scholarly journals Kinetic and Mechanism of Uncatalytic Oxidation of Dl-Threonine by Cerium (Iv) in Aqueous Acid Medium

Author(s):  
Gajanand Sahu ◽  
Sanjay Ghosh

Kinetic of uncatalyzed oxidation of DL-Threonine has been studied by Ce (IV) in acidic medium has been investigatigated by spectrophotometer technique.  The rate of reaction determined at three different temperatures ranging from 298 K to 318 K at the interval of 10 K. The reaction has been found to be a first order reaction in presence or in absence of KCl, CTAB, and SDS. The rate constant, decreases with increasing the concentration of [HSO4-] and [H+] ion. The various thermodynamic parameters were calculated at 298 K, 308 K and 318 K. The proposed mechanism and results is discussed.

2019 ◽  
Vol 292 ◽  
pp. 01063
Author(s):  
Lubomír Macků

An alternative method of determining exothermic reactor model parameters which include first order reaction rate constant is described in this paper. The method is based on known in reactor temperature development and is suitable for processes with changing quality of input substances. This method allows us to evaluate the reaction substances composition change and is also capable of the reaction rate constant (parameters of the Arrhenius equation) determination. Method can be used in exothermic batch or semi- batch reactors running processes based on the first order reaction. An example of such process is given here and the problem is shown on its mathematical model with the help of simulations.


EKUILIBIUM ◽  
2015 ◽  
Vol 14 (1) ◽  
Author(s):  
Paryanto Paryanto

<p>Abstract: Carbon dioxide content in biogas produced by fermentation is still high. Because of<br />that, biogas need a process purification to reduce carbon dioxide content. In this work, Ca(OH)2<br />solution was contacted with biogas in a column for reducing the CO<br />2<br />content. This research<br />studied the effect of packing type used in absorber column on the rate of CO<br />2<br />reduction. Based<br />on experimental data and modelling, it was found that the reaction between CO<br />2<br />followed first order reaction. The constant of rate reaction was affected by the packing type<br />which using glass ball, plastic pipe, ceramic, wood, and clay roof, the constant rate were 0.781,<br />0.464, 0.916, 0.637, and 0.987 min<br />Keywords: Biogas, CO<br />2<br />, Ca(OH)2<br />-1<br />, respectively.<br />, absorber, rate of reaction</p>


1968 ◽  
Vol 46 (2) ◽  
pp. 191-197 ◽  
Author(s):  
A. T. C. H. Tan ◽  
A. H. Sehon

The pyrolysis of phenylmercaptoacetic acid was investigated by the toluene-carrier technique over the temperature range 760–835 °K. The main products of the decomposition were phenyl mercaptan, carbon dioxide, acetic acid, phenyl methyl sulfide, carbon monoxide, and dibenzyl.The overall decomposition was a first-order reaction with respect to phenylmercaptoacetic acid and could be represented by the two parallel steps:[Formula: see text]Reaction [1] was shown to be a homogeneous first-order dissociation process, and its rate constant was represented by the expression[Formula: see text]The activation energy of this reaction, i.e. 58 kcal/mole, was identified with D(C6H5S—CH2COOH).


2013 ◽  
Vol 380-384 ◽  
pp. 4395-4399
Author(s):  
Qin Li ◽  
Xiao Jun Zhou ◽  
Ke Wei Sun

Based on the hydration kinetics of the cement matrix material, the paper presents a chemical analysis method by means of analyzing the contents of Ca(OH)2 in cement matrix material. The kinetics constant for the cement, ash fly in the residues system solidified by recycled cement, ash fly was determined at different temperature. The hydration kinetics characteristic of the residues system after being hydrated 7 days is first order reaction.


2018 ◽  
Vol 16 (3) ◽  
pp. 347
Author(s):  
Candra Purnawan ◽  
Sayekti Wahyuningsih ◽  
Pramudita Putri Kusuma

Synthesis of graphite/PbTiO3 composite as a catalyst in photodegradation and photoelectrodegradation process of methyl orange have been conducted. The purposes of this research are to study the effect of radiation time, composition of composite, voltage and pH of solution for methyl orange degradation. Photodegradation process of methyl orange was carried out for 5; 10; 15; 20; 25 and 30 min. Ratio of graphite : PbTiO3 (w/w) were varied at 1:3; 1:2; 1:1; 2:1 and 3:1. Meanwhile, the applied voltages were 7.5; 10 and 12.5 V and the photoelectrodegradation was conducted under pH condition of 3; 7; and 11, respectively. The result showed that optimum composition of graphite/PbTiO3 in the methyl orange photodegradation was obtained at 1:1 ratio for 30 min with degradation up to 90.43% ± 0.062. The degradation reaction follows first order reaction with a rate constant of 0.0688 min-1. The optimum voltage is 10 V, in which it reduced the methyl orange concentration up to 92.65% ± 0 with a rate constant 0.0941 min-1 for first order reaction. The optimum pH is pH = 11, that provide methyl orange reduction up to 95.28% ± 0.082.


2019 ◽  
Vol 9 (1) ◽  
pp. 159-164
Author(s):  
Narayan V. Lawale ◽  
Bhagwan Singh Dobhal ◽  
Sandip Singh Gaur ◽  
Rajendra Pardeshi

Permanganatic oxidation of Neomycine sulphate salt has been studied at different temperatures using spectrophotometer under alkaline conditions. The effect of variation of substrate Neomycine sulphate salt (NS), oxidant (KMnO4) and NaOH was studied under pseudo first order reaction conditions. The effect of different salts and solvents on oxidation of NS was also studied. The reaction was found to be first order with respect to oxidant, substrate and NaOH.. Keywords: Neomycine sulphate salt (NS), KMnO4 , permanganatic  oxidation, alkaline permanganate


1952 ◽  
Vol 30 (11) ◽  
pp. 879-889 ◽  
Author(s):  
M. W. Lister

The rate of decomposition of hypochlorous acid has been measured in aqueous solution in the presence of much sodium hypochlorite. The rate is nearly independent of the hypochlorite concentration, and proportional to the square of the hypochlorous acid concentration. Hence the mechanism proposed is[Formula: see text][Formula: see text]The first step is the slower. The reaction[Formula: see text]also occurs, but is much slower. Oxygen is also evolved, by a first order reaction. Values for the rate constants at different temperatures of all these reactions are given. Measurements are also reported on certain equilibria present in these solutions: the ionization of hypochlorous and chlorous acids, and the reaction [Formula: see text].Details of modified analytical methods for hypochlorite and chlorate in the presence of chlorite are given.


2019 ◽  
Author(s):  
Chem Int

The kinetic and thermodynamic properties of pharmaceutical drug (gabapentine) by potassium bromate (KBrO3) in presence of Micro amount of Ir(III) chloride as catalyst in acidic medium was studied in the temperature range 30 to 45 0C. The reaction is carried out in the presence of mercuric acetate as a scavenger for chloride ion. 1-carboxy cyclohexane l-acetic acid was obtained as the oxidation product and identified chromatographically. The rate law followed a first order and zero order dependence with respect to KBrO3 and GBP respectively. The reaction followed first order with respect to Ir(III) chloride and [H+]. Negligible effect of [Hg(OAc)2] and ionic strength of the medium was observed. Chloride ion positively influenced the rate of reaction. The values of rate constants observed at different temperatures (30 to 45 0C) were utilized to calculate the activation parameters. Feasible mechanism is proposed which are composed with the kinetics, stochiometry and product of the reaction. The rate law has been derived from obtained kinetic data.


1963 ◽  
Vol 41 (10) ◽  
pp. 2487-2491 ◽  
Author(s):  
James N. Butler ◽  
Robert D. McAlpine

The thermal cis–trans isomerization of crotononitrile has been studied in the gas phase at pressures from 0.2 to 20 mm and temperatures from 300 °C to 560 °C. For the equilibrium cis → trans, ΔH = 0.17 ± 0.12 kcal/mole, and ΔS = −0.39 ± 0.19 cal/mole °K. The isomerization is a homogeneous, unimolecular, reversible first-order reaction, the rate constant for the reaction cis → trans being given by[Formula: see text]The only side reaction with appreciable rate was a surface polymerization.


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