Mesoporous MFI Zeolite Nanosponge as a High-Performance Catalyst in the Pechmann Condensation Reaction

Abstract

A zeolite nanosponge possessing MFI framework type was hydrothermally prepared by a seed-assisted synthesis method using C 22 H 45 −N + (CH 3 ) 2 −C 6 H 12 − N + (CH 3 ) 2 −C 6 H 13 as a structure-directing agent. The nanosponge morphology was composed of a three-dimensional disordered network of MFI nanolayers with 2.5 nm thickness supporting each other. Catalytic performance of the MFI nanosponge was investigated in the Pechmann condensation of bulky reactants (pyrogallol and resorcinol) with ethyl acetoacetate and compared with conventional zeolites MFI, BEA, and USY) and also layered MFI, pillared MFI, and selfpillared MFI. The investigation revealed outstanding catalytic performance of the MFI nanosponge, which can be attributed to the contribution of strong acid sites located on the external surfaces accessible for the reaction of bulky reactants.

Effect of Si/Al Ratio on the Catalytic Activity of Two‐Dimensional MFI Nanosheets in Aromatic Alkylation and Alcohol Etherification

“…As expected, the acid site density increases with decreasing Si/Al ratio or increasing Al content. However, it does vary for the same Si/Al ratio if the morphology is different, as seen in the case of 3D MFI (21) vs 2D MFI (25) and also reported by previous studies …”

“…Based on the kinetic model proposed by Zhang et al., the effectiveness factor was calculated. In these calculations, the fraction of external acid sites was assumed to be approximately 30 % based on the previous works by Ryoo et al . on 2D MFI nanosheets.…”

“…The effect of Si/Al ratio has also been studied in case of MFI with a nanosponge morphology. Kim et al [26] studied the Pechmann condensation of pyrogallol and resorcinol with ethyl acetoacetate to understand the effect of the density of acid sites by varying the Si/Al ratio on the catalytic activity of MFI nanosponge. They found that the activity per acid site reduced with increasing density of sites achieved by decreasing the Si/Al ratio.…”

The Role of External Acidity of Hierarchical ZSM‐5 Zeolites in n‐Heptane Catalytic Cracking

“…However, the catalytic applications of ZSM‐5 zeolites are limited by mass transport in the microporous network if bulky molecules are involved in the reaction . In this regard, the introduction of mesopores into microporous zeolites to obtain hierarchical ones, possessing the catalytic features of microporosity and the improved mass transport consequence of mesoporosity, would be an optimal choice for better performance …”

Recyclable cellulose nanocrystal supported Palladium nanoparticles as an efficient heterogeneous catalyst for the solvent‐free synthesis of coumarin derivatives via von Pechmann condensation

“…[1][2][3][4] Besides, they are used greatly as primary materials in preparation of insecticides, pesticides and optical brighteners, [5] laser dyes, [6] antioxidant, [7] anti-HIV, antibacterial and analgesic. The nanocatalyst demonstrated outstanding performance in Pechmann condensation between different substituted phenols and ethyl acetoacetate to obtain coumarin derivatives in good to excellent yields.…”