Densities and viscosities of the binary aqueous mixtures of tetrahydrofuran and 1,2-dimethoxyethane at 298, 308 and 318 K

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1 Indian Journal of Chemical Technology Vol. 1, March 1994, pp Densities and viscosities of the binary aqueous mixtures of tetrahydrofuran and 1,2-dimethoxyethane at 298, 308 and 318 K Bijan Das. Mahendra Nath Roy & Dilip K Hazra* Department of Chemistry, North Bengal University. Darjeeling India Received 10 June 1993: accepted 13 October 1993 The densities and viscosities have been determined for the binary systems of water with tetrahydrofuran and 1,2-dimethoxyethane at 298, 308 and 31~ K. From the experimental results, the exces~ molar volumes (VE) and the deviation of viscosity from the mole fraction average (11,,) have been derived. These are explained on the basi~ of molecular interactions between the components of the mixtures. There has been a recent upsurge of interest I -I in The kinematic viscosities were measured hy the thermodynamic properties of binary liquid means of a suspended Uhhelohde-type viscometer mixtures. These have been extensively used to oh- with a flow time of water of about 539 s at 298 tain information on the intermolecular interac- K. Temperatur~ control during viscosity measuretions and geometrical effects in these systems-l. ments was ::I: 0.01 K. The precision of the viscos- We have presented here the densities and viscosit- ity measurements was ::I: 0.05%. The kinematic ies for tetrahydrofuran-water and 1,2-dimethoxy- viscosities (v) were converted into the absolute ethane-water mixtures at 298, 308 and 318 K. viscosities (1]) by multiplying the former with.. density (p). Experimental Procedure The purification of 1,2-dimethoxyethane (Fluka, Results purum) has been described earlier~. The solvent The experimenal results of densities and viscowas shaken well with FeSO~ (A.R., BDH) for 1-2 sities at various mole fractions of organic solvents h, decanted and distilled. The distillate was ref- and at three different temperatures are reported luxed for 12 h and redistilled over metallic sodi- in Table 1. urn. The purified solvent had a density of kgm 1 and a coefficient of viscosity of Binary liquid mixture viscosities have heen rep- resented by a number of correlations in terms of mpa s at 298 K which agree well with the report- their pure component properties and interaction ed values". parameters. Grunberg and Nissanx proposed the Tetrahydrofuran (Merck, India) kept several following equation: d~y~ over KOH, ~as refluxed for 24. h and then In" = x I In "1 + x ~ In,,~+ x I x ~ d...(i) dlstll~~d ove~ LI.AIH~. The de~slty ( where xland X2 are the mole fractions of tetrahydkgm.) and viscosity ( mPa s) at 298 K of rofuran (or 1,2-dirnethoxyethane) and water rethe ;olvent co~pared well with the rep<?rted ~a- spectively, "I, "II and "I~ are the respective coeffilu~s..all s<;>l~tlons were prepared hy weight with cients of viscosity of the mixture, tetrahydrofuran deionized dl.s~llled water.. (or 1,2 -dimethoxyethane) and water, and d is a The densities were measure~ with an Ostwald- constant proportional to the interaction energy Sprengel type pycn.ometer h~vmg a bulb volu~e and is regarded as a measure of interaction beof 25 cn1' and an Internal diameter of the capl~- tween the components. The values of d are given, brated lary of at about 298, mm. and The 318 pycnometer K with doubly was calldis- In.T a bl e I..11d t Th t t t I h d The excess molar volumes have been calculated ti e wa er. e empera ure con ro a an ac- h h 4' II.. f K h d.bit. f h Y t e.o owing equation: curacy 0 -.; t e repro UCI Ity 0 t e dellsitymeasurementwas ::1:3 x 10--'kgm-J. VF= V-(x1 V1+x~ V~)...(2).Autht' to whom correspondence should be addressed where JI; VI and V 2 are the molar volumes of the mixture, tetrahydrofuran (or 1,2-dimethoxyethane)

2 94 INDIAN J. CHEM. TECHNOL., MARCH 1994 Table I-Values of densities (p), viscosities (,,) and Grunberg- Nissan par~meters (It JI.\"( p " d Xl P '1 4 kgm-j mpas kgm-3 mpas Tetrahydrofuran( 1 )-water(2) 1,2-Dimethoxyethane( 1 )-water(2) 2~ 298 K ,! , R K K ~.293 ~.~O :~ ' : ' } :5499, ' K : ~ ' 977: l !! ~ ~, , ' K , ! i S , 965; ' ; ; , "O.419R , (Contd)

3 DAS et al.: BINARY UQUID MIXTURES 95 Tab!.: 1-- V3Iu.:~ of densilie~ (,oj, vi~cositie~ (1]) anu Grullbcrg- Ni~san paraml..tcr~ (.1)j- Contd. :.."1 P '1.1 XI P 1] d kgm"" mpas k~-3 mpas () O.755{) ; O.R I.OS H , ; -04 ~ 05-0 A. E E. n 1:"'0-1. E U oq 101- > 03 M 0-1~ -08 0r XI Zc. 0.,4 0'6. 0~8 1 Fig. 2 -Variation of ~ 1] for the system tetrahydrofuran( I )-water(2) at 298 K (0), 308 K «t) and 318 K (8). Fig. I-Variation of VE for the system tetrahydrofuran(l)-wa- where Y is VE (cm3 mol-i) or 6.1] (mpa s) and ter(2) at 298 K (0), 308 K «t) and 318 K (8). ~;,AI,A2,..., etc. are' adjustable parameters. water, respectively. The molar volume V is These parameters were evaluated by the method defined by of least-squares. The values of these parameters! ( M IXI+ M ) 1 2X21P (...3 ) along with the standard deviations defined by a( Y) of Y asl' here M, and M2 are the.molecular.weights of t~e a( Y)=[1: (~bsd -~alcd)2/(n- M)]o.s...(6} pure components and p IS the density of the mix- " lure. 'are given In Table 2. In Eq. (6), N is the number The deviation of the viscosity from the mole of parameters. fraction average is calculated from: Discussion ~1]= 1]-(x,1]1 +X21]2)...(4) It ~ ~ell-knownl() t~at the sign and magnitude Graphical r~presentations of VE and 6.1] as a ~f V. give a. goo~ estimate. of the s!rength of unfunction of x, are given in Figs 1-4. The propert- like.!ntera;tions In the binary. ~Ix~res. Large ies VE and 6.1] were fitted to the Redlich-Kister positive. V values are taken as ~dicative of weak equation9: InteractIons whereas large negati~e valu~s of VE are usually found when these InteractIons are y= XI X2 I ~ (X2 -XIY...(5) strong and intermolecular association "complexes" - j are believed to be present..

4 9~ INDIAN J. CHEM. TECHNOL., MARCH 1994 The systems tetrahydrofuran-water and 1,2- present in the self-associated water molecules and dimethoxyethane-water show negative VE values (ii) the intermolecular dipolar interactions in tetraover the entire mole fraction range and over the hydrofuran and 1,2-dimethoxyethane. Secondly, entire range of temperatures studied (Figs 1 and the effect which gives a negative contribution to 3). Several effects may contribute to the VE va- VE is the difference in molecular sizes between lues. One of the effects which may contribute to the two components in the mixtures. The molar VE is the disruption of (i) the hydrogen bonds volumes of water, tetrahydrofuran and 1,2-dimethoxyethane at 298 K are 18.05, and cm3, respectively, which might allow the components to fit into each others' structures both in tetrahydrofuran-water and 1,2-dimethoxyethane-water systems, so that a reduction in vo lume occurs in each case.. A third effect whose '0 09 e n..08 " fj n. 07 > 0.6 E~ o~ c- o<! ", O~ I X XI I 0" Fig. 3-Variation of ye for 1,2-dimethoxyethane(I)-water(2) Fig. 4-Variation of ~1J for 1,2-dimethoxyethane(I)-water(2) at 298 K (0), 308 K «I) and 31H K (8). at 298 K (0), 308 K «I) and 318 K (8). Table 2-Coefficients of Eq. 5 for ye and ~1J and the standard deviation~ 0( Y)at and 318 K Y Temp. ~) AI Az A, A.j 0( Y) K Tetrahydrofuran-water ye ) O6R ~1J I Dimethoxyethane-water ye ] ] ~1J

5 DAS et al.: BINARY UQUID MIXTURES 97 contribution to VI' is also expected to be negative Thus from the present.study it is clear that for is the existence of hydrogen-bond interactions both these binaries hydrogen-bonding interactions between unlike molecules. between the unlike molecules predominate over The actual value of VF would depend upon the the other effects. balance between the two opposing contributions. The experimental values indicate that the negative contributions predominate in these binaries. References For these two systems studied at three different 1 Aminabhavi T M & Raikar S K, J Chern Eng Data, 38 e temperatures, over the entire values compositional of 1\1/ are found range to (Figs be 2 MarchettI 1]1J1J.1).1]O. A, Pretl C, Tagllazucchl M & TassI L, J Chsrn )... d... d. h En!!. Data. 36 (1991-) and ~. ThIs poslt.lve evlatlon m I~ate~ t e.1 RitzouiisG,(anJChern,67(19!!9) 105. predommc)nce of specific hydrogen bonding mter- 4 Douheret G & Pal A, J Chern Eng Dala, 33 (1988) 40. n between the unlike molec,ules.(t~ form ad- 5 Nandi D, Das S & Hazra D K, Indian J Chern, 27A ducts between them) over the dissociation effects (1988) 574. in both systemsll.12, This results in a liquid struc- 6 Rena~dE&Jus~iceJ-C,J!J'olurio~Chenl,.3(1974)6~3. ture where the flow is rather difficult than would 7 PhY~lcal CnemlStryof ~~anlc Solvent Systems, edited by Covington A K & DIckinson T (Plenum, New York), be expected on the basis of the VIscosIties of the pure components. X Grunberg L & Nissan A P-!, Nature (London), 164 (1949): The Grunberg and Nissan parameter d is found 799. to be positive (Table 1) for both the systems. This 9 R~dlic.h 0 & Kister A T, Ind Eng.chern, 40 (1948) 345. su port); the formation of intermolecular com- 10 Prigogtne I, The Theory of Solutions (North-Holland, Amp. sterdam),(1971). plcxcs between the unlike molecules through hy- 11 FortRJ,MooreWR, Trans FaradaySoc, 62 (1966) orogen bonding. 12 Nigam R K & Singh P P, IndianJ Chern, 9 (1971)691.!