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: Barrault et al. as discussed by the authors showed that the use of porous and basic solid catalysts could induce a shape selectivity modifying the monoglyceride selectivity, and obtained glycerol monolaurate with selectivity and yield of about 80%.
53 citations
TL;DR: In this paper, the catalytic performance of Pt-Pd/MCM-41 bimetallic catalysts for total toluene oxidation was investigated for one-step synthesis method.
52 citations
TL;DR: In this paper, a series of bifunctionalized hexagonal mesoporous silicas, CoPh-HMS, were designed and successfully synthesized by a one-step co-condensation route.
Abstract: According to the characteristics of the cyclohexane oxidation reaction a series of bifunctionalized hexagonal mesoporous silicas, CoPh-HMS, were designed and successfully synthesized by a one-step co-condensation route. The results of small-angle XRD, TEM, and N2 adsorption-desorption measurements showed that the resultant materials had well-ordered mesoscopic structures. Co 2+ ions were incorporated into the frameworks in tetrahedral coordination along with phenyl groups immobilized on the surface, confirmed by a careful spectroscopic (FT-IR, UV-visible, and 29 Si MAS NMR) study. The surfaces of the materials were proved to be more hydrophobic with higher Ph loading, and the largest water droplet contact angle is up to 110.50°. These materials were applied in the liquid-phase oxidation of cyclohexane with molecular oxygen as oxidant and tert-butyl hydroperoxide as initiator under solvent-free conditions. High activity could be obtained with these bifunctionalized catalysts being used. The modification effect of phenyl groups played an important role in the activity enhancement.
52 citations
TL;DR: In this paper, the synthesis of titanium-containing MCM-41 mesoporous molecular sieves in the presence of dye molecules results in a well developed hexagonal structure if the powder dye is dissolved in a surfactant solution.
52 citations
TL;DR: In this article, mesoporous VMCM-48 molecular sieves with Si/V (molar) ratios of 25-200 were synthesized hydrothermally and systematically characterized by various analytical and spectroscopic techniques, viz, XRD, N 2 sorption, TG-DTA, TEM, EPR, 51 V MAS-NMR, FT-IR, and DRUV-VIS XRD studies suggest that the substitution of vanadium occurs in the silicate framework structure of MCM- 48.
Abstract: Mesoporous VMCM-48 molecular sieves with Si/V (molar) ratios of 25–200 were synthesized hydrothermally and systematically characterized by various analytical and spectroscopic techniques, viz, XRD, N 2 sorption, TG-DTA, TEM, EPR, 51 V MAS-NMR, FT-IR, and DRUV-VIS XRD studies suggest that the substitution of vanadium occurs in the silicate framework structure of MCM-48 TEM and ED investigations confirm the highly ordered cubic structure of VMCM-48 EPR and 51 V NMR studies indicate the presence of pentavalent vanadium ions in tetrahedral framework positions, while DRUV-VIS spectra show their existence in two different environments The catalytic activity of these well-characterized (both in the calcined and the washed forms) materials was evaluated for cyclohexane oxidation under mild reaction conditions All these catalysts gave high substrate conversion and excellent product (cyclohexanol) selectivity Furthermore, unlike many other vanadium-based heterogeneous catalysts reported, the mesoporous VMCM-48 catalysts show minimal leaching of the active vanadium species This was confirmed by washing, recycling and quenching experiments where only a small amount of vanadium ions leaches out in the case of calcined samples, while vanadium was not detected for the washed ones Finally, the catalytic activity of VMCM-48 was also compared with mesoporous VMCM-41 as well as microporous VS-1 catalyst The results indicate that the former showed superior activity to those of the latter two, such superiority could, however, be directly related to the amount of vanadium incorporated in MCM-48 being larger than the amounts in MCM-41 and MFI structures
52 citations