Insight into solid-liquid and liquid-liquid phase equilibrium behavior of vanillin and ethyl vanillin

•Lower polarity and stronger hydrophobicity leading to lower solubility of EVA.•The relative contribution of enthalpy decreases with increasing n-propanol content.•LLPS is mainly dependent on solute and solvent properties but not temperature.•EVA is more prone to LLPS due to greater steric hindrance and hydrophobicity.•Water and oil phase satisfies optimal and suboptimal stable ratio, respectively.