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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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Journal ArticleDOI
TL;DR: In this paper, the authors describe the successful preparation of siliceous mesoporous materials MCM-41 with pores of ordered 2-dimensional hexagonal structure by condensation-polymerization using quaternary ammonium salt as structure directing agent and supernatant of the coal fly ash (CFA) as silica precursor.

96 citations

Journal ArticleDOI
15 Nov 2016-Fuel
TL;DR: In this article, a hybrid material POM@MOF-199@MCM-41 (PMM) was found by a one pot and POM template self-construction.

96 citations

Journal ArticleDOI
TL;DR: The probe catalytic cracking reaction of n-dodecane shows the superiority of the unique core-shell structure over pristine ZSM-5, and Insight into the core- shell composite structure with hierarchical pore and graded acidity distribution show great potential for petroleum catalytic processes.
Abstract: A series of core-shell-structured composite molecular sieves comprising zeolite single crystals (i.e., ZSM-5) as a core and ordered mesoporous silica as a shell were synthesized by means of a surfactant-directed sol-gel process in basic medium by using cetyltrimethylammonium bromide (CTAB) as a template and tetraethylorthosilicate (TEOS) as silica precursor. Through this coating method, uniform mesoporous silica shells closely grow around the anisotropic zeolite single crystals, the shell thickness of which can easily be tuned in the range of 15-100 nm by changing the ratio of TEOS/zeolite. The obtained composite molecular sieves have compact meso-/micropore junctions that form a hierarchical pore structure from ordered mesopore channels (2.4-3.0 nm in diameter) to zeolite micropores (approximate to 0.51 nm). The short-time kinetic diffusion efficiency of benzene molecules within pristine ZSM-5 (approximate to 7.88 x 10(-19) m(2) s(-1)) is almost retainable after covering with 75 nm-thick mesoporous silica shells (approximate to 7.25 x 10(-19) m(2)s(-1)), which reflects the greatly opened junctions between closely connected mesopores (shell) and micropores (core). The core-shell composite shows greatly enhanced adsorption capacity (approximate to 1.35 mmolg(-1)) for large molecules such as 1,3,5-triisopropylbenzene relative to that of pristine ZSM-5 (approximate to 0.4 mmolg(-1)) owing to the mesoporous silica shells. When Al species are introduced during the coating process, the core-shell composite molecular sieves demonstrate a graded acidity distribution from weak acidity of mesopores (predominant Lewis acid sites) to accessible strong acidity of zeolite cores (Lewis and Bronsted acid sites). The probe catalytic cracking reaction of n-dodecane shows the superiority of the unique core-shell structure over pristine ZSM-5. Insight into the core-shell composite structure with hierarchical pore and graded acidity distribution show great potential for petroleum catalytic processes.

95 citations

Journal ArticleDOI
TL;DR: In this paper, the SO42−/ZrO2/MCM-41 catalysts showed high activity with a selective conversion of >95 mol% ButOH to MTBE at low temperatures below 160°C.

94 citations

Journal ArticleDOI
TL;DR: In this paper, a series of Cu 2+ -phthalocyanine and Co 2 + -perfluorophthalocyanines were synthesized inside the pores of MCM-41 by synthesis from o -dicyanobenzene.
Abstract: A series of Cu 2+ -phthalocyanine and Co 2+ -perfluorophthalocyanine has been prepared inside the pores of MCM-41 (MPcMCM-41) by synthesis from o -dicyanobenzene. The complexes were characterized by comparison of the UV–Vis diffuse reflectance and IR spectra with that of the same unsupported complexes. Transition metal ion exchange levels higher than 40% were found necessary for the success of the synthesis. o -Cyanobenzoic acid and phthalic anhydride were isolated as byproducts. Differential scanning calorimetry indicates that the complexes are more stabilized inside MCM-41 than within the supercages of Y faujasite. This has been interpreted as a reflection of the different conformations (planar for MCM-41 and distorted for Y faujasite) depending on the pore size of the host. The catalytic performance of novel MPcMCM-41 for cyclohexane oxidation was compared with that of the same unsupported complexes or when encaged within Y faujasite. tert -Butyl hydroperoxide was found as a more convenient oxidizing reagent than hydrogen peroxide. No leaching of the MPc or uncomplexed metal ions was observed. It was found that CoF 16 PcMCM-41 was more active and selective than CoF 16 PcY or unsupported CoF 16 Pc. However, in the case of the CuPc complex, the highest activity and selectivity was achieved using CuPcY. Our work shows the influence that the void dimensions of the porous host can play in the performance of metallophthalocyanines as oxidation catalysts.

94 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202334
202258
202172
202071
201993
201890