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 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.

Photolysis of Di-tert-butyl Peroxide at High Pressure

1972 ◽  
Vol 50 (10) ◽  
pp. 1531-1534 ◽  
Author(s):  
C. K. Yip ◽  
H. O. Pritchard
Keyword(s):  
Thermal Decomposition ◽  
High Pressure ◽  
Gaseous Phase ◽  
Chemical Reactivity ◽  
Hydrocarbon Concentration ◽  
Tert Butyl ◽  
Butyl Peroxide ◽  
Butoxy Radical ◽  
Peroxide Molecule

Di-tert-butyl peroxide has been photolyzed at 2537 Å in the gaseous phase in the presence of up to 47 amagats (2.10 mol/l) of propane and of cyclopropane. It was confirmed that no acetone is formed in the limit of infinite hydrocarbon concentration and therefore that the primary chemical act leading to the eventual formation of acetone is the formation of two tert-butoxy radicals from the excited peroxide molecule; in addition, some crude information was obtained concerning relative rates of photochemical vs. deactivation processes. It was also found that at these densities the tert-butoxy radical formed in the photolysis of di-tert-butyl peroxide did not appear to differ in chemical reactivity from the tert-butoxy radical formed in the thermal decomposition of di-tert-butyl peroxide.

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.

FREE RADICALS BY MASS SPECTROMETRY: XXXV. THE HEAT OF FORMATION OF ALLYL RADICAL FROM BIALLYL PYROLYSIS

1966 ◽  
Vol 44 (18) ◽  
pp. 2211-2217 ◽  
Author(s):  
J. B. Homer ◽  
F. P. Lossing
Keyword(s):  
Mass Spectrometry ◽  
Activation Energy ◽  
Thermal Decomposition ◽  
Total Pressure ◽  
Heat Of Formation ◽  
Kcal Mole ◽  
Allyl Radical ◽  
First Order ◽  
Secondary Reactions ◽  
Gas Pressures

The thermal decomposition of biallyl has been investigated from 977 – 1 070 °K at helium carrier gas pressures of 10–50 Torr. Under these conditions the rate of central C—C bond fission to give two allyl radicals can be measured without interference from secondary reactions. The reaction at the pressures employed is first order with respect to biallyl, but between first and second order in the total pressure. The temperature dependence of the rate constants, extrapolated to infinite pressure, and corrected to 298 °K, gives an activation energy of 45.7 kcal/mole for the reaction, corresponding to ΔHf(allyl) = 33.0 kcal/mole.

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 reaction of Carbon with Hydrogen at High Pressure

1959 ◽  
Vol 12 (1) ◽  
pp. 14 ◽  
Author(s):  
JD Blackwood
Keyword(s):  
Carbon Dioxide ◽  
High Pressure ◽  
Partial Pressure ◽  
Total Pressure ◽  
Rapid Evolution ◽  
The Other ◽  
Methane Formation ◽  
Kcal Mole ◽  
Straight Line ◽  
Active Centres

A study has been made of the reactions of a number of carbons with hydrogen at pressures up to 40 atm and in the temperature range 650-870 �C. The effect of total pressure and hydrogen partial pressure has been examined and the rate of methane formation for a given carbon can be expressed as ��������������������� rate= kpH2. Values of log k when plotted against 1/T give a straight line and the "apparent" energy of activation is approximately 30 kcal mole-1. The value of the constant k for a given temperature of reaction is dependent on the oxygen content of the carbon which is, in turn, dependent on the temperature of preparation of the carbon. For carbons containing no oxygen the methane rate is zero, The oxygen appears to be associated with at least two types of active centres. One type, considered to have a lactone structure, is responsible for an initial rapid evolution of methane and water and is destroyed during the first few minutes of hydrogenation. The other centre, responsible for the slow steady evolution of methane, appears to be associated with structures such as chromene or benzpyran which activate certain sites on the carbon crystallite. Neither steam nor carbon dioxide will activate the carbon for the formation of methane.

A Kinetic Study of High Pressure Aqueous Oxidations of Organic Compounds Using Elemental Oxygen

1974 ◽  
Vol 52 (10) ◽  
pp. 1925-1933 ◽  
Author(s):  
Jay E. Taylor ◽  
John C. Weygandt
Keyword(s):  
Carbon Dioxide ◽  
High Pressure ◽  
Butyl Alcohol ◽  
Primary Alcohols ◽  
Isobutyl Alcohol ◽  
First Order ◽  
Tert Butyl ◽  
Tert Butyl Alcohol ◽  
First Time ◽  
Bimolecular Mechanism

The high pressure (< 136 atm) and high temperature (< 250°) reactions of elemental oxygen with aqueous solutions of selected soluble alcohols, ketones, and acids have been examined in detail for the first time. Saturated acids and methyl alcohol are not oxidized under the imposed conditions. The end product for the oxidation of ketones and primary alcohols is mainly carbon dioxide at 200 °C; however, appreciable yields of acids are obtained at 250 °C. tert-Butyl alcohol and secondary alcohols form the corresponding ketones which are then further oxidized. Those alcohols and ketones which were studied quantitatively all exhibited second-order kinetics, first order in organic compound and first order in oxygen. The compounds are listed below in the order of decreasing rate at 200°, ΔH≠ in kcal/mol and ΔS≠ in entropy units are noted in parentheses: 2-butanone (16.0, −25) > tert-butyl alcohol (24.2, −9) > cyclopentanone (12.4, −36) > isobutyl alcohol (21.5, −17) > sec-butyl alcohol (23.9, −15) > n-butyl alcohol > (21.3, −22) > acetone (15.1, −37). The alcohols have both higher entropies and enthalpies of activation than the ketones. Two non-chain mechanisms are proposed. (I) A ketone equilibrates with its enol which oxidizes to a metastable oxygenated intermediate. At 250° the intermediate decomposes to an acid or at 200° it is further oxidized to carbon dioxide. (II) Alcohols oxidize by an initial bimolecular mechanism to the corresponding ketone or aldehyde which may then be oxidized further.

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