Effect of Alkyl Group/s and Type of Aromatic Conjugation on Transalkylation Reactions of Alkyl Aromatics

Abstract

Alkyl group removal (not necessarily transalkylation) from the aromatic ring favoured sterically strained molecules and if there is less strain then removal from the ring with the most alkyl groups is favoured over considerations of the alkyl group size. The amount and type of aromatic ring conjugation also plays an important role in the alkyl-transfer reactions of alkylaromatics. The position of the alkyl group on the aromatic moiety also affects alkyl-transfer due to both electronic effects and more importantly the steric factors. Contrary to the ease of dealkylation or alkyl group removal favouring conjugation, alkylation or alkyl group acceptance favoured smaller aromatics or reduced conjugation. With the above observations in mind and the fact that the ease of alkyl group removal increased with aromatic conjugation and considering the fact that benzene derivatives required stronger acid sites for activation. The calculations suggest that use of less acidic large pore zeolites like MCM-41 and MCM-48 might result in a selective one-way (no reverse reactions) alkyl-transfer from bulky molecules to smaller benzene derivatives.