Solvent-free synthesis of imines via N-alkylation of aromatic amines with alcohols over Co2+-exchanged zeolites

•Co2+-exchanged zeolites are firstly used in liquid-phase synthesis of imines via N-alkylation of aromatic amines with alcohols.•89.8 mol% conversion of aniline with an imine selectivity of 100% is obtained over Co-13X.•A new route to catalyze the solvent-free synthesis of imines from aromatic amines and alcohols.

Co2+-exchanged zeolite catalysts were prepared by an ion-exchange route and firstly applied in the N-alkylation of aromatic amines with alcohols to imines. For the N-alkylation of aniline with benzyl alcohol, the aniline conversion of 89.8 mol% with an imine selectivity of 100% was achieved over Co-13X at 433 K under optimal conditions. The results showed that many factors including the Co loading, the support, the temperature, the alkali, could influence the reactions. Investigations carried out by XRD, SEM and recycling studies indicated that the Co-13X catalyst still remained porous structures of 13X zeolite and possessed a stable catalytic activity.

Graphical abstractCo2+-exchanged zeolites were firstly applied in the liquid-phase synthesis of imines via N-alkylation of aromatic amines with alcohols in a solvent-free system, displaying highly catalytic activities.Figure optionsDownload full-size imageDownload as PowerPoint slide