نتایج جستجو برای: aluminosilicates
تعداد نتایج: 371 فیلتر نتایج به سال:
The acid properties of mesostructured aluminosilicates synthesized from gels precursors of colloidal ZSM-5 zeolite have been studied by FTIR spectroscopy of basic probe molecules (ammonia, CO and propene). It is shown that these materials possess stronger acid sites with higher thermal stability than those of conventional Al-MCM-41. These results explain the enhaced m-xylene isomerization activ...
Highly ordered hexagonal mesoporous aluminosilicates (MAS-5) with uniform pore sizes have been successfully synthesized from assembly of preformed aluminosilcate precursors with cetyltrimethylammonium bromide (CTAB) surfactant. The aluminosilicate precursors were obtained by heating, at 100--140 degrees C for 2--10 h, aluminasilica gels at the Al(2)O(3)/SiO(2)/TEAOH/H(2)O molar ratios of 1.0/7....
Magnetic, Mössbauer, and I.R. studies of nanosize particles of Fe and Co species dispersed in a cage of aluminosilicates structure, in relation to syngas (CO+H2) Fischer Tropsch conversion. The difference in the catalytic activity of such species have shown dependancy on their degree of dispersion. The carbonyl impregnation gave ultra-fine Super Paramagnetic Fe3O4, whereas the nitrate impregnat...
We have developed a computational framework for the adsorption of linear alkanes in protonated aluminosilicates. These zeolites contain trace amounts of water that form hydrated proton complexes. The presence of hydrated protons makes the simulations at the fully atomistic level difficult. Instead of constructing an elaborate and complex model, we show that an approach based on a coarse-grainin...
Sol-gel synthesis of filled aluminosilicates with macromolecules having a dendrimer morphology (Mcalc ≈ 480000) was developed. The software package Gaussian B3LYP/6-31G(d) was used to assess the possible mechanism by which nuclei of dendrimer molecules are created, with the subsequent generation of crowns of branched ensembles capable of accommodating up to 80 wt % nano-AlOOH as a filler. The d...
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