Synthesis of Quinolines by the Skraup Reaction:Hierarchical Zeolites vs Microporous Zeolites

摘要

The activity,selectivity,and stability of microporous highly dispersed zeolites(H-Y,H-ZSM-5)and granulated hierarchical zeolites(H-Yh and H-ZSM-5h)were studied in the synthesis of quinolines by the Skraup reaction.Texture,porous structure,morphology of crystals,acidic properties were characterized by XRD,XRF,N2 adsorption-desorption,SEM,NH3-TPD methods.It was found that quinoline,2-and 4-methylquinolines are the main products in the reaction of aniline with glycerol in the presence of the studied catalysts.H-ZSM-5h and H-Yh catalysts are more efficient than catalysts H-ZSM-5 and HY and provide a yield of quinolines to 72.4(H-ZSM-5h)and 60.2%(H-Yh)at 450℃,0.2 h~(-1),the molar ratio of aniline:glycerol=1:3.The high activity and selectivity of hierarchical zeolites are due to the presence of meso-and macropores,as well as nanocrystals of 15-100 nm size.It was reported that hierarchical catalysts exhibit higher stability in the reaction compared with microporous zeolites.