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Linear‐reactor‐infrared‐matrix and microwave spectroscopy of the cis ‐2‐butene gas‐phase ozonolysis
Author(s) -
Kühne Heinz,
Forster Martin,
Hulliger Jürg,
Ruprecht Heidi,
Bauder Alfred,
Günthard HansHeinrich
Publication year - 1980
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.19800630725
Subject(s) - chemistry , ozonide , ozonolysis , photochemistry , infrared spectroscopy , double bond , matrix isolation , formic acid , acetic acid , organic chemistry
Investigation of the formation of complex products in the gas‐phase ozonolysis of cis ,‐2‐butene by linear‐reactor‐infrared‐matrix and linear‐reactor‐microwave spectroscopy is reported. The following species have been unequivocally detected: secondary 2‐butene ozonide, acetic acid, peracetic acid, glycolaldehyde, dimethyl ketene, the simple and mixed anhydrides of formic and acetic acid, 2,3‐epoxybutane and 2‐butanone, besides polyatomic products already known. In contrast, the primary ozonide has been detectable neither by LR.‐MW. nor by LR.‐IR. Observation of both stereoisomeric epoxides and kinetic modelling are used to support the intermediate formation of the O'Neal‐Blumstein radical CH 3 CH(O 2 )CH(O)CH 3 and the existence of a reaction channel in which the two carbon atoms of the C, C double bond of the olefin remain connected. As the dominant reaction path a mechanism with a Criegee type split into methyldioxirane (ethylidene peroxide) and acetaldehyde is considered and subsequently proposed to explain formation of many complex products by either unimolecular or bimolecular processes of the peroxide. For the reactions considered, thermochemical estimates of reaction enthalpies and activation data are included. Kinetic modelling for a partial reaction mechanism involving at least two different paths of decay of the O'Neal‐Blumstein biradical into Criegee ‐type intermediates and the 2, 3‐epoxybutanes is discussed.