Photochemical Reactions in the Gas Phase Systems: Di-t-butyl Peroxide, Peroxide—Butadiene and Acetone—Butadiene

Volman, David H.; Graven, Wendell M.

doi:10.1021/ja01109a021

Cited by 34 publications

(9 citation statements)

References 15 publications

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“…No significant change in Rco was observed with the addition of unsaturated hydrocarbon, thereby indicating the absence of addition of acetyl radicals. This was probably due to the low concentrations of unsaturated hydrocarbon, since Volman and Graven (10) found that larger concentrations of butadiene decreased Ro in the photolysis of acetone.…”

Section: ( a )mentioning

confidence: 99%

Addition of Methyl Radicals to Unsaturated Hydrocarbons

Mandelcorn¹,

Steacie²

1954

Can. J. Chem.

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The rates of addition of methyl radicals, produced by the photolysis of acetone between 140" C. and 240" C., to u n s a t~~r a t e d hydrocarbons were determined by two independent methods. From the kinetics of the addition and the methyl radical combination reactions, addition of methyl radicals to ethylene, propylene, acetylene, and butadiene was found to proceed with activation energies of 7.0, 6.0, 5.5, and -2.5 kcal. respectively and stcric factors of the order of 10-". INTRODUCTIONThe kinetics of a simple free radical addition reaction such as CH3 + C213.1-4 C3H7 kd are generally difficult to investigate because of complications arising from the various other reactions in which the reactants also participate, and from the nature of the product, which is a free radical. The main difficulty obviously lies in the tendency for the unsaturated hydrocarbon to polymerize, which may obscure the fate of the free radicals in the system, and often pi-events quantitative study of any single process.In this investigation the unsaturated hydrocarbons were kept a t as low concentrations as possible to prevent them from participating in reactions other than addition by methyl radicals. Methods of Determining the Rate of AdditionIn a previous paper (5) it was shown that almost all the methyl radicals in the photolysis of acetone between 100" C. and 284" C. are accounted for by the following reactions:This conclusion was based on the fact that, within 3y0, where Rx is the rate of formation of the product X. I t follows that, if in the presence of an ~lnsaturated hydrocarbon the only other reaction of nlethyl radicals is addition, and Rco is unaffected, the rate of addition, designated as R', for this method; may be obtained from

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Section: ( a )mentioning

confidence: 99%

Addition of Methyl Radicals to Unsaturated Hydrocarbons

Mandelcorn¹,

Steacie²

1954

Can. J. Chem.

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“…Reaction 49 will cause the yield of carbon monoxide to increase as the temperature is raised, since it has an activation energy of 13-18 kcal. per mole (10,116). The fraction a, which probably does not have the same value in the presence as in the absence of iodine, must increase as the wavelength absorbed decreases.…”

Section: E the Nature Of The Primary Processmentioning

confidence: 98%

The Primary Photochemical Process In Simple Ketones

Noyes¹,

Porter²,

Jolley³

1956

Chem. Rev.

127

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“…I t may, however, be concluded that k3/kZ2 G0.5 X10-l5 in m~lecules-~/(sec-~ cc-I). From this conclusion it is possible to calculate the maximum amounts of t-butyl alcohol and t-butylene oxide formed by reaction [3]. Such calculations indicate that t-butyl alcohol is mainly, if not only, formed by abstraction reaction [GI rather than by disproportionation of t-butoxy radicals.…”

Section: T a B L E I1 Ratios Of Rate C O N S T A N T Smentioning

confidence: 99%

“…The absence of an intercept would prove that reaction [3], the disproportionation of two t-butoxy radicals, would not occur. I t may, however, be concluded that k3/kZ2 G0.5 X10-l5 in m~lecules-~/(sec-~ cc-I).…”

Section: T a B L E I1 Ratios Of Rate C O N S T A N T Smentioning

confidence: 99%

REACTIONS OF ALKOXY RADICALS: V. PHOTOLYSIS OF DI-t-BUTYL PEROXIDE

McMillan¹,

Wijnen²

1958

Can. J. Chem.

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A B S T R A C T T h e photolysis o f di-1-butyl peroxide has been investigated over t h e teniperature range 25"t o 7g0 C. As reactio~l products were observed : acetone, t-butyl alcohol, methyl t-butyl ether, i-butylene oxide, ethane, methane, and carbon monoxide. T h e follo~ving reactions, involving t h e t-butoxy radical, have been studied:A n activation energy difference o f E ? -E 6 = 3 lccal has been obtained. I N T R O D U C T I O NPrevious work (1, 2, 3) on the photolysis of di-t-butyl peroxide has established that the primary process consists of the breakage of the 0--0 bond, thus producing two t-butoxy radicals. I t could also be sholvn that the t-butoxy radical is relatively unstable and decomposes according to reaction [2] :As most recent values for the activation energy of reaction [' I have been reported 11.2&2 (3) and 1 3 . 2~t 2 . 4 (4) ltcal.Such a value for E? ivould, however, indicate that especially a t low temperatures the t-butoxy radical might survive long enough to taltc part in abstraction and recombination reactions. While the formation of t-butyl alcohol through hydrogen abstraction b y t-butoxy radicals has been reported frequently (5, 6) no illformation was available regarding the activation energy for the abstraction of a hydrogen atom from di-t-butyl peroxide. In the photolysis of di-t-butyl peroxide a considerable amount of ethane is produced by recombination of methyl radicals, originating from reaction [2]. I t seemed, therefore, likely that especially a t low temperatures some methyl t-butyl ether might be produced via recombiilatioil reactions, although this compound had thus far not been reported among the reaction products. I n order to clear these questions the photolysis of di-t-butyl peroxide has been studied again.

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Photochemical Reactions in the Gas Phase Systems: Di-t-butyl Peroxide, Peroxide—Butadiene and Acetone—Butadiene

Cited by 34 publications

References 15 publications

Addition of Methyl Radicals to Unsaturated Hydrocarbons

Addition of Methyl Radicals to Unsaturated Hydrocarbons

The Primary Photochemical Process In Simple Ketones

REACTIONS OF ALKOXY RADICALS: V. PHOTOLYSIS OF DI-t-BUTYL PEROXIDE

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