Scalable Green Synthesis of 1-Butyl-3-methylimidazolium Chloride

• • Optimal synthesis conditions: 76 °C, 1:1.3 molar ratio (N-methylimidazole:1-chlorobutane), 36 h reaction time, achieving 95.6% single-pass yield; compared to 1:1.1 ratio, the 1:1.3 ratio shortens time to 95% yield by ~12 h and reduces production cost by 7 percentage points. • • Activation energy (Ea) of ~135.7 kJ/mol indicates strong temperature sensitivity; precise temperature control is critical for industrial scalability to maintain high conversion and avoid side reactions. • • Closed-loop recycling achieves 99.5% recovery of 1-chlorobutane and 98.1% recovery of ethyl acetate via stepwise distillation, preventing azeotrope formation and enabling near-zero emissions with >98% overall raw material recovery. • • The process integrates green chemistry principles and process intensification, offering a cost-effective and environmentally sustainable route for industrial [Bmim]Cl production, with potential transferability to other ionic liquids.