نتایج جستجو برای: nh2 nh mcm 41

تعداد نتایج: 115477  

Journal: :Chemical communications 2015
Xi-Jie Lin Ai-Zhi Zhong Yong-Bin Sun Xing Zhang Wei-Guo Song Rong-Wen Lu An-Min Cao Li-Jun Wan

Pd nanoparticles were successfully introduced into the channels of mesoporous silica MCM-41 with their dispersion well-tuned. We identified the dual role played by CTAB, which was critical for both the micelle template and Pd grafting, leading to the formation of a highly active Pd-MCM-41 nanocomposite for catalysing the Suzuki reaction.

2005
Susmit Basu Himadri Paul Chinnakonda S. Gopinath Sumit Bhaduri Goutam Kumar Lahiri

Anionic platinum carbonyl cluster has been ion paired with cinchonidium groups that are chemically bound to the surface of MCM-41 and fumed silica. In the hydrogenation of methyl pyruvate or acetophenone the fumed silica-based catalyst gives zero enantioselectivity, but under optimum conditions enantiomeric excesses of > 90 and ∼ 40%, respectively, are obtained with the MCM-41-based catalyst.

2008
N. Kazemi F. Farzaneh

Ti-MCM-41 was synthesized at pH 3, 7 and 11. The titanium content was determined by AAS and found to be 4%, 3.2% and 4.5%, respectively. In order to increase the titanium content in Ti-MCM-41, Ti(IV) ions were grafted onto TiMCM-41 using TiCl4 in toluene and Ti(OBu)4 in ethanol. The incorporation of Ti was determined to be 28% and 30%, respectively. The oxidation of olefins such as cyclopentene...

Journal: :Journal of Korean Society of Environmental Engineers 2011

2012
Aidong Tang Yuehua Deng Jiao Jin Huaming Yang

A novel nanocomposite ZnFe(2)O(4)-TiO(2)/MCM-41 (ZTM) was synthesized by a sol-gel method and characterized through X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), N(2) adsorption-desorption, Raman spectroscopy, and ultraviolet visible (UV-vis) spectrophotometry. The results confirmed the incorporation of ZnFe(2)O(4)-TiO(2) nanoparticles inside the pores of th...

Journal: :Dalton transactions 2013
Thomas K Nielsen Abhi Karkamkar Mark Bowden Flemming Besenbacher Torben R Jensen Tom Autrey

Ammonium borohydride, NH(4)BH(4), has a high hydrogen content of ρ(m) = 24.5 wt% H(2) and releases 18 wt% H(2) below T = 160 °C. However, the half-life of bulk NH(4)BH(4) at ambient temperatures and pressures, ~6 h, is insufficient for practical applications. The decomposition of NH(4)BH(4) (ABH(2)) was studied at variable hydrogen and argon back pressures to investigate possible pressure media...

Journal: :Journal of the Turkish Chemical Society, Section A: Chemistry 2019

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه فردوسی مشهد - دانشکده مهندسی 1393

در این پژوهش، سنتز و مشخصه یابی نانوساختارهای mcm-41 وα-fe2o3/mcm-41 انجام پذیرفت. اصلاح سطحی mcm-41 توسط گروه های آمینی، به صورت همزمان و در حین سنتز mcm-41 و قرار دادن نانوذرات α-fe2o3 درون ساختار آن از روش بارور سازی مرطوب، توسط نمک نیترات آهن و سپس کلسیناسیون نمونه در دمای ℃550 انجام گرفت. بررسی اثر حضور نانوذرات α-fe2o3 درون حفرات mcm-41، به وسیله آنالیزهایtga ,ft-ir ,xrd، tem و تست جذب و ...

Hamid Reza Pouretedal Mina Ahmadi

The direct and indirect methods in solvent media and grinding method in a solvent-free media were used to prepare the MCM-41/ZnO and MCM-48/ZnO photocatalysts. The X-ray diffraction (XRD) patterns showed that zinc oxide nanoparticles were put into MCM-41 and MCM-48 substrates and there were ZnO crystallites as secondary phase in the extra framework of mesoporous materials. The decrease of surfa...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه یزد 1389

در این پایان نامه مشتقات کینوکسالین در حضور کاتالیس تهای اسیدی جامد بر پایه -? از تراکم با 2،1 - دی کربونیل ها و 2،1 - د یآمین ها همچنین اکسایش و تراکم mcm-41 هیدروکسی کتون ها با مشتقات اورتو-فنیلن دی آمین سنتز شده اند. tpa/mcm-) mcm- کاتالیست های 12 -تنگستو فسفریک اسید نشانده شده بر روی 41 sem و xrd ،ft-ir سنتز و مشخصات آ نها با روش های tpa 41 ) با مقادیر مختلف بارگذاری روی سطح بستر با حف...

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