نتایج جستجو برای: nh2 nh mcm 41
تعداد نتایج: 115477 فیلتر نتایج به سال:
در این پایان نامه مشتقات پیریدین در حضور کاتالیست های اسیدی جامد بر پایه سیلیکای مـزوپور سنتز شده اند. کاتالیست های zr-mcm-41پر کلراته شده clo4¯/zr-mcm-41)) در شرایط مختلف، سنتز و مشخصات آن ها با روش های ft-ir، xrd و sem تعیین گردید. نتایج به دست آمده نشـان دهـنده وجـود ساخـتار مزوپور کاتالیسـت است. فـعالیت کاتالیتـیکی clo4¯/zr-mcm-41 با نسبت 25 si/zr = برای سنتز دی هیدروپیریدین حاصل از واکـنش ...
MCM-48 and SBA-1 samples were characterized using powder X-ray diffraction and nitrogen adsorption in a wide range of relative pressures. X-ray diffraction provided direct evidence for the high degree of pore structure ordering for the materials under study. Nitrogen adsorption showed that highly ordered MCM-48 materials exhibited sharp steps of capillary condensation and narrow pore size distr...
A heterogeneous catalyst, nanosized MCM-41-Pd, was used to catalyze the Sonogashira coupling of aryl and heteroaryl halides with terminal alkynes in the presence of CuI and triphenylphosphine. The coupling products were obtained in high yields using low Pd loadings to 0.01 mol%, and the nanosized MCM-41-Pd catalyst was recovered by centrifugation of the reaction solution and re-used in further ...
A novel method for the rapid extraction and determination of a ppt level of Pb2+ and Cu2+ ions using partial silylated MCM-41 modified by a new salophen and inductively coupled plasma atomic emission spectrometry (ICP-AES) is introduced. The preconcentration factor of the method is 500, and the detection limits of Pb2+ and Cu2+ are 335 and 34 ng L(-1), respectively. The time and efficiency of e...
The new rhodium(I) complexes [Rh(Cl)(COD)(R-NHC-(CH2)3Si(O Pr3)3)] (R = 2,6-diisopropylphenyl (2a); n-butyl (2b)) have been synthesised and fully characterised. The study of their application as ketone hydrosilylation catalysts showed a clear N-substituent effect, 2a being the most active catalyst precursor. Complex 2a has been immobilised in the mesoporous materials MCM-41 and KIT-6. The new h...
Ce-modified mesoporous silica materials MCM-41 and SBA-15, namely 32 wt % Ce-Si-MCM-41, 16 wt % Ce-H-MCM-41 and 20 wt % Ce-Si-SBA-15, were prepared, characterized and studied in the selective preparation of trans-carveol by α-pinene oxide isomerization. The characterizations of these catalysts were performed using scanning electron microscopy, X-ray photoelectron spectroscopy, nitrogen adsorpti...
Mesoporous silica thin films (MCM-41) functionalized with ethylenediamine groups were electrochemically fabricated on electrode surfaces. These ligand functionalized film were a promising matrix for the immobilization of cobalt ions and preparation of cobalt complexes covalently bound to the MCM-41 support. The constructed MCM-41 were characterized by TEM, EDS and TGA analysis. This method yiel...
Three ordered mesoporous siliceous (OMS) materials known as MCM41s-unmodified MCM-41C16 ("C16"), and two MCM41s with different surface functionalities: MCM-41C16-SH ("C16-SH") and MCM-41C16-NH2 ("C16-NH2")-were synthesized and studied by inverse gas chromatography in order to determine their acceptor-donor properties. The specific retention volumes of nonpolar and polar probes that were chromat...
سنتز جاذب MCM-41 به روش هیدروترمال در حضور اتانول بهعنوان حلال و ماده فعال سطحی کمکی و در محیط قلیایی انجام پذیرفت. جاذب معدنی ZnCl2-MCM-41 به روش پیوند کووالانسی با توزیع مواد در حلال تولوئن و از اندرکنش بین ذرههای ZnCl2 با گروههای سیلانول روی دیوارۀحفرههای MCM-41 تهیه شد. تعیین مشخصات این جاذب با استفاده از آزمایشهای جذب نیتروژن، XRD، طیف سنجی FTIR و SEM انجام شد....
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