THE THERMAL DECOMPOSITION OF PERACETIC ACID IN AROMATIC SOLVENTS

1963 ◽  
Vol 41 (7) ◽  
pp. 1826-1831 ◽  
Author(s):  
F. W. Evans ◽  
A. H. Sehon
Keyword(s):  
Thermal Decomposition ◽  
Rate Constant ◽  
Peracetic Acid ◽  
First Order ◽  
Aromatic Solvents ◽  
Temperature Range ◽  
Polymeric Compounds

The thermal decomposition of peracetic acid in toluene, benzene, and p-xylene was studied over the temperature range 75–95°C. The main products of decomposition were found to be CH4, CO2, CH3COOH; small amounts of methanol, phenols, and polymeric compounds were also detected.The rate of the overall decomposition was first order with respect to peracetic acid, and the results could be explained by postulating the participation of the two simultaneous reactions:[Formula: see text] [Formula: see text]The rate constant of reaction (1) was independent of the solvent, whereas k2 was dependent on the solvent. The ratio k2/k1 was about 10.

The thermal decomposition of azobenzene

1983 ◽  
Vol 61 (8) ◽  
pp. 1712-1718 ◽  
Author(s):  
Donald Barton ◽  
Michael Hodgett ◽  
Paul Skirving ◽  
Michael Whelton ◽  
Keith Winter ◽  
...  
Keyword(s):  
Thermal Decomposition ◽  
Equilibrium Constant ◽  
Trans Isomer ◽  
Rate Constant ◽  
Volume Ratio ◽  
Order Rate Constant ◽  
Small Concentration ◽  
First Order ◽  
Temperature Range ◽  
Cis Isomer

The rate of nitrogen formation during the thermal decomposition of azobenzene in static and stirred-flow systems was measured over the temperature range of 368.9 °C to 437.4 °C. The first order rate constant was found to be given by the expression[Formula: see text]A consideration of the equilibrium constant between cis-azobenzene and trans-azobenzenc, and the rate of attainment of equilibrium, leads to the conclusion that a small concentration of cis-azobenzene is always present, at equilibrium with the trans isomer. Since the cis isomer is likely to be more reactive than the trans isomer the rate constant cannot be ascribed to the trans isomer alone. No effect of variation of surface-to-volume ratio could be detected. Some preliminary experiments in which toluene and ethylene were employed as additives indicated that these did not affect the rate of formation of nitrogen. Nevertheless, because of a certain amount of scatter in the results, a small effect could not be excluded. There were at least nine products, in addition to nitrogen.

Consecutive reactions in the thermal decomposition of phenylalkyldiazirines

1977 ◽  
Vol 55 (20) ◽  
pp. 3596-3601 ◽  
Author(s):  
Michael T. H. Liu ◽  
Barry M. Jennings
Keyword(s):  
Thermal Decomposition ◽  
Kinetic Parameters ◽  
Diazo Compounds ◽  
First Order ◽  
Temperature Range ◽  
Decomposition Reactions ◽  
Consecutive Reactions ◽  
Rate Processes ◽  
Subsequent Decomposition

The thermal decomposition of phenyl-n-butyldiazirine and of phenylmethyldiazirine in DMSO and in HOAc have been investigated over the temperature range 80–130 °C. The intermediate diazo compounds, 1-phenyl-1-diazopentane and 1-phenyldiazoethane respectively have been detected and isolated. The decomposition of phenyl-n-butyldiazirine and the subsequent decomposition of its product, 1-phenyl-1-diazopentane, are an illustration of consecutive reactions. The kinetic parameters for the isomerization and decomposition reactions have been determined. The isomerization of phenylmethyldiazirine to 1-phenyldiazoethane is first order and probably unimolecular but the kinetics for the subsequent reactions of 1-phenyldiazoethane are complicated by several competing rate processes.

Substituent effects of rate constants for thermal [4π + 2π] cycloreversion of spiro-fused β-lactam oxadiazolines

1993 ◽  
Vol 71 (6) ◽  
pp. 907-911 ◽  
Author(s):  
Michel Zoghbi ◽  
John Warkentin
Keyword(s):  
Thermal Decomposition ◽  
Rate Constant ◽  
Rate Constants ◽  
Transition States ◽  
Substituent Effects ◽  
Ground States ◽  
Phenyl Substituent ◽  
First Order ◽  
Average Value ◽  
Carbonyl Ylide

Twelve Δ3-1,3,4-oxadiazolines in which C-2 is also C-4 of a β-lactam moiety (spiro-fused β-lactam oxadiazoline system) were thermolyzed as solutions in benzene. Substituents in the β-lactam portion affect the rate constant for thermal decomposition of the oxadiazolines to N2, acetone, and a β-lactam-4-ylidene. The total spread of first-order rate constants at 100 °C was 47-fold and the average value was 6.7 × 10−4 s−1. A phenyl substituent at N-1 or at C-3 was found to be rate enhancing, relative to methyl. At C-3, H and Cl were also rate enhancing, relative to methyl. The data are interpreted in terms of the differential effects of substituents on the stabilities of the ground states, and on the stabilities of corresponding transition states for concerted, suprafacial, [4π + 2π] cycloreversion. The first products, presumably formed irreversibly, are N2 and a carbonyl ylide. The latter subsequently fragments to form acetone (quantitative) and a β-lactam-4-ylidene.

The thermal decomposition of cyclobutane-1,2-dione

1985 ◽  
Vol 63 (11) ◽  
pp. 2945-2948 ◽  
Author(s):  
J.-R. Cao ◽  
R. A. Back
Keyword(s):  
Activation Energy ◽  
Thermal Decomposition ◽  
Vapor Pressure ◽  
Gas Phase ◽  
Rate Constant ◽  
Surface Reaction ◽  
Order Rate Constant ◽  
Reaction Vessel ◽  
Arrhenius Parameters ◽  
First Order

The thermal decomposition of cyclobutane-1,2-dione has been studied in the gas phase at temperatures from 120 to 250 °C and pressures from 0.2 to 1.5 Torr. Products were C2H4 + 2CO, apparently formed in a simple unimolecular process. The first-order rate constant was strongly pressure dependent, and values of k∞ were obtained by extrapolation of plots of 1/k vs. 1/p to1/p = 0. Experiments in a packed reaction vessel showed that the reaction was enhanced by surface at the lower temperatures. Arrhenius parameters for k∞, corrected for surface reaction, were log A (s−1) = 15.07(±0.3) and E = 39.3(±2) kcal/mol. This activation energy seems too low for a biradical mechanism, and it is suggested that the decomposition is probably a concerted process. The vapor pressure of solid cyclobutane-1,2-dione was measured at temperatures from 22 to 62 °C and a heat of sublimation of 13.1 kcal/mol was estimated.

THE THERMAL DECOMPOSITION OF PERACETIC ACID IN THE VAPOR PHASE

1963 ◽  
Vol 41 (7) ◽  
pp. 1819-1825 ◽  
Author(s):  
C. Schmidt ◽  
A. H. Sehon
Keyword(s):  
Thermal Decomposition ◽  
Vapor Phase ◽  
Dissociation Energy ◽  
Peracetic Acid ◽  
Kcal Mole ◽  
Temperature Range ◽  
Primary Reactions

The thermal decomposition of peracetic acid in a stream of toluene was studied over the temperature range 127–360 °C. The main products of the reaction were CO2, CH3COOH, C2H6, CH4, HCHO, O2, and traces of CO. Dibenzyl was also formed.The overall decomposition of peracetic acid was partly heterogeneous and was represented by the two parallel primary reactions[Formula: see text] [Formula: see text]The dissociation energy of the O—O bond in peracetic acid was estimated to be 30–34 kcal/mole.

THE DECOMPOSITION OF SILYL PEROXIDES

1964 ◽  
Vol 42 (5) ◽  
pp. 985-989 ◽  
Author(s):  
Richard R. Hiatt
Keyword(s):  
Thermal Decomposition ◽  
Rate Constant ◽  
Half Life ◽  
Order Rate Constant ◽  
Butyl Alcohol ◽  
Base Catalysis ◽  
First Order ◽  
Tert Butyl ◽  
Tert Butyl Alcohol ◽  
Acid And Base

The thermal decomposition of tert-butyl trimethylsilyl peroxide has been investigated and found to be sensitive to acid and base catalysis and to the nature of the solvent. In heptane and iso-octane the first-order rate constant could be expressed as 1.09 × 1015e−41200/RT and in 1-octene as 3.90 × 1015e−41200/RT (sec−1). The half life at 203 °C was about 1 hour. The reaction was faster in aromatic solvents; in chlorobenzene it was complicated by formation of HCl from the solvent.Products of the reaction were acetone, tert-butyl alcohol and hexamethyldisiloxane.

The thermal decomposition of n-propyl bromide

1968 ◽  
Vol 21 (4) ◽  
pp. 973 ◽  
Author(s):  
JTD Cross ◽  
VR Stimson
Keyword(s):  
Thermal Decomposition ◽  
Rate Constant ◽  
Hydrogen Bromide ◽  
Bromine Atom ◽  
Order Reaction ◽  
Chain Mechanism ◽  
Initial Concentration ◽  
First Order ◽  
Reaction Proceeds ◽  
Atom Chain

Mechanisms already proposed or formally possible for the decomposition of n-propyl bromide as a 312-order reaction are shown to be unsatisfactory, and the reaction has been reinvestigated. Two reactions occur simultaneously: (a) a first-order reaction identifiable with the maximally inhibited reaction and presumably molecular; (b) a reaction second order in the initial concentration and somewhat autocatalysed as the reaction proceeds. The rate constant is given by k2 == 1018.1exp(-49300/RT)sec-1ml mole-1 Reaction (b) is catalysed by hydrogen bromide and inhibited by propene, and a bromine atom chain mechanism with hydrogen bromide catalysed initiation is proposed. Bromine-catalysed decomposition has also been studied. The mechanism of the inhibition is discussed.

KINETICS AND MECHANISMS OF THE PYROLYSIS OF DIMETHYL ETHER: II. THE REACTION INHIBITED BY NITRIC OXIDE AND PROPYLENE

1963 ◽  
Vol 41 (8) ◽  
pp. 1993-2008 ◽  
Author(s):  
D. J. McKenney ◽  
B. W. Wojciechowski ◽  
K. J. Laidler
Keyword(s):  
Nitric Oxide ◽  
Thermal Decomposition ◽  
Dimethyl Ether ◽  
Chain Process ◽  
Maximal Inhibition ◽  
First Order ◽  
Temperature Range ◽  
Maximum Inhibition ◽  
A Chain

The thermal decomposition of dimethyl ether, inhibited by nitric oxide and by propylene, was studied in the temperature range of 500 to 600 °C. About 1.5 mm of nitric oxide gave maximal inhibition, the rate then being approximately 8% of the uninhibited rate. With propylene, approximately 70 mm gave maximal inhibition, the rate being slightly higher than that using nitric oxide (~12.5% of the uninhibited rate). In both cases the degree of inhibition was independent of the ether pressure. In the maximally inhibited regions both reactions are three-halves order with respect to ether pressure. As the pressure of nitric oxide was increased beyond 10–15 mm, the overall rate increased, and in this region the reaction is first order with respect to both nitric oxide and ether. A 50:50 mixture of CH3OCH3 and CD3OCD3, with enough NO to ensure maximum inhibition, was pyrolyzed. Even at very low percentage decomposition the CD3H/CD4 ratio was approximately the same as that in the uninhibited decomposition, proving that the inhibited reaction is largely a chain process. Detailed inhibition mechanisms are proposed in which the inhibitor is involved both in initiation and termination reactions.

The thermal decomposition of diethyl ether. III. The action of inhibitors and the mechanism of the reaction

1958 ◽  
Vol 245 (1240) ◽  
pp. 49-67 ◽  
Keyword(s):  
Nitric Oxide ◽  
Thermal Decomposition ◽  
Diethyl Ether ◽  
Rate Constant ◽  
Initial Pressure ◽  
Direct Analysis ◽  
Reaction Products ◽  
First Order ◽  
Molecular Decomposition ◽  
Induced Reaction

Small quantities of nitric oxide reduce the rate of thermal decomposition of diethyl ether at 525 °C to about one-quarter. Much larger amounts accelerate the decomposition, but the concentration ranges in which the ‘ maximally inhibited ’ reaction and the ‘ nitric-oxide-induced’ reaction can be studied are so widely separated that these reactions can be treated as two distinct entities. The ‘uninhibited’ reaction constitutes a third. Reaction products and kinetics are recorded for all three, and nitric oxide consumption is measured for the first two. In all three the major products are the same, with secondary differences which are discussed. In the presence of nitric oxide small amounts of cyanides and other compounds are formed. In the nitric-oxide-induced reaction 1.4 molecules of ether are decomposed for each molecule of nitric oxide used up: in the maximally inhibited reaction the ratio, which is dependent on the ether pressure, is very much greater. The rate of the maximally inhibited reaction is independent of the concentration of nitric oxide, or of propylene, and the same for the two inhibitors (as is now proved by direct analysis). The first-order rate constant varies with the initial pressure of ether according to the equation k inhib. = ( A [ether])/(1 + B [ether]) + C [ether]. The rate constant of the uninhibited reaction varies with ether pressure according to an expression which, although probably of different algebraical form, is empirically similar to the above over a considerable range. The nitric-oxide-induced reaction is nearly of the first order with respect both to ether pressure and to nitric oxide pressure. The maximally inhibited reaction is shown to be most probably a molecular decomposition of the ether. The uninhibited reaction is predominantly a chain reaction, the mechanism of which is discussed. The nitric-oxide-induced reaction, it is suggested on the basis of the experimental evidence, is largely initiated by a generation of radicals in an attack of nitric oxide on ether. It is possibly also in part a molecular decomposition of ether caused by collision with nitric oxide.

THE THERMAL DECOMPOSITION OF ETHANE: PART I. INITIATION AND TERMINATION STEPS

1966 ◽  
Vol 44 (4) ◽  
pp. 505-514 ◽  
Author(s):  
M C. Lin ◽  
M. H. Back
Keyword(s):  
Thermal Decomposition ◽  
High Pressure ◽  
Rate Coefficients ◽  
First Order ◽  
Temperature Range ◽  
Order Rate ◽  
Ethyl Radical ◽  
Initiation Reaction ◽  
Ethyl Radicals

The rates of production of methane and butane in the pyrolysis of ethane have been measured over the temperature range 550–620 °C and at pressures of 40–600 mm. At high pressure the rates of formation of both products were first order in ethane, but below 200 mm the first-order rate coefficients decreased. The ratio of methane to butane was consistent with the interpretation that methane is a measure of the initiation reaction and that the combination and disproportionation of ethyl radicals is the main termination step. The order of the decomposition of the ethyl radical with respect to ethane varied between 0.38 and 0.59. The results are discussed in terms of the mechanism of the overall process.

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