Synthesis of Mordenite Nanocrystals by Using a Hydrophobic Structure-directing Agent

Abstract

Mordenite nanocrystals of around 80 nm in length along the c axis were synthesized successfully by using a hydrophobic structure-directing agent (SDA). The nanometer-sized mordenite catalyst showed higher activity than the micron-or submicronsized versions in cumene cracking.

Facilely Synthesized H-Mordenite Nanosheet Assembly for Carbonylation of Dimethyl Ether

“…17 The H-MOR nanosheets synthesized with the template of tetraethylammonium showed the high activity for cracking of cumene. 18 Reducing particle sizes of mordenite membranes using the template of tetraethylammonium bromide enhanced the H 2 /N 2 separation efficiency. 19 However, employing template agents may unfortunately bring disadvantages of high costs, as well as production of aqueous and gaseous pollutions.…”

“…The reduced crystal sizes can shorten diffusion pathways for coke precursor species migrating out of channels, and then inhibit hard coke formation. , The crystal size of H-MOR zeolites is generally larger than 10 μm, causing slow mass diffusion. Employing expensive template agents can controllably adjust morphologies and sizes of H-MOR to induce pronouncing performances. − For example, the H-MOR nanoparticles synthesized with the template of N,N,N,N′,N′,N′-hexaethylpentanediammonium cations showed the higher catalytic performance for DME carbonylation, as compared with conventional big ones . The H-MOR nanosheets synthesized with the template of tetraethylammonium showed the high activity for cracking of cumene .…”

“…Employing expensive template agents can controllably adjust morphologies and sizes of H-MOR to induce pronouncing performances. − For example, the H-MOR nanoparticles synthesized with the template of N,N,N,N′,N′,N′-hexaethylpentanediammonium cations showed the higher catalytic performance for DME carbonylation, as compared with conventional big ones . The H-MOR nanosheets synthesized with the template of tetraethylammonium showed the high activity for cracking of cumene . Reducing particle sizes of mordenite membranes using the template of tetraethylammonium bromide enhanced the H 2 /N 2 separation efficiency .…”

Creation of Mesopores in ZSM-5 Zeolite Crystals by a Novel Double-acyloxy Organosilane Surfactant

“…7,8 So far, a lot of researches on the structural control of ZSM-5 zeolites have been carried out in order to solve their diffusion limitation problems, such as layer-bylayer nanoarchitectonics, 9 synthesis of nanocrystalline zeolites containing open mesopores in the intercrystalline void space, 10,11 synthesis of zeolites with micro-mesopore hierarchical structures using hard templates, 12,13 or soft templates. [14][15][16][17][18] Among these researches, the soft-template method was an interesting attempt for the creation of mesopores in zeolites. 13,15 Up to 1961, zeolites were prepared using only inorganic resource, and all zeolites in that period (such as the classical synthetic zeolites A, X, and Y) were synthesized in this manner.…”

“…20 It seemed that the templating agents for mesopore formation, not only having larger hydrophobic group to deserve low critical micelle concentration, but also possessing a zeolite structure-directing function were needed. 17,21 According to the above-mentioned consideration, we herein designed and synthesized a novel silicon alkoxidecontaining template for mesopore formation, ( 11 H 23 ]I, BTDAI), a double-acyloxy organosilane quaternary ammonium salt. As shown in Figure 1, the synthesized double-acyloxy siliceous ammonium salt surfactant BTDAI contains a mesopores structure-directing hydrolysable methoxysilyl moiety and a blocky double hydrophobic alkyl chains moiety.…”