Zeolites A, X and HS were synthesized from natural Iranian Kaolinite by alkaline fusion,,followed by refluxing the mixture. The transformation of zeolites X to HS and Y to P were studied at different time intervals by X-ray diffraction and Scanning Electron Microscopy (SEM). It was revealed that in solution, zeolites HS and P are more stable than zeolites X and Y respectively

The performance of a variety of high-level composite procedures, as well as lower-cost density functional theory (DFT)- and second-order perturbation theory (MP2)-based methods, for the prediction of absolute and relative R-X bond dissociation energies (BDEs) was examined for R = Me, Et, i-Pr and t-Bu, and X = H, CH(3), OCH(3), OH and F. The methods considered include the high-level G3(MP2)-RAD...

Zeolites are widely applied as solid acid catalysts in various technological processes. In this work we have computationally investigated how catalytic reactivity scales with acidity for a range of zeolites with different topologies and chemical compositions. We found that straightforward correlations are limited to zeolites with the same topology. The adsorption energies of bases such as carbo...

O NE OF THE methods currently being investigated for the regenerable removal of carbon dioxide from space vehicle atmospheres involves its adsorption on synthetic zeolites. These materials, known commercially as "molecular sieves" (Linde Company) or "microtraps" (Davison Chemical Company) are crystalline alumino silicates of alkali and alkaline earth metals. Synthetic zeolites being crystalline...

ZnO modified ZSM-5 and Y zeolites are synthesized by performing atomic layer deposition (ALD) of ZnO to HZSM-5 and HY using diethyl zinc and water as the precursors. The surface area and pore volume of ZSM-5 and Y zeolites are progressively reduced with the increasing number of ZnO ALD cycles. XRD and SEM characterization methods show that highly dispersed ZnO species are deposited on the inter...

Mesopore walls of hierarchically meso-/microporous zeolites (MFI, BEA and LTA) are covered with silanol groups, so that the zeolites can be functionalized with various organic groups via silylation; the organic-functionalized hierarchical zeolites exhibit hydrothermal stability and reusability in catalytic applications, as compared with organic-functionalized mesoporous silica.

Synthetic zeolites are used widely throughout the petroleum refining and chemical process industries as selective adsorbents, catalysts and ion exchangers. The research described in this thesis focuses on the characterization and environmental applications of faujasite zeolites, including nanocrystalline Y zeolites that have particle sizes less than

A novel methodology, called ADOR (assembly-disassembly-organisation-reassembly), for the synthesis of zeolites is reviewed here in detail. The ADOR mechanism stems from the fact that certain chemical weakness against a stimulus may be present in a zeolite framework, which can then be utilized for the preparation of new solids through successive manipulation of the material. In this review, we d...

A simplified approach to treating the electron correlation energy is suggested in which only the alpha-beta component of the second order Møller-Plesset energy is evaluated, and then scaled by an empirical factor which is suggested to be 1.3. This scaled opposite-spin second order energy (SOS-MP2), where MP2 is Møller-Plesset theory, yields results for relative energies and derivative propertie...

In this Account strategies using zeolites as media to achieve chiral induction are presented. Diastereomeric excesses as high as 90% and enantiomeric excesses up to 78% have been obtained with selected systems within zeolites. The same systems show no asymmetric induction in solution. Chiral induction is dependent on the alkali ions present in the zeolites. Alkali ions control not only the exte...