16187-01-2Relevant academic research and scientific papers
High-Field Rapid Injection NMR: Observation of Unstable Primary Ozonide Intermediates
McGarrity, John F.,Prodolliet, Jacques
, p. 4465 - 4470 (1984)
A "rapid injection" NMR system is described for use on a 360-MHz superconducting spectrometer.The major advantages of the high-field sytem over our original system are increased sensitivity, resolution, and rapidity.The technique was used to study the ozonolysis of tetramethylethylene and (briefly) cis-but-2-ene, particularly the decomposition of the corresponding primary ozonides 2 and 4, with half-lives of 0.74 and 0.06 s, respectively, at -92 deg C.It was found that the decomposition of 2 in CD2Cl2 (a) had Δ H(excit) = 39 kJ/mol and Δ S(excit) = 28 J/(molK), (b) was unaffected by the presence of TCNE, but (c) was acid-catalyzed.The effects of substituents, solvent, and acid catalysts on the decomposition of primary ozonides are discussed.
Stereochemical Effects in the Ozonolysis of (E)- and (Z)-1-Ethoxypropene
Wojciechowski, Brenda J.,Pearson, William H.,Kuczkowski, Robert L.
, p. 115 - 121 (2007/10/02)
The ozonolysis of (E)-1-ethoxypropene (or (Z)-1-ethoxypropene) gave cis and trans pairs of 1,2-dioxolanes, 1,2,4-trioxolanes (ozonides), and 1,2,4,5-tetroxanes.Ozonolysis of mixtures of the E and Z alkenes led to variation in the dioxolane stereoisomer ratios but not in the trioxolane ratios.Ozonolysis in the presence of added alcohol or aldehydes produced hydroperoxides or ozonides, respectively, from the methyl-substituted carbonyl oxide.The results are consistent with a Criegee ozonolysis mechanism if the two alkenes produce different relative amounts of the syn and anti carbonyl oxide (CH3HCOO), which recombine at different rates with dipolarophiles.
MECHANISM OF THE OZONOLYSIS OF PROPENE IN THE LIQUID PHASE.
Choe,Srinivasan,Kuczkowski
, p. 4703 - 4704 (2007/10/02)
Propylene was ozonized in isobutane, hlorodifluoromethane, and methyl chloride solvents. Propylene ozonide, ethylene ozonide, and 2-butene ozonide (cis and trans isomers) were obtained in ratios of about 82:16:2. The amount of butene ozonide increased while that of ethylene ozonide usually decreased for reactions in the presence of added acetaldehyde. The cis-trans stereochemistry of the butene cross ozonide from propylene was studied at various conditions. Usually the cis isomer was preferentially formed, but addition of acetaldehyde could alter this. The cis-(trans-butene ozonide ratio was 67/33 when formed from cis- or trans-2-butene in CHClF//2 and 50/50 as a cross ozonide from trans-2-pentene. The kinetic secondary isotope effects upon ozonolysis of propene-2-d//1 (k//H/k//D equals 0. 88 (6) and propene-1-d//1 (0. 88 (8) were evaluated. These results are discussed with reference to the Criege mechanism of ozonolysis. 37 refs.
