Ternary mesoporous structure of ultrastable zeolite CSZ-1

Caṙtlidge, S.; Nissen, H.‐U.; Wessicken, R.

doi:10.1016/0144-2449(89)90083-3

Cited by 36 publications

(13 citation statements)

References 11 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…This often leads to discrepancies with TEM images shown. [29,53,65] Sometimes the BJH method is applied to the adsorption branch of the nitrogen isotherm. However, many programs treat the adsorption isotherm as if it was a desorption isotherm in order to apply the BJH method.…”

Section: A Nitrogen Physisorptionmentioning

confidence: 99%

“…Because the image formed is a projection of the mass-density of the entire crystallite the exact shape and size of the mesopores is often obscured. After steaming of zeolite Y the observed mesopores appear spherical, [27,30,65] although Choi-Feng et al [33] have demonstrated very nicely that in regions with high defect concentrations the mesopores "coalesce" to form channels. Pellet et al [38] and Ajot et al [49] have shown that the mesopores in steamed ferrierite and zeolite Y respectively appear structured.…”

Section: Electron Microscopymentioning

confidence: 99%

See 1 more Smart Citation

Generation, Characterization, and Impact of Mesopores in Zeolite Catalysts

et al. 2003

View full text Add to dashboard Cite

Amongst the current developments in the field of hierarchical pore structures, the creation of mesopores in zeolite crystals is the most frequently employed way to combine micropores with mesopores in one material. In this review an overview is presented of the different approaches to generate and characterize mesopores in zeolite crystals and establish their impact on the catalytic action. Mesopores can be created via several routes from which steaming and acid leaching are the most frequently applied. Novel approaches using secondary carbon templates that are removed after synthesis have recently been launched. For the characterization of mesopores, nitrogen physisorption and electron microscopy are commonly used. More recently, it was shown that electron tomography, a form of three-dimensional transmission electron microscopy, is able to reveal the three-dimensional shape, size, and connectivity of the mesopores. The effect of the presence of mesopores for catalysis is demonstrated for several industrially applied processes that make use of zeolite catalysts: the cracking of heavy oil fractions over zeolite Y, the production of cumene and hydroisomerization of alkanes over mordenite, and synthesis of fine chemicals over Y, ZSM-5, and Beta. For these processes, the mesopores ensure an optimal accessibility and transport of reactants and products, while the zeolite micropores induce the preferred shapeselective properties.

show abstract

Section: A Nitrogen Physisorptionmentioning

confidence: 99%

Section: Electron Microscopymentioning

confidence: 99%

Generation, Characterization, and Impact of Mesopores in Zeolite Catalysts

et al. 2003

View full text Add to dashboard Cite

show abstract

“…To avoid this problem, hierarchically porous zeolites with mesopores or macropores14–18 are attracting much attention and these zeolites exhibit remarkably improved catalytic performance. Moreover, hollow zeolites are also known as an example of hierarchically porous zeolites and have been synthesized by using various methods, such as the use of hard templates, like polystyrene beads,19–23 and the selective dissolution of zeolite cores by desilication,24–26 dealumination,27 or the removal of other metallosilicates 28. The self‐construction of core–shell and hollow zeolites by recrystallization from the surface to the core has been reported for small‐pore zeolites, such as analcime,29 zeolite A,30 and Na‐P1 31.…”

Section: Introductionmentioning

confidence: 99%

Bis(dipyridophenazine)(2‐(2′‐pyridyl)pyrimidine‐4‐carboxylic acid)ruthenium(II) Hexafluorophosphate: A Lesson in Stubbornness

et al. 2014

View full text Add to dashboard Cite

Ruthenium complexes are currently considered to be among the most promising alternatives to platinum anticancer drugs. In this work, thirteen structural analogues and organelle/receptor-targeting peptide bioconjugates of a cytotoxic bis(dppz)-Ru(II) complex [Ru(dppz)2 (CppH)](PF6 )2 (1) were prepared, characterized, and assessed for their cytotoxicity and cellular localization (CppH=2-(2'-pyridyl)pyrimidine-4-carboxylic acid; dppz=dipyrido[3,2-a:2',3'-c]phenazine). It was observed that structural modifications (lipophilicity, charge, and size-based) result in the cytotoxic potency of 1 being compromised. Confocal microscopy studies revealed that unlike 1, the screened complexes/bioconjugates do not have a preferential accumulation in mitochondria. The results of this important structure-activity relationship strongly support our initial hypothesis that accumulation in mitochondria is crucial for 1 to exert its cytotoxic action.

show abstract

“…While another simple approach to modify zeolites with some mesopores has been known as post-synthesis treatments of zeolites, although it is usually adopted to change the properties connected with the silica/alumina ratio such as cation-exchange capacity and catalytic activity. In the faujasites, mainly zeolite Y, post-synthesis hydrothermal dealumination treatments and other chemical treatments form defect domains 5-50 nm in size, which are attributed to mesopores (Lynch et al, 1987;Patzelova et al, 1987;Cartlidge et al, 1989;Choi-Feng et al, 1993;Corma et al, 2002). Previous investigation on dissolution of high silica pentasils (silicalite-1, ZSM-5) with different Al content in 5 M aqueous sodium hydroxide solution showed selective removal of the siliceous species from the zeolite framework due to a relative inertness of tetrahedral aluminum centers towards hydroxide attack (Cizmek et al, 1995;Cizmek et al,1997).…”

Section: Introductionmentioning

confidence: 99%

Developments and structures of mesopores in alkaline-treated ZSM-5 zeolites

2006

View full text Add to dashboard Cite

ZSM-5 zeolites with SiO 2 /Al 2 O 3 molar ratio of 24 were treated in 0.05 M aqueous sodium hydroxide solution at 325 K in different periods. The samples were characterized by means of nitrogen adsorption at 77 K, field emission scanning electron microscopy, X-ray diffractometry, and Fourier transform infrared spectroscopy. Analysis of the experimental results showed that the alkaline treatment periods have influence on the developments and structures of mesopores in the alkaline-treated ZSM-5 zeolites. Alkaline treatment initially develops mesopores mainly from the boundary portion of MFI zeolites to the bulk, while prolonged treatment destroys the mesopores, and an optimum mesoporosity is obtained by the treatment for 1.5 h. On the other hand, crystallinities and short-range order in alkaline treated zeolites have remained virtually unchanged according to the examination from X-ray diffractometry and Fourier transform infrared spectroscopy.

show abstract

Ternary mesoporous structure of ultrastable zeolite CSZ-1

Cited by 36 publications

References 11 publications

Generation, Characterization, and Impact of Mesopores in Zeolite Catalysts

Generation, Characterization, and Impact of Mesopores in Zeolite Catalysts

Bis(dipyridophenazine)(2‐(2′‐pyridyl)pyrimidine‐4‐carboxylic acid)ruthenium(II) Hexafluorophosphate: A Lesson in Stubbornness

Developments and structures of mesopores in alkaline-treated ZSM-5 zeolites

Contact Info

Product

Resources

About