We have modeled the formation kinetics of nitrogen-substituted (nitrided) zeolites HY and silicalite; we have also modeled the stability of nitrided sites to heat and humidity. These kinetic calculations are based on mechanisms computed from DFT-computed pathways reported in our previous work. Reactant ammonia and product water concentrations were fixed at various levels to mimic continuous nit...

Nanopore silicalite type membranes were prepared on the outer surface of a porous-mullite tube by in situ liquid phase hydrothermal synthesis. The hydrothermal crystallization was carried out under an autogenously pressure, at a static condition and temperature of 180 °C with tetrapropylammonium bromide (TPABr) as a template agent. The molar composition of the starting gel of silicalite zeolite...

We present an application of valence to core X-ray emission spectroscopy to understand the electronic structure of the industrially relevant catalyst titanium silicalite-1. The experimental spectrum was modelled within density functional theory, adopting a one electron approach, investigating the effects of different basis sets, density functionals and cluster sizes. The description of titanium...

A simple method for preparing orthorhombic single crystals of benzene-silicalite-1 was developed. A silicalite-1 crystal was pressed with a weight of 2 g along the +c and -c crystallographic axes while the temperature was increased to 473 K. The temperature was then slowly reduced to 313 K, and these heating and cooling steps were repeated three times. After the orthorhombic single crystals ads...

The adsorption structures of dimethyl ether (DME) on silicalite-1 zeolite (MFI-type) are determined using single-crystal X-ray diffraction. The structure of low-loaded DME-silicalite-1 indicates that all DME molecules are located in the sinusoidal channel, which is the most stable sorption site based on the van der Waals interaction between DME and the framework. The configuration of guest mole...

a new polymorph crystalline silica composition having uniform pore dimensions were synthesized by calcining a crystalline hydrated alkyl-ammonium silicate. the pore dimensions approximately were 6 angstrom for silicalite-1 and 11 angstrom for silicalite-2 units. the silicalite-1 was prepared hydrothermally at a ph of about 10 from a reaction mixture consist of water, amorphous silica and a quat...

In this work, we explore the ability of an inhomogeneous integral equation approach to provide a full three dimensional description of simple fluids under conditions of confinement in porous media. Explicitly, we will consider the case of argon adsorbed into silicalite-1, silicalite-2, and an all-silica analogue of faujasite, with a porous structure composed of linear (and zig-zag in the case o...

A post-synthesis deposition of vanadium silicalite-1 zeolite nanoparticles in the pores of SBA-15 results in a highly ordered hexagonal templated silica material with V-silicalite zeolitic plugs, giving rise to an increased crystallinity of the amorphous mesoporous walls.

Amorphous silica and crystalline silicalite (MFI structure) are demonstrated to be active and environmentally benign catalysts for propionic acid ketonisation at 450-500 °C to form 3-pentanone. The silicalite is particularly efficient, and its ketonisation selectivity is increased by base modification probably through generation of silanol nests.

We report, for the first time, a theoretical prediction of the (129)Xe nuclear magnetic resonance chemical shift tensor of xenon atom in a single crystal of silicalite at near-zero occupancy and the temperature dependence of the Xe NMR chemical shift tensor for the polycrystalline silicalite at maximum occupancy. The former is a measure of the sensitivity of the Xe tensor components to the loca...