Competing processes for poly(aryl ether-ketone) synthesis, 3: Polymerization reactions of 1,3-bis(4-chlorobenzoyl)benzene and 1,3-bis(4-fluorobenzoyl)benzene in N-methyl-2-pyrrolidinone

The effects of N-methyl-2-pyrrolidinone (NMP) as solvent on the polymerizaton reactions of 1,3-bis(4-chlorobenzoyl)benzene (1,3-CBB) and 1,3-bis(4-fluorobenzoyl)benzene (1,3-FBB) with 4,4′-isopropylidenediphenol (bisphenol-A) were examined. The failure of these reactions to produce high molecular weight polymers in the presence of anhydrous potassium carbonate is due to dehalogenation of 1,3-CBB via substitution radical-nucleophilic unimolecular (S_RN1) processes. On the other hand, 1,3-FBB undergoes nucleophilic aromatic substitution reactions (S_NAR) with the carbonate anion at elevated temperatures. However, it is possible to synthesize high molecular weight polymers from 1,3-FBB and bisphenol-A in NMP either by first forming the bisphenoxide with stoichiometric amounts of aqueous sodium hydroxide or in the presence of anhydrous potassium carbonate at a lower reaction temperature.