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

IR spectroscopy in catalysis

The past, present and future of heterogeneous catalysis

Thermal/catalytic cracking of liquid hydrocarbons for the production of olefins: A state-of-the-art review II: Catalytic cracking review

Improvement in capacitive deionization function of activated carbon cloth by titania modification

Titanium-substituted mesoporous molecular sieves were prepared post-synthetically by applying Ti-butoxide in ethanol solutions of different concentrations to MCM-41, MCM-48, and KIT-1. The catalysts obtained were characterized by XRD, FT-IR, UV–Vis spectroscopies, XAS, and N 2 physisorption. Incorporation of Ti seems to promote further crosslinking of the mesoporous walls of the samples, and resulted in wall thickness increases. The post-synthetically prepared Ti-mesoporous derivatives using titanium butoxide grafting were catalytically active for the selective oxidation of 2,6-di- tert -butylphenol with H 2 O 2 . Their activities depended on the Ti concentration of the catalysts. Comparison works with hydrothermally prepared Ti-MCM-41, Ti-HMS or post-synthetically prepared Ti-mesopore catalysts, either using titanocene grafting or by TiCl 4 atom planting method, are also reported.

Post-synthetic preparations of titanium-containing mesopore molecular sieves

Catalytic cracking of n-octane has been studied over FAU, FER, MWW, MFI, BEA and MOR zeolites in order to investigate the effects of pore structure and acidity on their catalytic properties. The conversion of n-octane was largely dependent on the number of strong acid sites, while their pore structure determined the rate of catalyst deactivation due to carbon deposit. Continuous and high catalytic activity, therefore, was obtained on the MFI zeolite with sinusoidal pores and small Si/Al molar ratio, because its pores suppress the formation of large intermediate and its large number of strong acid sites accelerates the cracking of n-octane. urated hydrocarbons, they are also active for the catalytic cracking. Strong acidity, therefore, is required for the catalytic cracking, but strong acid sites simultaneously initiate a rapid deactivation of cat- alysts due to carbon deposit. As a result, catalysts suitable for the catalytic cracking of paraffin should have a large number of strong acid sites to initiate the cracking reaction by producing reactive in- termediates and specific pore structures to suppress the formation of large hydrocarbons which are converted to high boiling carbon- eous materials. The high hydrothermal stability of the catalysts is also indispensable because the catalytic cracking is operated at high temperatures in the presence of steam.

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Catalytic Cracking of n-Octane over Zeolites with Different Pore Structures and Acidities

Catalytic reduction of dissolved oxygen by hydrazine at room temperature was investigated on Pt catalysts supported on KTT-1 mesoporous material and Y and ZSM-5 zeolites. Pt catalyst supported on A1KIT-1 mesoporous material exhibited high performance ascribed to the high dispersion of Pt and the large diameter lowering diffusion restriction.

The reduction of dissolved oxygen by hydrazine over platinum catalyst supported on disordered mesoporous materials

Titania was impregnated on MCM-41 mesoporous material by the liquid-phase reaction of titanium butoxide followed by washing and calcination. The impregnated titania was highly dispersed on the pore wall with tetrahedral coordination. The impregnating amount of titania was considerably larger than 23%, and produced the peroxo radical upon the addition of hydrogen peroxide.

Physico-Chemical State of Titania Impregnated on MCM-41 Mesoporous Material Upon Liquid-Phase Reaction of Titanium Alkoxide

Acetone cyclic triperoxide (ACTP) was formed over titania-incorporated mesoporous material catalysts from a mixture of acetone and hydrogen peroxide under a mild and acid-free condition. Formation of ACTP was confirmed by single-crystal X-ray crystallography. The formation of ACTP could be observed in this study because of using the catalyst with a large amount of titania-incorporation at 23 wt.% and its large pore size.

Tae Jin Kim

Papers

Post-synthetic preparations of titanium-containing mesopore molecular sieves

Catalytic Cracking of n-Octane over Zeolites with Different Pore Structures and Acidities

The reduction of dissolved oxygen by hydrazine over platinum catalyst supported on disordered mesoporous materials

Physico-Chemical State of Titania Impregnated on MCM-41 Mesoporous Material Upon Liquid-Phase Reaction of Titanium Alkoxide

Formation of acetone cyclic triperoxide over titania-incorporated mesoporous materials