Ionic Liquid Brush as a Highly Efficient and Reusable Catalyst for On‐Water Nucleophilic Substitutions

Abstract A very efficient and reusable catalyst has been developed for the on‐water nucleophilic substitution of alkyl halides and tosylates with azide or thiocyanate in excellent to quantitative yields. The reaction proceeds smoothly and cleanly without any organic cosolvent or other adductive, and the brush can be reused at least 10 times without noticeable loss of the catalytic activity. The high efficiency, simplicity of product and catalyst isolation, outstanding recyclability, and organic‐solvent‐free conditions show promise for the use of this catalyst in the laboratory and in industry.