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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 paper, a comparison of catalytic activities of tin-containing mesoporous materials prepared by two different routes, viz. direct hydrothermal method and grafting method, was made.
Abstract: Tin-containing ordered mesoporous silica materials (Sn-OMS) were synthesized by two different routes, viz. by the direct hydrothermal method (Sn–MCM-41, Sn–MCM-48) and by the grafting method (Sn/MCM-41, Sn/MCM-48, Sn/SBA-15). The materials were characterized in detail by ICP-OES analysis, XRD, FTIR, N 2 adsorption–desorption, SEM and UV–vis analysis. The catalytic activity of the tin-modified mesoporous materials was ratified in the Meerwein–Ponndorf–Verley reduction of carbonyl compounds using secondary alcohols (2-butanol and 2-propanol) as hydrogen transfer agents. A comparison of catalytic activities of tin-containing mesoporous materials prepared by the two routes, dictates that tin-grafted mesoporous materials show higher catalytic activity than the tin incorporated mesoporous catalysts, even though both the materials had similar tin loadings. Among the tin-grafted catalysts, the samples prepared using the tin precursor, Me 3 SnCl, showed better activity than the other precursors Bu 3 SnCl, Ph 3 SnCl and Ph 2 SnCl 2 and among the mesoporous supports, Si–MCM-41 shows better catalytic results than the other supports like Si–MCM-48 and Si–SBA-15.
42 citations
TL;DR: In this article, the catalytic thermal degradation of polypropylene over aluminum containing ordered mesoporous MCM-41 and SBA-15 based materials was studied in a semi-batch reactor.
42 citations
TL;DR: In this article, two Pd-MCM-41 materials were synthetized by using the cationic surfactant tetradecyltrimethylammonium bromide (C 14 TABr) for both the stabilization of the Pd particles and the construction of the mesoporous structure.
Abstract: Pd–MCM-41 materials were synthetized by using the cationic surfactant tetradecyltrimethylammonium bromide (C 14 TABr) for both the stabilization of the Pd particles and the construction of the mesoporous structure of MCM-41. Two Pd–MCM-41 samples, for which the Pd particles were generated before and after formation of the MCM-41 framework (Pd-A and Pd-B, respectively), were investigated. Structural characterization of the samples was carried out by ICP-AES, N 2 sorption, XRD and TEM measurements. It was established that the highly ordered structure of MCM-41 was not appreciably affected by the formation of the Pd particles. Further, a similar particle size control was achieved for both Pd–MCM samples. However, both the location and the size distribution of the Pd particles were found to depend strongly on the preparation procedure. For Pd-A, the Pd nanoparticles were essentially situated on the external surface of MCM-41, whereas for Pd-B, the particles were found to be encapsulated inside the mesopores. For the liquid-phase hydrogenations of alkynes, the catalytic activity of Pd-A clearly surpassed that of Pd-B, indicating that the external Pd crystallites were more readily accessible for the reactants than those incorporated in the MCM-41 framework. The limited activity observed for Pd-B was attributed to mass transport limitations due to diffusion of the reactants into the mesopores of the MCM-41 host.
42 citations
TL;DR: In this article, the performance of the 0.7Cu/MCM-41 catalysts for EC hydrogenation was evaluated and the results indicated that the Cu/Si ratio significantly influenced the formation of Cu0 and Cu+ active sites over the catalysts.
42 citations
TL;DR: In this paper, the mesoporous molecular sieves MCM-41 and HSiW were used for the esterification of oleic acid with methanol.
Abstract: 12-silicotungstic acid (H4SiW12O40, HSiW) was successfully immobilized in the mesoporous molecular sieves MCM-41, which was prepared by an open synthesis method without hydrothermal process, to form a novel catalyst. The HSiW/MCM-41 catalysts preserve the hexagonal mesoporous features of MCM-41 and the typical Keggin structure of bulk HSiW. Up to a loading of 45 wt.%, the HSiW species are found to be homogeneously dispersed on the surfaces or inside the pores of MCM-41 frameworks. The influences of various catalytic reaction parameters such as the reaction temperature, reaction time and types of alcohol on the conversion of levulinic acid were investigated to characterize the catalytic performances of the mesoporous catalysts. Remarkably, the results show that the conversion value could reach 100% under the optimized conditions. The esterification reaction of oleic acid with methanol was also utilized to evaluate the catalytic performances of the mesoporous materials. The HSiW/MCM-41 catalysts exhibit excellent reusability in the esterification reactions and the yield of methyl oleate is as high as 81.2%.
42 citations