Indian Journal of Chemistry Vol. 37A, June 1998, pp. 507 - 511 Excess molar volumes, and excess partial molar volumes for binary mixtures of 2-butoxyethanol with ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol and dimethyl suiphoxide at 313.15 K Amalendu PalzyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA *. Wazir Singh & Harish Kumar Sharma Department of Chemistry. Kurukshetra University. Kurukshetra 136 119. India Received 12 May 1997; revised 27 July 1997 The excess molar volumes for, binary liquid mixtures containing 2- butoxyethanol (BE) and ethylene glycol (EG). diethylene glycol (Di-EG). triethylene glycol (Tri-EG). propylene glycol (PG). and dimethyl sulphoxide (DMSO) have been measured using a continuous dilution dilatometer over the entire mole fraction range at 313.15 K. The excess volumes are negative over the whole composition range for the systems 2-butoxyethanol + ethylene glycol. + diethylene glycol. + triethylene glycol. + dimethylsulphoxide and positive for the remaining system. 2- butoxyethanol + propylene glycol. The results are used to estimate the excess partial molar volumes of the components. As part of our research programme to determine excess thermodynamic functions of binary mixtures containing the oxygen (-0-) and hydroxyl (-OH) functional groups':" it is necessary to obtain values of excess volumes of some mixtures of an alk- oxyethanol with an organic solvent Our aim is to provide the information required for the charac- terisation of the molecular interactions of these groups. In this paper, we report directly measured values of excess molar volumes of 2-butoxyethanol + ethylene glycol, + diethylene glycol, + triethylene glycol, + propylene glycol, and + dimethyl sulphox- ide over the complete composition range at 313.15 K. Excess partial molar volumes have been calculated from densities obtained from excess volume meas- urements over the entire composition range. An at- tempt has been made to interpret the results in terms of intermolecular interaction between like and unlike components. Materials and Methods 2-Butoxyethanol (S.D. Fine Chemicals, A.R. grade, 99%) was purified by standard methods '. Di- methy 1sulphoxide (E. Merck India, G.R. grade, 99%) was directly used to aVOId decomposition during distillation. Other materials were of the same origin and purity as used in earlier studies'v'. All samples were kept over 4A molecular sieves to reduce water content and protected from atmospheric moisture and C02. The purity of all liquids was checked by the density determinations at 313.15 ± 0.01 K. The den- sities of the pure liquids of2-butoxyethanol, ethylene glycol, diethylene glycol, triethylene glycol, propyl- ene glycol and dimethyl sulphoxide at 313.15 K were 0.8840, 1.0992, 1.1030, 1.1092, 1.0215 and 1.081Og cm', in good agreement with the available literature data 5 . 8 . Liquid components were introduced by mass, with a precision of ± 0.05 mg, into the bulb of dilatometer using a glass syringe. The pure liquids were thor- oughly degassed under vacuum just prior to loading them into the dilatometer so as to avoid air bubble. The accuracy of the mole fraction was ± I x 10- 4 . The excess molar volumes, accurate to ± 0.003 crrr'mol", were measured using a continuous dilution dilatome- ter similar to that described by Dickinson, Hunt and McLure 9 Qverthe entire mole fraction range at 313.15 K. Details of its calibration, experimental set-up and operational procedure have been described else- where 10. I 1. Densities of pure liquids were measured using a double armed pycnometer with an accuracy of ± I x 10-4 gcm', All the measurements were carried out in a thermostatically controlled, well- stirred water bath whose temperature did not vary by more than ± 0.01 K. Each run covered just over half of the mole fraction range so as to give an overlap between two runs.