Synthesis of SAPO-34 using metakaolin in the presence of β-cyclodextrin

Facile synthesis of SAPO-34 nanocrystallites with excellent performance for the dehydration of carbohydrates to 5-hydroxymethylfurfural

“…In addition to three methoxysilane groups, the AC-230 molecule contains an oxygen-containing epoxy group, which strengthens the interactions between the organosilane and the nuclei surface via the coordination of the lone pair electrons of oxygen atoms. 33,35,36 Through the hydrolyzed silanol group and epoxy group at both ends of the molecule, the organosilane serves as an immobilization agent to construct a segregated network of crystal nuclei, inhibiting the redissolution and overgrowth of the crystal nuclei and thus resulting in SAPO-34 nanoaggregates. In the absence of the seeds, excessive AC-230 molecules may wrap up the rare crystal nuclei, which severely obstructed the crystal growth to obtain crystalline products.…”

“…Organosilanes have been proved to be the most prominent crystal growth inhibitor to fabricate nanosized SAPO-34 through the formation of the R-Si-O-Al bond between organosiloxane groups and the inorganic framework. 30,31 Various oxygen-rich small molecules, or polymers, such as citric acid, 32 β-cyclodextrin, 33 1,2,3-hexanetriol, 34 polyoxyethylene lauryl ether 35 and polyethylene glycol 35,36 have also been claimed to interact with the SAPO-34 framework via the coordination of lone pair of electrons of oxygen atoms to limit the crystal growth. It is thus envisioned that low-cost organosilanes, which contain both an oxygen-containing group and an organosilane group, may have the potential for the efficient synthesis of high-quality nanosized SAPO-34.…”