ISOBARIC VAPOR-LIQUID EQUILIBRIUM FOR THE BINARY MIXTURE OF ETHANOL (1) + 1-HEXANOL (2) AT 100 kpa

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1 ISOBARIC VAPOR-LIQUID EQUILIBRIUM FOR THE BINARY MIXTURE OF ETHANOL (1) + 1-HEXANOL (2) AT 100 Pa Dhon Hartanto 1), Asall Mustan 2), Bayu Trwbowo 1), Aula Septan Muta 1) 1) Department of Chemcal Engneerng, Faculty of Engneerng, Semarang State Unversty 2) Department of Chemcal Engneerng, State Polytechnc of Malang dhon.hartanto@mal.unnes.ac.d ABSTRACT The sobarc vapor-lqud equlbrum (VLE) data for the bnary mxture of ethanol + 1- hexanol were determned at 100 Pa through the measurements of bolng pont temperature by usng modfed Othmer recrculaton stll. No azeotrope was formed n the nvestgated bnary system. The Wlson, nonrandom two-lqud (NRTL), and unversal quaschemcal (UNIQUAC) models were used to correlate the expermental data to obtan bnary nteracton parameters. These three models yeld satsfactory results. Keywords : ethanol, 1-hexanol, vapor-lqud equlbrum Introducton In the recent years, the ol prce has been rsng globally. On the other hand, the number of new ol resources are sgnfcantly decrease. Alcohol s one of the promsng alternatve energy to overcome these problem. Mxed alcohols whch conssts of C1-C8 alcohols can be produced by usng coal through new chemcal synthess technology (Wang & Bao, 2013). Dstllaton process s employed to separate those mxed alcohols n order to obtan sngle alcohol such as ethanol, 2-butanol, 1- pentanol, 1-hexanol, etc. To develope the separaton process, vapor lqud equlbrum (VLE) data of the related mxtures are essental and play mportant rule n the desgn and optmzaton of the process. Several studes on the VLE measurement of mxed alcohols have been publshed. The sobarc VLE data for bnary systems of methanol wth 1-propanol, 1-butanol, and 1- pentanol at Pa were reported by Hll & Van Wnle (1952). For the system contanng ethanol, sobarc VLE data of ethanol wth 1-butanol, 2-butanol, and 1- pentanol at Pa were reported by Hellwg & Van Wnle (1953), wth sobutanol at Pa by Resa et al. (2004), wth tert-butanol at Pa by Yang & Wang (2002). For 1-propanol system, Ballard & Van Wnle (1952) reported the sobarc VLE of 1-propanol wth 2-propanol at Pa. For the bnary mxture contanng 2-propanol, sobarc VLE data of 2-propanol wth methanol, ethanol, and 2-butanol at Pa were determned by Ballard & Van Wnle (1952), wth 1-butanol and 1-pentanol at Pa by Wang & Bao (2013), wth 2- butanol at Pa by Tamr & Wsna (1975). The sobarc VLE data at Pa of 1-butanol wth 2-butanol and tert-butanol were reported by Wsna & Tamr (1976), wth sobutanol at Pa by Tamr & Wsna (1975), wth 1-propanol at (53.3 and 91.3) Pa by Mohsen-Na & Memarzadeh (2010). The other bnary mxture, sobutanol + tert-butanol was measured at 94.9 Pa by Darwsh & Al- Anber (1997). The systems contanng bnary mxture of ethanol + 1-hexanol has not been fully nvestgated. In ths present study, the sobarc VLE data were measured through bolng pont for the bnary systems of ethanol wth 1-hexanol at 100 Pa by usng an Othmer-type recrculaton stll. The VLE data of ethanol + 1-hexanol measured n ths study have not 173

2 been found n the nvestgated pressure. The expermental data were correlated usng the actvty coeffcents models such as the Wlson (Wlson 1964), NRTL (Renon & Prausntz 1968), and UNIQUAC (Abrams & Prausntz 1975). Research Methods Materals The specfcaton of materals used n ths study were lsted n Table 1. Ethanol was used wthout addtonal purfcaton. 1- Hexanol was dred usng 3A molecular seve adsorpton wth fnal mass fracton purty better than Table 1. The Specfcaton of Materals Compound Source Mass Fracton MW Purty (g mol -1 ) Ethanol Merc Hexanol Merc Apparatus and procedures The bolng temperatures were measured usng an Othmer-type recrculaton stll. The detaled dagram and worng procedure of the apparatus were explaned by Morrson et al. (1990). The top part of the equlbrum stll condensor was opened to the ar to ensure the pressure nsde the stll n standard atmospherc condton. The pressure condton of the expermental envronment was 100±0.2 Pa. The atmospherc pressure was measured usng calbrated-tfa barometer (Germany) whch has stablty ±0.1 Pa. The mxture was njected about 150 cm 3 n each expermental run. The temperature of the mxtures was ept for at least 1 hour to ensure equlbrum condtons acheved. The equlbrum temperature was measured by usng a calbrated K type-dgtal thermometer (TK4S-14RN, USA) wth uncertanty ±0.1 K. As equlbrum temperature was attaned, lquds n equlbrum condton were collected for analyss. A gas chromatograph (GC) (Aglent 6820, USA) equpped wth flame onzaton detector (FID), HP-5 Column (P/N : 19091J-413) and a carrer gas of helum wth purty > n mass fracton was used to analyze the lqud phase composton. The temperature operatons of GC were K for the front nlet, K for the column, and K for the detector temperature. Results and Dscusson The bolng temperature data have been measured for the bnary system of ethanol (1) + 1-hexanol (2) at 100 Pa as lsted n Table 2 and the T-x-y dagram was shown n Fgure 1. Table 2. Vapor-Lqud Equlbrum Data for Bnary System of Ethanol (1) + 1- Hexanol (2) at 100 Pa a x 1 T (K) , a u(x 1 ) = 0.001, and u(t) = 0.1 K The expermental VLE data were correlated usng the Wlson, NRTL, and UNIQUAC models. The relatonshp of vapor and lqud phases n equlbrum s descrbed as follows: y Φ P = x γ P (1) sat where y, x, Φ, γ, and P refer to vapor phase composton, lqud phase composton, 174

3 vapor phase correcton factor, actvty coeffcent and pressure, respectvely. The superscrpt sat stands for saturated, and the subscrpt represent component. The vapor phase correcton factor n ths wor was consdered 1 as represent the deal vapor phase. equaton for each component as lsted n Table 3 (Polng et al., 2001). Table 3. Parameters of the Antone Equaton for Pure Compounds Component A B C Ethanol Hexanol The physcal propertes and parameters of each component used n the actvty coeffcents correlaton for the Wlson, NRTL, and UNIQUAC models are gven n Table 4. Fgure 1. VLE phase (T x 1 y 1 ) dagram for bnary system of ethanol (1) + 1- hexanol (2) at 100 Pa The objectve functon used for the optmzaton s shown n equaton 2. N exp = ( cal OF ) T T (2) where N and are the total number of expermental data ponts and the pont, respectvely. T and T refer to exp cal expermental temperature and calculated temperature n equlbrum, respectvely. Antone equaton was used to calculate the saturated pressure of pure component as shown n equaton 3. B log P sat = A (3) T + C where P sat s n bar and T s n K. A, B, and C are the parameters of the Antone Table 4. Physcal Propertes and Parameters of Pure Components Used n the Actvty Coeffcents Correlaton Component (cm 3 mol -1 ) Ethanol Hexanol a Polng et al., 2001 b Hansen et al., 1991 V a The actvty coeffcents models used n ths study are able to correlate well to the expermental data. As shown n Fgure 1, the devatons between the expermental and calculated ponts are small. The best ftted bnary nteracton parameters and the average absolute devatons (AAD) for each model were lsted n Table 5. Table 5. Ftted Bnary Interacton Parameters of Actvty Coeffcent Models and Average Absolute Devatons (AAD) for Bnary System of Ethanol (1) + 1- Hexanol (2) at 100 Pa. Model Parameters AAD a A 12 (K) A 21 (K) (%) Wlson b NRTL c UNIQUAC d a ( ) n AAD = 1 n ( T T ) r b q b = cal T 1 exp exp.100%, where n s the number of data ponts. b Λ = ( V V ) exp ( A T ) c j j j, where V s the molar volume of the component. τ, the value of α was fxed to be 0.3. j = A j T d τ = exp( T ) j A j 175

4 Conclusons The sobarc VLE data have been measured expermentally for the bnary system of ethanol (1) + 1-hexanol (2) at 100 Pa by usng modfed Othmer recrculaton stll through bolng ponts temperatures. The bnary system nvestgated n ths study has no azeotrope formaton. The Wlson, NRTL, and UNIQUAC models were used to correlate the VLE data of bnary system. These models showed satsfactory results n the VLE data correlaton. Acnowledgments The authors than to DIPA-Semarang State Unversty for fnancal support provded for the achevement of ths wor through grant no. DIPA /2014. Bblography Abrams, D.S., Prausntz, J.M Statstcal Thermodynamcs of Lqud Mxtures: A New Expresson for the Excess Gbbs Energy of Partly or Completely Mscble Systems. AlChE J., 21 (1), Ballard, L.H., Van Wnle, M Vapor-Lqud Equlbra at 760 Mm. Pressure. 2-Propanol-Methanol, 2- Propanol-Ethyl Alcohol, 2-Propanol- Propanol, and 2-Propanol-2-Butyl Alcohol Systems. Ind. Eng. Chem., 44 (10), Darwsh, N.A., Al-Anber, Z.A Vapor-Lqud Equlbrum Measurements and Data Analyss of Tert-Butanol Isobutanol and Tert- Butanol Water Bnares at 94.9 Pa. Flud Phase Equlb., 131 (1 2), Hansen, H.K., Rasmussen, P., Fredenslund, A., Schller, M., Gmehlng, J Vapor-Lqud Equlbra by UNIFAC Group Contrbuton. 5. Revson and Extenson. Ind. Eng. Chem. Res., 30 (10), Hellwg, L.R., Van Wnle, M Vapor-Lqud Equlbra for Ethyl Alcohol Bnary Systems. Ind. Eng. Chem., 45 (3), Hll, W.D., Van Wnle, M Vapor- Lqud Equlbra of Methanol Bnary Systems. Methanol-Propanol, Methanol-Butanol, and Methanol- Pentanol. Ind. Eng. Chem., 44 (1), Mohsen-Na, M., Memarzadeh, M.R Isobarc (Vapour + Lqud) Equlbra for the (1-Propanol + 1- Butanol) Bnary Mxture at (53.3 and 91.3) Pa. J. Chem. Thermodyn., 42 (6), Morrson, J.F., Baer, J.C., Meredth, H.C., Newman, K.E., Walter, T.D., Masse, J.D., Perry, R.L., Cummngs, P.T Expermental Measurement of Vapor-Lqud Equlbrum n Alcohol/Water/Salt Systems. J. Chem. Eng. Data, 35 (4), Polng, B.E., Prausntz, J.M., O Connell, J.P The Propertes of Gases and Lquds, 5th ed. New Yor: McGraw-Hll. Renon, H., Prausntz, J.M Local Compostons n Thermodynamc Excess Functons for Lqud Mxtures. AlChE J., 14 (1), Resa, J.M., González, C., Goenaga, J.M., Iglesas, M Densty, Refractve Index, and Speed of Sound at K and Vapor Lqud Equlbra at Pa for Bnary Mxtures of Ethyl Acetate + 1-Pentanol and Ethanol + 2-Methyl-1-propanol. J. Chem. Eng. Data, 49 (4), Tamr, A., Wsna, J Vapor- Lqud Equlbrums of Isobutanol-n- Butanol and Isopropanol-sec-Butanol Systems. J. Chem. Eng. Data, 20 (4), Wang, J., Bao, Z Investgaton on Vapor Lqud Equlbrum for 2- Propanol + 1-Butanol + 1-Pentanol at 176

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