Abstract
Flames from town gas-oxygen, hydrogen-oxygen, and ethylene-oxygen mixtures, when blown against the surface of an aqueous solution of amines and amino acids, induced an oxidation reaction in the aqueous phase, while an acetylene-oxygen flame failed to oxidize the compounds in solution. The hydrogen flame caused direct hydroxylation of the aromatic rings of phenylglycine homologs. The isomeric ratio of o-, m-, and p-hydroxyphenyl-amino acids produced was in accordance with that obtained by using the reaction systems of Fe2+-H2O2-EDTA and Fe2+-ascorbic acid-H2O2-EDTA, which are known to involve a hydroxyl radical as the agent for hydroxylating the aromatic rings. These results strongly suggest that the active species of flame-induced oxidation in an aqueous solution was the hydroxyl radical which was produced in the flames and extracted into the aqueous phase.
