THE THERMAL CIS–TRANS ISOMERIZATION OF CROTONONITRILE

1963 ◽  
Vol 41 (10) ◽  
pp. 2487-2491 ◽  
Author(s):  
James N. Butler ◽  
Robert D. McAlpine
Keyword(s):  
Gas Phase ◽  
Rate Constant ◽  
Side Reaction ◽  
Order Reaction ◽  
First Order Reaction ◽  
Kcal Mole ◽  
Surface Polymerization ◽  
First Order ◽  
Trans Isomerization

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.

scholarly journals Pyrolysis of phenylmercaptoacetic acid

1968 ◽  
Vol 46 (2) ◽  
pp. 191-197 ◽  
Author(s):  
A. T. C. H. Tan ◽  
A. H. Sehon
Keyword(s):  
Carbon Dioxide ◽  
Activation Energy ◽  
Carbon Monoxide ◽  
Acetic Acid ◽  
Rate Constant ◽  
Order Reaction ◽  
First Order Reaction ◽  
Kcal Mole ◽  
Dissociation Process ◽  
First Order

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).

scholarly journals Determination of exothermic batch reactor specific model parameters

2019 ◽  
Vol 292 ◽  
pp. 01063
Author(s):  
Lubomír Macků
Keyword(s):  
Rate Constant ◽  
Reaction Rate ◽  
Batch Reactor ◽  
Specific Model ◽  
Reaction Rate Constant ◽  
Order Reaction ◽  
First Order Reaction ◽  
Model Parameters ◽  
Reactor Model ◽  
First Order

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.

The formation of O2(a1Δg) in homogeneous and heterogeneous atom recombination

1986 ◽  
Vol 64 (12) ◽  
pp. 1614-1620 ◽  
Author(s):  
A. A. Ali ◽  
E. A. Ogryzlo ◽  
Y. Q. Shen ◽  
P. T. Wassell
Keyword(s):  
Kinetic Study ◽  
Gas Phase ◽  
Molecular Oxygen ◽  
Rate Constant ◽  
Room Temperature ◽  
High Efficiency ◽  
Flow System ◽  
Order Reaction ◽  
Third Order ◽  
First Order

The recombination of oxygen atoms has been studied in a discharge flow system at room temperature. The yield of O2(a1Δg) in the recombination on Pyrex has been found to be 0.08 (±0.02). In the gas phase, O2(a) was found to be formed in a process that is second order in [O] and first order in [N2]. The rate constant for this third-order reaction was found to be 3.4 (±0.4) × 10−34 cm6∙molecule−2∙s−1, representing a yield of 0.07 (±0.02). In the presence of molecular oxygen, the rate of production of O2(a) was found to increase. A kinetic study of this effect led to the conclusion that collisions of molecular oxygen with an unidentified precursor can produce O2(a) with high efficiency.

Analysis of the Rate Constant for Hydration Kinetics of the Cement and Ash Fly in the Solidified Residues System Based on the Measurement of Ca(OH)2

2013 ◽  
Vol 380-384 ◽  
pp. 4395-4399
Author(s):  
Qin Li ◽  
Xiao Jun Zhou ◽  
Ke Wei Sun
Keyword(s):  
Chemical Analysis ◽  
Rate Constant ◽  
Matrix Material ◽  
Order Reaction ◽  
First Order Reaction ◽  
Cement Matrix ◽  
Analysis Method ◽  
Hydration Kinetics ◽  
First Order ◽  
Kinetics Of

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.

scholarly journals Photocatalytic and Photoelectrocatalytic Degradation of Methyl Orange Using Graphite/PbTiO3 Composite

2018 ◽  
Vol 16 (3) ◽  
pp. 347
Author(s):  
Candra Purnawan ◽  
Sayekti Wahyuningsih ◽  
Pramudita Putri Kusuma
Keyword(s):  
Methyl Orange ◽  
Rate Constant ◽  
Order Reaction ◽  
First Order Reaction ◽  
Methyl Orange Degradation ◽  
First Order ◽  
Photoelectrocatalytic Degradation ◽  
Methyl Orange Concentration ◽  
Degradation Reaction ◽  
Radiation Time

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.

Vulcanization of Elastomers. 21. Vulcanization of Natural Rubber with Thiuram Disulfides. VI

1959 ◽  
Vol 32 (2) ◽  
pp. 566-576
Author(s):  
Walter Scheele ◽  
Klaus Hummel
Keyword(s):  
Activation Energy ◽  
Natural Rubber ◽  
Temperature Dependence ◽  
Sulfur Content ◽  
Rate Constants ◽  
Order Reaction ◽  
First Order Reaction ◽  
Kcal Mole ◽  
First Order ◽  
Limiting Value

Abstract Bound sulfur in a pure thiuram vulcanizate increases relatively rapidly at first at all temperatures, reaches a poorly defined maximum at about 27 to 30%, independent of temperature, and then recedes slightly to reach a limiting value of 25% also independent of temperature, based on the original thiuram disulfide. The rise in sulfur content at the start points to a temperature-independent limiting value of 33%. It is shown that the combination of sulfur in this region initially follows a first order reaction, and goes at the same rate as the reduction in concentration of thiuram disulfide. It can be seen from the above that sulfur may be combined in thiuram vulcanization without simultaneous crosslinking. The dithiocarbamate formation increases rapidly in the region of longer vulcanization times, after the maximum in bound sulfur has been reached, without further combination of sulfur with the vulcanizate. The rate constants for thiuram decrease, for dithiocarbamate increase and for sulfur combination were calculated. The temperature dependence of each of these reactions has practically the same activation energy, 23 kcal/mole. The bound sulfur content of the vulcanizates in pure thiuram vulcanizations is no criterion of the state of vulcanization.

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

2021 ◽  
pp. 51-63
Author(s):  
Gajanand Sahu ◽  
Sanjay Ghosh
Keyword(s):  
Thermodynamic Parameters ◽  
Acid Medium ◽  
Rate Constant ◽  
Acidic Medium ◽  
Order Reaction ◽  
First Order Reaction ◽  
First Order ◽  
Aqueous Acid ◽  
Rate Of Reaction ◽  
Different Temperatures

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.

CYCLOADDITIONS: X. KINETICS OF THE THERMAL DECARBONYLATION OF DICYCLOPENTADIENE-1.8-DIONE

1966 ◽  
Vol 44 (17) ◽  
pp. 2051-2056 ◽  
Author(s):  
John E. Baldwin
Keyword(s):  
Carbon Monoxide ◽  
Activation Parameters ◽  
Order Reaction ◽  
First Order Reaction ◽  
Kcal Mole ◽  
First Order ◽  
Kinetics Of ◽  
Thermal Decarbonylation

The thermal cycloelimination of carbon monoxide from dicyclopentadiene-1,8-dione is a kinetically well-behaved first-order reaction. At 380 °K the activation parameters for the process are ΔH≠ = 34.5 ± 0.8 kcal mole−1 and ΔS≠ = +9.8 ± 2.3 e.u. mole−1. Application of the theoretical proposals of Woodward and Hoffmann indicates that this necessarily disrotatory decarbonylation may be concerted.

scholarly journals Kinetics of degradation of ascorbic acid by cyclic voltammetry method

2015 ◽  
Vol 21 (2) ◽  
pp. 351-357 ◽  
Author(s):  
Veselinka Grudic ◽  
Nada Blagojevic ◽  
Vesna Vukasinovic-Pesic ◽  
Snezana Brasanac
Keyword(s):  
Ascorbic Acid ◽  
Cyclic Voltammetry ◽  
Rate Constant ◽  
Oxidation Reaction ◽  
Order Reaction ◽  
First Order Reaction ◽  
First Order ◽  
Other Substances ◽  
Kinetics Of Degradation ◽  
Kinetics Of

Cyclic voltammetry was used to examine the kinetics of degradation of ascorbic acid (AA) at different temperatures. It has been shown that the reduction of the concentration of AA in all temperatures follow the kinetics of the first order reaction. The rate constant of the oxidation reaction increases with temperature as follows: 5x10-5; 2x10-4; 1x10-3 and 3x10-3 min-1 at temperatures of 25?C, 35?C, 65?C and 90?C, respectively. The temperature dependence of the rate constant follows Arrhenius equation, and the value of activation energy of the reaction degradation is 48.2 kJ mol-1 . The effect of storage time at a temperature of 90 ?C on AA content in fresh juice of green peppers was investigated. It was shown that AA oxidation reaction in the juice is also the first order reaction, while the lower rate constant in relation to the pure AA (5x10-3 min-1) indicates the influence of other substances present in peppers.

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