Modeling of Refractive Indices for Binary Aqueous Solutions of Some Alkane Polyols at Constant Temperature and Pressure

In this research, a theoretical study has been undertaken on the density and also on the relationship between refractive index and density for aqueous solutions. A simple linear equation is suggested to show this relationship. Also, a semi-empirical equation has been developed for estimating the constant of this linear equation. By using our suggested equations, the refractive indices of aqueous solutions of alkane polyols [R(OH)n, n = ۲ to ۶ -OH,s) and also polyols with one ring (monosaccharide) can be calculated. Moreover, the refractive indices of some alcohols and other components have been collected from the various literature. Our suggested equations have been tested for aqueous solutions of these molecules. For aqueous solutions of alkane polyols [R-(OH)n, n = ۲ to ۶ –OH,s) and monosaccharide, a good agreement is observed between experimental refractive indices and theoretical ones. Other molecules show positive and/or negative deviations from the results of our suggested equations. For various liquid solutions, the refractive indices can be correlated and fitted with our linear equation. Also, the value of the constant of this linear equation, Kref, shows the power of interaction between solute and solvent molecules. The interaction between solute and solvent molecules increases when the value of constant, Kref increases.

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KEYWORDS: Refractive index ، alkane polyols ، Hydrogen bonding ، aqueous solution ، negative and positive deviation