نتایج جستجو برای: nanostructured vanadium catalysts

تعداد نتایج: 56195  

Journal: :Chemical communications 2011
Samir El Hankari Blanca Motos-Pérez Peter Hesemann Ahmed Bouhaouss Joël J E Moreau

Mesoporous hybrid silica bearing zwitterionic species were synthesized via template-directed hydrolysis-polycondensation reactions from zwitterionic ammonium sulfonate precursors. The formation of the nanostructured phases involves specific precursor-template interactions. The obtained materials are efficient heterogeneous catalysts in Biginelli reactions.

1997
Kenneth S. Suslick Taeghwan Hyeon Mingming Fang

The sonochemical decomposition of volatile organometallic compounds produces high surface area solids that consist of agglomerates of nanometer clusters. For iron pentacarbonyl and tricarbonylnitrosylcobalt, nanostructured metals and alloys are formed; for molybdenum hexacarbonyl, the metal carbide is produced. These sonochemically produced nanostructured solids are active heterogeneous catalys...

Journal: :Chemosphere 2008
T Oberg B Bergbäck M Filipsson

Polychlorinated benzenes, dibenzo-p-dioxins (PCDD), and dibenzofurans (PCDF) may be formed below the combustion temperature in fly ash from municipal solid waste incinerators (MSWI). Copper catalyzes this formation, possibly by the Deacon reaction. Many other elements are also Deacon catalysts or promoters, and here we report results from a statistically designed experiment with 15 metal oxides...

2011
Julie E. Molinari Lingaiah Nakka Taejin Kim Israel E. Wachs

Molybdenum-based Keggin polyoxometalates (POMs) containing vanadium, with the formula H3+xPMo12 xVxO40 (MPAV) and x varying from0 to 3, exhibit unique catalytic properties because of their bifunctional nature and have been investigated as catalysts both for acidic and for oxidative reactions. 3 The addition of vanadium centers are beneficial for redox catalysis, shifting the molybdophosphoric a...

Journal: :Angewandte Chemie 2011
Deidra L Gerlach Nicolai Lehnert

The unique catalytic activity of vanadium nitrogenase suggests a new direction for the direct production of biofuels from CO with either synthetic catalysts or nitrogenase-containing bacteria. The reduction of CO by V nitrogenase to light hydrocarbons shows striking similarities to the established Fischer-Tropsch process; however, the enzyme does not use H(2) directly for this reaction. ADP=ade...

2013
Hyeonhee Choi Jung-Hyun Bae Do Heui Kim Young-Kwon Park Jong-Ki Jeon

MCM-41 was used as a support and, by using atomic layer deposition (ALD) in the liquid phase, a catalyst was prepared by consecutively loading titanium oxide and vanadium oxide to the support. This research analyzes the effect of the loading amount of vanadium oxide on the acidic characteristics and catalytic performance in the dehydration of butanol. The physical and chemical characteristics o...

Journal: :Chemical communications 2012
Juan Su Xiao-Xin Zou Guo-Dong Li Lu Li Jun Zhao Jie-Sheng Chen

A vanadium-doped porous titania rich in active hydrogen (V-TiO(2)(H*)) has been successfully prepared and demonstrated to be an efficient and green reductant with renewable capacity. This V-TiO(2)(H*) material can instantly (<10 s) and selectively reduce nitroarenes to aminoarenes under ambient conditions without catalysts.

Journal: :Chemical communications 2014
Long Han Chuan Liu Wei Zhang Xiao-Xin Shi Shu-Li You

An enantioselective epoxidation of tryptophols followed by an intramolecular epoxide opening reaction was realized by chiral vanadium catalysts derived from C2 symmetric bis-hydroxamic acid (BHA) ligands. 3a-Hydroxyfuroindoline derivatives with up to 89% yield and 90% ee were obtained under mild reaction conditions.

1997
Israel E. Wachs Jih-Mirn Jehng Goutam Deo Bert M. Weckhuysen V. V. Guliants J. B. Benziger S. Sundaresan

Fundamental Studies of Butane Oxidation over ModelSupported Vanadium Oxide Catalysts: Molecular Structure-Reactivity Relationships Israel E. Wachs,∗ Jih-Mirn Jehng,∗,1 Goutam Deo,∗,2 Bert M. Weckhuysen,∗,3 V. V. Guliants,† J. B. Benziger,† and S. Sundaresan† ∗Zettlemoyer Center for Surface Studies, Department of Chemical Engineering, Lehigh University, Bethlehem, Pennsylvania 18015; and †Depart...

Journal: :Inorganica Chimica Acta 2021

Oxo- and imido-vanadium(V) metal complexes supported by bis(phenolate)-functionalized N-heterocyclic carbene (NHC) ligands were synthesized structurally identified. In the presence of [(Ph3P)2N]Cl ([PPN]Cl), saturated NHC oxo-vanadium showed activity in coupling CO2 cyclohexene oxide (CHO) into cis-cyclohexene carbonate (cis-CHC). More importantly, complex bearing less electron-donating benzann...

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