Production of polyetheretherketone in ionic liquid media

Polyetheretherketones were successfully synthesised in an ionic liquid, namely 1-butyl-3-methylimidazolium bis{(trifluoromethyl)sulfonyl}amide, by polycondensation reactions of hydroquinone with 4,4′-dihalobenzophenones in the presence of potassium carbonate at elevated temperatures (up to 320 °C). The materials thus produced were similar to polymers prepared in the solvent usually employed in commercial processes, i.e. diphenyl sulfone, as suggested by spectroscopic techniques and X-ray crystallography. By replacing volatile diphenyl sulfone with the effectively involatile ionic liquid, the separation efficiency was significantly improved but the molecular weights were lower.