1.6.1.1 Introduction

Ozone is triatomic oxygen species with a characteristic smell and pale blue color. It is less stable and highly reactive and slightly soluble in water but more soluble in non-polar solvents such as carbon tetrachloride.

1.6.1.2 Preparation

Ozone is prepared by passing dry oxygen through two electrode connected with AC current.

1.6.1.3 Ozonolysis

The reactions of alkenes with ozone can produce alcohols, aldehydes, ketones and carboxylic acids depending on the reaction conditions (Scheme 2-3). This degradation of alkenes with ozone

Scheme 1

is called ozonolysis. The reaction is performed in common solvents such as dichloromethane, methanol and acetone at -78°C. A reductive work up with Me₂S or PPh₃ or thiourea or zinc dust produces aldehydes and ketones, where as sodium borohydride (NaBH₄) produces alcohols and the oxidative work up with H₂O₂ provides acids.
Examples:

Scheme 2