Confining task-specific ionic liquid in silica-gel matrix by sol-gel technique: A highly efficient catalyst for oxidation of alcohol with molecular oxygen

A novel catalytic system was developed through confinement of TEMPO task-specific ionic liquid (TEMPO-IL) with CuCl2 in a silica-gel matrix by sol-gel technique. The obtained TEMPO-IL/CuCl2/silica-gel catalytic system was effective for the transformation of a series of benzylic, allylic and heterocyclic alcohols to the respective carbonyl compounds under O2 atmosphere. Notably, the system facilitates ease separation of the catalyst and product and shows good reusability in the reaction.

Graphical AbstractA novel catalytic system was developed through confinement of TEMPO task-specific ionic liquid (TEMPO-IL) with CuCl2 in a silica-gel matrix by sol-gel technique. The obtained TEMPO-IL/CuCl2/silica-gel catalytic system was effective for the transformation of a series of benzylic, allylic and heterocyclic alcohols to the respective carbonyl compounds under O2 atmosphere. Notably, the system facilitates ease separation of the catalyst and product and shows good reusability in the reaction.Figure optionsDownload as PowerPoint slideResearch Highlights
► TEMPO-IL and CuCl2 were entrapped in the pores of silica-gel by sol-gel method.
► TEMPO-IL/CuCl2/silica-gel is highly efficient for the aerobic alcohol oxidation.
► The solvent has an important effect on the catalytic activity.
► TEMPO-IL/CuCl2/silica-gel can be easily recovered and reused.