The Reactions of Methyl Radicals with Acetone

Jaquiss, M.T.; Roberts, J. S.; Szwarc, M.

doi:10.1021/ja01143a054

Cited by 10 publications

(4 citation statements)

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“…I . This leads to a rate constant, kl = 2.5XlOl6 exp(-38,70O/RT) sec-', in excellent agreement with those previously determined (3,4,5,6,7,8 …”

Section: Peroxide Alonesupporting

confidence: 89%

The Reaction of Methyl Radicals With Formaldehyde

Blake¹,

Kutschke²

1959

Can. J. Chem.

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The pyrolysis of di-t-butyl peroxide has been reinvestigated and used as a source of methyl radicals to study the abstraction reaction between methyl radicals and formaldehyde. At low [IHCIlO]/[peroxidc] ratios the system was simple enough for kinetic analysis, and a value of 6.6 Iccal/mole was obtained for the activation energy. At higher [HCHOl/[peroxide] ratios the system became very complicated, possibly due to the increased inlportance of addition reactions. INTRODUCTIONThe reaction between methyl radicals and formaldehyde has been previously studied by Kodama and Taltezalti (1) and by Toby and ICutschke (2), who used the photolysis of azomethane as a source of inethyl radicals. They obtained values of 5.6 and 6.2 kcal/ mole, respectively, for the activation energy of the process. I t seemed desirable to reinvestigate the reaction using the pyrolysis of di-t-butyl peroxide as a source of methyl radicals. This source possesses the advantage that there is little abstraction reaction between methyl radicals and the n~olecule which produces the radicals.Methyl radicals were produced by the pyrolysis of di-t-butyl peroxide in a Pyrex glass reaction vessel (volume = 550 cm3) the temperature of which was controlled to within 0.1" C. T o start the reaction the reactants were expanded into the cell from a preheater maintained a t 80" C, a t which temperature no measurable decomposition of the peroxide took place in a period of 30 minutes. The reaction was stopped by expansion into a liquid-nitrogen-cooled trap. The products were analyzed by conventional methods. CHI and CO were separated from the remaining products a t -210" C, and the CO measured as C 0 2 after oxidation in a copper oxide furnace a t 260' C. Methane was removed directly from the furnace and measured. Ethane was distilled from Ward stills a t -180" C. The purity of each fraction was checked lnass spectrolnetrically in some experiments. The remailling lnixture of liquid products and unreacted starting materials was removed for further analysis. Liquid product analyses for acetone, t-butanol, and acetaldehyde mere carried out gas chro~natographically on a 10-ft column consisting of 30% nonyl-phthalate on firebrick, with a small proportion of polyethylene glycol added to the phthalate to cut down tailing of the peaks. No substances were detected other than the residual reactants and those products for which analyses are given.Di-t-butyl peroxide, fro111 the Novadel-Agene Corporation, contained traces of acetone and methanol and approximately 1/2% t-butanol. The first two were entirely removed by chromatographic purification; the t-butanol content was reduced to < 0.1% by this treatment. Isobutane mas Phillips Research Grade. Formaldehyde was prepared by heating a-polyoxy~nethyle~le followed by distillation in vacz~o. All these materials were thoroughly outgassed before use.lA!fanz~script recei-ded M a y 14, 1969.

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“…I . This leads to a rate constant, kl = 2.5XlOl6 exp(-38,70O/RT) sec-', in excellent agreement with those previously determined (3,4,5,6,7,8 …”

Section: Peroxide Alonesupporting

confidence: 89%

The Reaction of Methyl Radicals With Formaldehyde

Blake¹,

Kutschke²

1959

Can. J. Chem.

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“…íerí-CíHeOOCíHe-íerí....................... 34 ± 2 and 36 ± 1; 38 (180,23) 36 to 40; 37; 38 (163,32,130) 37.0 38.6; 39.5 (214, 217) íerí-CeHiiOOCtHiHerí...................... peroxides may be achieved by any of three methods: pyrolysis, photolysis, and catalysis by redox mechanisms. All three classes have been studied kinetically and by product analysis.…”

Section: • -> Dimermentioning

confidence: 99%

The Thermochemistry And Reactivity Of Alkoxyl Radicals

Gray¹,

Williams²

1959

Chem. Rev.

255

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“…9 and those from experiments in which di-tert-butyl peroxide was the radical source (14,18) tity of data involved in the present evaluation, the more rigorous approach employed, and the errors found in some of the reported Arrhenius parameters, the agreement between the Arrhenius parameters proposed in the earlier evaluations and those recommended here must be regarded as fortunate. It is our opinion that the performance of a particular experimental system can be considered satisfactory only if the data obtained with it for CH, attack on acetone yield Arrhenius parameters that lie within four standard deviations of the values given in eq.…”

Section: Results and Discussion Ch3 Attack On Acetonementioning

confidence: 53%

Structure cristalline du complexe de magnésium de la calcimycine (A. 23187)

Alléaume¹,

Barrans²

1985

Can. J. Chem.

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The 1:2 magnesium ion complex of the antibiotic calcimycine (A. 23187) crystallizes in the space group P21, with cell dimensions a = 11.152(2), b = 27.684(2), c = 10.168(2) Å, β = 107.02(2)°, and Z = 2. The structure was refined to an R = 0.063 based on 3473 observed reflections. The octahedral coordination of the Mg2+ ion is highly symmetrical. Each calcimycine ion is bound to Mg2+ through a carboxyl oxygen, a carbonyl oxygen, and the nitrogen of the benzoxazole ring system. The Mg—O distances are respectively 2.00 Å and 2.06 Å, the Mg—N distances 2.23 Å [Formula: see text].

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The Reactions of Methyl Radicals with Acetone

Cited by 10 publications

References 0 publications

The Reaction of Methyl Radicals With Formaldehyde

The Reaction of Methyl Radicals With Formaldehyde

The Thermochemistry And Reactivity Of Alkoxyl Radicals

Structure cristalline du complexe de magnésium de la calcimycine (A. 23187)

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