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: The mesoporous molecular sieves of the MCM-41S family have little intrinsic catalytic activity, but it is possible to functionalize the material by grafting organic side chains on the walls as discussed by the authors.
Abstract: The mesoporous molecular sieves of the M41S family have little intrinsic catalytic activity. However, it is possible to functionalize the material by grafting organic side chains on the walls. These organic–inorganic hybrid materials maintain the advantages of the inorganic support, notably a high surface area and structural stability at elevated temperature and pressure. Catalysts based on MCM-41 functionalized with either hindered amine bases or free primary amino groups have been evaluated for the facile synthesis of monoglycerides from fatty acids and glycidol. Yields as high as 95% in 8 h have been achieved. The catalysts can be reused several times with little loss of activity.
55 citations
TL;DR: In this article, a mesoporous MCM-41 silica was synthesized at a nominal Si:Ga ratio of 16:1 for a parent gel containing no cations other than NH4+ and cetyltrimethylammonium.
55 citations
TL;DR: In this article, the pincer-pincer palladium(II) complexes were characterized by IR spectroscopy, solid-state CP/MAS NMR ( 13 C, 31 P, and 29 Si), and elemental analyses.
Abstract: ECE-pincer palladium(II) complexes {ECE = (C6H3A2E)2-2,6) ,E = PPh2 and SPh} teth- ered to a trialkoxysilane moiety through a carbamate linkage were immobilized on ordered mesoporous silicas SBA-15 and MCM-41 using a grafting process. The resulting hybrid materials were characterized by IR spectroscopy, solid-state CP/MAS NMR ( 13 C, 31 P, and 29 Si), and elemental analyses. These analyses showed the integrity of the pincer-metal complexes on the supports, which highlights their stability under the applied immobilization conditions. An H-bond- ing interaction between the carbamate carbonyl group of the complex and free silanol groups on the silica surface was also established. The hybrid mate- rials were found to act as Lewis acid catalysts in the aldol reaction between methyl isocyanoacetate and benzaldehyde. SBA-15 modified with the PCP-pincer Pd complex was used in up to five runs without loss of activity. Control experiments showed the true het- erogeneous nature of the catalyst in this reaction. Ni- trogen physisorption data, XRD, and TEM/EDX analyses of the hybrid materials revealed that the mesoporous structure of these materials was retained during the immobilization process as well as during catalysis.
55 citations
TL;DR: In this paper, the structural properties of mesoporous silica materials modified by manganese have been investigated using surfactants containing different numbers of carbon atoms, and it has been found that structural properties are strongly related to the type of surfactant used, the amounts and the way of Mn introduction.
55 citations
TL;DR: In this paper, the mesoporous material sieves in pure silica form (MCM-41 and MCM-48) and Al, Fe, Cu and Zn containing, having different pore diameters (corresponding to those between the upper limit for zeolites and the lower end of the mesophorous materials), high pore volumes (>0.8 cm 3 /g) and high specific surface areas (>1000 m 2 /g), were presented.
55 citations