Ozonolysis of vinyl compounds, CH2CH–X, in aqueous solution—the chemistries of the ensuing formyl compounds and hydroperoxides

Organic & Biomolecular Chemistry Pub Date: 2003-02-19 DOI: 10.1039/B212194H

Abstract

Reactions of ozone with some vinyl compounds of the general structure CH2[double bond, length half m-dash]CH–X were studied in aqueous solution. Rate constants (in brackets, unit: dm3 mol?1 s?1) were determined: acrylonitrile (670), vinyl acetate (1.6 × 105), vinylsulfonic acid (anion, 8.3 × 103), vinyl phenylsulfonate (ca. 200), vinyl diethylphosphonate (3.3 × 103), vinylphosphonic acid (acid, 1 × 104; mono-anion, 2.7 × 104; di-anion, 1 × 105), vinyl bromide (1 × 104). The main pathway leads to the formation of HOOCH2OH and HC(O)X. As measured by stopped flow with conductometric detection, the latter one may undergo rapid hydrolysis by water, e.g.HC(O)CN (3 s?1). Other HC(O)X hydrolyse much slower, e.g.HC(O)PO3(Et)2 (7 × 10?3s?1) and HC(O)P(OH)O2? (too slow to be measured). The OH?-induced hydrolyses range from ca. 5 dm3 mol?1 s?1 [HC(O)PO32?] to 3.8 × 105 dm3 mol?1 s?1 [HC(O)CN]. HC(O)Br mainly decomposes rapidly (too fast for the determination of the rate) into CO and Br? plus H+, and the competing hydrolysis is of minor importance (3.7%). The slow hydrolysis of HC(O)PO32? at pH 10.2, where HOOCH2OH is rapidly decomposed into CH2O plus H2O2, allows an H2O2-induced decomposition (k = 260 dm3 mol?1 s?1) to take place. Formate and phosphate are the final products.

Graphical abstract: Ozonolysis of vinyl compounds, CH2 [[double bond, length half m-dash]] CH–X, in aqueous solution—the chemistries of the ensuing formyl compounds and hydroperoxides
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