Mesoporous silica gel as an effective and eco-friendly catalyst for highly selective preparation of cyclohexanone oxime by vapor phase oxidation of cyclohexylamine with air

•An environmentally benign method of synthesis of cyclohexanone oxime has been developed.•Mesoporous silica gel is demonstrated as an effective and eco-friendly catalyst.•Surface silicon hydroxyl groups are responsible for excellent catalytic performance.•Silica gel catalyst has highly stable reactivity, easy regeneration, and reusability.•This approach has the potential to enable sustainable production of cyclohexanone oxime.

A simple and environmentally benign approach to highly selective preparation of cyclohexanone oxime by vapor phase catalytic oxidation of cyclohexylamine with air over mesoporous silica gel under atmospheric pressure has been successfully developed in this work. The results demonstrate that the nonmetallic mesoporous silica gel is an effective and eco-friendly catalyst for the vapor phase selective oxidation of cyclohexylamine to cyclohexanone oxime and the surface silicon hydroxyl groups as active sites are responsible for the excellent catalytic performance of silica gel. The present silica gel catalyst has advantages of low cost, long-time stable reactivity, easy regeneration, and reusability. This method employing inexpensive mesoporous silica gel as catalyst and air as green terminal oxidant under facile conditions is a promising process and has the potential to enable sustainable production of cyclohexanone oxime from the selective oxidation of cyclohexylamine with air in industrial applications.

Graphical abstractFigure optionsDownload full-size imageDownload high-quality image (161 K)Download as PowerPoint slide