Influence of some heavy foreign gases on the thermal decomposition of di-tertiary butyl peroxide

1958 ◽  
Vol 247 (1250) ◽  
pp. 381-389 ◽  
Keyword(s):  
Thermal Decomposition ◽  
Nitrous Oxide ◽  
Pressure Range ◽  
Order Rate Constant ◽  
Chemical Effect ◽  
Sulphur Hexafluoride ◽  
Tertiary Butyl ◽  
First Order ◽  
Butyl Peroxide ◽  
Limiting Value

The first-order rate constant for the thermal decomposition of di-tertiary butyl peroxide in the pressure range 0 to 600 mm follows an equation of the form k = A 1 n /(1+ A' 1 n + A 2 n , where n is the peroxide pressure. For a given value of n additions of sulphur hexafluoride (which appears from analysis to have no chemical effect) raise k to a limiting value, k n ,∞. This value is itself a function of the peroxide pressure approximately of the form k n , ∞ = An /(1+A' n )+B. In the light of previous work on nitrous oxide and on paraffins, these results are tentatively explained in terms of a scheme in which energized molecules go reversibly to special activated states from which decomposition follows either spontaneously or when induced by collisions.

The thermal decomposition of nitrous oxide I. Secondary catalytic and surface effects

1955 ◽  
Vol 231 (1185) ◽  
pp. 162-178 ◽  
Keyword(s):  
Nitric Oxide ◽  
Thermal Decomposition ◽  
Nitrous Oxide ◽  
Surface Reaction ◽  
Order Rate Constant ◽  
Side Reactions ◽  
Chain Reactions ◽  
First Order ◽  
Reaction Vessels ◽  
Decomposition Of Nitrous Oxide

In the region of pressure 0 to 500 mrn approximately to the equation the thermal decomposition of nitrous oxide conforms approximately to the equation k = an /1 + a'n + bn , where k is the form al first-order rate constant, — (1/n) d n /d t , n the initial concentration and a, a' and b are nearly constant. Above about 100 m m this expression approximates to k = A + bn , which holds up to several atmospheres. Fresh and more detailed experiments have once again disproved the suggestion that the first term in these expressions is due to a surface reaction. (In certain states of reaction vessels, made of a particular brand of silica, a surface reaction may appear but is immediately recognizable by special criteria, and can be eliminated.) Detailed study of the formation of nitric oxide in the course of the decomposition, and of the effect of inert gas upon this process, shows that side reactions involving oxygen atoms, chain reactions and catalysis by nitric oxide play only minor parts in determining the shape of the k-n curve. The form of this curve, which is an inherent character of the reaction N 2 O = N 2 + O, raises theoretical questions of considerable interest.

Catalytic influence of certain foreign gases on the thermal decomposition of di-tertiary butyl peroxide

1959 ◽  
Vol 249 (1257) ◽  
pp. 173-179 ◽  
Keyword(s):  
Activation Energy ◽  
Thermal Decomposition ◽  
Carbon Tetrachloride ◽  
Rate Constant ◽  
Tertiary Butyl ◽  
Extended Theory ◽  
Uncatalyzed Reaction ◽  
Butyl Peroxide ◽  
Limiting Value ◽  
Induced Reaction

Silicon tetrafluoride accelerates the decomposition of di-tertiary butyl peroxide, the rate constant k n,x for a given pressure, n , of the peroxide rising with the fluoride pressure, x , to a limiting value k n ,∞ . This value is different for different values of n . The activation energy of the induced reaction is 27 ± 1 kcal compared with 37 kcal for the uncatalyzed reaction. The products are little different from those of the normal decomposition except that the ratio of methane to ethane is slightly increased. The order of effectiveness of fluorides is SiF 4 > SF 6 > CF 4 , the inverse order of the ease with which they should release fluorine atoms. Carbon tetrachloride causes acceleration comparable with that caused by the silicon fluoride with a much more drastic shift in the product ratios. The mechanism of these actions is discussed in relation to the extended theory of unimolecular reactions.

Thermal decomposition of di-tert-butyl peroxide at high pressure

1968 ◽  
Vol 46 (16) ◽  
pp. 2721-2724 ◽  
Author(s):  
D. H. Shaw ◽  
H. O. Pritchard
Keyword(s):  
Carbon Dioxide ◽  
Thermal Decomposition ◽  
High Pressure ◽  
Shock Tube ◽  
Total Pressure ◽  
Order Rate Constant ◽  
Kcal Mole ◽  
First Order ◽  
Tert Butyl ◽  
Butyl Peroxide

The thermal decomposition of di-tert-butyl peroxide has been studied in the presence of carbon dioxide at total pressures from 0.05 to 15 atm and temperatures from 90–130 °C. The first-order rate constant for the decomposition is independent of total pressure in this range, with Arrhenius parameters E = 37.8 ± 0.3 kcal/mole and log A(s−1) = 15.8+0.2. A reevaluation of previous data on this reaction leads us to recommend E = 37.78 ± 0.06 kcal/mole and log A(s−1) = 15.80 ± 0.03 over the temperature range 90–350 °C; extension of this range to higher temperatures using a shock tube would be worthwhile.

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 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.

Di-tert-butyl peroxide decomposition behind shock waves

1976 ◽  
Vol 54 (4) ◽  
pp. 581-585 ◽  
Author(s):  
David K. Lewis
Keyword(s):  
Thermal Decomposition ◽  
Gas Phase ◽  
Single Pulse ◽  
First Order ◽  
Tert Butyl ◽  
First Order Kinetics ◽  
Peroxide Decomposition ◽  
Butyl Peroxide ◽  
Temperature Work ◽  
Lower Temperature

The homogeneous, gas phase thermal decomposition of di-tert-butyl peroxide has been studied in a single pulse shock tube. Samples containing 0.05% to 0.5% reactant in argon were heated to 528–677 K at total pressures of about 1 atm. Acetone and ethane were the only significant products. The reaction obeyed first order kinetics. The Arrhenius parameters, log A (s−1) = 15.33 ± 0.50, Eact (kJ/mol) = 152.3 ± 5.8, are in agreement with the bulk of the earlier reported results of lower temperature work, and with a recently reported result obtained via the very low pressure pyrolysis technique. Indications from some of the earlier work that the A factor may decline at high temperatures are not supported by the present study.

The thermal decomposition of nitrous oxide II. Influence of added gases and a theory of the kinetic mechanism

1955 ◽  
Vol 231 (1185) ◽  
pp. 178-197 ◽  
Keyword(s):  
Carbon Dioxide ◽  
Thermal Decomposition ◽  
Nitrous Oxide ◽  
Initial Pressure ◽  
Kinetic Mechanism ◽  
Gas Pressure ◽  
Unimolecular Reactions ◽  
Chemical Decomposition ◽  
First Order ◽  
Decomposition Of Nitrous Oxide

The influence of foreign gas additions (argon, nitrogen, carbon dioxide, carbontetrafluoride and mixtures of them) on the thermal decomposition of nitrous oxide at a series of different initial pressures has been studied. The curves of k , the formal first-order constant, as a function of x , the foreign-gas pressure, show regions of rapidly falling slope analogous to those found in the curves of k against n , the initial pressure of nitrous oxide. The forms of the curves have been investigated in some detail, and suggest very strongly the existence of potentially rate-determining processes other than those normally assumed in unimolecular reactions (which are energization of molecules in collisions and chemical decomposition of these molecules). It is now postulated that spontaneous and collision-induced transfers of energized nitrous oxide molecules to trip let states constitute the processes in question, and on this basis the forms of the k , n and k , x curves are interpreted. This postulate links up with certain spectroscopic considerations previously advanced by Herzberg.

Pyrolysis of trifluoroacetaldehyde, initiated by di-tertiary-butyl peroxide decomposition

1979 ◽  
Vol 57 (17) ◽  
pp. 2201-2210 ◽  
Author(s):  
Leon F. Loucks ◽  
Michael T. H. Liu ◽  
David G. Hooper
Keyword(s):  
Thermal Decomposition ◽  
Decomposition Product ◽  
Reaction Order ◽  
Methyl Radicals ◽  
Reaction Products ◽  
Decomposition Products ◽  
Tertiary Butyl ◽  
Decomposition Reactions ◽  
Peroxide Decomposition ◽  
Butyl Peroxide

The thermal decomposition of 95:5 mixtures of trifluoroacetaldehyde (TFA) and di-tert-butyl peroxide (DTBP) has been studied at 100 Torr over the temperature range of 390 to 440 K. The major decomposition products included CO, CF3H, CH3COCH3, and CH4 while C2F6, CF3CHOHCH3, CF3CH3, CF3COCH3, C2H6, (CF3)2CHOH, and H2 were also found. In addition to the usual reactions for TFA thermal decomposition, reactions of methyl radicals with TFA to form isopropoxyl radicals were found. The alcohol products result from H atom abstraction reactions of the isopropoxyl radicals while CF3COCH3 is a decomposition product. Arrhenius parameters for several reactions were determined: for DTBP decomposition, log k = 15.82 − 37.73/2.303RT; for H abstraction from TFA by CH3, log k = 8.30 − 7.37/2.303RT; for H abstraction from TFA by CF3, log k = 8.98 − 8.61/2.303RT. Consideration has also been given to several rate constant ratios for the formation and decomposition of isopropoxyl radicals.A study of the reaction order for the formation of CF3H, C2F6, and CH4 showed that the orders were 3/2, 1, and 1 respectively for these three products. A reaction mechanism involving 14 individual steps is proposed to explain the reaction products and the observed orders of reaction.

Thermal decomposition of methyl azide

1970 ◽  
Vol 48 (7) ◽  
pp. 1140-1147 ◽  
Author(s):  
M. S. O'Dell Jr. ◽  
B. deB. Darwent
Keyword(s):  
Thermal Decomposition ◽  
Rate Constant ◽  
Order Rate Constant ◽  
First Order ◽  
Hexamethylene Tetramine ◽  
Order Rate

The thermal decomposition of gaseous methyl azide has been investigated at conversions of less than 1% at 155, 170, and 200 °C. The reaction has been shown to be homogeneous and unimolecular, the first-order rate constant being kun1 = 2.85 × 1014 exp − (40 500/RT). The decomposition results in the formation of CH3N(X3∑−) and N2(X1∑g+). The CH3N(X3∑−) do not react with CH3N3 to produce N2, but do form a polymer of composition similar to hexamethylene tetramine and also react with olefins. The major products are N2 and polymer; small amounts of H2 and CH4, but no C2H6, are formed.

Inhibition phenomena in the decomposition of di- t -butyl peroxide

1961 ◽  
Vol 261 (1306) ◽  
pp. 293-302 ◽  
Keyword(s):  
Carbon Tetrachloride ◽  
Gas Phase ◽  
Methyl Chloride ◽  
Major Product ◽  
Sulphur Hexafluoride ◽  
Peroxide Decomposition ◽  
Butyl Peroxide ◽  
A Chain ◽  
Catalytic Effects ◽  
Limiting Value

Carbon tetrachloride vapour accelerates the gas phase decomposition of di- t -butyl peroxide, the rate constant k n, z , for a given pressure, n , of the peroxide rising with the chloride pressure, x , to a limiting value k n, ∞ . The normal products of the reaction are somewhat changed, acetone being still a major product but methane largely replacing ethane while methyl chloride and probably iso -butene oxide also appear. The effects of the carbon tetrachloride can be largely inhibited by the addition of ammonia, propylene or iso -butene. Similar phenomena are observed with certain other chlorine compounds, and the accelerations are now interpreted in terms of a chain reaction involving chlorine atoms. Acceleration of the peroxide decomposition is also caused by silicon tetrafluoride, sulphur hexafluoride or fluoroform. Propylene considerably inhibits the actions of these compounds and ammonia slightly. Although the interpretation is less certain, it seems likely that the catalytic effects of the fluorides are at least partly due to chemical chain processes.

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