Reddy-Doraiswamy equation

Reddy and Doraiswamy, 1967 (24] modified equation (1.18) by replacing the association factor in this equation for the square root of the solvent molar volume, they proposed... 

When water is the solute, values from Eq. (6.3-9) should be multiplied by a factor of 1/2,3 (Rl). Equation (6.3-9) predicts diffusivities with a mean deviation of 10-15% for aqueous solutions and about 25% in nonaqueous solutions. Outside the range 278-313 K, the equation should be used with caution. For water as the diffusing solute, an equation by Reddy and Doraiswamy is preferred (R2). Skelland (S5) summarizes the correlations available for binary systems. Geankoplis (G2) discusses and gives an equation to predict diffusion in a ternary system, where a dilute solute A is diffusing in a mixture of B and C solvents. This case is often approximated in industrial processes. 

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