Reaction of Phenyl Glycidyl Ether with Xylenols

Abstract

We discussed the behavior of epoxy groups in the curing reaction; of ammoniacal resol with epoxy resin using phenyl glycidyl ether (PGE), 2,4-xylenol (2,4-X) and its hydroxymethyl derivative (2,4-XM) as models of above resin. And, (DBAO) which acts as catalyst was added tcrthis mixture as a model of intermediate reaction product of ammoniacal resol. The reaction conditions were studied in the range from room temperature to 210°C. We confirmed by using NMR that,epoxy groups react mainly with phenolic hydroxyl groups and form secondary hydroxyl groups, while hydroxymethyl groups in the resol produce methylene or dimethylene ether linkage by intramolecular condensation reaction. We could not find any evidences for the reaction between epoxy and hydroxymethyl groups, although hydfbxymethyi groups seemed to accelerate the reaction of epoxy groups with phenolic hydroxyl groups. Then we considered that proton released from phenolic hydroxyl groups as a result of intermolecular hydrogen bonding between hydroxymethyl groups and phenolic hydroxyl groups accelerated the above reaction. DBAO promotes also the reaction of PGE with 2,4-X or 2,4-XM. While with rising temperature, the ratio of reacted epoxy. groups to phenolic hydroxyl groups increases remarkably. This fact suggests that the epoxy groups react with secondary groups wjhich are formed by the reaction between epoxy groups and phenolic hydroxyl groups. © 1975, The Chemical Society of Japan. All rights reserved.