Zeolite membranes – state of their development and perspective

Steam cracking of hydrocarbons has been the major source of light olefins for more than half a century. The recent studies have reported that ethylene and propylene can also be produced through the cracking of hydrocarbons over modified ZSM-5 zeolites in a considerable amount. This paper highlights the important current ideas about acid-catalyzed hydrocarbon cracking that has resulted in high yield of ethylene and propylene. Light olefin production via catalytic cracking of various industrial feedstocks, ranging from heavy hydrocarbons to ethane, over modified ZSM-5 zeolites, has been reviewed in the present paper. Furthermore, the influence of various employed promoters, i.e., alkali and alkaline earth, transition, rare earth elements, and phosphorus, on the chemical properties of the modified ZSM-5 and the performance of resulting catalyst in enhancing the selectivity to light olefins, have been addressed. Moreover, the influences of different factors, including the zeolite acidity, Si/Al ratio and the temperature, on the light olefin production and the reaction scheme have been specified. The role of incorporated element in the catalytic cracking mechanism is also summarized.

Catalytic cracking of hydrocarbons over modified ZSM-5 zeolites to produce light olefins: A review

Note: Chevron, Energy Technology Company, 100 Chevron Way, Richmond, California 94802-0627 Reference EPFL-ARTICLE-200588doi:10.1021/cr8002642 URL: http://pubs3.acs.org/acs/journals/doilookup?in_doi=10.1021/cr8002642 URL: http://pubs.acs.org/doi/pdfplus/10.1021/cr8002642 Record created on 2014-08-14, modified on 2017-05-12

Molecular Simulations of Zeolites: Adsorption, Diffusion, and Shape Selectivity

The exponential increase in computational processor speed, the development of novel computational architectures, together with the tremendous advances in ab initio theoretical methods that have emerged over the past two decades have led to unprecedented advances in our ability to probe the fundamental chemistry that occurs on complex catalytic surfaces. In particular, advances in density functional theory (DFT) have made it possible to elucidate the elementary steps and mechanisms in surface-catalyzed processes that would be difficult to explore experimentally. The advanced state of plane wave DFT has made it possible to rapidly examine systematic changes to the metal or the reactant in order to establish structure-property relationships. As a result, extensive data based on the energetics for various different surface-catalyzed reactions has been generated. This invites a detailed theoretical analysis of the factors that control reaction paths and corresponding potentialenergy surfaces of surface reactions. Such a theoretical analysis will not only provide interesting new insights into the intricate relationship between the chemical bonding features, structure, and energies of transition states but also serve as a basis for the development of analytical expressions that relate transitionstate properties to more easily accessible thermodynamic properties. The Brønsted-Evans-Polanyi (BEP) relationship is one such example which has been widely applied in the analysis of surface elementary reaction steps.1-8 δEact )RδEr (1)

Reactivity Theory of Transition-Metal Surfaces: A Brønsted−Evans−Polanyi Linear Activation Energy−Free-Energy Analysis

https://ris.utwente.nl/ws/files/6651605/Lercher96infra-red.pdf

Infrared studies of the surface acidity of oxides and zeolites using adsorbed probe molecules

Monomolecular conversion of light alkanes over H-ZSM-5

https://ris.utwente.nl/ws/files/6651366/Narbeshuber97dehydrogenation.pdf

Dehydrogenation of light alkanes over zeolites

Infrared microscopic study of sorption and diffusion of toluene in zsm-5

The conversion of light linear and branched alkanes on two faujasite samples containing different concentrations of free Bronsted acid sites and extraframework alumina (EFAL) was studied between 733 K and 813 K. Protolytic cracking and bimolecular hydride transfer proceeded solely on Bronsted acid sites. For cracking of n-alkanes, the variation of the concentration of extraframework aluminum did not affect the catalytic activity per accessible Bronsted acid site. The activity to dehydrogenation is enhanced in the presence of EFAL and, unlike protolytic cracking, it decreased with time on stream. At high conversions relatively high concentrations of olefins change the selectivity and decrease the turnover frequencies. Compared to n-alkanes, the catalytic activity to convert iso-alkanes is enhanced in the presence of extralattice alumina.

/pdf/the-influence-of-extraframework-aluminum-on-h-fau-catalyzed-xdzybayjfn.pdf

The influence of extraframework aluminum on H-FAU catalyzed cracking of light alkanes

https://ris.utwente.nl/ws/files/6861574/Narbeshuber96hydrogen.pdf

Thomas F. Narbeshuber

Papers

Monomolecular conversion of light alkanes over H-ZSM-5

Dehydrogenation of light alkanes over zeolites

Infrared microscopic study of sorption and diffusion of toluene in zsm-5

The influence of extraframework aluminum on H-FAU catalyzed cracking of light alkanes

Hydrogen/Deuterium Exchange duringn-Butane Conversion on H-ZSM-5