PDF Publication Title:
Text from PDF Page: 061
12 and 20. At 373 K the selectivity range was increased to 18–30 revealing the positive impact of the selective permeation of 1-hexene across the silicalite-1 membrane towards the Pt/TiO2 particles in principle and the temperature influence in addition. By applying a hydrothermal synthesis including two crystallization steps, the same working group prepared thinner silicite-1 membranes with improved quality. In that case, the authors adopted first a short crystallization step under rotation in order to increase the number density of crystal nuclei at the particle surface responsible for the small crystal size. Then, athinner membrane was crystallized in a second synthesis at 453 K for 48 h without rotation. The so prepared core-shell catalyst exhibited even higher hydrogenation selectivities (selectivity of 1-hexene/3,3-dimethylbut-1-ene at 323 K of 35 and 80 at 373 K) due to higher permselectivity of the linear/branched alkene mixture through the membrane revealing the enormous impact of the membrane quality in terms of the thickness on the reaction rate [250]. Moreover, it was shown that due to the coating procedure the reaction rate of the process was changed from kinetic-controlled to diffusion-controlled, pointing once again that the permeation of 1-hexene and 3,3-dimethylbut-1-ene is the rate controlling step in the hydrogenation reaction. In addition, reduced catalyst deactivation ascribed to the catalyst protection against poisoning impurities from the feed by the zeolite membrane was reported. The concept of reactant selectivity was further demonstrated by Zhong et al. [251] by applying defect-free zeolite-4A coated on Pt/γ-Al2O3 particles prepared via two-step hydrothermal synthesis in a model oxidation reaction of CO and n-butane mixture. The permeation of n-butane was obviously restrained due to sieving effects, so that only CO and O2 were able to pass the zeolite membrane and react in the catalyst core. The authors pointed out that the membrane coated catalyst might be attractive for applications where the hydrocarbon feed streams contain a trace amount of CO and it should be removed in order to prevent the catalyst poisoning. Ren et al. [265] suggested the encapsulation of noble metal particles with protective, size-selective zeolite shells as an effective strategy to overcome deactivation problems [266,267] occurring during liquid phase reactions, e.g., for targeted production of fine or intermediate chemicals. As an example the selective oxidation of alcohols was chosen. The significantly improved selectivity and the core catalyst protection (Ag and Pt nanoparticles) by a silicalite-1 membrane coating compared to commercial catalysts was attributed to selective permeation through the zeolite membrane. Under those circumstances, the diffusion of large reactants and poison molecules in the reaction environment was restricted due to the shape selectivity of the membrane resulting respectively in retention of the catalytic activity. Moreover, as the ICP-AES analysis revealed, almost no Pd leaching from the core-shell catalyst after 6 cycles of recycling was observed, pointing out the benefit of coating on the reusability of the catalyst. 46PDF Image | Zeolite Catalysis
PDF Search Title:
Zeolite CatalysisOriginal File Name Searched:
Zeolite_Catalysis.pdfDIY PDF Search: Google It | Yahoo | Bing
NFT (Non Fungible Token): Buy our tech, design, development or system NFT and become part of our tech NFT network... More Info
IT XR Project Redstone NFT Available for Sale: NFT for high tech turbine design with one part 3D printed counter-rotating energy turbine. Be part of the future with this NFT. Can be bought and sold but only one design NFT exists. Royalties go to the developer (Infinity) to keep enhancing design and applications... More Info
Infinity Turbine IT XR Project Redstone Design: NFT for sale... NFT for high tech turbine design with one part 3D printed counter-rotating energy turbine. Includes all rights to this turbine design, including license for Fluid Handling Block I and II for the turbine assembly and housing. The NFT includes the blueprints (cad/cam), revenue streams, and all future development of the IT XR Project Redstone... More Info
Infinity Turbine ROT Radial Outflow Turbine 24 Design and Worldwide Rights: NFT for sale... NFT for the ROT 24 energy turbine. Be part of the future with this NFT. This design can be bought and sold but only one design NFT exists. You may manufacture the unit, or get the revenues from its sale from Infinity Turbine. Royalties go to the developer (Infinity) to keep enhancing design and applications... More Info
Infinity Supercritical CO2 10 Liter Extractor Design and Worldwide Rights: The Infinity Supercritical 10L CO2 extractor is for botanical oil extraction, which is rich in terpenes and can produce shelf ready full spectrum oil. With over 5 years of development, this industry leader mature extractor machine has been sold since 2015 and is part of many profitable businesses. The process can also be used for electrowinning, e-waste recycling, and lithium battery recycling, gold mining electronic wastes, precious metals. CO2 can also be used in a reverse fuel cell with nafion to make a gas-to-liquids fuel, such as methanol, ethanol and butanol or ethylene. Supercritical CO2 has also been used for treating nafion to make it more effective catalyst. This NFT is for the purchase of worldwide rights which includes the design. More Info
NFT (Non Fungible Token): Buy our tech, design, development or system NFT and become part of our tech NFT network... More Info
Infinity Turbine Products: Special for this month, any plans are $10,000 for complete Cad/Cam blueprints. License is for one build. Try before you buy a production license. May pay by Bitcoin or other Crypto. Products Page... More Info
CONTACT TEL: 608-238-6001 Email: greg@infinityturbine.com (Standard Web Page)