The effect of potassium iodide on the viscosity of vegetable oil + N, N-dimethylformamide solvent at different temperatures

The viscosity of different concentrations of sunflower oil + DMF and corn oil + DMF solvents in the presence of potassium iodide was measured at temperatures of 303.15–323.15 K in steps of 5.0 K. The viscosity increased with the increase in the concentration of potassium iodide and oil, while an increase in temperature decreased the viscosity. The change in the viscosity was used to evaluate the structural changes and electrostatic interactions produced by the addition of potassium iodide to the oil + DMF solvent. The structure-breaking or structure-promoting behavior of potassium iodide was evaluated by applying the Jones–Dole, Vand, and Breslau–Miller equations. The increase in viscosity B-coefficients with the temperature confirmed the structure-breaking behavior of potassium iodide in the oil + DMF solvent. The ionic B-coefficients were evaluated by subjecting the experimental data to the mathematical approximations available in the literature. The Moulik and Einstein relations were also found applicable to the viscosity of the oil + DMF solvent while deviations were observed from the Thomas relation. The thermodynamic parameters of the viscous flow also supported the obtained results about the ionic interactions.