STUDIES ON HOMOGENEOUS FIRST ORDER GAS REACTIONS: VI. THE DECOMPOSITION OF METHYLENE DIACETATE, METHYLENE DIPROPIONATE, AND METHYLENE DIBUTYRATE

1937 ◽  
Vol 15b (5) ◽  
pp. 229-236 ◽  
Author(s):  
C. C. Coffin ◽  
W. B. Beazley
Keyword(s):  
Activation Energy ◽  
Experimental Error ◽  
Pressure Change ◽  
Reaction Rates ◽  
Reaction Velocity ◽  
First Order ◽  
Exact Position ◽  
Gas Reactions ◽  
Homogeneous Decomposition ◽  
Large Experimental Error

The homogeneous decomposition of methylene diacetate vapor to formaldehyde and acetic anhydride at temperatures between 220° and 305 °C. and at pressures ranging from several centimetres of mercury to several atmospheres has been studied. Reaction rates were determined by analytical and by pressure change methods. The first order decomposition is opposed by a second order recombination. A secondary reaction makes it impossible to determine the exact position of the resulting equilibrium. Within the rather large experimental error, methylene diacetate has the same activation energy (33,000 cal.) as its homologues. Its specific reaction velocity is smaller than that of the ethylidene esters. Methylene dipropionate and dibutyrate decompose at the same rate as the diacetate. These facts are in accord with the hypothesis that the extent to which a radical can contribute to the energy of activation is dependent upon its position in the molecule. Veolcity constants are given by the equation [Formula: see text]

STUDIES ON HOMOGENEOUS FIRST ORDER GAS REACTIONS: VIII. THE DECOMPOSITION OF TRICHLORETHYLIDENE DIACETATE AND TRICHLORETHYLIDENE DIBUTYRATE

1937 ◽  
Vol 15b (6) ◽  
pp. 254-259 ◽  
Author(s):  
N. A. D. Parlee ◽  
J. R. Dacey ◽  
C. C. Coffin
Keyword(s):  
Activation Energy ◽  
Experimental Error ◽  
Acid Anhydride ◽  
Exchange Energy ◽  
Reaction Velocity ◽  
First Order ◽  
Measurable Rate ◽  
Gas Reactions

Trichlorethylidene diacetate and trichlorethylidene dibutyrate have been found to decompose at temperatures between 200° and 290 °C. at a measurable rate to give chloral and an acid anhydride. The reactions are homogeneous and of the first order, and have the same specific velocity in both the liquid and vapor states. The activation energy is identical (within experimental error) with that previously found for non-chlorinated members of this series of esters. The two compounds decompose at the same rate, in agreement with the hypothesis that the anhydride radicals do not easily exchange energy with the bonds that break. This reaction velocity, which is somewhat smaller than that of ethylidene diacetate at any temperature, is given by the equation [Formula: see text].

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: 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].

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].

STUDIES ON HOMOGENEOUS FIRST ORDER GAS REACTIONS: XI. THE DECOMPOSITION OF BENZYLIDENE DIACETATE, o-CHLOROBENZYLIDENE DIACETATE AND BENZYLIDENE DIBUTYRATE

1940 ◽  
Vol 18b (8) ◽  
pp. 223-230 ◽  
Author(s):  
N. A. D. Parlee ◽  
J. C. Arnell ◽  
C. C. Coffin
Keyword(s):  
Double Bond ◽  
Steric Factor ◽  
Reverse Reaction ◽  
Breaking Point ◽  
Reaction Velocity ◽  
First Order ◽  
Gas Reactions

Benzylidene diacetate, o-chlorobenzylidene diacetate, and benzylidene dibutyrate decompose unimolecularly at rates given by the equation previously found for crotonylidene diacetate and furfurylidene diacetate, viz., [Formula: see text]. The fact that these esters all have a double bond at the same distance from the breaking point of the molecule is considered significant in connection with their identical reaction velocity, which is about six times that of ethylidene diacetate. Benzylidene diacetate decomposes at the same rate in both the liquid and vapour states to reach an equilibrium given by the equation [Formula: see text]. The reverse reaction with a rate given by [Formula: see text] is characterized by a steric factor of 10−4.

THE KINETICS OF CUPRENE GROWTH

1950 ◽  
Vol 28b (7) ◽  
pp. 358-372
Author(s):  
Cyrias Ouellet ◽  
Adrien E. Léger
Keyword(s):  
Nitric Oxide ◽  
Activation Energy ◽  
Carbon Monoxide ◽  
Apparent Activation Energy ◽  
Copper Catalyst ◽  
Maximum Velocity ◽  
Static System ◽  
Reaction Velocity ◽  
First Order ◽  
Kinetics Of

The kinetics of the polymerization of acetylene to cuprene on a copper catalyst between 200° and 300 °C. have been studied manometrically in a static system. The maximum velocity of the autocatalytic reaction shows a first-order dependence upon acetylene pressure. The reaction is retarded in the presence of small amounts of oxygen but accelerated by preoxidation of the catalyst. The apparent activation energy, of about 10 kcal. per mole for cuprene growth between 210° and 280 °C., changes to about 40 kcal. per mole above 280 °C. at which temperature a second reaction seems to set in. Hydrogen, carbon monoxide, or nitric oxide has no effect on the reaction velocity. Series of five successive seedings have been obtained with cuprene originally grown on cuprite, and show an effect of aging of the cuprene.

STUDIES ON HOMOGENEOUS FIRST ORDER GAS REACTIONS: III. THE DECOMPOSITION OF PARALDEHYDE

1932 ◽  
Vol 7 (1) ◽  
pp. 75-80 ◽  
Author(s):  
C. C. Coffin
Keyword(s):  
Activation Energy ◽  
Total Pressure ◽  
Mercury Vapor ◽  
Constant Volume ◽  
Reverse Reaction ◽  
First Order ◽  
Partial Pressures ◽  
Gas Reactions ◽  
Points Of View

The gaseous decomposition of paraldehyde to acetaldehyde has been studied from points of view already outlined. The reaction, which was followed by increase of pressure at constant volume, is homogeneous, accurately first order, and is presumably uncatalyzed. Its velocity has been measured between 209° and 270 °C. at initial pressures of from 1.18 to 52.0 cm. of mercury. It goes to completion under these conditions of pressure and temperature at a rate which is independent of the total pressure and of the partial pressures of paraldehyde, acetaldehyde and mercury vapor. The activation energy is 44160 cal. per mol. The velocity constants are given by the equation [Formula: see text]. The bearing of the data on the probably trimolecular reverse reaction as well as on work already reported is discussed.

THE THERMAL DECOMPOSITION OF METHYL HYDROPEROXIDE

1965 ◽  
Vol 43 (8) ◽  
pp. 2236-2242 ◽  
Author(s):  
Alexander D. Kirk
Keyword(s):  
Activation Energy ◽  
Thermal Decomposition ◽  
Gas Phase ◽  
Rate Constants ◽  
Dimethyl Phthalate ◽  
Kcal Mole ◽  
First Order ◽  
Methyl Hydroperoxide ◽  
Expected Values ◽  
Homogeneous Decomposition

The thermal decomposition of methyl hydroperoxide has been studied in solution and in the gas phase. The decomposition was found to be partly heterogeneous in solution in dimethyl phthalate and no reliable rate constants were obtained. Use of the toluene carrier method for the gas phase work enabled measurement of the rate constant for the homogeneous decomposition. The first order rate constants obtained range from 0.19 s−1 at 292 °C to 1.5 s−1 at 378 °C, leading to log A, 11± 2, and activation energy, 32 ± 5 kcal/mole. These results are compared with the expected values of log A, 13–14, and activation energy, 42 kcal/mole. The significance of these findings is discussed.

STUDIES ON HOMOGENEOUS FIRST ORDER GAS REACTIONS: IV. THE DECOMPOSITION OF PARA-n-BUTYRALDEHYDE AND PARA-ISOBUTYRALDEHYDE

1933 ◽  
Vol 9 (6) ◽  
pp. 603-609 ◽  
Author(s):  
C. C. Coffin
Keyword(s):  
Experimental Error ◽  
Degrees Of Freedom ◽  
Activation Energies ◽  
Energy Of Activation ◽  
Velocity Constant ◽  
First Order ◽  
Temperature Range ◽  
Measurable Rate ◽  
Gas Reactions ◽  
Internal Degrees Of Freedom

The gaseous decompositions of para-n-butyraldehyde and para-isobutyraldehyde to n-butyraldehyde and isobutyraldehyde respectively are homogeneous and first order over the pressure and temperature range investigated (1.3 to 55 cm. of mercury; 215 to 261 °C). Under these conditions the reactions go to completion at a measurable rate without complications. Within experimental error the activation energies of these reactions are equal and are approximately the same as that of the paracetaldehyde decomposition. This value is between 42,000 and 44,000 calories per mole. The rates of decomposition of the two parabutyraldehydes are very nearly the same at any temperature. At 500° abs. the velocity constant of the iso-compound is about 15% greater than that of the normal and about 100% greater than that of paracetaldehyde. The velocity constants at any temperature are given by the equations: para-n-butyraldehyde, [Formula: see text]; para-isobutyraldehyde, [Formula: see text]. The data are consistent with the idea that, for a series of reactions with the same energy of activation, an increase in the number of contributory internal degrees of freedom of a molecule will increase the probability of reaction.

scholarly journals The effect of solvent on reaction velocity. IV.—The rate and critical increments of some chlorination reactions

1933 ◽  
Vol 140 (840) ◽  
pp. 71-78 ◽  
Keyword(s):  
Kinetic Energy ◽  
Collision Frequency ◽  
Reaction Rates ◽  
Quaternary Ammonium Salts ◽  
Ammonium Salts ◽  
Reaction Velocity ◽  
Effect Of Solvent ◽  
Calculated Rate ◽  
Gas Reactions ◽  
Nonpolar Molecules

Moelwyn-Hughes has recently shown that the observed rates of a number of reactions in solution approximate to those calculated from the collision frequency of the reacting molecules and the critical increment of the reaction. At first sight, this fact brings reaction velocity in solution in line with reaction velocity in bimolecular homogeneous gas reactions, where a sufficient hypothesis to explain the observed reaction rates, is that reaction occurs whenever two molecules collide with a combined kinetic energy equal to, or greater than, the critical increment. There are, however, a number of reactions in solution, considered by Moelwyn-Hughes, which have a relatively low critical increment for which the calculated rate is several thousand times greater than that observed. The conclusion drawn is that the observed critical increment of these reactions is false. The reactions which show this anomalous behaviour are reactions of the type where quaternary ammonium salts are formed. In such reactions relatively nonpolar molecules are forming a salt. A reaction of the converse type where polar molecules are forming molecules of a less polar nature is the interaction of acetic anhydride and ethyl alcohol. Here also it is found that the calculated rate is many thousand times greater than that observed.

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