Entropy Scaling of Viscosity for Imidazolium Ionic Liquids with Dissolved Refrigerants Based on the Soft-SAFT Equation of State

The mixtures of ionic liquid/refrigerant are a promising working pair in absorption refrigeration, their viscosity, which is crucial for process design, changes significantly with composition and operating conditions, making existing models inadequate. This study presents an extended application of entropy scaling theory coupled with the soft-SAFT equation of state for viscosity estimation in pure imidazolium-based ionic liquids (ILs) and their mixtures with refrigerants. The methodology was validated through a comprehensive analysis of 4,265 experimental viscosity data points for pure ILs over a wide range of temperatures and pressures, achieving an average absolute relative deviation (AARD) of 5.76% between calculated and experimental values. When the model was extended to IL/refrigerant mixtures, a modified Grunberg–Nissan mass mixing rule was employed, resulting in an AARD of 12.84% across 248 experimental data points.