Topic
MCM-41
About: MCM-41 is a research topic. Over the lifetime, 2355 publications have been published within this topic receiving 91416 citations.
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TL;DR: In this article, the macrocyclization reaction of calix(4)pyrroles and porphyrins prepared by zeolite catalyzed synthesis in liquid phase under microwave irradiation conditions was subsequently optimized for quantitative yields.
Abstract: The macrocyclization reaction of calix(4)pyrroles and porphyrins prepared by zeolite catalyzed synthesis in liquid phase under microwave irradiation conditions was subsequently optimized for quantitative yields. The reactions are carried out with different zeolite catalysts such as HZSM-5, HY and mesoporous Al-MCM-41 molecular sieves and the reactions are monitored by HPTLC for performance evaluation of the catalysts. The present method to synthesize macrocycles, using molecular sieves, such as solid acid catalysts in heterogeneous system, was selective and quantitative. Al-MCM-41 (pore diameter more than 20 A) performs better as to facilitate good selectivity towards quantitative yield and demonstrated excellent conversions when compared to other catalysts.
24 citations
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TL;DR: In this paper, a photo-assisted deposition (PAD) method was used to synthesize highly active Pd nanoparticles using a single-site photocatalyst under UV-light irradiation for hydrogen peroxide (H2O2) from H2 and O2.
Abstract: An efficient methodology to synthesize highly active Pd nanoparticles using a single-site photocatalyst under UV-light irradiation has been developed for the synthesis of hydrogen peroxide (H2O2) from H2 and O2. By the photo-assisted deposition (PAD) method, Pd precursor can be deposited directly on the photo-excited tetrahedrally coordinated metal-oxide moiety within the silica frameworks, and subsequently transformed into Pd nanoparticles by H2 reduction. The mean diameter of the deposited Pd particles determined by CO adsorption and the catalytic activities in the direct synthesis of H2O2 were strongly dependent on the preparation method and kind and/or amount of metal-oxide moieties. Here, the use of Ti-containing mesoporous silica (Ti/Si = 0.01) acted as a most efficient support for the above reaction. The PAD method also provides PdAu bimetallic nanoparticles from an aqueous solution of mixture of PdCl2 and HAuCl4. The PdAu/Ti-MCM-41 catalyst prepared by the PAD method was shown to perform significantly better activity than the pure Pd/Ti-MCM-41.
24 citations
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TL;DR: In this paper, a mesoporous catalysts for the epoxidation of propylene with two alkyl hydroperoxides were obtained by chemical vapor deposition (CVD) of TiCl4 on silica MCM-41 in the 700-900°C temperature range.
24 citations
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TL;DR: In this paper, the MCM-41-based catalysts have been compared with that of the platinum on activated carbon catalysts and they have been characterised by X-Ray diffraction, Raman, SEM and BET surface area.
24 citations
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TL;DR: In this paper, the catalysts containing all alkali metals (from Li to Cs) supported on mesoporous niobosilicate molecular sieve, NbMCM-41, and for comparison also loaded on silicate MCM41, were characterized by N2 adsorption, XRD and test reactions.
24 citations