Formation and Decomposition of Hydroperoxides of Atactic Polypropylene

1963 ◽  
Vol 36 (2) ◽  
pp. 532-536 ◽  
Author(s):  
Z. Manasek ◽  
D. Berek ◽  
M. Micko ◽  
M. Lazar ◽  
J. Pavlinec
Keyword(s):  
Molecular Weight ◽  
Energy Of Activation ◽  
Effective Energy ◽  
Kcal Mole ◽  
Atactic Polypropylene ◽  
Temperature Range ◽  
Kinetics Of Formation ◽  
Kinetics Of

Abstract 1. The authors study the kinetics of formation and decomposition of peroxides in the oxidation of atactic polypropylene in air in the temperature range from 20° to 120°. 2. The effective energy of activation of accumulation of peroxide (24 to 25 kcal/mole) and of decomposition of peroxides (27 kcal/mole) are determined. 3. It is found that the reduction in the molecular weight is a function of the concentration of peroxides in the polymer.

scholarly journals Pyrolysis of azetidinones. Part 2. Kinetics and mechanism of thermolysis of β-lactams and β-thiolactams

2016 ◽  
Vol 94 (9) ◽  
pp. 788-793 ◽  
Author(s):  
Nouf S. Al-Hamdan ◽  
Alya M. Al-Etaibi ◽  
Rasha F. Al-Bashir ◽  
Yahia A. Ibrahim ◽  
Nouria A. Al-Awadi ◽  
...  
Keyword(s):  
Gas Phase ◽  
Rate Constants ◽  
Kinetics And Mechanism ◽  
Energy Of Activation ◽  
The Novel ◽  
Temperature Range ◽  
Entropy Of Activation ◽  
Kinetics Of ◽  
Thermolysis Reaction

The kinetics of the gas-phase thermolysis reaction of seven β-lactams and their thione analogues were investigated over the temperature range 533–603 K for the β-lactams and 463–542 K for the β-thiolactams. The average values of the energy of activation (Ea) (kJ mol−1) and Arrhenius log A (s–1) were, respectively, 170.8 ± 18.6 and 12.4 ± 1.6 for the lactams and 131.7 ± 18.2 and 11.0 ± 2.0 for the thione analogues. The entropy of activation (ΔS#) was negative for of the substrates and slightly positive for three. The rate constants (k) (s−1) were calculated for 510 K and compared for the two series of azetidinones. The effects of substituents on rates and the novel role played by the C=O and C=S moieties on the relative reactivities of the cyclic amides are rationalized on the basis of a formal retro[2+2]cycloaddition mechanism used earlier to explain the products of the gas-phase thermolysis reaction of the present azetidinones.

scholarly journals The rupture of carbon-nitrogen bonds. Kinetics of the thermal decomposition of ω-azotoluene vapour

1936 ◽  
Vol 156 (888) ◽  
pp. 455-462 ◽  
Keyword(s):  
Thermal Decomposition ◽  
Energy Of Activation ◽  
Azo Compounds ◽  
Temperature Range ◽  
The Difference ◽  
Lower Temperature ◽  
Nitrogen Bonds ◽  
Kinetics Of

The energy of activation found for the benzalazine decomposition is somewhat higher than those hitherto recorded for the decompositions of azo-compounds. The difference between the azine- and azo-decompositions can only be appreciated, however, on comparing the decomposition of benzalazine with that of its aromatic azo-analogue, i . e ., ω-azotoluene. According to Thiele,* when the latter substance is heated in vacuo , gas liberation begins at 15°-180° C. C 6 H 5 . CH 2 ─ N = N ─ CH 2 . C 6 H 5 = N 2 + C 6 H 5 . CH 2 . CH 2 . C 6 H 5 . This reaction is analogous to the benzalazine decomposition (measured at 318°- 180° C), C 6 H 5 . CH = N ─ N = CH. C 6 H 5 = N 2 + C 6 H 5 . CH = CH. C 6 H 5 , and resembles the aliphatic azo-decompositions investigated by Rams-perger over the temperature range 250° - 350° C, though occurring at a lower temperature than these.

Kinetics of the Reaction between Silver and Nitric Acid

1962 ◽  
Vol 15 (2) ◽  
pp. 181 ◽  
Author(s):  
JJ Batten
Keyword(s):  
Activation Energy ◽  
Nitric Acid ◽  
Induction Period ◽  
Acid Concentration ◽  
Maximum Rate ◽  
Kcal Mole ◽  
Temperature Range ◽  
Induction Rate ◽  
Rate Of Dissolution ◽  
Kinetics Of

The rate of dissolution of silver gauze in nitric acid at various concentrations and temperatures was measured in a static system. The solution process was measured by the weight of silver dissolved in various time intervals. In general, induction periods were observed, but after this period the dissolution proceeded with an appreciable velocity. To examine the influence of acid concentration and temperature on the kinetics of the reaction, the duration of the induction period, the rate of dissolution during this period, and the subsequent maximum rate were taken as kinetic parameters of the reaction. The induction rate was found to be highly dependent on the initial acid concentration (approx. seventh power), whereas over most of the concentration range accessible to study, the maximum rate was proportional to the square of the concentration. It was also observed that increase in temperature sharply increases the induction rate, but has little effect upon the subsequent maximum rate over most of the temperature range studied. The activation energy of the induction rate was greater than 20 kcal/mole, whereas that of the maximum rate was about 4 kcal/mole over most of the temperature range studied. This difference in the activation energy during and after the induction period is explained by a shift in the mechanism controlling the rate of the process from a chemical reaction at the surface to a diffusion process.

THE KINETICS OF THE FORMATION OF THE MONOSULPHATO COMPLEX OF IRON (III) IN AQUEOUS SOLUTION

1962 ◽  
Vol 40 (9) ◽  
pp. 1836-1845 ◽  
Author(s):  
G. G. Davis ◽  
W. MacF. Smith
Keyword(s):  
Experimental Data ◽  
Aqueous Solution ◽  
Ionic Strength ◽  
Continuous Flow ◽  
Hydrogen Ions ◽  
Kcal Mole ◽  
Forward Reaction ◽  
First Order ◽  
Kinetics Of Formation ◽  
Kinetics Of

The kinetics of formation of the monosulphato complex of iron (III) has been examined spectrophotometrically using a continuous-flow technique over the range of temperatures 15.6 to 34.5 °C in an aqueous medium of ionic strength 0.5 and a range of concentrations of hydrogen ions 0.05 to 0.30 M. The experimental data may be interpreted on the assumption that the significant reactions are a bimolecular association opposed by a first-order dissociation [Formula: see text] For the forward reaction ΔH≠ is 18.0 kcal mole−1 and ΔS≠ is 19.4 cal mole−1 deg−1.

Research on Kinetics of Hydrolysis Preparation of Micro-Molecular Dextran

2013 ◽  
Vol 748 ◽  
pp. 295-298
Author(s):  
Shu Qiong Liao ◽  
Xiao Yu Peng ◽  
Xue Wang Zhang ◽  
Ke Lin Huang ◽  
Ben Wang ◽  
...  
Keyword(s):  
Activation Energy ◽  
Molecular Weight ◽  
Kinetics Equation ◽  
Temperature Range ◽  
Kinetics Of Hydrolysis ◽  
Kinetics Of ◽  
Hydrolysis Of

Micro-molecular dextran was prepared in sub-critical water and sub-critical Water/CO2by hydrolysis of dextran20. The obtained products were mainly characterized by GPC. The kinetics of hydrolysis of dextran20 has been studied in the temperature range of 423.15K-463.15K. It was found that the level of dextran20 hydrolysis in sub-critical water and sub-critical water/CO2was first level kinetics equation. The activation energy was also calculated. The results demonstrated that the molecular weight of micro-molecular dextran could be controlled.

The kinetics of the ordering process in triclinic NaAlSi3O8

1960 ◽  
Vol 32 (249) ◽  
pp. 436-454 ◽  
Author(s):  
J. D. C. McConnell ◽  
Duncan McKie
Keyword(s):  
Activation Energy ◽  
Kinetic Analysis ◽  
Vapour Pressure ◽  
Polymorphic Transformation ◽  
Water Vapour Pressure ◽  
Kcal Mole ◽  
Temperature Range ◽  
Self Diffusion ◽  
Dry Heating ◽  
Kinetics Of

SummaryA kinetic analysis is presented of the data of MacKenzie (1957) on the hydrothermal treatment of NaAlSi3O8 under isobaric, isothermal conditions in the temperature range 450° C. to 1000° C.The analysis indicates the existence of a smeared polymorphic transformation in the temperature range around 600° C. The activation energy for the transformation is about 60 kcal. mole−1 and has been equated with the process of self-diffusion involved in Al-Si ordering in the structure. Some dry-heating experiments and the influence of varying water vapour pressure are discussed.

Notizen:Kinetics of Ester-interchange between Methyl Acetate and Ethanol

1972 ◽  
Vol 27 (10) ◽  
pp. 1529-1530 ◽  
Author(s):  
T. Rao ◽  
B. Gandhe
Keyword(s):  
Reaction Rate ◽  
Methyl Acetate ◽  
Second Order ◽  
Energy Of Activation ◽  
Chromatographic Technique ◽  
Kcal Mole ◽  
Specific Reaction Rate ◽  
Ester Interchange ◽  
Specific Reaction ◽  
Kinetics Of

Abstract Kinetics of ester-interchange between methyl acetate and ethanol has been studied in the range 80 - 105°, using gas chromatographic technique. The reaction is of the second order, and the specific reaction rate is 29.6-10-8 l/mole-sec at 105°. The energy of activation is 16.7 kcal/mole and the en-tropy of activation is -44.3 cal/mole-deg.

Kinetics of the Reaction of Nickel(II) and 2,2′-Bipyridine in Ethanol

1973 ◽  
Vol 51 (23) ◽  
pp. 3975-3977 ◽  
Author(s):  
M. L. Sanduja ◽  
W. MacF. Smith
Keyword(s):  
Kinetic Parameters ◽  
Rate Constant ◽  
Order Rate Constant ◽  
Second Order ◽  
Stopped Flow ◽  
Ligand Specificity ◽  
Temperature Range ◽  
Kinetics Of Formation ◽  
The Difference ◽  
Kinetics Of

The kinetics of formation of the monobipyridine complex of nickel(II) in ethanol has been studied with stopped-flow methods over the temperature range 7 to 35 °C. The value of the second order rate constant kf at 25 °C of 6.6 × 10−3M−1 s1 and the values of ΔH≠ (10.1 ± 1.0 kcal mol−1) and of ΔS≠ (−7.3 ± 3.4 cal deg−1 mol−1) are close to the corresponding values for ethanol exchange on nickel(II) and suggest that the mechanism is dissociative interchange. However the difference in the values of the kinetic parameters of this reaction and those previously reported for the reactions involving the chemically similar phenanthroline imply a degree of ligand specificity for the reactions in ethanol which is considerably larger than is the case for reactions in water and methanol and that a common Id mechanism with monodentate formation being rate controlling is not applicable to both reactions.

Sign in / Sign up

Export Citation Format

Share Document