The density ( ), viscosity ( ), and surface tension ( ) of binary mixtures of carboxylic acids (CAs) (ethanoic acid (EA), propanoic acid (PA), butanoic acid (BA)) + benzene (BEN) or acetophenone (ACT) have been measured at 298.15, 308.15, and 318.15？K. From the experimental results, excess values of molar volume ( ), viscosity ( ), Gibb's free energy for the activation of low ( ), and surface tension ( ) were evaluated and fitted to a Redlich-Kister type of equation. The parameter “ ” of Grunberg and Nissan expression has also been calculated. From the sign and magnitude of , , , , and “ ” values, it is concluded that specific interactions are present in CA+ACT system and these interactions are absent in CA + BEN mixtures. Various viscosity and surface tension models have been used to test the consistency of the data. 1. Introduction Studies on thermophysical properties of binary liquid mixtures containing carboxylic acids are not extensive [1–3]. In view of this, we have undertaken studies on binary mixtures of carboxylic acids (CAs), namely, ethanoic acid (EA), propanoic acid (PA), and butanoic acid (BA) which are self-associated solvents, with a nonpolar solvent benzene (BEN) and polar acetophenone (ACT). These acids exist as cyclic dimers in the pure state. However, trimers also exist which are formed because of strong interactions between ring dimers and monomers [4–6]. The excess properties , , , , and Grunberg and Nissan parameter “ ” computed from the experimental data (density ( ), viscosity ( ), and surface tension) ( )) of binary mixtures of carboxylic acids (EA, PA, BA) with benzene and acetophenone have been determined. Benzene interacts with acid through Vander Waal's or London dispersion forces and acetophenone forms chemical aggregates with acid through hydrogen bonding. The results are used to theoretically justify the validity of various viscosity and surface tension models. The main thrust of the investigation is to correlate the experimental data in terms of the interacting components of the mixtures and to stress the factors affecting these interactions. 2. Experimental Section Ethanoic acid, propanoic acid, butanoic acid, benzene, and acetophenone were purified by the standard methods described in the literature . Ethanoic acid (BDH, 99% assay) was washed with a calculated amount of acetic anhydride for about 10？h and was subjected to fractional distillation. Propanoic acid and butanoic acid (E. Merck, 99% assay) were dried over anhydrous sodium sulfate for two days and the samples were distilled over potassium permanganate.
R. Ahluwalia, R. K. Wanchoo, and J. L. Vashisht, “Some physical properties of binary liquid systems: (ethanoic acid or propanoic acid or butanoic acid + ethanenitrile),” Physics and Chemistry of Liquids, vol. 29, pp. 87–96, 1995.
R. K. Wanchoo, J. Narayan, G. K. Raina, and V. K. Rattan, “Excess properties of (2-propanal + ethylacetate or benzene) binary liquid mixture,” Chemical Engineering Communications, vol. 81, no. 1, pp. 145–156, 1989.
G. C. Franchini, A. Marchetti, M. Tagliazucchi, L. Tassi, and G. Tosi, “Ethane-1,2-diol-2-methoxyethanol solvent system. Dependence of the relative permittivity and refractive index on the temperature and composition of the binary mixture,” Journal of the Chemical Society, Faraday Transactions, vol. 87, no. 16, pp. 2583–2588, 1991.
A. B. K. Stevanovic, G. M. Babic, M. Lj Kijevcanin, S. P. Serbanoviv, and D. K. Grozdanic, “Correlation of the liquid mixture viscosities,” Journal of the Serbian Chemical Society, vol. 77, no. 8, pp. 1083–1089, 2012.
A. S. Teja and P. Rice, “A generalized corresponding states method for the prediction of the thermal conductivity of liquids and liquid mixtures,” Chemical Engineering Science, vol. 36, no. 2, pp. 417–422, 1981.
T. R. Kubendran, S. P. Palaniappan, M. R. V. Krishnan, and G. S. Laddha, “Viscosities of binary and ternary liquid mixtures involving acetone carbon-tetrachloride and benzene,” Indian Journal of Technology, vol. 24, no. 1, pp. 22–25, 1986.
W. Zihao and F. Jufu, “Surface Tension of Binary liquid mixtures,” in Proceedings of the Joint Meeting of Chemical Industry and Engineering Society of China and AIChE, p. 143, Beijing, China, September 1982.
P. Rice and A. S. Teja, “A generalized corresponding-states method for the prediction of surface tension of pure liquids and liquid mixtures,” Journal of Colloid and Interface Science, vol. 86, no. 1, pp. 158–163, 1982.
B. S. Lark, S. Singh, S. K. Aggarwal, and S. Makkar, “Excess volumes of n-butyric acid + various polar and nonpolar solvents,” Journal of Chemical and Engineering Data, vol. 30, no. 4, pp. 467–469, 1985.
P. Venkateswarlu and G. K. Raman, “Excess volumes of ethanoic, propanoic, and butanoic acids with 1,2-dichloroethane and 1,2-dibromoethane,” Journal of Chemical and Engineering Data, vol. 30, no. 2, pp. 180–181, 1985.
R. Palepu, J. Oliver, and D. Campbell, “Thermodynamic and transport properties of o-chlorophenol with aniline and N-alkylanilines,” Journal of Chemical and Engineering Data, vol. 30, no. 3, pp. 355–360, 1985.