Synthesis, characterization and catalytic activity of actinide Th-MCM-41 and U-MCM-41 hexagonal packed mesoporous molecular sieves

2001 ◽  
Vol 171 (1-2) ◽  
pp. 229-241 ◽  
Author(s):  
Rodica Tismaneanu ◽  
Biswajit Ray ◽  
Rafael Khalfin ◽  
Rafi Semiat ◽  
Moris S. Eisen
Keyword(s):  
Catalytic Activity ◽  
Molecular Sieves ◽  
Mesoporous Molecular Sieves ◽  
Mcm 41

Emission Control Catalyst Derived from Mesoporous Molecular Sieves

1996 ◽  
Vol 431 ◽  
Author(s):  
Partha P. Paul ◽  
Michael A. Miller ◽  
Martin J. Heimrich ◽  
Stuart T. Schwab
Keyword(s):  
Catalytic Activity ◽  
Fuel Economy ◽  
Molecular Sieves ◽  
Emission Control ◽  
Mesoporous Molecular Sieves ◽  
Exhaust Gas ◽  
Engine Exhaust ◽  
Combustion Processes ◽  
Mcm 41

AbstractA lean NOx catalyst is needed to control NOx emissions generated by oxygen-rich combustion processes to obtain higher fuel economy. We have developed such a catalyst using modified mesoporous molecular sieves (MCM-41). An iron(II)-complex impregnated MCM-41 has been synthesized which has been further treated with [Pd(NH3)4]Cl2. This treatment resulted in further exchange of Na+ ions of the molecular sieves with Pd(NH3)42+ thus forming Catalyst A. The catalytic activity towards NOx, CO and HC was studied using simulated exhaust gas, as well as engine exhaust gas.

Synthesis of Al-Containing Mesoporous Molecular Sieves and their Catalytic Performance to Isomerization Reaction of Endo-Tetrahydrodicyclo-Pentadiene

2011 ◽  
Vol 233-235 ◽  
pp. 234-237 ◽  
Author(s):  
Sa Liu ◽  
Jian Wei Guo ◽  
Chu Fen Yang ◽  
Long Huan Li ◽  
Yi Hua Cui
Keyword(s):  
Catalytic Activity ◽  
Molecular Sieves ◽  
Catalytic Performance ◽  
Mesoporous Molecular Sieves ◽  
Isomerization Reaction ◽  
Inorganic Acid ◽  
Ft Ir ◽  
Desorption Isotherms ◽  
Adsorption Desorption ◽  
Mcm 41

Al-containing mesoporous molecular sieves(Al-MCM-41) were synthesized at ambient temperature. The structures of samples were characterized by XRD, N2-adsorption/desorption isotherms and FT-IR, etc. The evaluation results showed that Al-MCM-41 had higher catalytic activity for isomerization conversion of endo-tetrahydrodicyclo-pentadiene (endo-TCD) into exo-tetrahydrodicyclo-pentadiene (exo-TCD) and adamantane (AdH). Loading inorganic acid on the surface of Al-MCM-41 led increase of its catalytic activity and the yield of adamantane.

Synthesis, Characterization and Modification of Mcm-41 Molecular Sieves

1994 ◽  
Vol 371 ◽  
Author(s):  
A. Sayari ◽  
V.R. Karra ◽  
J.S. Reddy ◽  
I.L. Moudrakovski
Keyword(s):  
Catalytic Activity ◽  
Solid State ◽  
Molecular Sieves ◽  
Solid State Nmr ◽  
Hexagonal Phase ◽  
Mesoporous Molecular Sieves ◽  
Ammonium Bromide ◽  
Final Phase ◽  
Dimethyl Ammonium ◽  
Mcm 41

AbstractA series of crystalline mesoporous molecular sieves were prepared using alkyl hexadecyl dimethyl ammonium bromide salts (C16H33)(CnH2n + 1)(CH3)2NBr, 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)3N+ and C16H33(CH3)3N+ 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.

Hybrid Catalysts for Acetylenes Polymerization Prepared by Anchoring [Rh(cod)Cl]2 on MCM-41, MCM-48 and SBA-15 Mesoporous Molecular Sieves - The Effect of Support Structure on Catalytic Activity in Polymerization of Phenylacetylene and 4-Ethynyl-N-{4-[(trimethylsilyl)ethynyl]benzylidene}aniline

2003 ◽  
Vol 68 (10) ◽  
pp. 1861-1876 ◽  
Author(s):  
Hynek Balcar ◽  
Jan Sedláček ◽  
Jan Svoboda ◽  
Naděžda Žilková ◽  
Jiří Rathouský ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Molecular Sieves ◽  
Catalyst Support ◽  
Mesoporous Molecular Sieves ◽  
Chain Growth ◽  
Homogeneous Catalyst ◽  
Molecular Weights ◽  
Hybrid Catalysts ◽  
Effect Of Support ◽  
Mcm 41

Hybrid catalysts for polymerization of acetylenes were prepared by anchoring, via (3-aminopropyl)trimethoxysilane linker, the [Rh(cod)Cl]2 complex on siliceous mesoporous molecular sieves differing in the pore size and architecture (MCM-41, MCM-48 and SBA-15). In comparison with [Rh(cod)Cl]2 used as homogeneous catalyst, all hybrid catalysts exhibited comparable or even higher catalytic activity in the polymerization of phenylacetylene and 4-ethynyl-N-{4-[(trimethylsilyl)ethynyl]benzylidene}aniline. The initial polymerization rate increased with increasing accessibility of mesoporous surface of catalysts in the order: MCM-41 < MCM-48 < SBA-15. Molecular weights of the prepared polymers increased in reverse order suggesting suppression of the chain growth termination reactions by space limitations in the pores. No effect of catalyst support on the microstructure of formed polymers was found.

Effect of rehydration on the porosity of MCM-41 mesoporous molecular sieves

1999 ◽  
Vol 35 (1) ◽  
pp. 52-56
Author(s):  
F. M. Bobonich ◽  
Yu. G. Voloshina ◽  
L. A. Matkovskaya ◽  
V. N. Solomakha ◽  
Yu. G. Gol’tsov
Keyword(s):  
Molecular Sieves ◽  
Mesoporous Molecular Sieves ◽  
Mcm 41

scholarly journals Hoveyda–Grubbs type metathesis catalyst immobilized on mesoporous molecular sieves MCM-41 and SBA-15

2011 ◽  
Vol 7 ◽  
pp. 22-28 ◽  
Author(s):  
Hynek Balcar ◽  
Tushar Shinde ◽  
Naděžda Žilková ◽  
Zdeněk Bastl
Keyword(s):  
Nmr Spectroscopy ◽  
Molecular Sieves ◽  
Direct Interaction ◽  
Mesoporous Molecular Sieves ◽  
Support Surface ◽  
Wall Surface ◽  
Ring Closing Metathesis ◽  
Immobilized Catalysts ◽  
Metathesis Catalyst ◽  
Mcm 41

A commercially available Hoveyda–Grubbs type catalyst (RC303 Zhannan Pharma) was immobilized on mesoporous molecular sieves MCM-41 and on SBA-15 by direct interaction with the sieve wall surface. The immobilized catalysts exhibited high activity and nearly 100% selectivity in several types of alkene metathesis reactions. Ru leaching was found to depend on the substrate and solvent used (the lowest leaching was found for ring-closing metathesis of 1,7-octadiene in cyclohexane – 0.04% of catalyst Ru content). Results of XPS, UV–vis and NMR spectroscopy showed that at least 76% of the Ru content was bound to the support surface non-covalently and could be removed from the catalyst by washing with THF.

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