Low-Transition-Temperature Mixtures (LTTMs): A New Generation of Designer Solvents

In the last three decades, the concept of 'green' has transformed significantly within the realm of chemistry, driven by the need for sustainable development and green chemistry principles. This study introduces Low-Transition-Temperature Mixtures (LTTMs) as a new class of designer solvents, which aim to replace non-green alternatives. The methodology includes the synthesis of these solvents, primarily through the interaction of urea and choline chloride to form eutectic mixtures characterized by a wide liquid range and favorable physical properties. The results demonstrate that hydrogen-bonding interactions are pivotal in enabling the customization of these solvent systems, allowing flexibility in physical properties and phase behavior to better suit various application needs. The challenges associated with solvent usage, such as environmental impact and economic viability, are addressed through innovative alternatives, advancing the field of solvent design and contributing to greener chemical processes.