Abstract
This study presents an environmentally benign DES-assisted approach for engineering mesoporous γ-Al₂O₃ supports and high-performance solid base catalysts. A choline chloride–urea deep eutectic solvent acted as both a reaction medium and a soft template, enabling the formation of large mesoporosity and abundant hydroxyl sites that facilitate uniform potassium dispersion. The resulting DES-30 K catalyst exhibits a favorable distribution of medium–strong basic sites, which drives efficient and selective transesterification of dimethyl carbonate with ethanol. Using response surface methodology, the interactive effects of process variables were quantitatively resolved and used to determine the optimal operating window, yielding 86.4% conversion and 82.7% selectivity under mild conditions. The catalyst retained structural and catalytic stability over repeated cycles, demonstrating its practical robustness. This work provides a green, low-cost design framework that links DES-induced structural features with catalytic function, offering broad potential for sustainable chemical and energy-related processes.