Aust. J. Chem., 1995, 48, 1193-1200 Associating Behaviour of Mixed Liquids: Dielectric Properties of the Ethane-l,2-diol+ 1,kDioxan Solvent System from -10 to +80°C Fulvio C o r r a d ~ n i , ~ Andrea M~rchetti,~ Mara ~a~liarucchi,~ Lorenzo Tassi AtB and Giuseppe Tosi A A Department of Chemistry, University of Modena, via G. Campi 183, 41100 Modena, Italy. Author to whom correspondence should be addressed. Abstract The associating behaviour of ethane-1,2-diol (component 1)+1,4-dioxan (component 2) in their binary mixtures has been investigated through their dielectric properties. The experimental measurements of the relative permittivity (E) in the temperature range -10 5 tl°C < 80 for nine binary mixtures covering the whole miscibility field 0 5 XI 5 1 have been utilized to test empirical equations representing the functions E = E(T), E = €(XI) and E = E(T, XI). Furthermore, the excess mixing function, eE, has been evaluated to obtain qualitative and quantitative information about the possibility of 'solvent-cosolvent' complex formation. Introduction Some of our recent researches have dealt with the physical-chemical properties of ethane-1,2-diol (ED; dipole moment p = 2.28 D*)' employed in pure form or in binary mixtures for acid-base equilibria in s ~ l u t i o n , ~ - ~ ionization and dissociation reaction ~ t u d i e s , ~ as well as thermomechanical properties of its binary mixtures with other polar liquids such as 2-methoxyethanol (ME; p = 2.04 D)6 and 1 ,Zdimethoxyethane (DME; p = 1 .17 D) .7 It has been ascertained that all of these species tend to form quite stable complexes in binary systems, and such heteroaggregation phenomena have been accounted for by the high dipole moments and by the possibility of a strong hydrogen-bonding network in the liquid state. We have now planned some investigations on binary mixtures of ED (component 1) and 1,4-dioxan (DX, component 2; p = 0-45 D).8 It should be noted that the molecular structure of DX may be related to ED, ME and DME; ME and DME are * 1 D x 3.33564~10-~~ c m. Bose, K., and Kundu, K. K., Can. J. Chem., 1979, 57, 2470. Franchini, G.C., Ori, E., Preti, C., Tassi, L., and Tosi, G., Can. J. Chem., 1987, 65, 722. Franchini, G.C., Preti, C., Tassi, L., and Tosi, G., Anal. Chem., 1988, 60, 2358. Franchini, G.C., Marchetti, A., Tassi, L., and Tosi, G., J. Chem. Soc., Faraday Trans. 1, 1988, 84, 4427. Franchini, G.C., Marchetti, A., Tassi, L., and Tosi, G., Anal. Chem., 1990, 62, 1004. Marchetti, A., Tagliazucchi, M., Tassi, L., and Tosi, G., J. Chem. Eng. Data, 1991, 36, 368. Goldoni, G., Maffei, E., Marcheselli, L., and Tassi, L., J. Chem. Eng. Data, 1992, 37, 262. McClellan, A. L., 'Tables of Experimental Dipole Moments' (W. H. Freeman: San Francisco, California, 1963). Manuscript received 28 November 1994 0004-9425/95/061193$05.00