Reactions of ozonides. VI. Conditions for by-product ester production in the oxidative ozonolysis of oleic acid

Abstract

Addition of water to various solvents used for oxidative ozonolysis of oleic acid increases acid product yield and diminishes ester by-product yield but the effect is non-stoichiometric. Hydrolysis of peranhydride intermediates and chain-termination mechanisms are possible explanations. Octyl nonanoate is identified as a by-product of nonanal autoxidation; its yield is diminished by adding water or ethanol. Reduced platinum oxide catalyzes oleic acid and 5-decene ozonide autoxidation but platinum on charcoal is without significant effect.

Ozonolysis

“…The classical ozonolysis solvent was chloroform, and it still finds use because ozonolysis products are often insoluble in other non-hydroxylic solvents. A polar sol- vent, such as an alcohol, has long been advocated for zwitterion stabilization (15) and to minimize ozonide decomposition to byproduct esters (16,17). Acetone is a good solvent, hitherto thought to be non-participating but now known to react with zwitterions (18).…”

“…Hydride reagents in reductive work-up give alcohols (22,23). Peroxide oxidation of ozonides (V: Ri = Ra = H) gives acids in good yield (16,17). Choice of an ozonization solvent depends largely upon the intended work-up procedure, for ozonides are rarely isolated (although some are stable enough to crystallize or even pass through a gas chromatograph) but in general they are used in situ for the next step.…”