Channel arrangements and activity of some ZSM zeolites

Brönsted and Lewis acid ZSM-5 zeolites for the catalytic dehydration of glucose into 5-hydroxymethylfurfural

“…Therefore, from this acidity study, it can be concluded that it is feasible to modify the nature of acid sites of ZSM-5 zeolites by thermal or ionexchange treatments of a commercial NH 4 -ZSM-5 zeolite. 27 Al solid state NMR spectra confirmed the presence of most Al species in tetrahedral environments, as inferred from the intense peak at a chemical shift of 55 ppm ( Figure 5). However, a small peak was observed at 0 ppm, indicating that a fraction of Al was present as extra-framework octahedral species.…”

“…1), and match well with that of a typical MFI structure, with main diffraction peaks at 2Ɵ = 10.16, 11.33, 23.08, 23.48 and 23.78º (PDF 00-037-0359) [26,27]. Diffraction signals associated to iron and copper oxides were not detected, pointing out that these cations were well dispersed into the zeolitic framework.…”

Evolution of Surface Morphology with Introduction of Stacking Faults in Zeolites

“…Specific SDAs such as [18]crown-6 (18C6) and [15]crown-5 (15C5) are used to synthesise the pure forms of EMT and FAU, respectively. By using a mixture of SDAs specific for each system in the synthesis gel (MFI-MEL [23,[28][29][30] and FAU-EMT [31][32][33] ), it is possible to vary the amount of intergrowths by varying the SDA compositional ratios. Such studies also help to develop an understanding of the role of organic templates in the crystal growth of zeolites.…”

Expressiveness of Adsorption Measurements for Characterization of Zeolitic Materials—A Review

“…All the above structural irregularities are adsorption centres of various affinities to different adsorbates and create together the final adsorption effect. However, adsorption properties also depend on crystal size (Shiralkar et al, 1991), crystal morphology (Foger et al, 1984;Kornatowski et al, 2003aKornatowski et al, , 2004, Si/Al ratio (Müller and Unger 1988;Choudhary et al, 1990), Al distribution (Zikanova and Derewinski, 1995;Müller et al, 1988), acidity and degree of ion exchange (Müller et al, 1988;Shiralkar et al, 1991;Choudhary et al, 1990), and the sorption history (Karsli et al, 1992). Adsorption on zeolitic materials with a highly ordered pore structure is more sensitive to modifications than that on amorphous micro-/mesoporous adsorbents.…”

“…For instance, one, two, or even three measurements could not demonstrate a relation between the isotherm step and metal content. Postulated influence of crystal dimensions (Shiralkar et al, 1991) and morphology (Foger et al, 1984) on adsorption might be justified for two-or threedimensional pore systems. For the one-dimensional pore systems (e.g., AFI type), these parameters have a secondary meaning.…”