Synthesis, characterization, and catalytic performance of bio-based deep eutectic solvents for sustainable organic transformations in green chemistry

Project Abstract

Synthesis, characterization, and catalytic performance of bio-based deep eutectic solvents for sustainable organic transformations in green chemistry investigates the design, preparation, and application of environmentally friendly solvent systems that combine renewable feedstocks with efficient catalytic activity for key organic transformations. This study systematically develops bio-based deep eutectic solvents (DESs) by pairing natural hydrogen bond donors and acceptors derived from agro-waste, carbohydrates, organic acids, and polyols to form low-melting, tunable solvents with intrinsic catalytic potential. The research first establishes a library of DESs using choline-derived, proline-derived, and glycerol-based quaternary ammonium-like components as hydrogen bond acceptors, paired with bio-based donors such as lactic acid, citric acid, urea, and sugars. A design-of-experiments approach guides the screening for physicochemical properties including melting point, viscosity, density, water tolerance, biodegradability, and miscibility with protic and aprotic organic substrates. Comprehensive characterization employs FT-IR and NMR spectroscopy to elucidate hydrogen-bond networks, along with DSC, TGA, and rheological measurements to capture thermal and flow behavior relevant to scalable processing. Catalytic performance is explored across representative reactions central to green chemistry, such as aldol condensations, Diels–Alder cycloadditions, Michael additions, and esterifications, under solvent-less or solvent-minimized conditions. The DESs are evaluated as dual-function media they act as reaction solvents and as co-catalysts, often leveraging intrinsic acidity/basicity and hydrogen-bonding networks to stabilize transition states and activate substrates. Reaction optimizations investigate temperature windows, DES composition ratios, water content effects, and catalyst loading, with performance metrics including yield, selectivity, turnover number, and turnover frequency. Green metrics such as E-factor, atom economy, and energy consumption are calculated to quantify sustainability improvements relative to conventional organic solvents and metal-catalyzed systems. To address recyclability and life-cycle impact, the study assesses DES reusability over multiple cycles, along with potential degradation products and toxicity toward model organisms. Mechanistic insights are probed via spectroscopic monitoring of reaction intermediates, isotopic labeling where applicable, and computational modeling to map hydrogen-bond networks and substrate activation pathways within DES matrices. The work also investigates the scope and limitations of bio-based DESs across substrate classes including carbonyl compounds, amines, and nucleophiles, identifying structure–function relationships that govern catalytic efficiency and selectivity. The culmination of the research presents a framework for selecting bio-based DESs tailored to specific green transformations, highlighting scalability considerations, supply-chain sustainability, and policy-relevant implications for reducing hazardous solvent use in chemical manufacturing. The outcomes demonstrate that carefully designed DESs from renewable resources can deliver competitive catalytic performance, lower environmental impact, and operational simplicity, thereby advancing sustainable practices in synthetic organic chemistry.

Project Overview

What This Project Is About

---

A plain-language overview of the topic and what the project investigates.

---

---

The Problem It Addresses

---

Describe a gap in current solvent technology: traditional solvents can be toxic, volatile, and harmful to the environment. Bio-based deep eutectic solvents offer a greener alternative, but their properties and practical catalytic usefulness need evaluation for common organic transformations.

---

---

Objectives of the Project

---

1. Understand what deep eutectic solvents (DES) are and why bio-based DES may be preferable.
2. Synthesize several bio-based DES mixtures using inexpensive, renewable components.
3. Characterize physical properties such as viscosity, conductivity, and polarity relevant to catalysis.
4. Test DES in simple catalytic reactions to assess activity, selectivity, and reusability.
5. Compare performance with conventional solvents and identify greener advantages.

---

---

What You Will Do Step by Step

---

1) Literature review to learn DES concepts and select reaction targets. 2) Prepare and mix bio-based components to form DES. 3) Measure basic properties (e.g., melting point, viscosity). 4) Conduct pilot reactions using DES as solvents or catalysts. 5) Analyze products via simple analytical methods and assess yield and selectivity. 6) Study solvent recyclability and stability over multiple cycles. 7) Compare results with traditional solvents. 8) Document findings and discuss environmental impact.

---

---

Expected Outcome

Anticipate identifying bio-based DES that promote efficient, greener organic reactions with acceptable lifetimes and ease of reuse, offering a viable alternative to conventional solvents and contributing to greener chemistry practice.