scholarly journals ‘Oxygen-Consuming Complexes’–Catalytic Effects of Iron–Salen Complexes with Dioxygen

Catalysts ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1462
Author(s):  
Katarzyna Rydel-Ciszek ◽  
Tomasz Pacześniak ◽  
Anna Miłaczewska ◽  
Paweł Chmielarz ◽  
Andrzej Sobkowiak
Keyword(s):  
Dft Calculations ◽  
Catalytic Effect ◽  
Active Species ◽  
Cyclohexene Oxidation ◽  
Effective Catalyst ◽  
Salen Complex ◽  
Salen Complexes ◽  
Catalytic Effects

[(salen)FeIII]+MeCN complex is a useful catalyst for cyclohexene oxidation with dioxygen. As the main products, ketone and alcohol are formed. In acetonitrile, [(salen)FeII]MeCN is rapidly oxidized by dioxygen, forming iron(III) species. Voltammetric electroreduction of the [(salen)FeIII]+MeCN complex in the presence of dioxygen causes the increase in current observed, which indicates the existence of a catalytic effect. Further transformations of the oxygen-activated iron(III) salen complex generate an effective catalyst. Based on the catalytic and electrochemical results, as well as DFT calculations, possible forms of active species in c-C6H10 oxidation have been proposed.

Effect of the ionizing radiation on the catalytic activity of the BASF K-3-10 catalyst in the low-temperature conversion of carbon monoxide by water vapour. Stability of the radiation catalytic effects

1986 ◽  
Vol 51 (8) ◽  
pp. 1571-1578 ◽  
Author(s):  
Alois Motl
Keyword(s):  
Carbon Monoxide ◽  
Catalytic Activity ◽  
Low Temperature ◽  
Catalytic Effect ◽  
Catalytic Properties ◽  
Beta Radiation ◽  
Fast Neutrons ◽  
Time Interval ◽  
The Stability ◽  
Catalytic Effects

The radiation catalytic properties of the BASF K-3-10 catalyst were studied, namely the dependence of these effects on the time interval between the catalyst irradiation and the reaction itself and also on the length of the catalyst use. The catalytic effects decrease exponentially with the interval between the irradiation and the reaction if the catalyst is kept in the presence of air. The stability of effects induced by various types of radiations increases in the sequence beta radiation - gamma radiation - fast neutrons. The radiation catalytic effect stability in the reaction increases in the same sequence.

scholarly journals The catalytic effects of sulfur in ethane dehydroaromatization

2020 ◽  
Vol 56 (40) ◽  
pp. 5378-5381 ◽  
Author(s):  
Farnoosh Goodarzi ◽  
Lars P. Hansen ◽  
Stig Helveg ◽  
Jerrik Mielby ◽  
Thoa T. M. Nguyen ◽  
...  
Keyword(s):  
Catalytic Effect ◽  
Direct Conversion ◽  
Catalytic Effects

In this work, we investigated the catalytic effect of adding sulfur on Zn/ZSM-5 catalyst for direct conversion of ethane to aromatics.

Studies of catalysis in fluoride solutions

1956 ◽  
Vol 234 (1197) ◽  
pp. 192-207 ◽  
Keyword(s):  
Hydrogen Fluoride ◽  
Acid Catalysis ◽  
Catalytic Effect ◽  
Base Catalysis ◽  
Hydrogen Ions ◽  
Acid Base ◽  
Fluoride Ions ◽  
Buffer Solutions ◽  
Catalytic Effects ◽  
Hydrolysis Of

Measurements are reported of the catalytic effect of aqueous hydrogen fluoride and fluoride buffer solutions in the following eight reactions: the hydrolysis of diethyl acetal, the depoly­merization of paraldehyde, the decomposition of nitramide, the bromination of ethyl acetoacetate and of ethyl cyclo pentanone-2-carboxylate, the iodination of acetonylacetone and of acetone, and the dehydration of acetaldehyde hydrate. In the first two, which are specifically catalyzed by hydrogen ions, the catalytic effect of the fluoride systems corre­sponds to the calculated hydrogen-ion concentrations, and it is suggested that under some conditions fluoride buffer solutions may be particularly useful for controlling pH. In the remaining six reactions there is also general acid-base catalysis by hydrogen fluoride mole­cules, or by fluoride ions, or by both. The catalytic effects of these two species are close to those predicted by relations previously established for carboxylic acids and their anions. The bifluoride ion has approximately the same effect as hydrogen fluoride in acid catalysis but has no detectable catalytic effect as a base. These findings are discussed in terms of the structures and thermodynamic properties of the species concerned.

Über den Einfluß äußerer Magnetfelder auf die Aktivität ferromagnetischer Katalysatoren

1953 ◽  
Vol 8 (9) ◽  
pp. 538-546 ◽  
Author(s):  
E. Justi ◽  
G. Vieth
Keyword(s):  
Catalytic Activity ◽  
Nickel Powder ◽  
Catalytic Effect ◽  
Theoretical Treatment ◽  
High Catalytic Activity ◽  
Experimental Proof ◽  
Apparent Lack ◽  
Low Field ◽  
Order Of Magnitude ◽  
Catalytic Effects

J.A. Hedvall has discovered “internal” magneto-catalytic effects; the activity of ferromagnetic catalyst changes upon transgressing the Curie-interval. The present publication deals with finding an “external” magneto-catalytic effect consisting of the influence of external magnetic fields upon the activity of ferromagnetic catalysts. This can be shown quite clearly in capillaries of high purity ferromagnetic nickel by experiments applying the o-p-hydrogen conversion. In this reaction the conversion rises so steeply with relatively low field strengths that even the magnetic earth field should enhance the catalytic activity of nickel in compact form; a few hundred oersted may suffice for doubling the conversion and at some 1000 or 10.000 oersted a saturation value of the conversion is reached. The connection between catalytic activity and magnetism finds further support by a corresponding catalytic retentivity.From the theory of ferromagnetism, especially the studies of Néel, it is known that extremely small ferromagnetic particles of the order of magnitude of Blochs walls, i. e. some 10—4 mm, posses high permanent magnetism. This fact appears significant in this connection for the high catalytic activity of finely divided powder catalysts such as Raney catalysts. This permanent magnetism explains also the apparent lack of the external magneto-catalytic effect when using a nickel powder catalyst. The theoretical treatment of the results cannot yet give a definite explanation; before this can be given the experiments must be extended to ordinary chemical reactions. To this end the prerequisits for such experiments are being established.Independently thereof the experimental proof for the external catalytic effect serves to ascertain that the internal Hedvall effects are primarily correlated to the ferromagnetic and paramagnetic states of matter.

scholarly journals Synthesis, Characterisation and Cytotoxic Activity Evaluation of New Metalsalen Complexes Based on the 1,2-bicyclo[2.2.2]octane Bridge

2020 ◽  
Author(s):  
Pierre Milbeo ◽  
François Quintin ◽  
Laure Moulat ◽  
Claude Didierjean ◽  
Jean Martinez ◽  
...  
Keyword(s):  
Cytotoxic Activity ◽  
Ball Mill ◽  
Hct116 Cell ◽  
High Yield ◽  
Cytotoxic Activities ◽  
Salen Complex ◽  
Salen Complexes ◽  
Preparation Route ◽  
The One ◽  
Salen Ligand

Diaminobicyclo[2.2.2]octane was used as starting material for the preparation, in solution or in a ball-mill, of a salen ligand. Five metal salen complexes were prepared in high yield and their cytotoxic activities were evaluated against HCT116 cell lines. Original manganese salen complex displayed the highest activity with a potency 16 fold higher than the one of cisplatin, demonstrating the benefit of the bridging backbone, compared to other salen systems. An alternative preparation route for this complex by mechanochemistry was also performed.<br>

scholarly journals Probing the Catalytically Active Species in POM-Catalyzed DNAmodel Hydrolysis

2020 ◽  
Author(s):  
Frederico Martins ◽  
Ángel Sanchez-Gonzalez ◽  
Jose Lanuza ◽  
Haralampos Miras ◽  
Xabier Lopez ◽  
...  
Keyword(s):  
Density Functional ◽  
Catalytic Effect ◽  
Molecular Model ◽  
Active Species ◽  
Functional Theory ◽  
Spectrometric Data ◽  
Ionisation Mass Spectrometry ◽  
Data Density ◽  
Catalytically Active ◽  
Hydrolysis Of

<div>Phosphoester hydrolysis is an important chemical step in DNA repair. One archetypal molecular model of phosphoesters is para-nitrophenylphosphate (pNPP). It has been shown previously that the presence of molecular metal oxide [Mo7O24]6– may catalyse the hydrolysis of pNPP through the partial decomposition of polyoxomolybdate framework resulting in a [(PO4)2Mo5O15]6– product. Real-time monitoring of the catalytic system using electrospray ionisation mass spectrometry (ESI-MS) provided a glance into the species present in the reaction mixture. Following up on the obtained spectrometric data, Density Functional Theory (DFT) calculations were carried out to characterise the hypothetical intermediate [Mo5O15(pNPP)2(H2O)6]6–</div><div>that would be required to form under the</div><div>hypothesised transformation. Surprisingly, our results point to the dimeric [Mo2O8]4- anion resulting from the decomposition of [Mo7O24]6– as the active catalytic species involved in the hydrolysis of pNPP rather than the originally assumed {Mo5O15} skeleton. A similar study was carried out involving the same species but substituting Mo by W. The mechanism involving W species showed a higher barrier and less stable products in agreement with the non-catalytic effect found in experimental results.</div>

Efficiency of Salen Functionalized Ionic Liquids and their Application towards Biological Activity

2020 ◽  
Vol 13 (4) ◽  
pp. 5020-5027
Author(s):  
C. Isac Sobanara ◽  
M. Antilin Princela
Keyword(s):  
Ionic Liquid ◽  
Biological Activity ◽  
Metal Ions ◽  
Morphological Changes ◽  
Vital Role ◽  
Spectroscopic Techniques ◽  
Salen Complex ◽  
Salen Complexes ◽  
Ft Ir ◽  
Ancient Times

Schiff bases were often used as chelating ligands for the stabilization of metal ions with various oxidation states. It is called privileged ligands, due to their own peculiar capacity to make a four and six coordinated salen complex to stabilize the metal ions. On the other hand, Ionic liquid (IL) also plays a key material in engineering and scientific fields. Due to their own physiochemical properties and widespread applications in different areas of research. It has been recently found that, the suitable choice and appropriate size of cation and anion can alter the geometry of ILs and it directly influenced the biological activity of ILs. Herein ionic liquid tagged new salen complexes of first row transition metals such as Fe, Co, Ni, Cu and Zn have been synthesized successfully and characterized. The structure of synthesized salen complexes were studied by UV, FT-IR, NMR and Mass spectroscopic techniques. Metal complexes play a vital role in drug discovery since ancient times. Especially, these complexes can interact with the cell membrane and make the morphological changes in the affected site. Moreover, the efficiency of salen complexes were assessed by antimicrobial and antifungal studies. Among all the IL tagged salen complexes the Ionic liquid tagged cobalt salen complexes was very effective against the tested microorganisms.

scholarly journals Thermo-Acoustic Catalytic Effect on Oxidizing Woody Torrefaction

Processes ◽  
2020 ◽  
Vol 8 (11) ◽  
pp. 1361 ◽  
Author(s):  
Edgar A. Silveira ◽  
Luiz Gustavo Oliveira Galvão ◽  
Lucélia Alves de Macedo ◽  
Isabella A. Sá ◽  
Bruno S. Chaves ◽  
...  
Keyword(s):  
Catalytic Effect ◽  
Eucalyptus Grandis ◽  
Severity Index ◽  
Second Step ◽  
Strength Analysis ◽  
Consecutive Reaction ◽  
Acoustic Coupling ◽  
Conversion Rates ◽  
Mild Pyrolysis ◽  
Catalytic Effects

The torrefaction (mild pyrolysis) process modifies biomass chemical and physical properties and is applied as a thermochemical route to upgrade solid fuel. In this work, the catalytic effect of thermo-acoustic on oxidizing woody torrefaction is assessed. The combined effect of two acoustic frequencies (1411, 2696 Hz) and three temperatures (230, 250, and 290 °C) was evaluated through weight loss and its deviation curves, calculated torrefaction severity index (TSI), as well as proximate, calorific, and compression strength analysis of Eucalyptus grandis. A new index to account for the catalytic effects on torrefaction (TCEI) was introduced, providing the quantitative analysis of acoustic frequencies influence. A two-step consecutive reaction numerical model allowed the thermo-acoustic experiment evaluation. For instance, the thermogravimetric profiles revealed that the acoustic field has a catalytic effect on wood torrefaction and enhances the biomass oxidation process for severe treatments. The kinetic simulation of the acoustic coupling resulted in faster conversion rates for the solid pseudo-components showing the boosting effect of acoustic frequencies in anticipating hemicellulose decomposition and enhancing second step oxidizing reaction.

Catalytic Effect of Active Carbon Black Chezacarb in Wet Oxidation of Phenol

1996 ◽  
Vol 61 (7) ◽  
pp. 1010-1017 ◽  
Author(s):  
Vratislav Tukač ◽  
Jiří Hanika
Keyword(s):  
Carbon Black ◽  
Active Carbon ◽  
Catalytic Effect ◽  
Copper Catalyst ◽  
Copper Catalysts ◽  
Wet Oxidation ◽  
Waste Waters ◽  
Oxidation Of Phenol ◽  
Catalytic Effects ◽  
Active Carbon Black

The catalytic effects of hydrophilic granulated active carbon black Chezacarb have been tested in the oxidation of dilute (5 000 ppm) aqueous solutions of phenol. The research was focused on combined utilization of sorption and chemical (oxygen functional groups) properties of carbon black which support formation of free radicals in oxidation and on the catalytic effects of metals (Fe, Ni and V) present in the sorbent mentioned. The oxidation was carried out in a stainless steel autoclave of 1.25 l capacity. The reaction temperatures and the total pressures varied in the intervals of 120-160 °C and 3-5 MPa, respectively. The reaction mixture was analyzed by means of HPLC with UV detection (254 nm). The experimental data were evaluated by means of the ASPEN PLUS 9.2 program. The model of laboratory autoclave involved the reaction kinetics as well as the phase equilibria and dissolution of oxygen and carbon dioxide in the reaction mixture. Although the active carbon black shows a lower catalytic activity than the usual copper catalyst in the wet oxidation, it has the advantage of avoiding the undesirable releases of heavy metals in waste waters, which escapes accompany the application of copper catalysts.

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