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 paper, magnetically functionalized mesoporous silica spheres with different size (average diameter, A.D.) from 150 nm to 2 μm and pore size distribution were synthesized by generating magnetic FexOy nanoparticles onto the mesoprofen hosts using the sol−gel method.
Abstract: Magnetically functionalized mesoporous silica spheres with different size (average diameter, A.D.) from 150 nm to 2 μm and pore size distribution were synthesized by generating magnetic FexOy nanoparticles onto the mesoporous silica hosts using the sol−gel method. The X-ray diffraction (XRD), field emission scanning electron microscope (FESEM), N2 adsorption/desorption results show that these composites conserved regular sphere morphology and ordered mesoporous structure after the formation of FexOy nanoparticles. XRD and X-ray photoelectron spectroscopy (XPS) analysis confirmed that the FexOy generated in these mesoporous silica hosts is mainly composed of γ-Fe2O3. Magnetic measurements reveal that these composites with different γ-Fe2O3 loading amounts possess super-paramagnetic properties at 300 K, and the saturation magnetization increases with increasing Fe ratio loaded. The ibuprofen-containing spheres were then coated with biodegradable poly(DL-lactide-co-glycolide) (PLGA) by the S/O/W single-emuls...
79 citations
TL;DR: In this paper, three catalysts with different chemical and physical properties were synthesized (one HZSM-5 zeolite and two ordered mesoporous aluminosilicates) and tested for the pyrolysis of four samples of commercial polymers (LDPE, PP, PS and EVA copolymer), using a thermobalance under nitrogen atmosphere at a heating rate of 10°C/min.
Abstract: In this work, three catalysts with different chemical and physical properties were synthesized (one HZSM-5 zeolite and two ordered mesoporous aluminosilicates—MCM-41a and MCM-41b) and tested for the pyrolysis of four samples of commercial polymers (LDPE, PP, PS and EVA copolymer), using a thermobalance under nitrogen atmosphere at a heating rate of 10 °C/min. The catalysts were characterized using X-ray powder diffraction, nitrogen adsorption at 77 K and 27 Al and 29 Si solid state nuclear magnetic resonance (NMR). The HZSM-5 zeolite showed the lowest activity in the catalytic pyrolysis of the four polymers. The two mesoporous catalysts, with a greater pore size, were the most active materials in the catalytic pyrolysis of the polymers, and the MCM-41b sample, with higher acidity, was the most active. The presence of MCM-41 samples during the pyrolysis of the high impact PS sample permits us to distinguish between different decomposition steps which are probably related to the pyrolysis of PS and polybutadiene domains. This processes separation was not observed in absence of the catalyst. Thus, catalytic pyrolysis of such samples in the presence of MCM-41 and other catalysts could be a promising technique to characterize this type of polymers.
79 citations
TL;DR: In this paper, a simple method for preparing highly active and dispersed supported metal catalysts was developed by co-impregnation, which could enhance interaction with MCM-41 surface, resulting in formation of very small NiO particle size (3.5 nm) and high dispersion of the active phase.
79 citations
TL;DR: In this paper, the Heck coupling of bromoarenes including deactivated Bromo derivatives has been studied using Ligand-free Pd-MCM41 catalysts.
79 citations
TL;DR: In this paper, mesoporous nanocomposite silicotungstic acid (STA) was successfully synthesized following different impregnation procedures, and the results showed that the catalyst preparation procedure had significant influence on its activity as well as the product distribution in ethanol dehydration.
Abstract: In this study, mesoporous nanocomposite silicotungstic acid (STA) incorporated MCM-41 and mesoporous aluminosilicate catalysts with narrow pore size distributions, in the range of 2.5–3.5 nm, were successfully synthesized following different impregnation procedures. Results showed that the catalyst preparation procedure had significant influence on its activity as well as the product distribution in ethanol dehydration. STAMCM41C catalyst, which was prepared by the impregnation of STA into calcined MCM-41 containing a W/Si ratio of 0.24, and STAMAS catalyst, which was prepared by the impregnation of STA into mesoporous aluminosilicate, showed very high activities in dehydration of ethanol. Ethylene yield showed an increasing trend with temperature, reaching to about 100% above 250 °C. In contrast to ethylene, DEE was formed at lower temperatures, reaching to a yield value of about 70% at 180 °C with STAMCM41C. DEE formation at lower temperatures was concluded to be due to the presence of Bronsted acid sit...
79 citations