ozonide

As described by Criegee [20] and Pryor et al [21], in presence of water the ozone directly interacts with the unsaturated sites in PUFAs due to their dipolar nature, giving origin to an "ozonide" that decomposes breaking the fatty acid carbon-carbon bond.

For example, as postulated in Scheme 3, intermediate 5 might undergo a nucleophilic addition to 4-vinylbenzoic acid 10 to form carbanionic intermediate 13, which may convert via dioxetane 14 or primary ozonide 15 to 4-carboxybenzaldehyde 12.

Ozonated materials, in which the ozone molecule is stabilized as an ozonide, have the capacity to deliver nascent oxygen deep into the treated area without causing irritation [24].

The mechanism of reaction has the ozone terminal oxygen atoms adding across the C=C bond, forming a primary ozonide five-membered ring, which then cleaves to form formaldehyde and the [H.sub.2]COO radical (so called Criegee intermediate (99)) as shown in Stage 1 of the proposed mechanism for reaction pictured on the next page.

(Ed.), The main products appear to be aldehydes and ketones in the case of polyethylene, while an ozonide or peroxidic complex, stable at intermediate temperatures, forms during polystyrene ozonization American Society for Testing and Materials, Phildelphia, 81-104.

The researchers inferred that inhalation of fine airborne particulates is an essential cofactor for ozonide production.

Reductive degradation of the resulting ozonide was performed by reaction with lithium aluminum hydride (LiA1[H.sub.4]) in diethyl ether, followed by decomposition of residual LiA1[H.sub.4] with water.

pentane, carbon tetrachloride) provide an opportunity to produce and study typical oxidation products of ozonolysis, such as ozonide [4].

Generally, ozone attacks the > C = C < bond of the limonene and forms a primary ozonide, which rapidly decomposes to carbonyls and Criegee biradi-cals.