نتایج جستجو برای: SAPO-34
تعداد نتایج: 116274 فیلتر نتایج به سال:
A series of H-SAPO-34 zeolites were synthesized by a hydrothermal method in fluoride media. The as-synthesized H-SAPO-34 zeolites were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), N2 physisorption, temperature-programmed desorption of NH3 (NH3-TPD) and nuclear magnetic resonance (NMR) measurements. The results showed that a certain concentration of F(-) anions p...
Introduction SAPO-34 is a silicoaluminophosphate zeolite with 8-membered ring windows (~0.38nm) displaying chabazite structure. SAPO-34 is an efficient catalyst showing improved catalytic performance in reactions such as methanol conversion to olefins [1], oxidative dehydrogenation of propane [2], conversion of light alkenes [3]. Its catalytic properties are mainly attributed to its mild acidit...
Silicoaluminophosphate SAPO-34 molecular sieve nanocrystals have been prepared by a post-synthesis milling and recrystallization method, which is further proven to be universally applicable to other SAPO molecular sieves. The obtained SAPO-34 with reduced Si enrichment on the external surface shows considerably improved catalytic performance in the MTO reaction.
Using an organosilane surfactant as the mesopore director, hierarchical porous silicoaluminophosphate SAPO-34 is obtained as an assembly of nanocrystallites intergrown into cubic micrometer-sized crystals, which show excellent performance in MTO reactions with a remarkably prolonged catalyst lifetime and enhanced selectivity of ethylene and propylene compared to the conventional microporous SAP...
In this paper, conventional SAPO-34 and Cerium Hierarchical SAPO-34 zeolites are synthesized using a hydrothermal method for methanol-to-propylene (MTP) reaction. The Ce-H-SAPO-34 catalyst shows a slightly larger crystal size, bimodal pore size distribution (microporous and mesoporous) and lower surface acidity compared to conventional SAPO-34 catalysts. According to these physicochemical prope...
Metal-incorporated SAPO-34 catalysts were prepared by one-step hydrothermal method. Effects of various parameters including the types metal ions, Cu2+ sources, structure directing agents (SDAs), temperature and time on catalyst activity metal-incorporated investigated. Three (Cu/SAPO-34, Fe/SAPO-34 Mn/SAPO-34) successfully obtained. Compared with Mn/SAPO-34 catalysts, Cu/SAPO-34 revealed comple...
در کار حاضر، کاتالیستهای نانوساختار sapo-34 و zsm-5 از کاتالیستهای شناخته شده برای فرآیند تبدیل متانول به الفینهای سبک (mto) هستند. کاتالیست sapo-34 انتخابپذیری بالایی برای الفینهای سبک دارد و کاتالیست zsm-5 دارای پایداری بالایی است. ترکیبی از این کاتالیستها میتواند منجر به تولید یک کاتالیست کامپوزیتی با انتخابپذیری و پایداری بهینه شود. در این مطالعه کاتالیست کامپوزیتی sapo-34/zsm-5 با ...
This study focuses on co-cations modified copper based molecular sieve catalyst CuCe/SAPO-34. The SCR performance and low temperature hydrothermal stability of Cu/SAPO-34 CuCe/SAPO-34 before after 70 ? aging were evaluated to conclude the impact Ce structure mechanism NH3-SCR reaction. For fresh samples, showed higher catalytic activity at whole range, especially below 250 above 400 in comparis...
غربال مولکولی نانوساختار SAPO-34 بهترین کاتالیست شناخته شده از جهت انتخاب پذیری برای فرایند تبدیل متانول به الفین های سبک ( MTO ) می باشد. در سنتز غربالهای مولکولی ماده الگوساز نقش های مهمی را ایفا میکند. در تحقیق حاضر، برای سنتز SAPO-34 از مخلوط الگوسازهای تری اتیل آمین و مورفولین استفاده شد. برای ارتباط دادن خواص کاتالیستهای سنتز شده با عملکرد آنها در فرایند از آنالیزهای XRD ، FESEM ، EDX...
Formation of adamantane hydrocarbons and their confinement in SAPO-34 caused the long induction period and the quick catalyst deactivation in methanol conversion. Via ship-in-a-bottle synthesis, adamantane and methyladamantanes could be produced from methanol conversion in the cage of 8-ring SAPO catalysts under very mild reaction conditions.
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