نتایج جستجو برای: zsm
تعداد نتایج: 1752 فیلتر نتایج به سال:
A simple amphiphilic surfactant containing a mono-quaternary ammonium head group (N-methylpiperidine) is effective in imparting substantial mesoporosity during synthesis of SSZ-13 and ZSM-5 zeolites. Highly mesoporous SSZ-13 prepared in this manner shows greatly improved catalytic performance in the methanol-to-olefins reaction compared to bulk SSZ-13.
This communication reports the discovery of several small-pore Cu-zeolites and zeotypes that produce methanol from methane and water vapor, and produce more methanol per copper atom than Cu-ZSM-5 and Cu-mordenite. The new materials include Cu-SSZ-13, Cu-SSZ-16, Cu-SSZ-39, and Cu-SAPO-34.
The present work highlights recent advances in elucidating the methane oxidation mechanism of inorganic Cu-ZSM-5 biomimic and in identifying the reactive intermediates that are involved. Such molecular understanding is important in view of upgrading abundantly available methane, but also to comprehend the working mechanism of genuine Cu-containing oxidation enzymes.
The Al siting in the ZSM-5 zeolite was investigated by (27)Al 3Q MAS NMR spectroscopy and QM/MM calculations. It was found that the occupation of the framework T-sites by Al and the concentration of Al in these T-sites are neither random nor controlled by a simple rule. They both depend on the conditions of the zeolite synthesis. At least 12 out of the 24 distinguishable framework T-sites of ZS...
ZSM-5 zeolite is an aluminosilicate that usually has a high silica-to-alumina ratio. It contains two sets of nanopores. One set of nanopores is straight, with the cross-sectional size of 5.3 5.6 Å; the other set is Sshaped, with the cross-sectional size of 5.2 5.5 Å. An A1 atom at the center of an AlO4 tetrahedron connects to adjacent SiO4 tetrahedron by sharing an O atom and thus generates a n...
Introduction Environmental restriction regarding the quality of transportation fuels and the emissions from them are the most important issues. Because of more stringent regulations and fuel specifications regarding development of better method for deep-desulfurization of fuels are important. There has been recent interest in developing adsorbents for selective desulfurisation by adsorption. Me...
1. Introduction The growing interest in the application of one-dimensional (1D) molecular sieves both as solid catalysts and selective adsorbents has stimulated considerable attention in the study of diffusive transport of guest molecules in the 1D pores. It has been established that normal Fickian diffusion is not necessarily applicable to describe the diffusion mechanism of guest-host interac...
پساب پالایشگاه نفت حاوی غلظتهای متفاوتی از هیدروکربنهای نفتی آروماتیک و آلیفاتیک است. با توجه به اینکه محتوای آروماتیک سمی بوده و با تصفیه متداول به راحتی حذف نمیشود، برای حذف این دسته از آلایندهها، روشهای پیشرفته نیاز است. در این مطالعه حذف و تخریب فتوکاتالیتیکی آلایندههای آلی پساب پالایشگاه نفت مورد بررسی قرار گرفت. ابتدا فتوکاتالیست TiO2-Fe-ZSM-5 با نشاندن TiO2 در...
in order to gain a better understanding of the chemistry of methanl-to-hydro-carbon conversion, it is necessary to determine the nature of the primary reaction products. experiments carried out in this work on h-zsm-11, using a continuous flow reactor linked to an on-line gas chromatograph demonstrated that ethylene and methane are the primary reaction products. the results obtained using solid...
Abstract Dehydroaromatization of methane (MDA) reaction was investigated over platinum modified Mo/H-ZSM-5 catalysts which were pre-carbided at 750 °C. The influence on the catalytic performance and product selectivity for MDA 700 °C studied. presence led to a slight decrease in conversion from 7.5 4.2%. Aromatic selectivities above 90% obtained with containing low loadings (0.5 1.0 wt.%), benz...
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