Current Status and Future Perspectives of Betaine and Betaine-Based Natural Deep Eutectic Solvents: A Review.

Betaine (BET)-based deep eutectic solvents (DESs) have emerged as promising substitutes for traditional organic solvents owing to their eco-friendly properties and versatility in various applications. This review provides a comprehensive overview of the current status and future perspectives of BET-based DESs, highlighting their definition, characteristics, and mechanisms of eutectic formation. The unique properties of BET, including its biodegradability and non-toxicity, make it an attractive hydrogen bond acceptor in the formulation of DESs. The review discusses common methods for preparing BET-based DESs and emphasizes their applications in extraction processes, catalysis, biocompatibility, and pharmaceutical applications. Additionally, challenges such as stability and fluidity limitations are addressed, along with regulatory and safety considerations. Future directions suggest an increasing industrial application of BET-based DESs in environmentally sustainable processes within the food and pharmaceutical sectors, underlining their potential as green solvents in next-generation chemical methodologies.