A Simple Route to Synthesize Mesoporous ZSM‐5 Templated by Ammonium‐Modified Chitosan

Abstract

Uniform mesoporous zeolite ZSM-5 crystals have been successfully fabricated through a simple hydrothermal synthetic method by utilizing ammonium-modified chitosan and tetrapropylammonium hydroxide (TPAOH) as the meso- and microscale template, respectively. It was revealed that mesopores with diameters of 5-20 nm coexisted with microporous network within mesoporous ZSM-5 crystals. Ammonium-modified chitosan was demonstrated to serve as a mesoporogen, self-assembling with the zeolite precursor through strong static interactions. As expected, the prepared mesoporous ZSM-5 exhibited greatly enhanced catalytic activities compared with conventional ZSM-5 and Al-MCM-41 in reactions involving bulky molecules, such as the Claisen-Schmidt condensation of 2-hydroxyacetophenone with benzaldehyde and the esterification reaction of dodecanoic acid and 2-ethylhexanol.

Synthesis, characterization and evaluations of micro/mesoporous ZSM-5 zeolite using starch as bio template

“…The presence of mesopores is clearly visible in the SEM image of the modified sample. The TEM images of the modified ZSM-5 zeolite sample demonstrate zeolite nanocrystals with many bright areas, indicating the presence of mesopores [24,27]. These results were complementary to BET and SEM analysis and support the successful generation of mesopores in the modified sample.…”

“…Krishnan and co-workers developed hierarchical ZSM-5 monolith using corn and sorghum stem pith as templates [23]. Jin et al [24] successfully synthesized mesoporous zeolite using ammonium-modified chitosan as template and demonstrated its high catalytic activity for Claisen-Schmidt condensation. A few attempts have been made in the past to use starch as template to introduce mesoporosity in zeolite.…”

Ordered Mesoporous ZSM‐5 Employing an Imidazolium‐Based Ionic Liquid

“…The obtained materials present in many cases a narrow size distribution of mesopores and in some cases ordered arranged mesoporosity. Mesoporous ZSM‐5 by soft templating techniques has so far been obtained by the employment of large copolymers (polystyrene‐co‐4‐polyvinylpyridine),10 by the use of ammonium functionalized silanes as [(CH 3 O) 3 SiC 3 H 6 N(CH 3 ) 2 C 16 H 33 ]Cl,11 or by biotemplates as modified chitosane 12…”

Advances in the Green Synthesis of Microporous and Hierarchical Zeolites: A Short Review

“…), thus avoiding the use of microporous templates and making the preparation process relatively economical and simple. Shi et al [82] modified the surface of chitosan to form cations and succeeded in synthesizing hierarchical zeolites.…”