Showing papers on "MCM-41 published in 1994"
TL;DR: An ultralarge pore titanium silicate with MCM-41 structure has been prepared by direct hydrothermal synthesis; this material gives rise to useful catalysts for the selective oxidation of small and large organic compounds.
Abstract: An ultralarge pore titanium silicate with MCM-41 structure has been prepared by direct hydrothermal synthesis; this material gives rise to useful catalysts for the selective oxidation of small and large organic compounds.
629 citations
TL;DR: In this paper, a mesoporous pure-silica molecular sieve MCM-41 was used for the synthesis of solid acid catalysts for the acid-type conversion and formation of organic compounds of large molecular size.
Abstract: New solid acid catalysts, consisting of heteropoly acid (HPA) H3PW12O40 (PW) supported on a mesoporous pure-silica molecular sieve MCM-41, have been prepared and characterized by nitrogen physisorption, X-ray diffraction, FT-IR, and31P magic angle spinning NMR. The PW/MCM-41 compositions with PW loadings from 10 to 50 wt% have ∼ 30 A uniformly-sized mesopores. HPA retains the Keggin structure on the MCM-41 surface and forms finely dispersed HPA species. No HPA crystal phase is developed even at HPA loadings as high as 50 wt%. PW/MCM-41 exhibits higher catalytic activity than H2SO4 or bulk PW in liquid-phase alkylation of 4-t-butylphenol (TBP) by isobutene and styrene. In the alkylation of TBP by styrene, PW/MCM-41 shows a size selectivity compared to bulk PW and PW/SiO2, providing higher yields of a 2-(1-phenylethyl)-4-t-butylphenol, at the expense of the more bulky 2,6-bis-(1-phenylethyl)-4-t-butylphenol. The PW/MCM-41 compositions, having strong acid sites and a regular mesoporous system, are promising catalysts for the acid-type conversion and formation of organic compounds of large molecular size.
321 citations
TL;DR: In this article, a mesoporous MCM-41 family was synthesized with a Si : Al ratio as low as 8.5 : 1, without observing octahedral aluminium.
Abstract: A Crystalline mesoporous member of the MCM-41 family has been synthesised with a Si : Al ratio as low as 8.5 : 1, without observing octahedral aluminium.
117 citations
TL;DR: In this article, a highly thermostable tin-molybdenum complex is encapsulated into the hexagonal mesoporous channel host MCM-41 and thermally transformed into supported metal clusters.
Abstract: A highly thermostable tin–molybdenum complex is encapsulated into the hexagonal mesoporous channel host MCM-41 and thermally transformed into supported metal clusters.
52 citations
TL;DR: In this article, a series of crystalline mesoporous molecular sieves were prepared using alkyl hexadecyl dimethyl ammonium bromide salts (C16H33)(CnH2n + 1)(CH3)2 NBr), in which the number of carbon atoms (n) in one alky group was varied from 1 to 12, and the influence of n value on the nature of the final phase obtained and on its pore size was investigated.
Abstract: A series of crystalline mesoporous molecular sieves were prepared using alkyl hexadecyl dimethyl ammonium bromide salts (C16H33)(CnH2n + 1)(CH3)2 NBr, in which the number of carbon atoms (n) in one alkyl group was varied from 1 to 12. The influence of (n) value on the nature of the final phase obtained and on its pore size was investigated. A hexagonal phase was obtained for n = 1, 3, 5 and 7, while a lamellar phase was obtained for all other templates. Vanadium and titanium modified MCM-41 molecular sieves were also prepared in the presence of C12H25(CH3)3 N+ and C16H33(CH3)3 N+ ions, respectively. These materials were characterized by XRD, nitrogen physisorption, FTIR, solid state NMR, XPS, UV-Vis and catalytic testing in the oxidation of 1-naphthol, 2,6-di-tert-butylphenol, norbornylene, n-hexane and propylamine. Ti-MCM-41 exhibited considerable catalytic activity only in the oxidation of aromatics, olefins and alcohols. V-MCM-41 was found to be a good catalyst in the oxidation of aromatics and alkanes.
21 citations
6 citations