Preparation of ‘high‐<i>ortho</i>’ novolak resins I. Metal ion catalysis and orientation effect

Abstract

Abstract In the phenol‐formaldehyde condensation reaction, the presence of electropositive bivalent metal ions such as Mn ++ , Zn ++ , Cd ++ , Mg ++ and Co ++ has been found to catalyse the production of 2‐ and 2 : 6‐substituted phenolic nuclei in the resulting novolak resins. The relative effectiveness of the different ions on the orientation effect and rate of condensation has been approximately determined. A fractionation technique for the resins has been developed and the molecular weight distributioin curves of resins prepared by different methods compared.