1H and 13C MAS NMR studies of light alkanes activation over MFI zeolite modified by Zn vapour

Kolyagin, Yu. G.; Ivanova, I. I.; Pirogov, Yu. A.

doi:10.1016/j.ssnmr.2009.01.005

Cited by 68 publications

(116 citation statements)

References 50 publications

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“…Santen et al [35] used DFT calculations to propose that Zn ions can polarize the C-H bond of methane leading to heterolytic cleavage and the formation of CH 3 − anions, which rapidly attach to Zn 2+ ions to produce zinc methyl species [Zn-CH 3 ] + . Ivanova et al [36] showed that the formation of these surface zinc methyl species did not lead to any further reaction, up to 500 • C. Similar results were reported showing that even at 600 • C Zn was inactive for producing aromatics [37]. Our approach was to study indirectly the active sites for noncarbidic zinc oxides during MDA.…”

Section: Introductionsupporting

confidence: 57%

Investigation of the stability of Zn-based HZSM-5 catalysts for methane dehydroaromatization

Abdelsayed

Smith

Shekhawat

2015

Applied Catalysis A: General

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Section: Introductionsupporting

confidence: 57%

Investigation of the stability of Zn-based HZSM-5 catalysts for methane dehydroaromatization

Abdelsayed

Smith

Shekhawat

2015

Applied Catalysis A: General

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“…5B, in addition to the apparent bands in the range 3350-3200 cm À1 , which were attributed to ammonia coordination on Lewis acid sites, two weak yet clear absorption peaks at 3220 and 3190 cm À1 emerged in the N-H stretching region. 26,28 It was clear that Zn modication not only produced a number of Lewis [14][15][16]30,31 can provide Lewis acid sites in Znmodied ZSM-5 or beta zeolite. Similarly, we speculated that the Lewis acid sites in Zn x /S-1 were also associated with their Zn species.…”

Section: -29mentioning

confidence: 99%

“…It has been accepted that Zn-containing catalysts were active in the dehydrogenation of alkanes. [14][15][16][19][20][21] Zn-modied HZSM-5 zeolites (Zn/ZSM-5) have been reported to be effective catalysts for low-temperature activation of light alkanes, with the modied Zn species playing a key role in light alkane dehydrogenation. [14][15][16] However, their commercial use in such processes is impeded by their poor alkene selectivity with respect to the formation of large amounts of cracked dry gas byproducts (C 1 and C 2 hydrocarbons), resulting from the strong acidic character of HZSM-5 zeolite.…”

Section: Introductionmentioning

confidence: 99%

Silicalite-1 zeolite acidification by zinc modification and its catalytic properties for isobutane conversion

Liu

et al. 2018

RSC Adv.

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A series of Zn-modified Silicalite-1 (S-1) zeolites (Zn x /S-1) were prepared by the wetness-impregnation method and applied in the catalytic conversion of isobutane. The structure and location of Zn species in Zn x /S-1 were investigated using UV-Vis and N 2 physical adsorption. The acidity and origin of the acid sites in Zn x /S-1 were studied by NH 3 -temperature programmed desorption and Fourier-transform infrared analysis. The catalytic performance of Zn x /S-1 for isobutane conversion was investigated in a fixed-bed microreactor. In the experiments, the acidity of S-1 zeolite was dramatically increased by modification with Zn, with both Lewis and Brønsted sites identified in Zn x /S-1. The relationship between Brønsted acid sites and Zn-OH groups on ZnO clusters of Zn x /S-1 was also revealed for the first time.Furthermore, Zn x /S-1 catalysts exhibited excellent catalytic performances in both isobutane dehydrogenation and butene isomerization reactions. A high selectivity of total butene products ranging from 84.6 to 97.2 was achieved on the catalysts with different Zn loadings. Moreover, the linear correlation between isobutane conversion and the acid amount (determined by NH 3 -TPD) confirmed that the weak-to-medium acid sites in Zn x /S-1 should play a key role in isobutane conversion.

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“…42,43 The catalyst predominantly contains Zn 2+ cations, almost excludes other zinc species such as ZnOH + or ZnO. Fig.…”

Section: Activation Of Light Alkanesmentioning

confidence: 99%

Recent development in in situ NMR study on heterogeneous catalysis: mechanisms of light alkane functionalisation

2012

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1H and 13C MAS NMR studies of light alkanes activation over MFI zeolite modified by Zn vapour

Cited by 68 publications

References 50 publications

Investigation of the stability of Zn-based HZSM-5 catalysts for methane dehydroaromatization

Investigation of the stability of Zn-based HZSM-5 catalysts for methane dehydroaromatization

Silicalite-1 zeolite acidification by zinc modification and its catalytic properties for isobutane conversion

Recent development in in situ NMR study on heterogeneous catalysis: mechanisms of light alkane functionalisation

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