The effects of MTG catalysis on methanol mobility in ZSM-5

Abstract

QENS shows that methanol is immobile in a fresh ZSM-5 catalyst and one used for methanol conversion at 623 K, but undergoes isotropic rotation within the mesopores generated in a catalyst used for methanol conversion at 673 K.

Molecular behaviour of phenol in zeolite Beta catalysts as a function of acid site presence: a quasielastic neutron scattering and molecular dynamics simulation study

“…25,26 Quasielastic neutron scattering (QENS) is particularly effective in the study of microporous catalysts, 27 allowing the measurement of molecular movements taking place over timescales of 2 ps-100 ns depending on the instrument, and thus it may be employed to measure both nanoscale diffusion, [28][29][30] and also local motions such as rotation. [31][32][33][34] Crucially, this technique can be employed on sub-micron crystals, in contrast to other methods, such as PFG-NMR, which have timescales from micro-to milliseconds and hence need crystal sizes in the order of micrometres or larger to be able to measure intracrystalline diffusion.…”

Overview of Current and Future Perspectives of Saudi Arabian Natural Clinoptilolite Zeolite: A Case Review

“…is in turn will help to create the optimum operational conditions for the variety of industrial applications and greatly assist local product development in Saudi Arabia. e use of a combination of techniques for Saudi zeolite characterization and its coke formation during methanol conversion is recommended [103]. Methanol test reaction was employed to convert hydrocarbons, either gasoline range (MTG) or light olefins (MTO) on zeolite type ZSM-5.…”

“…Methanol test reaction was employed to convert hydrocarbons, either gasoline range (MTG) or light olefins (MTO) on zeolite type ZSM-5. In addition to methanol gas phase test reaction, other techniques were also used to attest to the successful synthesis of zeolite, like neutron spectroscopy, nitrogen adsorption-desorption, and nuclear magnetic resonance spectroscopy [103]. e benefit of utilizing local Saudi zeolite has a number of advantages.…”

“…Additionally, using local zeolite in production will encourage greater interest in its research in academic institutions in Saudi Arabia together with the collaborative projects, which may potentially be established with institutes worldwide. Such future research should lead to the discovery of novel, beneficial methodologies and procedures for zeolite modification such as those suggested in this article [38,100,101,103]. e end goal is to gain a more detailed understanding and information about the structure, active sites, and chemical properties of local modified zeolites.…”

“…In addition, the identification of the active acidic centers by temperature-programmed desorption of ammonia is required. (iv) Based on previous studies [87,100,101,103,122,128], local investigation of natural clinoptilolite by acid or base treatment is required in order to gain a complete understanding of its properties and in discovering ways to exploit them and use the local zeolite in a variety of industrial applications such as in coke reduction. Performance of kinetics and thermodynamics investigations will be necessary to examine the diffusion limitation for the new formed nano local zeolite.…”