Viscous synergy and isentropic compressibility of some monoalkanols and cyclic ethers in water at 298.15Â K

Pure or aqueous alcohols are most widely used in industry, including in the manufacture of pharmaceuticals and cosmetic products. However, in the case of insolubility of some solutes in water, non-water solvents may be used possessing the common characteristic of being soluble in water; as a result, such solvents may be used with different purposes, such as increasing water solubility, or modifying the viscosity or absorption of the dissolved substance. Also, the nature of intermolecular forces between the solvents brings a marked effect on the thermodynamic properties such as density, viscosity and surface tension etc. The present study investigates viscous synergy and isentropic compressibility in the systems comprising some monoalkanols (C1-C4) and cyclic ethers (1,4-dioxane and tetrahydrofuran) in the proportion w/w = 1:1, in water at different concentrations (w/w) at 298.15 K to determine the proportion of monoalkanol + cyclic ether + water, at which maximum synergy occurs. The density and viscosity data have been analyzed using the equation developed by Kaletunc-Gencer and Peleg. Also a correlation between the density and viscosity increment for all the systems has been attempted. The ratio between maximum viscosity reached by the mixtures and pure state viscosity is expressed by the enhancement index defined as En = ηmax/η0.