Ozonation of Naphthalene with Water as Participating Solvent. Preparation of o-Phthalaldehyde

Abstract

The water in aqueous acetone solutions acts as a participating solvent in the reaction of naphthalene with ozone forming hydroperoxy intermediates which are reduced to o-phthalaldehyde by conventional agents. The results are markedly different from those obtained in anhydrous solvents. Yields of product requiring no purification are 63%.

Aqueous ozonolysis products of methyl- and dimethylnaphthalenes

“…One problem with these reports is that the precursors to many of the compounds produced were unknown. A simpler approach than studying the complex mixtures in ozone-treated natural or waste water is to characterize incomplete ozonation products from model compounds such as aliphatic alcohols, ketones, acids (9, 10), amino acids, sugars (11), and, perhaps most importantly, benzene derivatives (12-17) and polynuclear aromatic hydrocarbons (18)(19)(20)(21)(22)(23)(24)(25)(26).…”

“…Epoxides of the PAHs, in general, show a tendency to be toxic and carcinogenic (27). The reaction of the simplest PAH naphthalene with ozone in water has been reported (22)(23)(24)(25)(26), but only three of these reports had any specific information about the mechanism or products produced. There have been no studies involving the aqueous ozonation of the methyl-and dimethylnaphthalenes despite the fact that these compounds are known contaminants of potable water supplies at trace levels (28) and they are principal constituents of crude oils and oil products (29) that regularly contaminate our water systems.…”

Comparison of the ozonolysis products of the methylnaphthalenes and dimethylnaphthalenes in hexane, methanol, and water

“…Previous studies (31,36,37,41,131) indi cated that the peroxides in water are more susceptible to decomposition than the peroxides in methanol. The product mixtures in water were, therefore, made acidic to promote decomposition of the peroxides and facilitate extraction of acidic products.…”

“…Most studies which characterized incomplete ozonation products were done using model compounds. A few of these studies have involved aliphatic alcohols, ketones, acids (21,22), amino acids, and a sugar (23), but most have involved benzene derivatives (24)(25)(26)(27)(28)(29) and polynuclear aromatic compounds (30)(31)(32)(33)(34)(35)(36)(37). The increased in terest in the benzene derivatives was due to the fact that many, such as the phenols, are toxic and known to be present in industrial wastes.…”

“…There have been four reports of the reaction of the parent molecule, naphthalene, with ozone in water (34)(35)(36)(37), but only two of these reports had any specific information on the mechanism or products produced. In contrast, there have been many investigations of the ozonation of naphthalene in organic solvents and much is known about the actual mechanisms involved.…”