DISPROPORTIONATION AND RECOMBINATION OF CYANISOPROPYL RADICALS: REARRANGEMENT OF DIMETHYLKETENECYANISOPROPYLIMINE TO TETRAMETHYLSUCCINODINITRILE

1959 ◽  
Vol 37 (7) ◽  
pp. 1165-1169 ◽  
Author(s):  
M. Talât-Erben ◽  
A. N. Isfendiyaroğlu
Keyword(s):  
Experimental Data ◽  
Thermal Decomposition ◽  
Free Radicals ◽  
Molecular Mechanism ◽  
Reaction Scheme ◽  
Side Reactions ◽  
Minor Importance ◽  
Azo Compound ◽  
Kinetics Of ◽  
Good Agreement

Evidence is presented that the ketenimine intermediate formed in the thermal decomposition of azo-bis-isobutyronitrile (AIBN) rearranges quantitatively to tetramethylsuccinodinitrile (TMSDN), mainly by a molecular mechanism. Interpretation of experimental data on the basis of a reaction scheme consistent with the nature of the main products and the features of the kinetics of the decomposition permits estimation, by means of a simple diagram, of the extent of disproportionation, as well as that of the normal and abnormal recombination of cyanisopropyl radicals. The result obtained for the latter is in good agreement with that determined previously by an alternative method. The analysis does not exclude absolutely the possibility of side reactions in which the azo-compound partly decomposes by a molecular process, and the intermediate decomposes into free radicals. However, it is concluded that these side reactions, if any, must be of minor importance.

Diffusion model for deposition of epitaxial GaAs layers prepared by the MOCVD method

1991 ◽  
Vol 56 (10) ◽  
pp. 2020-2029
Author(s):  
Jindřich Leitner ◽  
Petr Voňka ◽  
Josef Stejskal ◽  
Přemysl Klíma ◽  
Rudolf Hladina
Keyword(s):  
Experimental Data ◽  
Growth Rate ◽  
Kinetic Model ◽  
Gas Phase ◽  
Substrate Surface ◽  
Deposition Process ◽  
Hydrogen Atmosphere ◽  
Epitaxial Gaas ◽  
Kinetics Of ◽  
Good Agreement

The authors proposed and treated quantitatively a kinetic model for deposition of epitaxial GaAs layers prepared by reaction of trimethylgallium with arsine in hydrogen atmosphere. The transport of gallium to the surface of the substrate is considered as the controlling process. The influence of the rate of chemical reactions in the gas phase and on the substrate surface on the kinetics of the deposition process is neglected. The calculated dependence of the growth rate of the layers on the conditions of the deposition is in a good agreement with experimental data in the temperature range from 600 to 800°C.

THE KINETICS OF THE THERMAL DECOMPOSITIONS OF THE LOWER PARAFFINS: V. THE NITRIC OXIDE INHIBITED DECOMPOSITION OF n-BUTANE

1940 ◽  
Vol 18b (1) ◽  
pp. 1-11 ◽  
Author(s):  
E. W. R. Steacie ◽  
H. O. Folkins
Keyword(s):  
Nitric Oxide ◽  
Thermal Decomposition ◽  
Free Radical ◽  
High Pressures ◽  
Free Radical Processes ◽  
Temperature Range ◽  
Radical Recombination ◽  
Radical Processes ◽  
Kinetics Of ◽  
Good Agreement

A detailed investigation of the inhibition by nitric oxide of the thermal decomposition of n-butane has been carried out over the temperature range 500° to 550 °C.In all cases it was found that inhibition decreased with increasing butane concentration. This suggests that radical recombination occurs in the normal decomposition by ternary collisions with butane molecules acting as third bodies.The activation energies of the normal and inhibited reactions have been determined. For high pressures the two values are in good agreement, viz., 58,200 and 57,200 cal. per mole respectively. The products of the inhibited reaction were also found to be the same as those of the normal reaction.It is concluded that free radical processes predominate, involving comparatively short chains.

IONIZATION POTENTIALS OF ALKYL FREE RADICALS AND n-ALKANES THROUGH C17H36 BY ENERGY-CALIBRATED MOLECULAR ORBITAL METHODS

1966 ◽  
Vol 44 (12) ◽  
pp. 1455-1462 ◽  
Author(s):  
Charles E. Melton ◽  
Hubert W. Joy
Keyword(s):  
Experimental Data ◽  
Free Radicals ◽  
Molecular Orbital ◽  
Ionization Potentials ◽  
Recent Experimental Data ◽  
Normal Alkanes ◽  
Atomic Orbitals ◽  
Large Molecules ◽  
Good Agreement ◽  
Expansion Scheme

Ionization potentials are calculated by simple energy-calibrated molecular orbital techniques for the normal alkanes through C17H36 and for some normal and branched alkyl free radicals. A model is formulated which allows the computations to be extended to extremely large molecules by using "radical" orbitals as well as atomic orbitals in the expansion scheme. Auto-ionization levels as well as ionization potentials are calculated for the radicals. Computed and observed values are in good agreement where recent experimental data are available.

Kinetic Model of Thermoelastic Martensite Transformation in Niti and NiMn Based Shape Memory Alloys

1995 ◽  
Vol 398 ◽  
Author(s):  
K. H. Wu ◽  
J.D. Shi ◽  
F. Yang ◽  
Z. J. Pu
Keyword(s):  
Experimental Data ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Martensite Transformation ◽  
Quantitative Model ◽  
Proposed Model ◽  
Series Of Experiments ◽  
The Relationship ◽  
Kinetics Of ◽  
Good Agreement

ABSTRACTA new, quantitative model was developed to describe the martensite transformation kinetics of thermoelastic shape memory alloys (SMAs). In addition, a series of experiments were conducted to study the Kinetics of thermoelastic martensite transformation in four SMA systems: NiTi, NiTi-15at%Hf, NiTi-20at%Zr and NiMn-7.5at%Ti alloys. Comparisons between data of the kinetic of martensite transformation with the present theoretic models show that the proposed model is in good agreement and concurs with the experimental data. Also, a comparison of data from the proposed model with data from existing kinetic models, such as Liang's and Magee's [1,7], indicates that the proposed model can better describe the experimental data, including the relationship between dξ(T)/dT and ξ, and dξ(T)/dT and T.

An Approach for Analyzing the Growth Kinetics of Fe2B Phase on AISI 1018 Steel

2010 ◽  
Vol 297-301 ◽  
pp. 269-274 ◽  
Author(s):  
Mourad Keddam
Keyword(s):  
Experimental Data ◽  
Carbon Steel ◽  
Growth Kinetics ◽  
Boron Content ◽  
Kinetic Constant ◽  
Mass Gain ◽  
Iron Boride ◽  
Simulation Results ◽  
Kinetics Of ◽  
Good Agreement

A simulation of the growth kinetics of iron boride forming on AISI 1018 carbon steel was done on the basis of a kinetic model. This model including the effect of the incubation time during the formation of iron boride, was applied in order to evaluate the kinetic constant at the ( ) interface, the layer thickness and the mass gain depending on the paste-boriding parameters such as time, temperature and boron potential reflected by the corresponding value of the surface boron content. The simulation results were found to be in a good agreement with the experimental data derived from the literature.

Quantitative aspects of base-catalyzed Michael addition: Mechanistic study of structural and medium effects on rate

1969 ◽  
Vol 47 (11) ◽  
pp. 1965-1979 ◽  
Author(s):  
John A. Markisz ◽  
Joseph D. Gettler
Keyword(s):  
Experimental Data ◽  
Ionic Strength ◽  
Ionization Constants ◽  
Mechanistic Study ◽  
Basic Solution ◽  
Ionic Charge ◽  
Quantitative Correlation ◽  
System A ◽  
Kinetics Of ◽  
Good Agreement

The quantitative kinetics of the reactions of acrylonitrile and methyl vinyl ketone with ethyl acetoacetate and 2,4-pentanedione, and those of acrylonitrile with ethanol and methanol in basic solution were studied as functions of base concentration, temperature, ionic strength, and solvent composition. An expression is obtained which relates the observed rates to the basicity of the solution for the 2,4-pentanedione reactions by the amount of anion in solution. For the other systems, reasonable values of ionization constants obtained empirically, similarly correlate observed rates with the concentration of base in the system. A quantitative correlation with activity coefficients as expressed by the expanded form of the Debye–Hückel equation gave good agreement for most of the experimental data with ionic strength. A derivation for the particular type of system employed indicated that the activity coefficient for the double-bonded compounds appears to have to be treated as an ion with partial ionic charge. On the basis of experimental data reported, the mechanism proposed involves, (i) anion attack on a polarized double bond, (ii) formation of a cyclic intermediate, severely restricted because of π orbital overlap, and (iii) protonation of this intermediate to form product.

scholarly journals The kinetics of the thermal decomposition of benzalazine vapour

1936 ◽  
Vol 156 (888) ◽  
pp. 444-455 ◽  
Keyword(s):  
Thermal Decomposition ◽  
Boiling Point ◽  
Azo Compounds ◽  
Azo Compound ◽  
Principal Reaction ◽  
Wide Range ◽  
Reaction Proceeds ◽  
Nitrogen Bonds ◽  
Kinetics Of ◽  
Single Bonds

Ramsperger has investigated the kinetics of the thermal decomposition of a number of aliphatic azo-compounds at temperatures between 250° and 330° C. The principal reaction is in each instance of the type R. CH - N = N - CH . R ' = N 2 + x . R . CH . CH . R + x . R ' . CH . CH . R ' + (1 - 2 x ) . R . CH . CH . R ' . For a symmetrical azo-compound (R = R ' ), x = 0. When heated to about 300° C., benzalazine undergoes an analogous decomposition, mainly to nitrogen and stilbene ; but the liberation of nitrogen from benzalazine involves the rupture of two double bonds, instead of two single bonds as in the azo-compounds C 6 H 5 CH = N - N = CHC 6 H 5 = N 2 + C 6 H 5 CH = CHC 6 H 5 . A study of the kinetics of the benzalazine decomposition therefore offers the opportunity for a comparison of the breakage of the single and double carbon-nitrogen bonds. We find that the reaction can be followed manometrically at temperatures between 315° and 360° C. These temperatures lie above the boiling-point of benzalazine and stilbene (b. p. 306°), and therefore the reaction proceeds with increase of pressure over a wide range of initial concentrations.

scholarly journals Further study on kinetic modeling of sunflower oil methanolysis catalyzed by calcium-based catalysts

2016 ◽  
Vol 22 (2) ◽  
pp. 137-144 ◽  
Author(s):  
Marija Miladinovic ◽  
Marija Tasic ◽  
Olivera Stamenkovic ◽  
Vlada Veljkovic ◽  
Dejan Skala
Keyword(s):  
Experimental Data ◽  
Mass Transfer ◽  
Kinetic Model ◽  
Sunflower Oil ◽  
Coefficient Of Determination ◽  
Reaction Conditions ◽  
High Coefficient ◽  
Relative Percentage ◽  
Kinetics Of ◽  
Good Agreement

The kinetic model, which was originally developed for sunflower oil methanolysis catalyzed by CaO.ZnO, was examined for several other calcium-based catalysts like neat CaO, quicklime and Ca(OH)2. This model including triacylglycerols mass transfer- and chemically-controlled regimes demonstrated a good agreement with the experimental data in terms of a high coefficient of determination (0.971?0.022) and acceptable mean relative percentage deviation (?15.9%). Hence, this model is recommended for modeling the kinetics of sunflower oil methanolysis over calcium-based catalysts under widely ranging reaction conditions.

scholarly journals Theoretical calculations of the kinetics of the OH reaction with 2-methyl-2-propen-1-ol and its alkene analogue

RSC Advances ◽  
2014 ◽  
Vol 4 (40) ◽  
pp. 20830-20840 ◽  
Author(s):  
Thaís da Silva Barbosa ◽  
Jorge D. Nieto ◽  
Pablo M. Cometto ◽  
Silvia I. Lane ◽  
Glauco Favilla Bauerfeldt ◽  
...  
Keyword(s):  
Experimental Data ◽  
Theoretical Calculations ◽  
Rate Coefficients ◽  
Kinetics Of ◽  
Good Agreement

The rate coefficients for the OH addition to 2-methyl-2-propen-1-ol and methylpropene have been determined, showing a non-Arrhenius profile and good agreement with the experimental data.

Experimental study and kinetics modeling of gas hydrate formation of methane–ethane mixture

2013 ◽  
Vol 38 (3) ◽  
pp. 273-286 ◽  
Author(s):  
Parisa Naeiji ◽  
Farshad Varaminian
Keyword(s):  
Experimental Data ◽  
Gas Hydrate ◽  
Formation Rate ◽  
Hydrate Formation ◽  
Initial Pressure ◽  
Constant Volume ◽  
Average Error ◽  
Gas Hydrate Formation ◽  
Kinetics Of ◽  
Good Agreement

Abstract. In this study, gas hydrate formation kinetics of methane and ethane binary mixtures has been studied and data of mixed methane–ethane hydrate formation at 0.1, 0.2, 0.3, 0.5, 0.68, 0.8, and 0.9 mole fractions of methane and at a temperature of 277.15 K and an initial pressure of approximately 3.6 MPa were collected. The thermodynamic natural path was used for modeling the hydrate formation rate in a constant volume process. The results show that there is good agreement between model prediction and experimental data, with an average error of 0.9%. It was observed that the values of these parameters are dependent on the concentration of components in the mixtures. The results indicate that this model can predict constant volume experimental data of binary mixture hydrate.

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