23-P-12 - Mechanistic study of aniline methylation over acidic and basic zeolites Y

Abstract

This chapter presents the mechanistic study of aniline methylation over acidic and basic zeolites Y. 13 C magic angle spinning nuclear magnetic resonance (MAS NMR) has been performed insitu under batch conditions to investigate the mechanism of aniline alkylation with methanol on acidic H-Y and basic CsNa-Y impregnated with cesium hydroxide. On acidic zeolite H-Y, methanol reacts with zeolitic hydroxyl groups to give surface methoxy groups that, in turn, play a role as alkylating species in aniline methylation. On the basic zeolite Y, methanol is converted into formaldehyde, which is responsible for the N-alkylation. Both on acidic and basic zeolites, N-methylaniline is the primary alkylation product. Toluidines and N-methyltoluidines are formed only on the acidic zeolite at elevated temperatures after the complete conversion of methanol into N-methylaniline.