Adsorption structure of dimethyl ether on silicalite-1 zeolite determined using single-crystal X-ray diffraction

Fujiyama, Shinjiro; Seino, Shintaro; Kamiya, Naoki; Nishi, Kazufumi; Yokomori, Yoshinobu

doi:10.1107/s2052520614015911

Cited by 7 publications

(7 citation statements)

References 37 publications

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“…3A shows the high-loaded structure of ZSM-5-MTBE, with the guest molecules located in both channels, in common with other non-aromatic hydrocarbons. [44][45][46] Although ZSM-5 is hydrophobic, difference Fourier maps revealed the presence of a further extra-framework site partially occupied by a low amount of water molecules (W site in Table S2 ESI †). On the whole, 8 MTBE molecules (corresponding to $11% zeolite dry weight (dw)) and about 2 water molecules (corresponding to about 0.5% zeolite dw) were detected.…”

Section: Resultsmentioning

confidence: 99%

Influence of water on the retention of methyl tertiary-butyl ether by high silica ZSM-5 and Y zeolites: a multidisciplinary study on the adsorption from liquid and gas phase

et al. 2015

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Section: Resultsmentioning

confidence: 99%

Influence of water on the retention of methyl tertiary-butyl ether by high silica ZSM-5 and Y zeolites: a multidisciplinary study on the adsorption from liquid and gas phase

et al. 2015

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“…Bent molecules prefer the sinusoidal channel and linear molecules prefer the straight channel. Indeed, the bent dimethyl ether is initially adsorbed in the sinusoidal channel 32 while the linear CO 2 is initially adsorbed in the straight channel. 33 These results may be explained by the structural differences between the channels.…”

Section: Adsorption Of 2-butynementioning

confidence: 99%

“…The details of the calculation have been reported elsewhere. 32 The potential map of the resulting U(x, y, z) values reflects the structural differences of the channels and a guest molecule at a stable sorption site will locate its atoms where U(x, y, z) is low. Fig.…”

Section: Adsorption Of 2-butynementioning

confidence: 99%

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Adsorption structures of non-aromatic hydrocarbons on silicalite-1 using the single-crystal X-ray diffraction method

Fujiyama

Seino

Kamiya

et al. 2014

Phys. Chem. Chem. Phys.

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The actual adsorption structures of non-aromatic hydrocarbons on the MFI-type zeolites have not yet been determined. This is due to the presence of twinning, which makes crystallographic analysis difficult. We recently overcame this problem, and now report the various adsorption structures of n-butane, n-pentane, n-hexane, 1-butene, cis and trans-2-butene, 2-butyne and isopentane on silicalite-1 (MFI-type zeolite) as determined via single-crystal X-ray diffraction. The structures were elucidated for both low and high loadings of each guest molecule in order to clarify the adsorption process. The low-loaded structures provide valuable insight into guest-framework interactions and initial adsorption behavior. The n-alkanes are initially adsorbed in the sinusoidal channel, while 2-butyne is adsorbed in the straight channel. In the case of the normal hydrocarbons, the molecular configuration (bent or linear) of the compound determines which channel is the preferred adsorption site. Bent molecules prefer the sinusoidal channel and linear molecules prefer the straight channel. In contrast, isopentane is initially adsorbed at the intersection, since the channels are too narrow to maintain the preferred distance between the framework and the bulky isopentane molecule. In the high-loaded structures, the guest molecules occupy additional sites, such that the normal hydrocarbons are located in both channels and isopentane is found at the intersection and the sinusoidal channel.

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“…Particularly, it seems that MTBE is only able to fill the half of micropore volume in the parent silicalite‐2 (consequently adsorption amounts of MTBE in the region is comparable for the two materials irrespective of the smaller micropore volume for L‐silicalite_423‐360), implying that some serious blockade of its pores in MTBE adsorption is present at the lower adsorption temperature. Certain structural defects together with the difficulty for the large MTBE molecule to enter into the inner adsorption sites through the longer micropore channel path may be considered for the reason. Thus, the results strongly suggest that the beneficial adsorption sites such as channel intersections becomes more exposed to be easier access by MTBE for L‐silicalite_423‐360 because of the peculiar 2D structure of h‐nanoplatelets.…”

Section: Resultsmentioning

confidence: 99%

Dissolution–Recrystallization Formation of Huge Thin 2D Silicalite Lamella for Promoted Sorption

Liu

Yang

Wang

et al. 2020

Adv Materials Inter

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An all silica MEL‐type silicalite‐2 nanocrystal is hydrothermally treated in coexistence with cetyltrimethylammonium bromide (CTAB) and tetrapropylammonium hydroxide (TPAOH) at ordinary and elevated temperatures. From monitoring its structural transition process by various physico‐chemical methodologies, it is found that, instead of simple delamination, silicalite‐2 nanocrystal changes with a dissolution and recrystallization mechanism by treatment at an elevated temperature and for a long time, that is, it is first dissolved and then reorganized to huge 2D platelets via an intermediate step forming periodic mesoporous material. The newly formed nanoplatelets (h‐nanoplatelets) from in‐plane growth along a (or b)‐, c‐directions (normal to b (or a)‐axis) are of silicalite (either MEL or MEL/MFI intergrowth)‐type framework topology with a thickness of 3.3 nm (the equivalent of ≈1.6 unit cell) and interspersed with a minor part of small square‐like MFI‐type nanoplatelets (s‐nanoplatelets). The h‐nanoplatelets have expanded lattice parameters and a larger micropore size compared to the parent silicalite‐2 nanocrystal and s‐nanoplatelets, whose micropore structure are modified so as to benefit from both equilibrium adsorption and desorption‐recovering ability of organic contaminants particularly at a low vapor pressure range. This is the first report regarding the dissolution–recrystallization formation of 2D lamella‐type silicalites mediated by popular types of surfactant and base species.

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Adsorption structure of dimethyl ether on silicalite-1 zeolite determined using single-crystal X-ray diffraction

Abstract: The most stable sorption site of dimethyl ether on silicalite-1 is the sinusoidal channel. The configuration of guest molecules (linear or bent) plays an important role in determining where the stable sorption site is situated.

Cited by 7 publications

References 37 publications

Influence of water on the retention of methyl tertiary-butyl ether by high silica ZSM-5 and Y zeolites: a multidisciplinary study on the adsorption from liquid and gas phase

Influence of water on the retention of methyl tertiary-butyl ether by high silica ZSM-5 and Y zeolites: a multidisciplinary study on the adsorption from liquid and gas phase

Adsorption structures of non-aromatic hydrocarbons on silicalite-1 using the single-crystal X-ray diffraction method

Dissolution–Recrystallization Formation of Huge Thin 2D Silicalite Lamella for Promoted Sorption

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