An Efficient, Sustainable, Ecological Protocol for the Catalytic Conversion of Alcohol to Primary Amide Using CuCl 2 /[Aemim]Br
Venugopal Vani, Selvarasu Uthayanila, Parasuraman KarthikeyanABSTRACT
The development of green and efficient catalytic systems for amide bond formation remains a central challenge in sustainable chemistry. Herein, we report a recyclable CuCl 2 /[Aemim]Br (1‐(2‐aminoethyl)‐3‐methylimidazolium bromide) as a robust catalyst for the aerobic oxidative amidation of alcohols with ammonia under aqueous conditions. The catalyst efficiently converts a wide range of benzylic and heteroaromatic alcohols to the corresponding amides with high selectivity and yields up to 92%. Systematic optimization studies revealed that both the ionic liquid (IL) and CuCl 2 play cooperative roles in facilitating the redox cycle through halide exchange and hydrogen‐bonding interactions, which enhance substrate activation, oxygen transfer, and ammonia solubility. The CuCl 2 /[Aemim]Br system exhibited remarkable turnover numbers (TON up to 920) and turnover frequencies (TOF up to 131 h − 1 ), outperforming conventional Cu salts and IL‐free systems. Notably, the catalyst retained its activity and selectivity over five consecutive cycles with negligible copper leaching, as confirmed by ICP‐OES. This study establishes CuCl 2 /[Aemim]Br as an efficient, sustainable, and reusable catalytic platform for direct amide synthesis via aerobic oxidative amidation of alcohols.