Mordenite Nanorods Prepared by an Inexpensive Pyrrolidine‐based Mesoporogen for Alkane Hydroisomerization

Abstract

The front cover artwork for Issue 12/2019 is provided by researchers from the group of Inorganic Materials and Catalysis, Eindhoven University of Technology (The Netherlands). The image shows how a novel surfactant based on methylpiperidine modified by a hydrophobic tail (C16NMP) can downsize the synthesis of mordenite zeolite from massive crystals into more accessible nanorods. See the Full Paper itself at https://doi.org/10.1002/cctc.201900298.

Hierarchically Porous (Alumino)Silicates Prepared by an Imidazole-Based Surfactant and Their Application in Acid-Catalyzed Reactions

“…An observed lattice distance of 1.33 nm is attributed to the [110] plane (Figure 13c, insert) and points to nanorods oriented parallel to the c-axis. 25,62,63 As discussed in our previous work, 25 the hydrophilic head group of the SDA molecule is likely located in the 8 MR side-pockets or at the interface between the 8MR and 12MR channels, while the hydrophobic tail is blocking crystal growth in the a-and b-directions.…”

“…The samples exhibited similar catalytic behavior, namely, a low selectivity to cracking products up to n-hexadecane conversion of 80% (Figure 12c), explained by the relatively weak acidity 25 of the amorphous materials (Table S4). The Pd/Com-ASA displayed a slightly "M-shaped" distribution of cracked product (Figure 12d), whereas the Pd/Al-LS sample showed a more symmetric distribution of cracked products at 50% conversion.…”

“…We have observed similar behavior in our previous work, where MOR nanorods were synthesized in the presence of a pyrrolidine-based mesoporogen. 25 Hierarchical zeolites are promising catalysts for Friedel− Crafts alkylation/acylation reactions with bulky reactants and/ or products due to their strong acidity and the presence of a second level of porosity, which helps to overcome the diffusion limitations. 67−69 We evaluated the obtained MOR zeolites in the model alkylation reaction of benzene (B) with benzyl alcohol (BA) that leads to diphenylmethane (DPM) in the presence of acid forms of MOR-15 and mMOR-15 catalysts (Scheme S1).…”

“…24 We recently demonstrated that an inexpensive mono-quaternary ammonium salt, containing a cyclic N-methylpyrrolidinium head group, can be an efficient surfactant for the direct synthesis of hierarchically porous mordenite (MOR) zeolite. 25 In this work, we developed a novel strategy to obtain several ordered mesoporous materials using 1,2-dimethyl-3-hexadecyl-1H-imidazol-3-ium bromide (C 16 dMImz) as an organic SDA. Amorphous layered silica with a high surface area (1200 m 2 g −1 ) was obtained in the absence of aluminum.…”

Facile synthesis of nanosized mordenite and beta zeolites with improved catalytic performance: non-surfactant diquaternary ammonium compounds as structure-directing agents

“…From the inorganic gel with a Si/Al ratio of 30, MOR zeolite was obtained in a low yield, pointing to poor incorporation of silicon into the zeolite as apparent from the low final Si/Al ratio and consistent with earlier studies (Table S3 †). 50,51 Fig. 3 and 4 show SEM and TEM images of the as-prepared samples, respectively.…”