Application of a nonisothermal thermogravimetric method to the kinetic study of the reduction of metallic oxides: Part I. A general treatment and its application to the reduction of the oxides of molybdenum by hydrogen

1992 ◽  
Vol 23 (3) ◽  
pp. 317-324 ◽  
Author(s):  
Du Sichen ◽  
S. Seetharaman
Keyword(s):  
Kinetic Study ◽  
General Treatment ◽  
Thermogravimetric Method ◽  
Metallic Oxides

scholarly journals Study of thermal behavior of phytic acid

2013 ◽  
Vol 49 (2) ◽  
pp. 275-283 ◽  
Author(s):  
André Luis Máximo Daneluti ◽  
Jivaldo do Rosário Matos
Keyword(s):  
Thermal Decomposition ◽  
Thermal Behavior ◽  
Mass Loss ◽  
Kinetic Study ◽  
Phytic Acid ◽  
Absorption Spectroscopy ◽  
Elemental Analysis ◽  
Reaction Order ◽  
Dehydration Process ◽  
Thermogravimetric Method

Phytic acid is a natural compound widely used as depigmenting agent in galenic cosmetic emulsions. However, we have observed experimentally that phytic acid, when heated to 150 ºC for around one hour, shows evidence of thermal decomposition. Few studies investigating this substance alone with regard to its stability are available in the literature. This fact prompted the present study to characterize this species and its thermal behavior using thermal analysis (TG/DTG and DSC) and to associate the results of these techniques with those obtained by elemental analysis (EA) and absorption spectroscopy in the infrared region. The TG/DTG and DSC curves allowed evaluation of the thermal behavior of the sample of phytic acid and enabled use of the non-isothermal thermogravimetric method to study the kinetics of the three main mass-loss events: dehydration I, dehydration II and thermal decomposition. The combination of infrared absorption spectroscopy and elemental analysis techniques allowed evaluation of the intermediate products of the thermal decomposition of phytic acid. The infrared spectra of samples taken during the heating process revealed a reduction in the intensity of the absorption band related to O-H stretching as a result of the dehydration process. Furthermore, elemental analysis results showed an increase in the carbon content and a decrease in the hydrogen content at temperatures of 95, 150, 263 and 380 °C. Visually, darkening of the material was observed at 150 °C, indicating that the thermal decomposition of the material started at this temperature. At a temperature of 380 °C, thermal decomposition progressed, leading to a decrease in carbon and hydrogen. The results of thermogravimetry coupled with those of elemental analysis allow us to conclude that there was agreement between the percentages of phytic acid found in aqueous solution. The kinetic study by the non-isothermal thermogravimetric method showed that the dehydration process occurred in two stages. Dehydration step I promoted a process of vaporization of water (reaction order of zero), whereas dehydration step II showed an order of reaction equal to five. This change in reaction order was attributed to loss of chemically bonded water molecules of phytic acid or to the presence of volatile substances. Finally, the thermal decomposition step revealed an order of reaction equal to one. It was not possible to perform the kinetic study for other stages of mass loss.

scholarly journals Kinetic Study of the Catalytic Pyrolysis of Oil-Containing Waste

2016 ◽  
Vol 11 (3) ◽  
pp. 330 ◽  
Author(s):  
Kirill Chalov ◽  
Yury Lugovoy ◽  
Yury Kosivtsov ◽  
Mikhail Sulman ◽  
Esther Sulman ◽  
...  
Keyword(s):  
Experimental Data ◽  
Kinetic Study ◽  
Catalytic Pyrolysis ◽  
Reaction Engineering ◽  
Catalyst Loading ◽  
Kinetic Investigation ◽  
Optimal Conditions ◽  
Optimal Parameters ◽  
Pyrolysis Process ◽  
Thermogravimetric Method

<p>Basing on the experimental data the optimal parameters of the pyrolysis of heavy and residual hydrocarbons of oil were defined as follows: temperature of 500 °С; catalyst  of CoCl<sub>2</sub> with the catalyst loading 5% (wt.) of the substrate weight. Under the optimal conditions the kinetic investigation of the pyrolysis process was carried out using the thermogravimetric method. According to the investigation, it was found that the activation energy of the catalytic pyrolysis of oil-containing waste decreased by 20-30 kJ/mol in comparison to non-catalytic process. Copyright © 2016 BCREC GROUP. All rights reserved</p><p><em>Received: 13<sup>th</sup> July 2015; Revised: 25<sup>th</sup> March 2016; Accepted: 1<sup>st</sup> April 2016</em></p><p><strong>How to Cite:</strong> Chalov, K., Lugovoy, Y., Kosivtsov, Y., Sulman, M., Sulman, E., Matveeva, V., Stepacheva, A. (2016). Kinetic Study of the Catalytic Pyrolysis of Oil-Containing Waste. <em>Bulletin of Chemical Reaction Engineering &amp; Catalysis</em>, 11 (3): 330-338 (doi:10.9767/bcrec.11.3.572.330-338)</p><p><strong>Permalink/DOI:</strong> <a href="http://doi.org/10.9767/bcrec.11.3.572.330-338">http://doi.org/10.9767/bcrec.11.3.572.330-338</a></p>

A kinetic study of controlling nitrogen in process for boron steel by using30N2isotope gas

2008 ◽  
Vol 105 (12) ◽  
pp. 601-608
Author(s):  
Seung Min Han ◽  
Dong Joon Min ◽  
Joo Hyun Park ◽  
Jung Ho Park ◽  
Jong Min Park
Keyword(s):  
Kinetic Study ◽  
Boron Steel

Kinetic Study of the Effect of Heparin on the Amidase Activity of Trypsin, Plasmin and Urokinase

1983 ◽  
Vol 49 (03) ◽  
pp. 199-203 ◽  
Author(s):  
V M Yomtova ◽  
N A Stambolieva ◽  
B M Blagoev
Keyword(s):  
Kinetic Study ◽  
Active Center ◽  
Simultaneous Presence ◽  
Amidase Activity ◽  
Competitive Inhibitors ◽  
Uncompetitive Inhibitor

SummaryIt was found that the effect of heparin on the amidase activity of urokinase (E C 3.4.21.31), plasmin (E C 3.4.21.7) and trypsin (E C 3.4.21.4) depended on the substrate used. No effect of heparin on the amidase activity of urokinase and trypsin was observed when Pyro Glu-Gly-Arg-p-nitroanilide (S-2444) and α-N-acetyl-L-lysine-p-nitroanilide (ALNA) were used as substrates. Heparin acted as a uncompetitive inhibitor of trypsin (Ki = 1.2×10-6 M), plasmin (Ki = 4.9×10-6 M) and urokinase (Ki = l.0×10-7 M) when Bz-Phe-Val-Arg-p-nitroanilide (S-2160), H-D-Val-Leu-Lys-p-nitroanilide (S-2251) and plasminogen, respectively, were used as substrates. These results, as well as the data obtained by studying the effect of the simultaneous presence of heparin and competitive inhibitors suggest that although heparin is not bound at the active center of these enzymes, it may influence the effectivity of catalysis.

A kinetic study of the metathesis of propene on a rhenium-aluminium catalyst

1981 ◽  
Vol 31 (1) ◽  
pp. 388-394 ◽  
Author(s):  
Mahmoud El-Sawi ◽  
Antonio Iannibello ◽  
Fernando Morelli ◽  
Ganfranco Gatalano ◽  
Francesco Intrieri ◽  
...  
Keyword(s):  
Kinetic Study
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