MCM-41

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

12-Tungstophosphoric acid supported on nano sized MCM-41 as an efficient and reusable solid acid catalyst for the three-component imino Diels–Alder reaction

Abstract: One pot three-component imino Diels-Alder reactions of various types of aldehydes, aniline and dihydropyrane were studied in the presence of nano sized MCM-41 supported 12-tungstophosphoric acid (TPA) as solid acid catalyst. MCM- 41 as solid support was synthesized in nano size and the catalysts with different loading amounts of TPA (5-30 wt%) were prepared and characterized by XRD, FT- IR and SEM techniques. The results confirm a good dispersion of the heteropoly acid on the solid supports and based on the experimental results, the catalyst with 10 wt% heteropoly acid shows the best catalytic activity using 0.5 mol% heteropoly acid relative to the aldehyde. The recovery experiments show that the catalyst is reusable after calcination without significant loss in its activity.

Cr Incorporated MCM-41 Type Catalysts for Isobutane Dehydrogenation and Deactivation Mechanism

Abstract: Cr incorporated MCM-41 type catalysts, which were prepared by direct hydrothermal synthesis and impregnation routes, were tested for dehydrogenation of isobutane. Among the surfactants (C17H38BrN, C19H42BrN, and C32H68BrN) used in the synthesis of MCM-41, C19H42BrN gave the best structure with ordered mesopores. Characterization results proved that chromium was very well dispersed within the MCM-41 lattice of the synthesized catalysts. In all of the synthesized catalysts, the presence of Cr6+ (2p3/2) in the form of chromates and Cr3+(2p1/2) in the form of CrOx or Cr2O3 was detected. All chromate types (mono, di, and poly) were observed in the catalyst synthesized hydrothermally according to the addition of metal solution simultaneously with silica source (CR_ALS). All characterization methods demonstrated that the highest amount of Cr6+ was present in this catalyst. Catalytic tests of the synthesized catalysts were carried out at 600 °C and at atmospheric pressure. The maximum conversion value (∼27%) was ...

Gas-phase hydrogenation of acetonitrile over Pt and Pt-Pd supported on mesoporous solids: influence of the metallic precursor

Abstract: Gas-phase hydrogenation of acetonitrile has been chosen as a test reaction to evaluate the catalytic behaviour of supported bimetallic catalysts prepared from dinuclear complexes precursors. Thus, Pd/Pt supported on zirconium doped mesoporous silica catalysts, with total metal loading of 1 and 2 wt.%, have been obtained by incipient wetness impregnation by using [PdPtCl 2 (μ-dppm) 2 ], after removing the ligands by calcination and subsequent reduction with H 2 . These catalysts have been compared with supported platinum or palladium/platinum catalysts with similar metal loadings prepared from classical inorganic salts ([Pt(NH 3 ) 4 ](NO 3 ) 2 , PdCl 2 and H 2 PtCl 6 ·6H 2 O). The metal-based catalysts have been characterized by powder XRD, adsorption–desorption of N 2 at 77 K, TEM, H 2 -TPR and NH 3 -TPD. A remarkable high degree of metal dispersion was attained when using the dinuclear precursor, giving rise to the highest yield of triethylamine in the gas-phase hydrogenation of acetonitrile, with a selectivity toward this tertiary amine close to 100%.