Design of Deep Eutectic Systems: A Simple Approach for Preselecting Eutectic Mixture Constituents.

Area of Science:

• Materials Science
• Green Chemistry
• Physical Chemistry

Background:

• Eutectic systems offer potential as novel green designer solvents.
• Selecting suitable compounds for eutectic systems is challenging due to the vast number of possibilities.
• Predictive methods are needed to streamline the discovery of new eutectic solvents.

Purpose of the Study:

• To present a straightforward approach for preselecting candidate compounds for eutectic systems.
• To correlate molecular structure with melting entropy and enthalpy for single compounds.
• To qualitatively predict and rank binary eutectic systems based on eutectic temperature depth.

Main Methods:

• Correlated melting entropy with molecular structure to calculate melting enthalpy for individual compounds.
• Qualitatively predicted eutectic temperatures for binary systems.
• Demonstrated the approach using six hydrophobic eutectic systems of L-menthol and monocarboxylic acids (linear and cyclic).

Main Results:

• Melting entropy of compounds with similar functionality correlates well with molecular structure.
• Compounds with more rigid molecular structures were found to form deeper eutectics.
• Rigid acids exhibited lower melting enthalpy compared to flexible acids when melting temperatures were similar.

Conclusions:

• The proposed method effectively predicts the potential for forming deep eutectics based on molecular rigidity.
• This approach reduces experimental effort in designing deep eutectic solvents, especially when pure component data is scarce.
• Facilitates the rational design of green solvents by simplifying compound selection.