STUDIES ON HOMOGENEOUS FIRST ORDER GAS REACTIONS: I. THE DECOMPOSITION OF ETHYLIDENE DIACETATE

1931 ◽  
Vol 5 (6) ◽  
pp. 636-647 ◽  
Author(s):  
C. C. Coffin
Keyword(s):  
Acetic Anhydride ◽  
Experimental Method ◽  
General Equation ◽  
Arrhenius Equation ◽  
Inert Gases ◽  
First Order ◽  
Theoretical Significance ◽  
Gas Reactions

The decomposition represented by the general equation[Formula: see text]has been found to take place according to the monomolecular law. In the case of the several homologous esters already investigated at pressures above 10 cm. of mercury the reaction is entirely homogeneous, is uninfluenced by the presence of inert gases and obeys the Arrhenius equation. This paper describes the experimental method and deals with the decomposition of ethylidene diacetate to acetaldehyde and acetic anhydride at temperatures of 220° to 268 °C. and at initial pressures of 11 to 46 cm. of mercury. The heat of activation is 32900 cal./mol and the velocity constants (sec−1) are given by the equation, ln [Formula: see text]. The theoretical significance of the data is discussed.

Acetoxylation by aryliodoso acetates. II. Kinetics of the reaction of phenyliodoso acetate with aceto-p-toluidide

1958 ◽  
Vol 11 (1) ◽  
pp. 34
Author(s):  
WD Johnson ◽  
NV Riggs
Keyword(s):  
Acetic Acid ◽  
Acetic Anhydride ◽  
Transition State ◽  
Arrhenius Equation ◽  
First Order ◽  
Temperature Range ◽  
Polar Transition ◽  
Kinetics Of

The reaction of phenyliodoso acetate and aceto-p-toluidide in acetic acid is first order in each reactant and measured rates fit the Arrhenius equation in the temperature range 15-45 �C. Addition of water to the solvent markedly accelerates the reaction, whereas addition of benzene lowers the rate and acetic anhydride has little effect. A polar transition state is indicated.

scholarly journals Pyrolysis of bromobenzene by the toluene carrier technique and determination of D(C6H5—Br)

1978 ◽  
Vol 56 (11) ◽  
pp. 1589-1592 ◽  
Author(s):  
R. John Kominar ◽  
Michael J. Krech ◽  
Stanley James W. Price
Keyword(s):  
Activation Energy ◽  
Experimental Method ◽  
Arrhenius Equation ◽  
First Order ◽  
Temperature Range

The pyrolysis of C6H5Br bas been studied by the toluene carrier technique over the temperature range 1018 to 1126 K using contact times of 1.18 to 2.85 s and total pressures of 3.8 to 4.4 kPa. Percent decomposition based on analyses of residual C6H5Br ranged from 4 to 89%. When HBr was trapped out and quantitatively determined it accounted for more than 95% of the bromine expected. Within the limits of the experimental method the decomposition was found to be homogeneous and first order.[Formula: see text]The Arrhenius equation for reaction [1] is[Formula: see text]Making an approximate correction of the activation energy to 298 K then gives D(C6H5—Br) = 313 ± 5.4 kJ mol−1.

STUDIES ON HOMOGENEOUS FIRST ORDER GAS REACTIONS: IX. THE DECOMPOSITION OF FURFURYLIDENE DIACETATE AND CROTONYLIDENE DIACETATE

1937 ◽  
Vol 15b (6) ◽  
pp. 260-263 ◽  
Author(s):  
J. R. Dacey ◽  
C. C. Coffin
Keyword(s):  
Activation Energy ◽  
Double Bond ◽  
Acetic Anhydride ◽  
Vapor Phase ◽  
Reaction Rates ◽  
Phase Decomposition ◽  
Specific Reaction ◽  
First Order ◽  
Gas Reactions

The vapor phase decomposition of furfurylidene diacetate and crotonylidene diacetate to acetic anhydride and their respective aldehydes is homogeneous, first order, and complete. The activation energy is that characteristic of the series, viz., 33,000 cal. The specific reaction rates of the two esters are the same, and are about six times as great as that of ethylidene diacetate at any temperature. It is suggested that the increased velocity is due to the presence of the double bond. Velocity constants are given by the equation [Formula: see text].

Pyrolysis of iodobenzene by the toluene carrier technique and determination of D[C6H5—I]

1976 ◽  
Vol 54 (19) ◽  
pp. 2981-2984 ◽  
Author(s):  
R. John Kominar ◽  
Michael J. Krech ◽  
Stanley James W. Price
Keyword(s):  
Activation Energy ◽  
Experimental Method ◽  
Arrhenius Equation ◽  
First Order ◽  
Temperature Range ◽  
Gaseous Products

The pyrolysis of C6H5I has been studied by the toluene carrier technique over the temperature range 861–955 K using contact times of 0.54–3.28 s and total pressures of 2.5–4.13 kPa. Percent decomposition based on analysis for residual C6H5I ranged from 5.6–93.3%. Only trace quantities of I2 were observed and when HI was trapped out the only other gaseous products were small quantities of hydrogen and methane in about a 2:1 ratio. Within the limits of the experimental method the decomposition was found to be homogeneous and first order.[Formula: see text]The Arrhenius equation obtained for reaction 1 is[Formula: see text]Making an approximate correction of the activation energy to 298 K then gives[Formula: see text]

STUDIES ON HOMOGENEOUS FIRST ORDER GAS REACTIONS: XII. THE DECOMPOSITION OF GLYOXAL TETRA-ACETATE

1940 ◽  
Vol 18b (12) ◽  
pp. 410-413 ◽  
Author(s):  
J. C. Arnell ◽  
J. R. Dacey ◽  
C. C. Coffin
Keyword(s):  
Activation Energy ◽  
Acetic Anhydride ◽  
Rate Constant ◽  
Order Rate Constant ◽  
Independent Factor ◽  
First Order ◽  
Order Rate ◽  
Gas Reactions

The decomposition of gaseous glyoxal tetra-acetate to acetic anhydride and glyoxal is homogeneous and unimolecular. Both the activation energy and the temperature independent factor of the first order rate constant are substantially larger than in the case of the diacetate esters. The decomposition velocity is given by the equation k = 1.8 × 1012e−39200/RT.

Kinetics and mechanism of the reaction between oxidized cytochrome c and ascorbic acid

1991 ◽  
Vol 56 (2) ◽  
pp. 478-490 ◽  
Author(s):  
Joaquin F. Perez-Benito ◽  
Conchita Arias
Keyword(s):  
Ascorbic Acid ◽  
Cytochrome C ◽  
Redox Reactions ◽  
Arrhenius Equation ◽  
Horse Heart Cytochrome ◽  
First Order ◽  
Acidic Form ◽  
Ph Range ◽  
Horse Heart Cytochrome C ◽  
Mechanism Of The Reaction

The reaction between horse-heart cytochrome c and ascorbic acid has been investigated in the pH range 5.5 – 7.1 and at 10.0 – 25.0 °C. The rate shows a first-order dependence on the concentration of cytochrome c, it increases in a non-linear way as the concentration of ascorbic acid increases, it increases markedly with increasing pH and, provided that the ionic strength of the medium is high enough, it fulfills the Arrhenius equation. The apparent activation energy increases as the pH of the solution increases. The results have been explained by means of a mechanism that includes the existence of an equilibrium between two forms (acidic and basic) of oxidized cytochrome c: cyt-H+ -Fe3+ + OH- cyt -Fe3+ + H2O, whose equilibrium constant is (6.7 ± 1.4). 108 at 25.0 °C, the acidic form being more reducible than the basic one. It is suggested that there is a linkage of hydrogenascorbate ion to both forms of cytochrome c previous to the redox reactions. Two possibilities for the oxidant-reductant linkage (binding and adsorption) are discussed in detail.

Catalysis by hydrogen halides in the gas phase. XIX. 2,3-Dimethylbutan-2-ol and hydrogen bromide

1968 ◽  
Vol 21 (10) ◽  
pp. 2385 ◽  
Author(s):  
RL Johnson ◽  
VR Stimson
Keyword(s):  
Gas Phase ◽  
Arrhenius Equation ◽  
Hydrogen Bromide ◽  
Phase Decomposition ◽  
Hydrogen Halides ◽  
First Order

The gas-phase decomposition of 2,3-dimethylbutan-2-ol into 2,3-dimethylbut-1-ene, 2,3-dimethylbut-2-ene, and water, catalysed by hydrogen bromide at 303-400�, is described. The rate is first-order in each reactant and the Arrhenius equation k2 = 1011.88 exp(-26490/RT) sec-l ml mole-1 is followed. The olefins appear to be in their equilibrium proportions. The effects of substitutions in the alcohol at Cα and Cβ on the rate are discussed.

STUDIES ON HOMOGENEOUS FIRST ORDER GAS REACTIONS: VII. THE DECOMPOSITION OF ETHYLIDENE DIBUTYRATE AND HEPTYLIDENE DIACETATE

1937 ◽  
Vol 15b (6) ◽  
pp. 247-253 ◽  
Author(s):  
C. C. Coffin ◽  
J. R. Dacey ◽  
N. A. D. Parlee
Keyword(s):  
Activation Energy ◽  
Homologous Series ◽  
Reaction Velocity ◽  
Vapor State ◽  
Specific Reaction ◽  
First Order ◽  
Gas Reactions

Ethylidene dibutyrate and heptylidene diacetate decompose in the vapor state at temperatures between 200° and 300 °C. to form an aldehyde and an anhydride. The reactions are homogeneous, unimolecular, and complete. The activation energy is the same as that previously found for other members of this homologous series. Ethylidene dibutyrate decomposes at the same rate as ethylidene diacetate, and thus provides further evidence that the specific reaction velocity is independent of the size of the anhydride radicals. Heptylidene diacetate decomposes at the same rate as butylidene diacetate. This indicates that after the aldehyde radical has attained a certain size (three or four carbon atoms) the addition of –CH2− groups leaves the specific reaction velocity unchanged. The velocity constants are given by the equations[Formula: see text]

STUDIES ON HOMOGENEOUS FIRST ORDER GAS REACTIONS: II. THE DECOMPOSITION OF THE ISOMERIC ESTERS BUTYLIDENE DIACETATE AND ETHYLIDENE DIPROPIONATE

1932 ◽  
Vol 6 (4) ◽  
pp. 417-427 ◽  
Author(s):  
C. C. Coffin
Keyword(s):  
Activation Energy ◽  
Degrees Of Freedom ◽  
Maximum Energy ◽  
Velocity Measurements ◽  
First Order ◽  
Gas Reactions ◽  
Points Of View ◽  
The Stability ◽  
Future Work ◽  
Internal Degrees Of Freedom

The gaseous decompositions of the esters butylidene diacetate and ethylidene dipropionate have been studied from points of view previously outlined in papers on the decomposition of ethylidene diacetate (2, 3). The decomposition velocities have been measured at initial pressures of from 5 to 56 cm. of mercury and at temperatures between 211 and 265 °C. The reactions are homogeneous and of the first order. They agree with the Arrhenius equation and give 100% yields (within experimental error) of an aldehyde and an anhydride. The preparation of the compounds and improvements in the technique of the velocity measurements are described.While the specific velocities of the three reactions at any temperature are somewhat different, their activation energies are the same. It is suggested that in the case of such simple reactions, which are strictly localized within the molecular structure, the activation energy can be identified as the maximum energy that the reactive bonds may possess and still exist; i.e., it may be taken as a measure of the stability of the bonds which are broken in the reaction. The suggestion is also made that for a series of reactions which have the same activation energy, the specific velocities can be taken as a relative measure of the number of internal degrees of freedom that contribute to the energy of activation. On the basis of these assumptions it becomes possible to use reaction-velocity measurements for the investigation of intramolecular energy exchange. The theoretical significance of the data is further discussed and the scope of future work in this connection is indicated.The monomolecular velocity constants (sec−1) of the decomposition of ethylidene diacetate, ethylidene dipropionate and butylidene diacetate are given respectively by the equations [Formula: see text], [Formula: see text], and [Formula: see text].

scholarly journals Kinetic and thermodynamic Studies Of Alanine Aminopeptidase(AAP) Isoenzymes I,II Partially Purified From Patient's Urine With Urinary Tract Cancer

2014 ◽  
Vol 11 (1) ◽  
pp. 70-80
Author(s):  
Baghdad Science Journal
Keyword(s):  
Urinary Tract ◽  
Arrhenius Equation ◽  
Kinetic Constant ◽  
Gel Filtration ◽  
First Order ◽  
Tract Cancer ◽  
Kinetics Studies ◽  
Urinary Tract Cancer ◽  
Alanine Aminopeptidase ◽  
Kinetic And Thermodynamic Studies

The activity of Alanine aminopeptidase( AAP ) was measured in the urine of healthy and urinary tract cancer patients , the results showed higher activity of (AAP) in patients compared to healthy . AAP was Purified from the urine of healthy and patients with urinary tract cancer by dialysis and gel filtration (Sephadex G – 50) and two isoenzymes of (AAP) were separated from urine by using ion-exchang resin (DEAE – Sephadex A – 50 ) in previous study. The kinetics studies showed that both isoenzymes I and II obeyed Michaelis – Menton equation . with optimal concentration of alanine-4-nitroanilide as substrate for isoenzymes I and II which was (2 x 10-3 mol/L ). The two isoenzymes obeyed Arrhenius equation up two 37° C and their Ea and Q10 constants were determined . The binding of alanine-4-nitroanilide by two isoenzymes I , II were studied and the kinetic constant ( k+1 , k-1 , Ka , Ks ) were indicated that the reaction was first order at 37° C .Thermodynamic parameters of the standard state ( ?G°, ?H° , ?S° ) and the transition state ( ?G*, ?H* , ?S* ) were determined by using Vant Hoff and Arrhenius equations.

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