Efficient Acylation of Anisole over Hierarchical Porous ZSM‐5 Structure

Abstract

Friedel-Crafts acylation is one of the most important methods to prepare aromatic ketones which are used in manufacturing fine and speciality chemicals, as well as pharmaceuticals. Herein, we report an efficient and convenient procedure for the acylation of anisole with acetic anhydride, using a hierarchical porous ZSM-5 catalyst. The hierarchical porous ZSM-5 catalyst was synthesized using styrene butadiene rubber (SBR) as macroporous template. The catalysts were characterized for their structural features by using XRD, SEM, and FT-IR analyses. The effect of temperature, molar ratio, and catalyst weight on the acylation of anisole was studied in detail. The reaction parameters such as anisole-to-acetic anhydride mole ratio, catalyst weight, and reaction temperature were optimized as 5:1, 0.2 g, and 70°C, respectively. The method described here is environmentally benign and replaces the conventional catalyst by a highly active and reusable catalyst.

Hierarchical porous materials: catalytic applications

“…Solid acid catalysed acylation of anisole with acetic anhydride has been achieved over a disordered, macroporous ZSM-5 skeleton. 112 This structure results from a combination of two structure directing agents; one imparts microporosity, while styrene butadiene rubber latex particles impart macroporosity. Superior diffusion through this novel architecture increases anisole conversion >80%, compared with only 66% and 14% reported for 90 nm 113 and micron-sized ZSM-5 crystals respectively.…”

Hierarchically Nanoporous Zeolites and Their Heterogeneous Catalysis: Current Status and Future Perspectives

“…A disordered, macroporous MFI zeolite was investigated during the solid-acid catalyzed acylation of anisole with acetic anhydride [123]. The macroporous structure provided the superior diffusion efficiency, which allowed increased anisole conversion more than 80 %.…”

Effect of copper on textural and acidic properties of hierarchical nanocrystalline ZSM‐5

“…The water adsorbed in the interporous structure shows band at 3,448 cm −1 corresponding to O–H stretching vibration. The bands related to internal linkages in SiO 4 or AlO 4 − of zeolite lattices are observed at 1,230, 1,100, and 796 cm −1 for modified and unmodified samples 24,31,32 . Typical changes observed in the FTIR spectra of copper‐modified samples are that the intensive adsorption bands at 1,100 cm −1 for nano‐ZSM‐5 shifted to a lower wave number and its intensity was found to have decreased with increasing concentration of metal nitrate solution 33 .…”