Hydrophobic deep eutectic solvents: Synthesis, properties, and emerging applications

Hydrophobic deep eutectic solvents (HDESs) have turned out to be promising replacements for traditional organic solvents. Regardless of widespread research on the design and characterization of HDESs, methodical insights into the molecular-level interactions that determine their physicochemical behavior and macroscopic performance remain inadequate. This review critically scrutinizes current development in the design and synthesis, focusing on recent synthesis techniques, mechanistic understanding, and structure – property relations that facilitate lucid HDES design instead of trial-and-error screening. Fundamental chemical interactions involved in synthetic schemes, particularly hydrophobic forces and hydrogen bonding has been discussed. Important physical properties such as density, viscosity, surface tension and thermal stability have been examined. HDES efficiency is influenced by tunable features and its effect across numerous applications, including extraction, separation, materials processing, biomedical, energy storage, environmental pollution remediation, and catalysis. By incorporating evolving trends with a critical investigation of challenges, this review outlines upcoming directions for developing next-generation HDESs line up with sustainable technological objectives.