نتایج جستجو برای: zsm 5
تعداد نتایج: 1215897 فیلتر نتایج به سال:
The density functional theory (DFT) model ONIOM(M06L/6-311++G(2df,2p):UFF was employed to reveal the catalytic activity of Cu(II) in the paddle-wheel unit of the metal-organic framework (MOF)-505 material in the Mukaiyama aldol reaction compared with the activity of Cu-ZSM-5 zeolites. The aldol reaction between a silyl enol ether and formaldehyde catalyzed by the Lewis acidic site of both mater...
To improve the yield of propylene in fluidized catalytic cracking, a series different Au/ZSM-5-TOS catalysts were prepared by modifying ZSM-5, using an external surface modification method and Au nanoparticles. The modified catalyst maintained MFI structure whereas pore-opening size zeolite relatively decreased, without affecting its internal structure. acidity especially Brønsted acidity, redu...
Due to crude oil is limited, new resources for fuel and petrochemicals are important to be developed. Biogas or NG (Natural Gas) can be easily converted into methanol which can be reacted over zeolite to produce olefins and gasoline. HZSM-5 zeolite catalyst has been used in this study and its modification by (0.5wt%, 1wt%, 2wt% and 4wt %) Ni to convert methanol to hydrocarbons (MTH). Catalysts ...
The adsorption and desorption of N2O on main-group ion-exchanged ZSM-5 was studied using temperature-programmed desorption (TPD) and density functional theory (DFT) calculations. TPD experiments were carried out to determine the desorbed temperature Tmax corresponding to the maximum mass intensity of N2O desorption peak and adsorption capacity of N2O on metal-ion-exchanged ZSM-5s. The results i...
Hierarchical micro-mesoporous ZSM-5 (MFI type) zeolite was synthesized by using corn plant stem pith powder from agricultural waste as hard template under simple hydrothermal method. The additional porosity generated this into the zeolites precursor gel yielded hierarchical (C-ZSM-5). Conventional micro porous (ConvZSM-5) also prepared same procedure without adding to compare catalytic performa...
The promotion of Ag–ZSM-5 by cerium for the selective catalytic reduction (SCR) of NO with methane in the presence of an excess of oxygen was studied in this work. Ce–Ag–ZSM-5 catalyzes the CH4-SCR of NOx over the temperature range of 450–600◦C. Rate measurements of NO reduction to N2 under SCR conditions and of the competing CH4 oxidation by O2 (CH4 combustion) show that incorporation of a sma...
در میان انواع تکنیک های حذف ترکیبات آلی فرار ، یکی از مناسبترین روش ها ، روش اکسایش کاتالیستی می باشد. ولی غیرفعال شدن کاتالیست ها در طول اکسایش کاتالیتیکی ترکیبات آلی فرار یکی از مسائل مهم می باشد. در این پروژه رفتارغیرفعال شدن کاتالیستهای mn-zsm-5 و cr-zsm-5 در طول اکسایش اتیل استات و ایزو پروپانل ، همچنین احیای این کاتالیست ها با هوای سنتزی بررسی شده است. نتایج نشان می دهد که تشکیل کک باعث غ...
The structure of a high-loading complex of ZSM-5 with 6.4 toluene molecules per unit cell has been determined by single-crystal X-ray diffraction. At least three kinds of toluene molecules were identified in the unit cell. Two disordered toluene molecules were located at the intersection of the straight and sinusoidal channels, the third in the sinusoidal channel. One (TOL1) of the two toluene ...
در این کار پژوهشی زئولیت zsm-5 بدون استفاده از تمپلیت سنتز می شود و بوسیله xrd , ir , sem مورد شناسایی قرار می گیرد. نانوکیتوسان بصورت امولسیون تحت امواج اولتراسونیک (ultrasonic) بر روی zsm-5 نشانده شده و هیبرید کامپوزیت دوتایی zsm-5 / chitosan برای اولین بار تهیه می شود و با xrd , ir , sem آنالیز می شود و همچنین نانو zno به روش تخریب ژل آکریل آمید آماده شده و هیبرید کامپوزیت سه تایی chitosan /...
Dehydroaromatization of methane (MDA) under non-oxidative conditions is a promising reaction for direct valorization natural gas and biogas. Typically, Fe-modified ZSM-5 catalysts display low aromatic productivity high coke selectivity in the MDA reaction. Herein, we show benefit starting from isomorphously substituted Fe-sites [Fe,Al]ZSM-5 zeolites prepared by hydrothermal synthesis. Upon calc...
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