Selective Synthesis of Poly(<i>m</i>-phenylene oxides) over Oxacalixarenes

Abstract

We report a high yielding AA−BB type step-growth synthesis of poly( m -phenylene oxides) ( m POs) by nucleophilic aromatic substitution (S N Ar) reactions. Previously, poly( m POs) have proven difficult to synthesize, especially by S N Ar, due to competing cyclooligomer (oxacalixarene) formation. We have found that the linear (polymeric) vs cyclic (oligomeric) product distribution is strongly dependent on the substitution pattern of the electrophilic monomer, and a model is described that predicts whether the reacting monomers will kinetically favor formation of poly( m POs) or oxacalixarenes. The polycondensation reaction tolerates a range of functional groups on both reactive monomers, and the synthesized poly( m POs) have high thermal and aqueous stability but are readily depolymerized in polar aprotic media.