Character of hydrocarbon activation and catalytic activity of solid catalysts in deep oxidation reactions

1981 ◽  
Vol 17 (3-4) ◽  
pp. 379-383
Author(s):  
V. D. Sokolovskii
Keyword(s):  
Catalytic Activity ◽  
Deep Oxidation ◽  
Oxidation Reactions ◽  
Solid Catalysts

Novel, benign, solid catalysts for the oxidation of hydrocarbons

2005 ◽  
Vol 363 (1829) ◽  
pp. 1001-1012 ◽  
Author(s):  
Paul Ratnasamy ◽  
Robert Raja ◽  
Darbha Srinivas
Keyword(s):  
Catalytic Activity ◽  
Molecular Sieves ◽  
Metal Ion ◽  
Copper Phthalocyanine ◽  
Zeolite Y ◽  
Copper Acetate ◽  
Porous Solids ◽  
Oxidation Reactions ◽  
Solid Catalysts ◽  
Oxidation Of Hydrocarbons

The catalytic properties of two classes of solid catalysts for the oxidation of hydrocarbons in the liquid phase are discussed: (i) microporous solids, encapsulating transition metal complexes in their cavities and (ii) titanosilicate molecular sieves. Copper acetate dimers encapsulated in molecular sieves Y, MCM-22 and VPI-5 use dioxygen to regioselectively ortho -hydroxylate l -tyrosine to l -dopa, phenol to catechol and cresols to the corresponding o -dihydroxy and o -quinone compounds. Monomeric copper phthalocyanine and salen complexes entrapped in zeolite-Y oxidize methane to methanol, toluene to cresols, naphthalene to naphthols, xylene to xylenols and phenol to diphenols. Trimeric μ 3 -oxo-bridged Co/Mn cluster complexes, encapsulated inside Y-zeolite, oxidize para -xylene, almost quantitatively, to terephthalic acid. In almost all cases, the intrinsic catalytic activity (turnover frequency) of the metal complex is enhanced very significantly, upon encapsulation in the porous solids. Spectroscopic and electrochemical studies suggest that the geometric distortions of the complex on encapsulation change the electron density at the metal ion site and its redox behaviour, thereby influencing its catalytic activity and selectivity in oxidation reactions. Titanosilicate molecular sieves can oxidize hydrocarbons using dioxygen when loaded with transition metals like Pd, Au or Ag. The structure of surface Ti ions and the type of oxo-Ti species generated on contact with oxidants depend on several factors including the method of zeolite synthesis, zeolite structure, solvent, temperature and oxidant. Although, similar oxo-Ti species are present on all the titanosilicates, their relative concentrations vary among different structures and determine the product selectivity.

scholarly journals Cobalt-Based Metal Organic Frameworks as Solids Catalysts for Oxidation Reactions

Catalysts ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 95
Author(s):  
Amarajothi Dhakshinamoorthy ◽  
Eva Montero Lanzuela ◽  
Sergio Navalon ◽  
Hermenegildo Garcia
Keyword(s):  
Aerobic Oxidation ◽  
High Surface ◽  
Metal Organic Frameworks ◽  
High Surface Area ◽  
Acid Sites ◽  
Crystalline Lattice ◽  
Oxidation Reactions ◽  
Solid Catalysts ◽  
Long Term Stability ◽  
Metal Organic

Metal organic frameworks (MOFs) are porous crystalline solids whose frameworks are constituted by metal ions/nodes with rigid organic linkers leading to the formation of materials having high surface area and pore volume. One of the unique features of MOFs is the presence of coordinatively unsaturated metal sites in their crystalline lattice that can act as Lewis acid sites promoting organic transformations, including aerobic oxidation reactions of various substrates such as hydrocarbons, alcohols, and sulfides. This review article summarizes the existing Co-based MOFs for oxidation reactions organized according to the nature of substrates like hydrocarbon, alcohol, olefin, and water. Both aerobic conditions and peroxide oxidants are discussed. Emphasis is placed on comparing the advantages of using MOFs as solid catalysts with respect to homogeneous salts in terms of product selectivity and long-term stability. The final section provides our view on future developments in this field.

Catalytic activity of Co-åkermanite and Co-pyroxene in oxidation reactions

2011 ◽  
Vol 89 (8) ◽  
pp. 939-947 ◽  
Author(s):  
Irena Mihailova ◽  
Dimitar Mehandjiev
Keyword(s):  
Catalytic Activity ◽  
Solid Phase ◽  
Sol Gel ◽  
Cobalt Content ◽  
Octahedral Coordination ◽  
Tetrahedral Coordination ◽  
Oxidation Reactions ◽  
Oxidation Of Co ◽  
Phase Synthesis ◽  
Catalytically Active

Two calcium–cobalt silicates were synthesized in which cobalt occupies different structural positions. The crystal phases belong to two main structural silicate types. In the Co-åkermanite structure (Ca2CoSi2O7), cobalt cations take tetrahedral coordination toward oxygen atoms. In the Co-pyroxene structure of CaCoSi2O6, cobalt displays octahedral coordination. Ca2CoSi2O7 was prepared by solid-phase synthesis and CaCoSi2O6 was prepared by sol–gel method. The synthesis of the phases was confirmed by XRD, FTIR, and EPR data. On the basis of the XPS analysis, it can be concluded that Co2+ cations exist in the studied silicates. Thus, it is possible to study the catalytic activity of two silicate phases containing Co2+ cations in different coordinations: tetrahedral and octahedral. It was found that cobalt silicates with crystal structures corresponding to pyroxene and åkermanite possess catalytic activity in the reactions of complete oxidation of CO and toluene. Co-pyroxene exhibits higher catalytic activity than Co-åkermanite, but the higher cobalt content on the surface of Co-pyroxene should also be taken into account. Then, it turns out that catalytically active complexes with Со2+ ions in tetrahedral coordination are more efficient than those with such ions in octahedral coordination when equal concentrations of cobalt were used on the surface of the catalysts.

Conglomerated system of Ag nanoparticles decorated Al2O3 supported cobalt and copper complexes with enhanced catalytic activity for oxidation reactions

2019 ◽  
Vol 462 ◽  
pp. 104-113 ◽  
Author(s):  
Tonmoy Chakraborty ◽  
Aratrika Chakraborty ◽  
Suvendu Maity ◽  
Debasis Das ◽  
Tanmay Chattopadhyay
Keyword(s):  
Catalytic Activity ◽  
Ag Nanoparticles ◽  
Copper Complexes ◽  
Oxidation Reactions

Green Oxidation Reactions by Polyoxometalate-Based Catalysts: From Molecular to Solid Catalysts

2010 ◽  
Vol 53 (13-14) ◽  
pp. 876-893 ◽  
Author(s):  
Noritaka Mizuno ◽  
Keigo Kamata ◽  
Kazuya Yamaguchi
Keyword(s):  
Oxidation Reactions ◽  
Solid Catalysts ◽  
Green Oxidation ◽  
Green Oxidation Reactions

scholarly journals The Study on the Reaction Order and Kinetics of Total Oxidation Reaction of m-xylene over LaMnO3 Perovskite Catalyst

2018 ◽  
Vol 34 (3) ◽  
Author(s):  
Tran Thi Thu Huyen ◽  
Dang Thi Minh Hue ◽  
Nguyen Thi Tuyet Mai ◽  
Tran Thi Luyen ◽  
Nguyen Thi Lan
Keyword(s):  
Catalytic Activity ◽  
Reaction Order ◽  
Catalytic Properties ◽  
Sol Gel ◽  
Deep Oxidation ◽  
Perovskite Oxide ◽  
Mixed Metal Oxide ◽  
Total Oxidation ◽  
Kinetics Of ◽  
Perovskite Type

Gases of m-xylene is one of the popurlar toxic pollutants in the exhaust gases, it is emitted into the environment from factories and engines because the fuel in the engine does not burn completely. The best solution in order to remove this toxic gases of m-xylene to protect the environment is transforming them completely into CO2 and H2O by catalysts. Perovskite of LaMnO3 is one of the catalysts that was synthesized and studied the catalytic properties in total oxidation of m-xylene in our previous report. Obtained results showed that the LaMnO3 perovskite has good catalytic characterizations such as large surface area and the amount of α-oxygen adsorbed on the catalyst is large too. So, it exhibits a good catalytic activity in total oxidation of m-xylene at relatively low reaction temperature. In present work, the reaction order  and kinetics of this reaction are determined. The obtained results demonstrated that the reaction order value with respect to m-xylene is equal to about 1, to oxygene is proximately equal to 0 and the order of reaction is equal to about 1. Based on reaction order data, it was thought that the pathway of m-xylene oxidation by air oxygen  over LaMnO3 may be followed through which the Langmuir - Hinshelwood mechanism. Keywords Catalyst, perovskite, oxidation, m-xylene, kinetics References [1] Penã M.A and Fierro J.L.G (2001), << Chemical Stuctures and Performance of Perovskite Oxide>>, Chem. Rev, 101, pp 1981-2018. [2] Seiyama T., Yamazoe N. and Eguchi K. (1985), <<Characterization and Activity of some Mixed Metal Oxide Catalysts>>, Ind. Eng. Chem. Prod. Res. Dev., 24, pp. 19-27.[3] [3] Van Santen R. A., Neurock M. (2006), Molecular Heterogeneous catalysis, Wiley – VCH, pp.62-244. [4] Petrovics, Terlecki - Baricevic A., Karanovic Lj., Kirilov - Stefanov P. , Zdujic M., Dondur V., Paneva D., Mitov I., Rakic V. (2008), <<LaMO3 (M = Mg, Ti, Fe) perovskite type oxides : Preparation, Characterization and Catalytic Properties in Methane deep Oxidation>>, Appl. Catal. B, Env., 79, pp. 186-198. [5] Spinicci R., Tofanari A., Faticanti M., Pettiti I. and Porta P. (2001), <<Hexane Total Oxidation on LaMO3 (M = Mn, Co, Fe) perovskite-type oxides>>, J. Mole. Catal., 176, pp. 247-252. [6] Trần Thị Thu Huyền, Nguyễn Thị Minh Hiền, Nguyễn Hữu Phú (2006), <<Study on the preparation of perovskite oxides La1-xSrxMnO3 (x = 0; 0,3; 0,5) by sol - gel citrate method and their catalytic activity for m-xylene toltal oxidation>>, Hội nghị xúc tác và hấp phụ toàn quốc lần thứ IV, Tp. Hồ Chí Minh, Tr. 477-482.[7] Trần Thị Thu Huyền, Nguyễn Thị Minh Hiền, Nguyễn Hữu Phú (2009), <<Nghiên cứu động học của phản ứng oxi hóa hoàn toàn m-xylen trên các xúc tác perovskit LaMnO3 và La0,7A0,3MnO3 (A = Sr, Ca, Mg)>>, Tạp chí Hóa học, T.47 (6A), Tr 132-136.[8] Geoffrey C. Bond, Catherine Louis, David T. Thompson (2006), <<Catalysis by Gold>>, Catalytic Science Series-Vol.6.

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