, India were treated (17.18) with
aqueous potassium carbonate solution and the mixture was
distilled to remove most of the water. The sample was dried for
4-5 days over anhydrous sodium sulfate and then stored over
anhydrous potassium uarbonate. The liquid was decanted and
fractionally distilled through a Im long fractionating column.
Spectroscopic grade sample of acetone supplied by EMerck was used
as such without any further purification treatment. The sample of
furfural was the one used In our previous studies (13). The
purified liquids were stored in brown bottles and fractionally
distilled immediately before use. The densities and the
refractive indexes of the purified solvents are compared with the
accepted literature values (17,181 in Table 1,
The molar excess volumes of mixing were computed from the
experimental density data. IJenaities of the liquids and the
liuuid mixtures were measured using a vibrating tube digital
density meter (UMA 60/602. Anton Paar). The details of the
experimental techniques have been described earlier(l2)_
Table l_ Densities and Refractive indexes of the liquiLds used at 298,15K,
-_--_------_----_______~-___-~______---____---_--_---_~~--~-----
Denfsitfea Refract+ve Indexes LIquida -----------------_---- ___-__---_____--____----
our value lit, value* our value lit, value* __---_----_-----________------_--_____-________--~~---~~---__---~
Furfural l-15493 l-1545 l-5236 l-52345
Acetone O-78451 o-7844 l-3569 l-3661
2-Butanonet O-79981 O-7997 l-3670 l-3761
2-Pentanone O-80158 -- 1-3857 --
s Ibference 17
42
Duplicate density measurement of the liquids and liquid mixtures
agreed to within + 5x10-5 -3 g-cm . This propagates a maximum
uncertainty of 3.008 cm3.mol -' in the VE values reported in this
paper.
The isentropic compressibilities (k,) were calculated from
the experimental density (p) and ultrasonic sound speed (u) of the
liquids using the relation :
k, = (u2. p)-l (1)
Tha ultrasonic speeds of sound were measured using a single
crystal path variable interferometer (Model F-81. Mittal
Enterprise, New Delhi, India) operating at a fixed frequency of
2 Ml%. The excess isentropic compressibility. ICE, of the mixtures
were computed from the relation:
KE= ks -&k,1 -+s2 (2) -
where #i and k,i are the volume fraction and isentropic
compressibility of the component Y' in the mixtures. The maximum
error in the measurement of 'u' was estimated to be 0.15 percent
and this propagates an unaertainty of +2 TPa-' in Lhe k, values
calculated using equation (2)-
The visaosities (7) of the liquids were measured using a
viscometer similar to the Ubbelohde suspended level viscometer
calibrated using purified benzene. toluene and water as reference
liquids. Kinetic energy corrections were applied to the
experimental data. The viscositY values were reproducible to
within 0.002 of a centipoise.
The solutions were prepared by weight in pyrex glass bottles
covered tightly with teflon septuma_ Details of the technique for
preparation of the solutions have been described earlier (12)-
Ketones being more volatile were introduced into the bottle first
43
and weighed, Furfural was then introduced into the bottle and the
content of the bottle were thoroughly mixed and weighed.
Corrections for bouyancy were applied to all the wsighings.
RESULTS AND DISCUSSION
The E experimental V . KE and?= for the binary mIxt.ures are
given in Tables 2-4 and shown graphically in Figures l-3
Table 2 5 Molar exaez3s volumes of mm, VE <am3aol-1) for the binary mixtures of furfural with aliphatia ketones-
-_-_____-_-__-_-_____-__~~~_~~__~_-_---~-~-~-~-_--------
x V= x V= _------_---_-_-_-____~---~-~-_---~-~-~~~-~~--~-~-~-~~~~~~
298_15K 308_15K
furfund+ acotona
0,0827 -0.25s O-1922 -0,438 0,274o -0-546 O-3508 -0,627 O-4264 -0,644 O-5247 -0-625 0_6096 -0,598 0-8395 -0,296 O-9236 -0,142
0_1070 O-1938 0.2776 O-4047 O-4843 0.5874 O-6605 O-7553 O-8714
0_0835 -0,258 0.2293 -0,557 O-2952 -0,649 O-4181 -0,736 O-4630 -0,725 O-5401 -0.702 Om6009 -0,656 O-7445 -0-482 O-8795 -0,235
furfural + 2-lmAJ3noneJ
O-0751 -0,142 0.1497 -0.273 O-2344 -0,292 O-3351 -0,487 O-4185 -0-531 0.5071 -0,529 0.6237 -0-467 O-7186 -0,382 O-8272 -0,254 -_-___---------- _-------
-0.227 0.0948 -0,229 -0-366 O-1895 -0,403 -0,471 O-3447 -0,562 -0,542 O-4605 -0-598 -0,553 O-5703 -0,570 -0,521 0.6449 -0,502 -0,462 0.7336 -0,408 -0.368 O-8022 -0,331 -0,218 O-9132 -0-162
fu.rFuraI + 2-pentanone
----__--
O-0898 -0,160 O-2113 -0-343 0,317o -0,453 O-4064 -0-490 O-5338 -0,485 O-5969 -0,444 O-6886 -0-377 O-7840 -0,285 O-8674 -0-188
,_-----_-_-_ --_-a .-----w--s
44
Table 3 = Volums fraction, @. density .Qm speed of sound. u. isentrophz comgreasibflity, k,, mnd BXc888
iSf3M2OpiC aompm3saibility. BF. for IACJ binary mix-txlrea of furfural with aliphatic ketones at
308-15 K_ __--_______---_--_----------~~~--_____~~--__-__--------_--_~-
k TPa=-1
O-0 O-1381 0.2660 0,4057 O-4628 O-5731 O-6900 0_7311 O-8517 O-9562 1-O
o-77337 1115 1040 Q-82831 1166 888 O-87839 1208 780 O-93217 1264 684 O-95373 1267 653 o-99431 1295 600 1103639 1328 547 l-05093 1338 532 1,093Ol 1366 490 1.12882 1392 457 l-14372 1404 444
furfural + z-butJ%none
O-0 O-1350 0_2166 O-3149 O-4460 O-4814 O-6192 0.7705 0.8335 o_s570 1.0
Oe78935 1155 950 O-84022 1195 833 0.87053 1225 765 O-90653 1244 713 o-s5390 1278 642 O-96647 1286 626 l-01482 1322 564 l-06678 1357 509 1,08810 1371 489 l-12944 1395 455 l-14372 1404 444
furfural + 2-pentanon
O-0 0.79047 1183 901 O-0936 0.82525 1202 839 O-1227 O-83566 1217 808 0_2693 0.88984 1246 724 O-3812 0.93018 1274 662 O-4548 O-95635 1291 627 O-5351 0_98460 1312 590 O-7081 1.04450 1343 531 O-8364 l-08958 1366 492 O-9246 l-11822 1385 466 l-00 1.14372 1404 444
furfural + acetone
-70 -101 -114 -111 -98 -82 -72 -42 -13
-
-49 -74 -78 -82 -80 -73 -51 -39 -11
-19 -37 -54 -65 -66 -66 -46 -27 -12
4s
Table 4 : lDeslit*~ (p.&K+. vlacosltlaa (92. cp) and excess vimzositias (q . cp) for the binary mlxturea of furfural with aU.phatic Latin05
__--__-__________~_-_~---_--_------__--_---_--__--__--___-------_--_------
furfural + acotona
308.15E
0.0964 O-1804 0.2705 O-3561 O-4327 O-5118 O-6013 O-7513 0.8688 0*8159 O-8517 O-8891 O-9232 0.9527 O-9822 l-0142 l-0653 1.1088 0.414 O-524 O-634 O-735 0.819 0.903 O-993 l-136 l-263 O-022 o-041 O-054 O-063 0.064 0.063 0.056 0.037 O-018
303.15 R
3c O-1083 0.2488 O-3465 0_4336 O-5007 O-6620 O-7622 0.8403 0.9253 P O-8262 O-8866 O-9248 0.9581 0_9833 l-0267 l-0742 l-0996 l-1263 %s 0,432 O-639 0.763 0.861 0.9s4 1.081 l-203 I-282 l-365 'I. 0.011 0.058 O-071 O-069 O-066 o-054 O-036 0.026 O-012
288-15 K
x O-0927 0_1922 0.2740 O-3508 O-4284 O-5247 0.6038 0.8S95 O-9236 0.8264 O-8677 0.9012 0_9320 O-9618 O-9975 l-0261 l-1051 1.1315 0.44s O-591 O-702 0,804 0.893 I.001 l-090 1.328 1.424 0.020 0,052 O-066 0,076 O-073 O-066 0.061 O-018 O-014
furfural + 2-butJxnona
308-15 K
0.1002 O-2134 0.3087 O-4301 : 0.8245 O-8643
0.5163 O-5746 O-6278 O-7079 O-8414 O-8980 O-9409 O-9715 0_9921 l_OllO l-0394 l-0869
0.460 O-587 0,694 O-822 o-911 0.967 1.018 l-094 1.218 O-010 0.022 0.031 0.036 0.037 0.033 O-030 0,025 0.013
303-15 K
b 0.1238 0.2186 O-3164 0.4005 0.5146 O-6332 O-7244 O-8024 0.9061 3 0.8378 O-516 O-016 0.8714 0.628 O-026 0.9059 0,744 O-037 0-9357 0.839 0.042 O_BY62 0,960 0.041 O-032 1.021 1.0183 O-026 1.0506 1.104 0.019 l-174 1.0783 O_OOB l-285 l-1155
298-15 K
"p O-1070 0.8373 O-1938 0_8879 O-2776 O-8976 O-4047 O-9426 O-4843 O-9709 0.5874 l-0076 0.6605 1.0335 O-7553 1.0673 0.8714 l-1089 h 0.517 0.625 0.729 O-881 O-969 l-078 l_lS6 1.255 l-973 5 O-015 O-026 O-036 O-046 0.046 o-039 O-035 0.026 O-016
fux-furel + 2-pentanonar
308.15 K
"p O-1062 O-8229 0.1754 O-8439 O-2946 0.8616 0.3839 0.9108 O-4777 0.9426 O-6010 O-9861 O-6837 1_0165 0.7683 l-0487 0.8639 l-0866 O-548 O-649 O-729 0.813 0.930 1.026 I-115 l-219
-0,027 -0.041 -0.047 -0-053 -0.046 -0.037 -0,030 -0,017
46
303-1s K
O-4426 0_5830 0_9357 O-9848 0.813 0_961
-0.056 -0.052
298-15 K
0.4064 0.5338 O-9287 O-9727 0,806 0.943
-0,060 -0.058 ---1---------
F 0_1134 0_8299
%c 0_516
"L -0-018
x 0_0896
O-1968 0.8556 O-587
-0-032
O-2113 0_3170 O-8652 0_8991 O-621 0.720
-0.035 -0.049 -------- -------
O-3042 O-8887 0,681
-0-047
O-6634 O-7580 O-8362 0-9118 l-0141 1_0499 1.0807 l-1115 l-052 l-157 l-246 1.335
-0.043 -0.034 -0,025 -0-013
0.5969 0.6886 0.7840 0_9951 1_0289 1.0657 l-013 l-120 l-233
-0,056 -0.047 -0.036 --------_ _--a-P --------
O-8674 1.0991 1.337
-0,022 ll_-----
r93pect1ve1y. The experimental excess values, YE(=VE ortE), were
fitted into a smoothing equations of the type :
YE = x1.x2CA0 + A1(x1-x2) + A2(x1-x21' + A3(~1-x~)~l (3a)-
KE= 1_ 2C% + AIC+l-~) + A2(#'l-fi)2 + A,(e-%)3l (3b).
where xi and#i are the mole fraction and the volume fraction of
the component 'i' in the mixture and Ai's are constants. The
values of the constants determined by method of least smxares are
given in Table 5 along with the standard deviation 6(YK) of the
fit. Since the 6(YE) values for all ths mixtures are less than
the experimental uncertainty involved in the measurement of YE.
the constants Ai's can be used to represent the experimental
results.
It is observed from figures 1 and 2 that the VE and KE
values for all the mixtures studied are negative over the entire
composition range. The q" for binary mixtures of furfural
containing acetone and 2-butanone are positive while for mixtures
containing 2-pentanone found to be negative over the entire
composition range (Figure 3). The plota of YE vs. composition are
more or less symmetrical to the composition axis with a maxima
(or minima) at around x=0.45 to 0.55. To the best of our
Table 5, values of p"pm eters Zm Eqs.<3a and 3bl and standard deviation 6<~ ) of exp~~imtmtal results at 308-15E-
Furfural +
Acetone -2-8860 O-5963 0.2068 0,2155 0,006 2-butanone -2,354o O-5346 0_0069 -0-2278 0,006 z-_pentanone -2.0867 -0.0641 O-5320 O-6292 0.008
Acetone -433 163 -52 23 3 L-butanone -325 102 -58 14 3 2-p43ntanona -264 83 57 36 4
Aaetona O_ 2525 -0.0956 -0,056O 0.0731 O-001 P-butanone O-1440 -0wO328 -0-0718 O-Q284 0.001 2-Pent.anona -0,200Q O-0335 O-0764 -0.0224 0_.002
x 00 0.2 0-L 0.0
on
-0.2
‘; ; -u
E
? -Q6
%
+.“I~ Fig.1 -VE Vs. x for the systems turfural+ acetone(o), + Zbutanone(v)
+ 2-pentanoneto 1 at 308.15K (broken lines at 298_15K I.
Fig.2 KEVs.@ f or the binary mixtures of turfural with acetone (0 1,
2-butanOne (v), and 2-pentonone(a1 at 308.15.
?, I-
! Fig.3.$ Vs. x for turfural + acetone (0 1. 2-buta none{ b), 2-pentononek)
at 29&15(O), 303_15(fi), and 308.15K(0) respectively.
48
knowledge there are no data available for any of the mixtures
considered here in the literature to compare our results-
The molecules of furfural are known to exist a5 dipolar
associates in the pure state(l9). The addition of a non-polar
solvent to furfural leads to breaking of these dipclar
associates. As the polarity of the solvent is increased Ii-e. on
gohf3 from a hydrocarbon to an aluohol) there is a decrease in
the 'structure breaking' and as a consequence thereof an increase
in the strength of the unlike interactions in the resultant
binary mixtures(l3.16)_
The m;>lecules of ketones also exist in the assouiated form
through dipolar interactions in pure state. Radojkovic et al<201
reported that addition of an alkane to an aliphatic ketone leads
to breaking UP of the dipclar associates. However, the presence
of strong unlike interaction between the component molecules of
binary mixtures containing a ketone and an aromatic hydrocarbon
has been reported in the literature (20-22).
In view of the above, the overall solution behaviour of the
binary mixtures under investigation may be envisaged as the
resultant of the two opposing effects namely 'structure breaking'
and 'structure making' effects in each of the components of the
binary mixtures_
The observed negative V E value8 for the binary mixtures
(Figure 1.) suggest that the unlike dipolar Interactions are
fairy strong and predominant over the structure breaking effects
in the mixtures. The large negative VB values as compared to the
binary mixtures of furfural with aliphatic alcohola are
indicative of the presenae of relatively stronger unlike
interactions in the mixtures containing ketones and hence follow
the expeuted trend.
50
At equimolar ooacentration. VK 0.5 follows the order:
acetone< Z-butanonec Z-pentanone indicating that the strength of
the unlike interactions decrease with the increase in t,he size of
the alkyl group of the ketone.. This may arise from I Ci) an
increase in the distance of olosest approach of the molecule and
(ii) also a decrease in dispersive interactions in the mixtures-
The observed negative temperature oo-effioient of VE (Figure 1)
appears to be due to the decrease in the molar volume of the
binary mixture formed from specifiu intermolecular interactions
which more than compensates for the volume changes arising from
the decrease in the extent of unlike dipolar interactions with
increase in temperature.
It is established that the presence of specifio interactions
between the aomponent molecules in liquid mixtures leads to a
decrease in the free-space thereby uontributing to a pO3itiVO
&viation in speeds of sound and negative exceaa isentropic
oompressibilities (23-26). The KE values are expected to become
increasingly negative as the strength of the unlike interactions
in the mixture increases. The large negative KE values observed
for these mixtures under consideration suggest the presence of
strong unlike dipole-dipole interaotions in the mixturas which
more than compensates the positive contribution to KE arising
from the mutual rupturing of the dipolar aggregates in furfural
and ketones by each other. A comparison of the KE values for the
furfural binary mixtures containing a ketone with those
containing an alcohol reveals that unlike interactions present in
the former systems are relatively stronger (16). It is also
observed form Figure 2. that KS increases as the chain len&h of
the alkyl group of the ketone increases which is indicative of
61
relatively weaker unlike interactions in the mixtures containing
higher ketones. These conclusions are in good agreement with the
conclusions arrived from the volumetric studies.
The observed positive rE values for the mixtures that
follows the trend acetone> 2-butanone> 2-pentanone Indicates the
presence of a relatively stronger dipolar interactions between
the unlike molecules in binary mixtures containing acetone and 2-
butanone as compared tp the ones containing 2-pentanone.
Further for mixtures containing acetone and 2-butanone ,)LE
decreases with the increase of temperature while an opposite
trend was observed for mixtures containing 2-pentanone. A
decrease in '2E with increasing temperature is expected in the
mixtures wherein strong unlike interactions are present. The.
strong dipolar interactions between the molecules would tend to
dissociate more at higher temperature resulting into a lesser
resistance to flow and hence a dearease in TE. The positive
temperature co-efficient for the mixtures containing '2-pentanone
indicates the predominance of the increased hindrance of rotation
over a decrease :n the resistance of flow due to decrease in
unlike interactions and corroborates the conclusions drawn from
the VE and KE studies.
References
1. s. Murakami. M. Kiyama and R. FuJishiro, Bull. Chem. Soa. Jap. 1968. a. 1540.
2. A.W. Andrews and K.W. Morkom. J.Chem.Thermodyn. 1971, 3, 513
3. D.D. Dsshpande and 6-L. Oswal. ibid. 1975. 1. 155.
4. R. Meyer, G. Guiati. M. Meyer and E.J. Vincent. Thermochim. Acta 1975, 13, 379.
5. M.D. Guillen and C.G. Losa. J.Chsm.Thermodyn. 1978. UT, 567
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6. H.V. Rehiaian. J.P.E. Grolier and G.C. Benson. J.Chem.Phya. 1978. B. 1031.
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H. Naorem and 6-K. Suri. Can.J.Chem. 1989. m. 1989.
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H.Naorem and S.K. Suri. (Communicated).
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