Английская Википедия:Dioxirane
Шаблон:Distinguish Шаблон:Chembox
In chemistry, dioxirane (systematically named dioxacyclopropane, also known as methylene peroxide or peroxymethane) is an organic compound with formula Шаблон:Chem. The molecule consists of a ring with one methylene and two oxygen atoms. It is of interest as the smallest cyclic organic peroxide, but otherwise it is of little practical value.
Synthesis
Шаблон:See also Dioxirane is highly unstable and the majority of studies of it have been computational; it has been detected during the low temperature (–196 °C) reaction of ethylene and ozone,[1] although even at these temperatures such a mixture can be explosive.[2] Its formation is thought to be radical in nature, preceding via a Criegee intermediate. Microwave analysis has indicated C-H, C-O and O-O bond lengths of 1.090, 1.388 and 1.516 Å respectively.[2] The very long and weak O-O bond (c.f. hydrogen peroxide O-O = 1.47 Å) is the origin of its instability.
Other dioxiranes
Dioxiranes are derivatives of this parent in which the hydrogens are replaced by other groups. Difluorodioxirane, which boils at about –80 to –90 °C, is one of the very few dioxirane derivatives that is stable in pure form at room temperature and is thermodynamically stable (ΔH° = –104 kcal/mol).[3][4] Dimesityldioxirane is another relatively stable derivative which has been characterized by X-ray crystallography.[5]
Dimethyldioxirane (DMDO) and the still more reactive methyl(trifluoromethyl)dioxirane have seen some use in organic synthesis,[6] Dioxiranes are intermediate in the Shi epoxidation reaction.
See also
References
