Mechanistic studies for the polymerization of 2,6-dimethylphenol to poly (2,6 -dimethyl -1,4 -phenylene ether) : LC-MS analyses showing rearrangement and redistribution products

摘要: Abstract For a detailed investigation of the mechanism oxidative coupling polymerization 2,6-dimethylphenol (DMP) to poly(2,6-dimethyl-1,4-phenylene ether) (PPE), reactions were carried out with mixture 4-(2′,6′-dimethylphenoxy)-2,6-dimethylphenol (DMP-dimer) and 2,4,6-trimethylphenol, under dioxygen atmosphere using copper(II)–NMeim catalyst (NMeim = N-methylimidazole). Oxidative experiments performed for very short reaction times in order detect any intermediate or hybrid compounds (i.e. when starting from mixtures parent phenols) generated during early stages process. The LC–MS chromatograms samples collected reveal peaks which indicate formation (i) DMP-monomer; (ii) dimer is phenols; (iii) DMP-trimer; (iv) trimer phenols. Formation DMP monomer these oligomers are support quinone-ketal reaction. phenol-ketal further undergoes redistribution (to form dimer) rearrangement trimers). So, studies corroborate already first steps