Brønsted acid sites in the Beta zeolite induced highly efficient amidation of styrene in the aqueous phase†
Abstract
Development of an environmentally friendly catalyst system is a highly attractive strategy for organic synthesis. In this work, a H-form mesoporous Beta (H-MBeta) zeolite with an irregular spherical particle shape was synthesized and was found to realize the direct amidation of styrene and nitriles for the synthesis of N-alkylated amides in the aqueous phase. This strong acidic H-MBeta catalyst exhibited superior activity and product selectivity compared with H-MBeta-0.3 and H-MBeta-1.0 zeolites obtained from the acid dealumination method. This was attributed to the presence of abundant strong Brønsted acid sites in the H-MBeta zeolite, which can induce the adsorption and activation of styrene through the CC bond interacting with protonic hydrogen, benefiting the formation of key intermediate carbocation.