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: Aluminium-containing mesoporous molecular sieves (AlMCM-41) with different Al contents (Si/Al=86.3, 43.9, 23.3 and 14.3) have been prepared using cetyltrimethylammonium bromide as an organic surfactant and characterized by XRD, MAS NMR, and N 2 sorption studies as discussed by the authors.
65 citations
TL;DR: In this article, real-time, in situ ATR/FTIR monitoring of M41S-type mesoporous silicate syntheses was performed which enabled the observation of simultaneous changes in both the organic and inorganic phases of the reaction mixtures.
65 citations
TL;DR: In this article, Ionic liquids (ILs) and immobilized ionic liquids were used as acid catalysts for the liquid phase alkylation of raffinate II and isobutane.
Abstract: Ionic liquids (ILs) and immobilized ionic liquids were used as acid catalysts for the liquid phase alkylation of raffinate II and isobutane. The influences of reactant concentration (molar ratio of iC4/C4 ), time, temperature and acid strength of the ionic liquids were studied. Using a step-up design under batch conditions with a very dilute mixture of isobutane and alkene, the conversion for a variety of ionic liquids was found to follow a pattern based on acid strength of the catalyst. Imidazolium based ILs were found to be superior to phosphonium based ILs. Novel Lewis-Acid Catalysts II (NLAC II, immobilization by grafting on siliceous MCM 41 or on silica FK 700) are better than other solid acid catalysts tested, such as SAC 13, zeolite H-Beta (Si/Al = 14) and NLAC I (impregnation of ILs on silica FK 700). Possible leaching of the ionic liquid from the catalyst surface was followed by ICP measurements of the catalyst after reaction and of the reaction mixture.
65 citations
TL;DR: Mesoporous Mn-MCM-41 (Si/Mn=29, 56, 73 and 104) materials were synthesized by hydrothermal process and their structures were characterized by X-ray diffraction (XRD).
Abstract: Mesoporous Mn-MCM-41 (Si/Mn=29, 56, 73 and 104) materials were synthesized by hydrothermal process. Their structures were characterized by X-ray diffraction (XRD). Surface area, pore size and wall thickness were calculated from BET equation and BJH method using nitrogen sorption technique. The thermal property of the as-synthesized materials was studied using thermogravimetric-differential thermal analysis (TG-DTA). Diffuse reflectance UV-Vis spectroscopy confirmed presence of manganese ion in the framework position of the MCM-41. Mn(II) species with a well-resolved singlet, centered at g=2.007, was assigned to have distorted tetrahedral symmetry. The oxidation of ethylbenzene has been carried out over Mn-MCM-41 (Si/Mn=29, 56, 73 and 104) using t-butylhydroperoxide as oxidant at 333–353 K. Mn-MCM-41 (29) was more active than other catalyst, and it retained activity for three cycles of operation. The major products were α-phenylethanol and acetophenone. Benzaldehyde and phenyl acetaldehyde were also observed in minor quantity. The difference in the product selectivity was explained based on the reaction intermediates.
65 citations
TL;DR: In this article, the swelling agent (toluene) was used as a transport medium to inject the Pt precursor, Pt(acetylacetonate)2, directly into the inner core of the surfactant micelles.
Abstract: Platinum-containing MCM-41 was synthesized in a one step approach. In this new procedure, the swelling agent (toluene) was used as a transport medium to inject the Pt precursor, Pt(acetylacetonate)2, directly into the inner core of the surfactant micelles. A 1 wt % metal loading was achieved without the loss of pore ordering, while samples with 2 wt % loading showed a less ordered structure. A total of 80−100% of the Pt precursor was incorporated in the porous host matrix depending on the precursor concentration and final loading. During the calcination process, platinum acts as a catalyst for the oxidative removal of the surfactant molecules, allowing one to decrease the calcination temperature significantly. The calcined material had a high surface area (1000−1200 m2 g-1). Platinum particles could be detected using transmission electron microscopy confirming also the absence of large particles outside the mesopore system. The in situ approach was also applied to prepare other metal/MCM-41 or oxide/MCM-4...
65 citations