- Method for producing acyl peroxides
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The invention relates to a method for producing acyl peroxides. According to said method, an acyl compound is reacted with an organic hydroperoxide and a base, the pH of the two-phase mixture so obtained is adjusted to 6 to 13, the obtained organic phase is extracted with an aqueous solution of a base and the aqueous extract is recirculated to the reaction step. The method according to the invention allows the recirculation of unreacted hydroperoxide to the reaction step.
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Page/Page column 4-5
(2010/02/17)
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- Continuous Method for Producing Acyl Peroxides
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The invention relates to a continuous method for producing acyl peroxides. According to said method, an acyl chloride, carboxylic acid anhydride or chloroformate is reacted with an organic hydroperoxide or hydrogen peroxide in at least two mixed reaction zones that are connected in series, the acyl compound, the peroxy compound and an aqueous solution of a base being supplied to the first reaction zone. The first reaction zone comprises a cycle for the two-phase reaction mixture via a heat exchanger in which the reaction mixture is cooled. The method allows the reaction to be carried out reliably and with high space-time yields.
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Page/Page column 4-5
(2010/03/02)
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- Process for the preparation of a tertiary perester
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The invention relates to a process for the preparation of a tertiary perester by contacting an acyl compound with a tertiary hydroperoxide in the presence of an enzyme catalyst. The acyl compound has the formula R1[C(O)OR2]n, wherein R1is a linear or branched, saturated or unsaturated C1-C22group, optionally containing one or more hetero atoms, R2represents hydrogen or has the same meaning as described for R1, and n is 1-5, or a polyalcohol ester of R1C(O)OH, wherein R1has the same meaning as described above. The tertiary hydroperoxide has the formula [HOOCR3R3]mR4, wherein R3represents either a methyl or an ethyl group, R4has the same meaning as described for R1, and m is 1-5.
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- Thermal decomposition mechanisms of tert-alkyl peroxypivalates studied by the nitroxide radical trapping technique
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The thermolysis of a series of tert-alkyl peroxypivalates 1 in cumene has been investigated by using the nitroxide radical-trapping technique. tert-Alkoxyl radicals generated from the thermolysis underwent the unimolecular reactions, β-scission, and 1,5-H shift, competing with hydrogen abstraction from cumene. The absolute rate constants for β-scission of tert- alkoxyl radicals, which vary over 4 orders of magnitude, indicate the vastly different behavior of alkoxyl radicals. However, the radical generation efficiencies of 1 varied only slightly, from 53 (R = Me) to 63% (R = Bu(t)), supporting a mechanism involving concerted two-bond scission within the solvent cage to generate the tert-butyl radical, CO2, and an alkoxyl radical. The thermolysis rate constants of tert-alkyl peroxypivalates 1 were influenced by both inductive and steric effects [Taft-Ingold equation, log(rel k(d)) = (0.97 ± 0.14)Σσ* - (0.31 ± 0.04)ΣE(s)(c), was obtained].
- Nakamura,Busfield,Jenkins,Rizzardo,Thang,Suyama
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- Homolytic Decomposition of t-Alkyl 2,2-Dimethylperoxypropionates
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Decomposition rates and products of t-alkyl 2,2-dimethylperoxypropionates were measured in cumene at several temperatures.The peroxyesters decomposed homolitycally, depending on the structure of the t-alkyl moiety.The relative rates of the t-alkyl moieties to the 1,1-dimethylethyl one were: 1,1-dimethylbutyl (1.14), 1,1-dimethylpropyl (1.19), 1,1,2-trimethylpropyl (1.85), 1,1,3,3-tetramethylbutyl (2.10), and 1,1-dimethyl-2-phenylethyl (2.34).The decomposition showed an isokinetic relationship and the importance of stabilization by hyperconjugation.Based on these data, the decomposition mechanism, which contains a slight stretching of the Cα-Cβ bond to the peroxyl oxygen at the transition state is, discussed.
- Komai, Takeshi,Matsuyama, Kazuo,Matsushima, Masaru
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p. 1641 - 1646
(2007/10/02)
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