A new efficient approach to 3-methylindole: Vapor-phase synthesis from aniline and glycerol over Cu-based catalyst

A novel efficient method for vapor-phase synthesis of 3-methylindole from aniline and glycerol has been developed over Cu-based catalysts. The catalysts were characterized by BET, XRD, H2-TPR and NH3-TPD techniques. The results indicated that Cu/SiO2-Al2O3 catalyst exhibited high activity. The yield of 3-methylindole could be up to 40% when the Cu loading was 5.41 wt% and the reaction temperature was 240 °C. Moreover, the catalyst could be reused without obvious loss of the yield even after reaction time of 46 h. Copper-based catalyst with good dispersion and large amount of weak acid sites was favorable for producing 3-methylindole. A possible reaction pathway for the catalytic synthesis of 3-methylindole was proposed.

Graphical abstractA novel efficient method for the vapor-phase synthesis of 3-methylindole from aniline and glycerol has been developed over Cu/SiO2-Al2O3 catalyst with the yield of 3-methylindole up to 40%.Figure optionsDownload full-size imageDownload as PowerPoint slideResearch Highlights► 3-Methylindole was synthesized from aniline and glycerol. ► Cu/SiO2-Al2O3 showed high activity and good stability. ► The yield of 3-methylindole was up to 40%. ► The weak acid sites and small copper particles on the catalyst facilitated the reaction.