Investigation of kinetics of initial stages of cobalt electrode passivation by voltamperometric method. Experiment and theory of consecutive surface electro-chemical reaction complicated by chemical steps of dissolution intermediates

Diffusion processes play a dominant part in the macro kinetics of Fe, Ni and Co oxidation by calcium and sodium sulfates. Here, the reaction product forms a compact covering which spatially divides the reagents on the surface in the same way as in the oxidation and sulfidization of metals by oxygen and sulfur. Therefore, it is possible to assume in advance that interaction of metals with calcium and sodium sulfates will be determined not by the actual chemical reaction properly but by the diffusion transport processes.

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Study of kinetics of reaction of lignin model compounds with propylene oxide

Holzforschung ◽

10.1515/hf.2008.025 ◽

2008 ◽

Vol 62 (2) ◽

pp. 169-175 ◽

Cited By ~ 3

Author(s):

Krishna K. Pandey ◽

Tapani Vuorinen

Keyword(s):

Chemical Reaction ◽

Propylene Oxide ◽

Aqueous Media ◽

Reaction Products ◽

Model Compounds ◽

Rapid Reduction ◽

Visible Absorption ◽

Lignin Model Compounds ◽

Lignin Model ◽

Kinetics Of

Abstract The etherification of phenolic groups has been found to inhibit photodegradation in wood and lignin rich pulps. The precise understanding of kinetics of chemical reaction between lignins or their model compounds and the etherifying agent is the first step for developing a viable modification procedure. In this study, we have investigated the reaction of lignin model compounds (namely, phenol and guaiacol) with propylene oxide in aqueous media. The kinetics of etherification reaction was studied under varying pH conditions in the temperature range 30–60°C. The etherified reaction products were characterized by gas chromatogram-mass spectrum (GC-MS). The extent of etherification of phenols and the rate of chemical reaction was followed by UV-Visible absorption spectroscopy. The reaction between lignin model compounds and propylene oxide was indicated by a rapid reduction in the absorbance accompanied by the development of a new band corresponding to etherified products. The reaction kinetics was investigated at pH ∼12 under the condition of excess concentration of propylene oxide. The reaction followed first order kinetics and rate constants increased linearly with an increase in the temperature and concentration of propylene oxide. The MS fragment data of reaction product support the proposed reaction scheme. The activation energy of the reaction of propylene oxide with phenol and guaiacol, calculated with the Arrhenius equation, was 56.2 kJ mol-1 and 45.4 kJ mol-1, respectively.

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Investigation of the Kinetics of Sulfite Oxidation on by-Production Recovery Process in WFGD

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.610-613.1980 ◽

2012 ◽

Vol 610-613 ◽

pp. 1980-1985 ◽

Cited By ~ 3

Author(s):

Hong Jian Xu ◽

Shu Fang Wang ◽

Wei Guo Pan ◽

Rui Tang Guo

Keyword(s):

Chemical Reaction ◽

Oxidation Kinetics ◽

Reaction Rate ◽

Recovery Process ◽

Orthogonal Test ◽

Sulfite Oxidation ◽

Air Ventilation ◽

Kinetics Of

The limestone-lime washing technology is the most widely used WFGD process, which normally we adopt to control the discharge of SO2 caused by coal’s combustion. Through the research on the oxidation kinetics of sulfite in this paper, it is indicated that macroscopic chemical reaction which responses to rate of sulfite is 1/2. And the results of orthogonal test can be concluded that: to the extent influence of oxidization reaction rate, the influences of temperature is the most significant, and influences of stirred speed is nearly negligible. The optimized operation factors may be shown as that temperature is controlled at 40°C, air ventilation is at 88ml/min,pH is 4.5 and stir speed is 500 r/min.

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SENSITIVITY ANALYSIS AND IDENTIFIABILITY OF A MATHEMATICAL MODEL OF A CHEMICAL REACTION

СИСТЕМЫ УПРАВЛЕНИЯ И ИНФОРМАЦИОННЫЕ ТЕХНОЛОГИИ ◽

10.36622/vstu.2021.84.2.003 ◽

2021 ◽

pp. 14-18

Author(s):

Л.Ф. Сафиуллина

Keyword(s):

Mathematical Model ◽

Inverse Problem ◽

Sensitivity Analysis ◽

Chemical Reaction ◽

Reaction Model ◽

Numerical Calculations ◽

Specific Reaction ◽

Uniqueness Of The Solution ◽

The Mathematical Model ◽

Kinetics Of

В статье рассмотрен вопрос идентифицируемости математической модели кинетики химической реакции. В процессе решения обратной задачи по оценке параметров модели, характеризующих процесс, нередко возникает вопрос неединственности решения. На примере конкретной реакции продемонстрирована необходимость проводить анализ идентифицируемости модели перед проведением численных расчетов по определению параметров модели химической реакции. The identifiability of the mathematical model of the kinetics of a chemical reaction is investigated in the article. In the process of solving the inverse problem of estimating the parameters of the model, the question arises of the non-uniqueness of the solution. On the example of a specific reaction, the need to analyze the identifiability of the model before carrying out numerical calculations to determine the parameters of the reaction model was demonstrated.

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