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.

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.

SINGULARITY FEATURES OF PORE-SIZE SOIL DISTRIBUTION: SINGULARITY STRENGTH ANALYSIS AND ENTROPY SPECTRUM

Fractals ◽  
2001 ◽  
Vol 09 (03) ◽  
pp. 305-316 ◽  
Author(s):  
F. J. CANIEGO ◽  
M. A. MARTÍN ◽  
F. SAN JOSÉ
Keyword(s):  
Image Analysis ◽  
Pore Size ◽  
Soil Samples ◽  
Second Step ◽  
Strength Analysis ◽  
Entropy Spectrum ◽  
Singular Measures ◽  
Experimental Measure ◽  
Soil Distribution ◽  
Smooth Density

In this paper, several features of pore-size soil distribution are first analyzed, suggesting that they are closer to those of singular measures than to those of distributions with smooth density. In a second step, the weighted singularity strength of an experimental measure obtained by image analysis of soil samples is evaluated. The results of this analysis show the singular nature of pore-size distribution. Finally, the distribution is characterized by means of a spectrum of entropies computed on distorted measures associated with the original experimental measure.

Oxidation of alkyl thiocyanates by peroxomonosulphate in acidic aqueous solution

1971 ◽  
Vol 24 (12) ◽  
pp. 2481 ◽  
Author(s):  
GJ Bridgart ◽  
IR Wilson
Keyword(s):  
Aqueous Solution ◽  
Rate Coefficient ◽  
Second Step ◽  
Consecutive Reaction ◽  
Comparable Rate ◽  
Acidic Aqueous Solution

Studies of the rates and mechanisms of oxidation of four alkyl thiocyanates by peroxomonosulphate are reported, Analysis of the data is consistent with the occurrence of two consecutive reaction steps of comparable rate coefficient. The product of the second step appears to be the sulphonyl cyanide, RSO2CN.

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.

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.

CATALYSIS OF THE CIS-TRANS ISOMERIZATION OF AZOBENZENE BY ACIDS AND CUPRIC SALTS

1959 ◽  
Vol 37 (11) ◽  
pp. 1903-1910 ◽  
Author(s):  
Stefania Ciccone ◽  
J. Halpern
Keyword(s):  
Acetic Acid ◽  
Hydrochloric Acid ◽  
Catalytic Effect ◽  
Catalytic Mechanism ◽  
Aqueous Ethanol ◽  
Metal Salts ◽  
Trans Isomerization ◽  
Conjugate Acid ◽  
Azo Group ◽  
Catalytic Effects

The catalytic effects of various acids and metal salts on the cis-trans isomerization of azobenzene in aqueous ethanol were examined kinetically. The effect of perchloric acid is apparently due to H+ ions and is interpreted in terms of a catalytic mechanism involving the conjugate acid of azobenzene. The much greater catalytic effect found for hydrochloric acid is attributed to an additional path involving catalysis by the undissociated acid. Acetic acid was found to be inactive. Of the metal salts examined only those of Cu++ showed pronounced activity which was attributed to co-ordination with the azo group. Kinetic evidence was obtained for a catalytic path involving Cu++ and H+ simultaneously.

scholarly journals Direct catalytic effect of nitrogen functional groups exposed on graphenic materials when acting cooperatively with Ru nanoparticles

RSC Advances ◽  
2017 ◽  
Vol 7 (70) ◽  
pp. 44568-44577 ◽  
Author(s):  
Carolina Ramirez-Barria ◽  
Cristina López-Olmos ◽  
Antonio Guerrero-Ruiz ◽  
Inmaculada Rodríguez-Ramos
Keyword(s):  
Functional Groups ◽  
Aqueous Phase ◽  
Catalytic Effect ◽  
Carbon Materials ◽  
Ru Nanoparticles ◽  
Phase Oxidation ◽  
Furandicarboxylic Acid ◽  
Catalytic Effects

Various carbon materials (including doped graphenic materials) have been used as supports of Ru nanoparticles to determine their catalytic effects in the base-free aqueous-phase oxidation of 5-hydroxymethylfurfural to 2,5-furandicarboxylic acid.

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.

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