Ozonolysis ethene

This compound was shown to be an intermediate in ozonolysis of some ethenes. In concentrated form it is very explosive minimal handling and working with strong gloves behind a blast screen are recommended. 

Horie, O., P. Neeb, S. Limbach, and G. K. Moortgat, Formation of Formic Acid and Organic Peroxides in the Ozonolysis of Ethene with Added Water Vapour, Geophys. Res. Lett., 21, 1523-1526 (1994). 

Wolff, S., A. Boddenberg, J. Thamm, W. V. Turner, and S. Gab, Gas-Phase Ozonolysis of Ethene in the Presence of Carbonyl-Oxide Scavengers, Atmos. Environ., 31, 2965-2969 (1997). 

A comparison of various calculations revealed <1997PCA9421> that an accurate description of the ozonolysis of ethene is obtained at the CCSD(T) level with a TZ+2P basis set, while other methods, which cover less correlation effects, fail to provide a consistent description of all reaction steps. It was shown that the primary ozonides (1,2,3-trioxolanes) are not collisionally stabilized under atmosphere conditions <1997PCA9421>. 

Another potential dark source of in the atmosphere, more particularly in the boundary layer, is from the reactions between ozone and alkenes. The ozonolysis of alkenes can lead to the direct production of the OH radical at varying yields (between 7 and 100%) depending on the structure of the alkene, normally accompanied by the co-production of an (organic) peroxy radical. As compared to both the reactions of OH and NO3 with alkenes the initial rate of the reaction of ozone with an alkene is relatively slow, this can be olfset under regimes where there are high concentrations of alkenes and/or ozone. For example, under typical rural conditions the atmospheric lifetimes for the reaction of ethene with OH, O3 and NO3 are 20 h, 9.7 days and 5.2 months, respectively in contrast, for the same reactants with 2-methyl-2-butene the atmospheric lifetimes are 2.0 h, 0.9 h and 0.09 h. 

The first asymmetric total synthesis of acosamine and daunosamine starting from a nonsugar precursor was reported by Fuganti and co-workers [288,289,290,291]. They found that baker s yeast catalyzes the asymmetric pinacolic cross-coupling of cinnamaldehyde and ethenal giving a ft-diol 156. This diol is protected as an acetonide and submitted to ozonolysis giving L-157. Olefination of L-157 with PhsP = CHCOOMe, followed by treatment with ammonia, provides 158 that is then converted into W-trifluoroacetylacosamine 158 (O Scheme 61). 

Ethene, like other alkenes, reacts also with ozone in the atmosphere. The older work on ozone reactions has been reviewed by Leighton (1961) and by Bufalini and Altshuller (1965). More recent work has done much to clarify the principal reaction mechanisms involved. Criegee (1957, 1962, 1975), who had studied the ozonolysis of alkenes in solution, suggested that ozone adds to the C=C double bond, forming an unstable intermediate, which then decomposes toward a carbonyl compound and a zwitterion fragment, for example ... 

This type of dipolar addition reaction was introduced in chapter 3 in connection with ozonolysis (sec. 3.7.B), as well as permanganate (sec. 3.5.A),346 and osmium (sec. 3.5.B) oxidation of alkenes. Ozone is a classical example of a dipolar molecule (see canonical forms of 424 +0—O—0 and 0—O—0+). Fleming showed that the HOMO/LUMO orbitals of ozone interact with those of ethene (as shown in Figure 11.21).347... 

Horie, O., Neeb, P., Limbach, S., and Moortgat, G.K. (1994b) Formation of formic acid and organic-peroxides in the ozonolysis of ethene with added water vapor, Geophys. Re.s. Letters, 21, 1523-1526. 

Thomas, W., Zabel, F., Becker, K. H., and Fink, E. H. (1995) A mechanistic study on the ozonolysis of ethene, in Tropospheric Oxidation Mechanisms, edited by K. H. Becker. European Commission. Report EUR 16171 EN, Luxembourg, pp. 315-320. 

The products of the ozonolysis of ethene in the presence of added water vapour were analysed for the hydroperoxides H2O2, HOCH2OOH (hydroxymethyl hydroperoxide = HMHP) and HOC2H4OOH (2-hydroxyethyl hydroperoxide = 2-HEHP). 

The ozonolysis of simple alkenes was studied in two different apparatus a 2 litre stirred tank reactor (for ethene, propene, fran.y-2-butene, butadiene, and isoprene) coupled via molecular beam sampling to a matrix isolation FTIR set-up [20, 21], and a 570 L spherical glass vessel "big sphere" (for ethene, 2-butene isomers, isobutene, and isoprene) where products were identified by Fl lR spectroscopy, GC and a scrubber sampling unit for analysis with HPLC (for peroxides) and IC (for organic acids). In the latter system, two extreme humidity conditions, one with 0.5 ppm and the other with 2 x 10" ppm (corresponding to ca. 60 % relative humidity at 298 K) were used, which are referred to as "dry" and "wet" conditions, respectively. Results of the studies performed in the "big sphere" are summarised here. 

According to currently accepted Criegee mechanism [20], the formation of the reaction products in the ozonolysis of ethene is explained in terms of the formation of the excited Criegee intermediate CH2OO and its subsequent decomposition and collisional stabilisation ... 

Formation of formic acid and organic peroxides in the ozonolysis of ethene with added water vapour,... 

Ozone selectively attacks olefinic double bonds in organic compounds (ozonolysis reactions). When reacted with ethene (ethylene) (Nederbragt s method), ozone gives an electronically excited methanol (formaldehyde) that emits visible light ... 

Alam, M.S., Camredon, M., Rickard, A.R., Carr, T., Wyche, K.P., Hornsby, K.E., Monks, P.S., Bloss, W.J. Total radical yields from tropospheric ethene ozonolysis. Phys. Chem. Chem. Phys. 13, 11002-11015 (2011)... 

Hasson, A.S., Orzechowska, G., Paulson, S.E. Production of stabilized Criegee intermediates and peroxides in the gas phase ozonolysis of alkenes 1. Ethene, trans-2-butene, and 2,3-dimethyl-2-butene. J. Geophys. Res. 106, 34131-34142 (2001)... 

Mihelcic, D., Heitlinger, M, Kley, D., Mnsgen, P., Volz-Thomas, A. Formation of hydroxyl and hydroperoxy radicals in the gas-phase ozonolysis of ethene. Chem. Phys. Lett. 301, 559-564 (1999)... 

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