MCM-41

About: MCM-41 is a research topic. Over the lifetime, 2355 publications have been published within this topic receiving 91416 citations.

Ethanol Conversion on MCM-41 and FSM-16, and on Ni-Doped MCM-41 and FSM-16 Prepared without Hydrothermal Conditions

Abstract: MCM-41 and FSM-16 were both prepared using no hydrothermal conditions, and nickel was doped into these catalysts (Ni-MCM-41 and Ni-FSM-16) using a template ion exchange method. FSM-16 and Ni-FSM-16 had greater catalytic activity for the conversion of ethanol than MCM-41 and Ni-MCM-41, indicating that FSM-16 has potential as a catalyst for the conversion of ethanol to propylene.

Novel europium complexes covalently bonded to MCM-41 and SBA-15: spatial confinement effects on photoluminescence behavior

Abstract: Novel organic-inorganic luminescent mesoporous hybrid materials were assembled through the coordination reaction between europium nitrate with chelated quinoline-amide type ligands immobilized in mesoporous materials (MCM-41 and SBA-15). The mesoporous hybrid materials were characterized by elemental analysis, Fourier-transform infrared spectra, powder X-ray diffraction (PXRD), transmission electron microscopy (TEM), and nitrogen (N(2)) adsorption-desorption. The results demonstrated that the highly ordered mesoporous structures were retained after the complexes covalently bonded to the channels of the matrices. The SBA-15-type hybrid materials, with pore sizes twice that of MCM-41, display more efficient emission due to the spatial confinement of the nanochannels of the mesoporous matrix. This deduction is strengthened by the fact that the influences are more obvious for complexes including rigid end group ligands. In addition, the Eu(3+) complexes coordinated with ligands containing rigid end groups in MCM-41 matrices exhibit better photoluminescence stability upon exposure to ultraviolet light.

Vapour phase isopropylation of phenol over zinc- and iron-containing Al-MCM-41 molecular sieves

Abstract: Al-MCM-41 molecular sieves containing zinc and iron are hydrothermally synthesised. The low angle X-ray powder diffraction (XRD) analysis shows that Zn and Fe incorporated Al-MCM-41 retains the hexagonal structure. The higher d-spacing values of Zn- and Fe-Al-MCM-41 catalysts than that of Al-MCM-41 indicate the incorporation of Zn and Fe into the framework. The mesoporous nature of the materials was confirmed by nitrogen adsorption isotherms. Electron paramagnetic resonance (EPR) and diffuse reflectance spectrum (DRS) techniques confirm the tetrahedral co-ordination of iron into the framework. The total acidity of the synthesised catalysts was analysed by both TPD of ammonia and of adsorbed pyridine FT-IR spectroscopy. Acidity measurements indicate that Zn and Fe incorporation increases both Lewis and Bronsted acidity of the catalysts, due to strengthening of Bronsted acid sites by appropriately positioned Zn2+ and Fe3+ Lewis acid metals. Vapour phase isopropylation of phenol with a new alkylating agent isopropyl acetate (IPA) was carried out over the H-forms of the above catalysts. On comparison, the Zn and Fe incorporated Al-MCM-41 catalysts show significantly higher phenol conversion and selectivity towards the important product 4-isopropyl phenol (4-IPP). Further, the undesired and dialkylated products selectivity are found to be lower over Zn and Fe incorporated Al-MCM-41 than pure Al-MCM-41 catalysts.