Catalysts for reacting vicinal epoxides with an aromatic hydroxyl-containing material result from the treatment of a solid substrate containing a plurality of ion-exchangeable cations with a polymer containing a multiplicity of quaternary onium cations in association with a reactive anion such that after treatment, there remains a sufficient quantity of the quaternary onium cations in association with the reactive anion to catalyze the reaction. These catalysts reduce the quantity of side reactions.