EXCESS PROPERTIES IN DIMETHYL SULFOXIDE + 1- BUTANOL AND 1,4-DIOXANE+1-BUTANOL BINARY MIXTURES AT K

Transcription

1 U.P.B. Sc. Bull., Seres B, Vol. 7, Iss. 4, 009 ISSN 454- ECESS PROPERTIES IN DIMETHYL SULFOIDE + - BUTANOL AND,4-DIOANE+-BUTANOL BINARY MITURES AT 98.5 K Anca FEDELEŞ, Oana CIOCÎRLAN, Olga IULIAN În lucrare sunt raportate denstăţ ş vscoztăţ pentru sstemele bnare dmetlsulfoxd+-butanol ş,4-doxan+-butanol în funcţe de compozţe la temperatura de 98.5 K. Dn datele expermentale s-au calculat volumul molar de exces, V E, devaţa în vscoztate, Δν, ş energa Gbbs de exces de actvare a curger vscoase, G *E. Apo valorle calculate s-au ftat cu ajutorul ecuaţe Redlch-Kster. Ambele ssteme prezntă valor poztve pentru V E ş negatve pentru Δν ş G *E pe întreg domenul de compozţ. Funcţle de exces calculate au fost analzate în termen de nteracţ moleculare între componenţ amesteculu. Datele de vscoztate au fost corelate cu ecuaţle Grunberg-Nssan, Solman ş McAllster. In ths paper denstes and vscostes of the bnary systems dmethyl sulfoxde+-butanol and,4-doxane+-butanol have been reported as functon of composton at 98.5 K. The excess molar volumes, V E, vscosty devaton, Δν, and excess Gbbs energy of actvaton of vscous flow, G *E, were calculated from expermental data. Then the computed quanttes were ftted to the Redlch-Kster equaton. Both systems exhbt postve devatons of V E and negatve values for Δν and G *E over the whole composton range. The resultng excess functons were analyzed n terms of molecular nteractons between the components of the mxture. The vscosty data have also been correlated wth Grunberg-Nssan, Solman and McAllster equatons. Keywords: densty, vscosty, -butanol, dmethyl sulfoxde,,4-doxane. Introducton Studes of excess functon of bnary lqud mxtures have consderable mportance n understandng the nature of molecular nteracton between unlke molecules. The study of molecular nteracton n mxed solvent systems s of great PhD student, Dept. of Appled Physcal Chemstry and Electrochemstry, Unversty POLITEHNICA of Bucharest, Romana, e-mal: ancafedeles@yahoo.com Assstant, Dept. of Appled Physcal Chemstry and Electrochemstry, Unversty POLITEHNICA of Bucharest, Romana, e-mal: cocrlan_o@yahoo.com Prof., Dept. of Appled Physcal Chemstry and Electrochemstry, Unversty POLITEHNICA of Bucharest, Romana, e-mal: olgaulan@yahoo.com

2 00 Anca Fedeleş, Oana Cocîrlan, Olga Iulan sgnfcance owng to the practcal applcatons of these systems n varous technologes, as they provde a wde choce of solutons wth approprate propertes. Research actvtes of our laboratory comprse, among others, the systematc measurements of volumetrc and transport propertes of dfferent organc compounds [, ]. Ths work represents a study concernng the behavor of bnary systems wth alkanols, and reports new data for the bnary systems dmethyl sulfoxde+-butanol and,4-doxane+-butanol at 98.5 K and atmospherc pressure. Knowledge of the soluton propertes of these mxtures wll be an mportant step n provdng a better understandng of many chemcal and bologcal processes n these meda. Dmethyl sulfoxde (DMSO) was partcularly chosen because of ts wde range of applcablty as a solvent. DMSO s a hghly assocated solvent, whch forms polymer chans by nteracton between ts sulphur and oxygen atoms. DMSO exhbts also dpole-dpole nteractons n the pure state because of ts farly hgh dpole moment (μ=4.0 D). The alkanols are self-assocated solvents through hydrogen bonds, and,4-doxane s an unassocated and non-aprotc solvent. The excess molar volumes, V E, vscosty devaton, Δν, and excess Gbbs energy of actvaton of vscous flow, G *E, were calculated from expermental data. The computed quanttes were ftted to the Redlch-Kster type polynomal equaton to derve the bnary coeffcents and estmate the standard devatons between expermental and calculated results. The vscosty data have been correlated wth Grunberg-Nssan, Solman and McAllster sememprcal equatons. In lterature volumetrc and transport propertes for the bnary systems DMSO+-butanol [-7] and,4-doxane+-butanol [8-] were reported.. Expermental Chemcals used n the expermental determnaton of the studed propertes were suppled by Merck (dmethyl sulfoxde havng a purty of 99.8%,,4- doxane, and -butanol wth a purty of 99.5%). They were used wthout further purfcaton. Expermental densty and vscosty of the pure components are n agreement wth the lterature values, as Table shows.

3 Excess prop. n dmethyl sulfoxde + -butanol and,4-doxane+-butanol bnary mxtures 0 Denstes and vscostes of pure components at 98.5 Compound ρ, (g cm - ) η, (mpa s) expermental lterature expermental lterature dmethyl sulfoxde [].980,4-doxane [8] [] -butanol [8] [0] [] Table All mxtures were prepared by weghng the approprate volumes of lquds n artght stoppered glass bottle. The expermental uncertanty n mole fractons was estmated to be less than ± Denstes of pure lquds and of mxtures were measured usng an Anton Paar DMA 4500 denstometer wth a precson of ± g cm -. The uncertanty n excess molar volume values was ±0 - cm mol -. The knematc vscosty ν (= η/ρ) of pure solvents and ther mxture were measured wth an Ubbelohde vscometer; the uncertanty n the knematc vscosty was ±0.00 mpa s. All measurements were performed n a thermostat mantaned at desred temperature wth accuracy of ± 0.05 K. The correspondng uncertanty n the knematc vscosty s ± m s -.. Results and Dscussons The obtaned expermental data of densty and vscosty for the bnary systems dmethyl sulfoxde+-butanol and,4-doxane+-butanol at 98.5 K are shown n Table. On the bass of expermental data, the correspondng excess propertes were calculated as follows: Excess molar volumes (V E ): V E = M ( ρ ) ρ () where s the mole fracton of component of the mxture; ρ s the densty of the mxture; M, ρ are the molar mass and densty of the pure compounds, respectvely. The vscosty devaton (Δη): Δ η = η η () where η and η are the dynamc vscosty of the mxture, and of the pure component, respectvely.

4 0 Anca Fedeleş, Oana Cocîrlan, Olga Iulan Excess Gbbs energy of actvaton of vscous flow (G *E ): G * E [ ln(v ) x ln(v η ] = RT η ) () where V and V are the molar volume of the mxture and of the pure components, respectvely. R s the gas constant and T, the absolute temperature. The excess propertes data, Y E, were correlated wth Redlch Kster equaton: Y p E = j k = 0 A k ( ) k j where A k are the fttng parameters and p s the degree of polynomal expanson. The standard devaton was defned: exp calc 0.5 (Y Y ) σ = (5) N exp N par where N exp s the number of expermental data and N par s the number of parameters. The fttng parameters A k (Eq. (4)) together wth the standard devatons σ (Eq. (5)) are gathered n Table. It should be noted that for studed systems three parameters were necessary for correlaton to obtan optmum standard devaton. Table Denstes and vscostes of the bnary systems DMSO () + -butanol () and,4-doxane () + -butanol () at 98.5K ρ, (g cm - ) η, (mpa s) ρ, (g cm - ) η, (mpa s) DMSO () + -butanol (),4-doxane () + -butanol () ( g cm - = 0 - kg m - ) (4)

5 Excess prop. n dmethyl sulfoxde + -butanol and,4-doxane+-butanol bnary mxtures 0 Table Parameters A k and standard devatons of excess functons for DMSO + -butanol and,4- doxane + -butanol systems A 0 A A σ DMSO + -butanol V E, (cm mol - ) Δη, (mpa s) G *E, (J mol - ) ,4-doxane + -butanol V E, (cm mol - ) Δη, (mpa s) G *E, (J mol - ) ( cm mol - = 0-6 m mol - ) The vscosty data have been correlated usng sememprcal or theoretcalbased models of Grunberg-Nssan (eq. (6)), Solman (eq. (7)), and McAllster (eq. (8)), wth one or two adjustable parameters. ln η = η + (6) lnη + ln G Accordng to Grunberg and Nssan [], the adjustable bnary parameter, G, s regarded as measure of the strength of nteractons between the mxng speces. McAllster s two-parameter equaton [4], based on Eyrng s theory of absolute reacton rates, takes nto account nteractons both of lke and unlke molecules by a two-dmensonal three-body nteracton. lnν = lnν + lnν + lnν + lnν + ln M + (7) + ln M ln( M + M ) + ln M + ln M = ( M M )/ = ( M M )/ M + M + where ν and ν are the knematc vscosty of the mxture and pure components, respectvely. The data were also correlated wth a modfed form of the McAllster equaton proposed by Solman [5], usng the form wth two-parameters. ν = lnν + lnν + ln A + (8) ln ν M M +

6 04 Anca Fedeleş, Oana Cocîrlan, Olga Iulan For all these models the standard devaton (σ) was calculated usng type (5) equaton. The correlaton parameters and standard devaton are presented n Table 4. The bnary systems DMSO + -butanol and,4-doxane +-butanol show postve devatons of V E, and negatve values for Δν and G *E over the whole composton range, as fgures - show. The values of V E and Δν functons correspond well wth lterature [, ]. Expermental fndngs and lterature survey reveals that for DMSO + - butanol system the effect due to the breakng up of self-assocated structures of the pure compounds s domnant over effect of hydrogen bondng and dpole dpole nteracton between unlke molecules. Postve values of excess molar volume for the,4-doxane + -butanol system also ndcate that the postve contrbutons from the breakng up of alcohol agglomerates and ether ether nteractons domnate over the negatve contrbuton resultng from heteromolecular nteracton. Table 4 Adjustable parameters and standard devaton of the Grunberg-Nssan, Solman and McAllster equatons DMSO + -butanol,4-doxane + -butanol Equaton Grunberg- Nssan Solman McAllster Grunberg- Nssan Solman McAllster Parameters / σ G σ A.4 ν.5687 σ 0.05 ν.886 ν.685 σ 0.08 G -.48 σ A ν.075 σ ν.0856 ν.946 σ 0.0 Accordng to Fort and Moore [6], negatve values of excess vscosty are observed for the systems of dfferent molecular sze n whch the dsperson forces are domnant. Negatve excess n G *E also ndcates that dsperson forces are prevalng n mxtures, as suggested by other authors [7, 8]. Thus, the observed varaton wth composton of Δν and G *E suggest that dsperson forces are operatve between unlke molecules of the nvestgated bnary mxtures.

7 Excess prop. n dmethyl sulfoxde + -butanol and,4-doxane+-butanol bnary mxtures 05 The vscosty data have been correlated wth sem-emprcal equatons of Grunberg-Nssan, Solman and McAllstar. For both studed systems, the values of the Grunberg-Nssan nteracton parameters are negatve, whch suggest weak nteractons between unlke molecules, whch s n accordance wth the excess propertes analyss. The equatons used for vscosty correlaton present small devatons, less than 0., wth very good results for theoretcal based McAllster and Solman equatons for DMSO + -butanol system V E, cm mol Δν, cst Fg. Excess molar volumes, V E, at 98.5K for the bnary systems: ( ),,4-doxane () +-butanol () and ( ), DMSO ()+ -butanol () Fg. Devatons of vscostes, Δν, at 98.5K for the bnary systems: ( ),,4-doxane () +-butanol () and ( ), DMSO ()+ -butanol () 0-00 G *E, J mol Fg. Excess Gbbs energy of actvaton of vscous flow, G *E, at 98.5K for the bnary systems: ( ),,4-doxane () +-butanol () and ( ), DMSO ()+ -butanol ()

8 06 Anca Fedeleş, Oana Cocîrlan, Olga Iulan 4. Conclusons New expermental data of denstes and knematc vscostes for the bnary systems DMSO + -butanol and,4-doxane + -butanol at 98.5 K have been reported. The obtaned excess molar volumes are all postve and devatons n vscosty and excess Gbbs energy of actvaton of vscous flow, G *E, are negatve over the whole composton range. Ths suggests that breakng up of selfassocated structures of the pure compounds s domnant over the hydrogen bondng and dpole dpole nteracton between unlke molecules. For the studed systems the negatve values of the Grunberg-Nssan parameters are n accordance wth the excess propertes analyss. The Grunberg-Nssan, Solman and McAllster equatons are sutable to estmate the mxng vscostes n terms of the pure component data. R E F E R E N C E S [] O. Cocrlan, O. Iulan, J. Serb. Chem. Soc., vol. 74, 009, pp. 7-9 [] O. Iulan, O. Cocrlan, F. Pperea, UPB Sc. Bull., vol. 64, seres b, no., 00, pp. -0 [] P.S. Nkam, M.C. Jadha, M. Hasan, J. Chem Eng. Data, vol. 4, 996, pp [4] P.S. Nkam, S.M.C. Jadhav, M. Hasan, J. Molec. Lquds, vol. 76, no. -, 998, pp. - [5] A. Al, S. Hyder, M. Tarq, Int. J. Thermophyscs, vol. 6, 005, pp [6] A. Al, K. Tewar, A.K. Nan, V. Chakravortty, Phys. Chem. Lq., vol. 8, 000, pp [7] A. Al, M. Tarq, Indan J. Chem. Tech., vol. 4, no., 007, pp [8] E. Calvo, P. Brocos, A. Pnero, M. Pntos, A. Amgo, R. Bravo, A.H. Roux, G. Roux- Desgranges, J. Chem. Eng. Data, vol. 44, no. 5, 999, pp [9] S.S. Raja, T.R. Kubendran, J. Chem. Eng. Data, vol. 49, no., 004, pp [0] I. Gascon, S. Martn, P. Cea, M. C. López, F.M. Royo, J. Soluton Chem., vol., 00, pp [] J.G. Barag, M.I. Aralagupp, T.M. Amnabhav, M.Y. Karduraganavar, S.S. Kulharn, J. Chem. Eng. Data, vol. 50, 005, pp [] M.I. Aralagupp, T.M. Amnabhav, S.B. Harogoppad, R.H. Balundg, J. Chem. Eng. Data, vol. 7, 99, pp [] L. Grunberg, A.H. Nssan, Nature, vol. 64, 949, pp [4] R.A. McAllster, AIChE J., vol. 6, 960, pp [5] K. Solman, E. Marschall, J. Chem. Eng. Data, vol. 5, 990, pp [6] R.J. Fort, W.R. Moore, Trans. Faraday Soc., vol. 6, 966, [7] C.M. Knart, W.J. Knart, A. Cwklnska, J. Thermodyn. Anal. Cal., vol. 68, 00, pp [8] R. Meyer, M. Meyer, J. Metzger, A. Peneloux, J. Chm. Phys. Phys. Chm. Bol., vol. 6, 97, pp