Production of polyetheretherketone in ionic liquid media

[EN] 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 degrees 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.