Catalytic Activity of Binary and Triple Systems Based on Redox Inactive Metal Compound, LiSt and Additives of Monodentate Ligands-Modifiers: DMF, HMPA and PhOH, in Selective Ethylbenzene Oxidation with Dioxygen

2016 ◽  
Vol 10 (3) ◽  
pp. 259-270
Author(s):  
Ludmila Matienko ◽  
◽  
Larisa Mosolova ◽  
Vladimir Binyukov ◽  
Gennady Zaikov ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Triple System ◽  
Metal Compound ◽  
Ethylbenzene Oxidation ◽  
Catalytic Systems ◽  
Triple Systems ◽  
Lithium Compound ◽  
Mechanism Of Catalysis ◽  
Monodentate Ligands

Mechanism of catalysis with binary and triple catalytic systems based on redox inactive metal (lithium) compound {LiSt+L2} and {LiSt+L2+PhOH} (L2=DMF or HMPA), in the selective ethylbenzene oxidation by dioxygen into -phenylethyl hydroperoxide is researched. The results are compared with catalysis by nickel-lithium triple system {NiII(acac)2+LiSt+PhOH} in selective ethylbenzene oxidation to PEH. The role of H-bonding in mechanism of catalysis is discussed. The possibility of the stable supramolecular nanostructures formation on the basis of triple systems, {LiSt+L2+PhOH}, due to intermolecular H-bonds, is researched with the AFM method.

THE REGULARITIES OF THE ACTIVE SURFACE FORMATION OF TUNGSTATE-CONTAINING ZIRCONIA AS A CATALYST FOR C7-ALKANES ISOMERIZATION

2019 ◽  
Vol 62 (1-2) ◽  
pp. 73-88
Author(s):  
M.D. Smolikov ◽  
V.A. Shkurenok ◽  
S.S. Yablokova ◽  
D.I. Kir’yanov ◽  
A.S. Belyi
Keyword(s):  
Catalytic Activity ◽  
Synthesis Method ◽  
Active Surface ◽  
Oil Refining ◽  
Catalytic Systems ◽  
Acid Properties ◽  
Highly Active ◽  
Actual Direction ◽  
High Octane

The paraffin hydrocarbons isomerization is one of the most important processes in the oil refining industry, aimed at obtaining high-octane environmental components of modern gasolines. The actual direction in isomerization is the processing of the fraction, containing C7-alkanes. The review is devoted to modern concepts of the active rface formation of tungstate-containing zirconia, which is a highly active catalytic system for the isomerization of heptanes. The review deals with the influence of synthesis method of tungstate-containing zirconia, it’s chemical composition, phase structure and acid properties on the formation of the active surface of WO3/ZrO2 systems and their catalytic activity. The role of platinum in the catalytic systems WO3/ZrO2 for C7-alkanes isomerization is considered.

scholarly journals Ni/CeO2 as catalyst for glycerol hydrogenolysis without external H2 supply: the role of synthesis conditions

2018 ◽  
Vol 6 ◽  
Author(s):  
Clara Jarauta Córdoba ◽  
Lucía García Nieto ◽  
Jesús Arauzo Pérez ◽  
Joaquín Ruiz Palacín ◽  
Miriam Oliva Alcubierre
Keyword(s):  
High Pressure ◽  
Catalytic Activity ◽  
Liquid Phase ◽  
Value Added ◽  
Catalytic Systems ◽  
Synthesis Conditions ◽  
Synthesis Parameters ◽  
Glycerol Hydrogenolysis ◽  
Thermochemical Processes

Aqueous phase processes at high pressure are considered one of the most promising thermochemical processes to valorize wet residual streams, in order to produce value-added chemicals. Among them, glycerol hidrogenolysis (HG) has been intensely studied. Although many different catalytic systems for HG have been studied in the last years, the Ni/CeO2 catalytic system has not been so deeply performed in liquid phase.  This work studies the hydrogenolysis of glycerol without external H2 supply as a pathway to obtain value-added chemicals using Ni/CeO2 catalysts. Different synthesis parameters were changed, in order to determine their influence on the catalytic activity. In this process, 1,2–propanediol and ethylene glycol are produced, compounds which are valuable due to their use in chemical synthesis, antifreeze fluids, and others.

scholarly journals Metal Complexes Bearing Sulfur-Containing Ligands as Catalysts in the Reaction of CO2 with Epoxides

Catalysts ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 825
Author(s):  
Veronica Paradiso ◽  
Vito Capaccio ◽  
David Hermann Lamparelli ◽  
Carmine Capacchione
Keyword(s):  
Catalytic Activity ◽  
Metal Complexes ◽  
Crucial Role ◽  
Comprehensive Overview ◽  
Catalytic Systems ◽  
Organic Carbonates ◽  
Sulfur Containing

Coupling of CO2 with epoxides is a green emerging alternative for the synthesis of cyclic organic carbonates (COC) and aliphatic polycarbonates (APC). The scope of this work is to provide a comprehensive overview of metal complexes having sulfur-containing ligands as homogeneous catalytic systems able to efficiently promote this transformation with a concise discussion of the most significant results. The crucial role of sulfur as the hemilabile ligand and its influence on the catalytic activity are highlighted as well.

Nickel (II) and oxovanadium (IV) complexes supported on MCM-41 mesoporous and their application in catalytic selective sulfide and thiol oxidation

2020 ◽  
Vol 23 ◽  
Author(s):  
Mohsen Nikoorazm ◽  
Maryam Khanmoradi ◽  
Masoumeh Sayadian
Keyword(s):  
Catalytic Activity ◽  
Room Temperature ◽  
Sol Gel ◽  
Reaction Times ◽  
Significant Loss ◽  
Spectral Studies ◽  
High Catalytic Activity ◽  
Catalytic Systems ◽  
Solvent Free Conditions ◽  
Mcm 41

Introduction:: MCM-41 was synthesized using the sol-gel method. Then two new transition metal complexes of Nickel (II) and Vanadium (IV), were synthesized by immobilization of adenine (6-aminopurine) into MCM-41 mesoporous. The compounds have been characterized by XRD, TGA, SEM, AAS and FT-IR spectral studies. Using these catalysts provided an efficient and enantioselective procedure for oxidation of sulfides to sulfoxides and oxidative coupling of thiols to their corresponding disulfides using hydrogen peroxide at room temperature. Materials and Methods:: To a solution of sulfide or thiol (1 mmol) and H2O2 (5 mmol), a determined amount of the catalyst was added. The reaction mixture was stirred at room temperature for the specific time under solvent free conditions. The progress of the reaction was monitored by TLC using n-hexane: acetone (8:2). Afterwards, the catalyst was removed from the reaction mixture by centrifugation and, then, washed with dichloromethane in order to give the pure products. Results:: All the products were obtained in excellent yields and short reaction times indicating the high activity of the synthesized catalysts. Besides, the catalysts can be recovered and reused for several runs without significant loss in their catalytic activity. Conclusion:: These catalytic systems furnish the products very quickly with excellent yields and VO-6AP-MCM-41 shows high catalytic activity compared to Ni-6AP-MCM-41.

Hydrogen peroxide decomposition on a two-component CuO-Cr2O3 catalyst

1988 ◽  
Vol 53 (8) ◽  
pp. 1636-1646 ◽  
Author(s):  
Viliam Múčka ◽  
Kamil Lang
Keyword(s):  
Hydrogen Peroxide ◽  
Catalytic Activity ◽  
Extreme Values ◽  
Catalytic Properties ◽  
Active Components ◽  
Catalytic Systems ◽  
Heterogeneous Catalytic ◽  
Peroxide Decomposition ◽  
Two Component ◽  
Catalytically Active

Some physical and catalytic properties of the two-component copper(II)oxide-chromium(III)oxide catalyst with different content of both components were studied using the decomposition of the aqueous solution of hydrogen peroxide as a testing reaction. It has been found that along to both basic components, the system under study contains also the spinel structure CuCr2O4, chromate washable by water and hexavalent ions of chromium unwashable by water. The soluble chromate is catalytically active. During the first period of the reaction the equilibrium is being established in both homogeneous and heterogeneous catalytic systems. The catalytic activity as well as the specific surface area of the washed solid is a non-monotonous function of its composition. It seems highly probable that the extreme values of both these quantities are not connected with the detected admixtures in the catalytic system. The system under study is very insensitive with regard to the applied doses of gamma radiation. Its catalytic properties are changed rather significantly after the thermal treatment and particularly after the partial reduction to low degree by hydrogen. The observed changes of the catalytic activity of the system under study are very probably in connection with the changes of the valence state of the catalytically active components of the catalyst.

scholarly journals Catalytic Systems Based on Cp2ZrX2 (X = Cl, H), Organoaluminum Compounds and Perfluorophenylboranes: Role of Zr,Zr- and Zr,Al-Hydride Intermediates in Alkene Dimerization and Oligomerization

Catalysts ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 39
Author(s):  
Lyudmila V. Parfenova ◽  
Pavel V. Kovyazin ◽  
Almira Kh. Bikmeeva ◽  
Eldar R. Palatov
Keyword(s):  
Diffusion Coefficients ◽  
Organoaluminum Compounds ◽  
Zirconium Hydride ◽  
Nmr Studies ◽  
Catalytic Systems ◽  
Selective Formation

The activity and chemoselectivity of the Cp2ZrCl2-XAlBui2 (X = H, Bui) and [Cp2ZrH2]2-ClAlEt2 catalytic systems activated by (Ph3C)[B(C6F5)4] or B(C6F5)3 were studied in reactions with 1-hexene. The activation of the systems by B(C6F5)3 resulted in the selective formation of head-to-tail alkene dimers in up to 93% yields. NMR studies of the reactions of Zr complexes with organoaluminum compounds (OACs) and boron activators showed the formation of Zr,Zr- and Zr,Al-hydride intermediates, for which diffusion coefficients, hydrodynamic radii, and volumes were estimated using the diffusion ordered spectroscopy DOSY. Bis-zirconium hydride clusters of type x[Cp2ZrH2∙Cp2ZrHCl∙ClAlR2]∙yRnAl(C6F5)3−n were found to be the key intermediates of alkene dimerization, whereas cationic Zr,Al-hydrides led to the formation of oligomers.

scholarly journals Role of CO2 During Oxidative Dehydrogenation of Propane Over Bulk and Activated-Carbon Supported Cerium and Vanadium Based Catalysts

2021 ◽  
Author(s):  
Petar Djinović ◽  
Janez Zavašnik ◽  
Janvit Teržan ◽  
Ivan Jerman
Keyword(s):  
Catalytic Activity ◽  
Activated Carbon ◽  
Oxidative Dehydrogenation ◽  
Active Phase ◽  
Lattice Oxygen ◽  
Chemisorbed Oxygen ◽  
Catalytically Active ◽  
Temperature Programmed ◽  
Propane Cracking

AbstractCeO2, V2O5 and CeVO4 were synthesised as bulk oxides, or deposited over activated carbon, characterized by XRD, HRTEM, CO2-TPO, C3H8-TPR, DRIFTS and Raman techniques and tested in propane oxidative dehydrogenation using CO2. Complete oxidation of propane to CO and CO2 is favoured by lattice oxygen of CeO2. The temperature programmed experiments show the ~ 4 nm AC supported CeO2 crystallites become more susceptible to reduction by propane, but less prone to re-oxidation with CO2 compared to bulk CeO2. Catalytic activity of CeVO4/AC catalysts requires a 1–2 nm amorphous CeVO4 layer. During reaction, the amorphous CeVO4 layer crystallises and several atomic layers of carbon cover the CeVO4 surface, resulting in deactivation. During reaction, V2O5 is irreversibly reduced to V2O3. The lattice oxygen in bulk V2O5 favours catalytic activity and propene selectivity. Bulk V2O3 promotes only propane cracking with no propene selectivity. In VOx/AC materials, vanadium carbide is the catalytically active phase. Propane dehydrogenation over VC proceeds via chemisorbed oxygen species originating from the dissociated CO2. Graphic Abstract

scholarly journals Role of arginine 292 in the catalytic activity of chondroitin AC lyase from Flavobacterium heparinum

2002 ◽  
Vol 1597 (2) ◽  
pp. 260-270 ◽  
Author(s):  
Ishan Capila ◽  
Yi Wu ◽  
David W Rethwisch ◽  
Allan Matte ◽  
Miroslaw Cygler ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Chondroitin Ac Lyase ◽  
Flavobacterium Heparinum

Isomerization ofn-butane on sulfated zirconia: Evidence for the dominant role of Lewis acidity on the catalytic activity

1994 ◽  
Vol 26 (3-4) ◽  
pp. 339-344 ◽  
Author(s):  
F. Pinna ◽  
M. Signoretto ◽  
G. Strukul ◽  
G. Cerrato ◽  
C. Morterra
Keyword(s):  
Catalytic Activity ◽  
Sulfated Zirconia ◽  
Dominant Role ◽  
Lewis Acidity
Sign in / Sign up

Export Citation Format

Share Document