Aniline alkylation with methanol: relationship nature and strength of active sites - catalytic activity

Abstract

The products of the alkylation of aniline (A) with methanol (M), both carbon alkylate and N-derivatives are important intermediaries in the organic synthesis. Thus, toluidine (To), N-methylaniline (NMA) and N-dimethylaniline (NNDMA), the main products of this reaction are used as intermediates in the manufacture of dyes, plastics and explosives. The preparation of these products in liquid phase has been widely studied. Naturally, this process in the presence of strong acids generates problems of corrosion and contaminating residues. A comparative analysis between all the reaction products obtained indicates that NMA is the initial product of aniline alkylation with methanol with the highest formation rate. The NNDMA would come from the alkylation of the NMA following a relatively similar behavior. NNDMT follows a particular behavior. It is always secondarily unstable except in SBS-SLS (Strong Bonsted - Strong Lewis site pairs), where it is stable at high conversion levels. To is always an unstable secondary product, except for the SBS-SBS (stable) group, with a maximum formation rate in SBS-SLS between 15-20% of aniline conversion and more than 20% in the neighboring SBS-SBS.