The microwave reaction of phenyl glycidyl ether with aniline on inorganic supports: a model for the microwave crosslinking of epoxy resins

Abstract

The microwave reaction between equivalent amounts of phenyl glycidyl ether and aniline is studied on solid inorganic supports in ‘dry media’, as a model for the crosslinking reaction of epoxy resins, to determine any chemical peculiarities due to the use of microwave energy. The resulting products are compared with standards given by the conventional heating reaction. The nature of the support is a major parameter. With or without microwaves, clays or silica gel (and especially clays with lamellar structures, such as montmorillonite K 10 or Tonsil BW3) provide epoxy conversion extents higher than aluminas, owing to their increased acidic properties. Besides the epoxy-amine addition products, etherification products of the phenyl glycidyl ether are formed by both hydroxyl-epoxy and epoxy-epoxy competitive reactions. When compared to conventional heating, microwaves do not qualitatively change the reaction products, but quantitatively modify their proportions, because both microwaves and the structure of the inorganic supports influence the relative kinetics of the different reaction paths.