POLYMERIZATION OF AROMATIC ALDEHYDES .3. CYCLOPOLYMERIZATION OF PHTHALALDEHYDE AND STRUCTURE OF POLYMER

The polymerizations of phthalaldehyde were carried out with anionic (t-BuOLi, etc.) and coordination catalysts (AlEt3-transition metal compounds, etc.) at –78°. All polymers were composed only of cyclized units (1,3-dialkoxyphthalan ring). The stereochemical structure (cis and trans) of the ether ring in the polymer was inferred from the comparison of the nmr spectra of the polymer with those of the isomeric 1,3-dialkoxyphthalans. Coordination catalysts gave high contents of the trans configuration. The amount of cis structure decreased in the following order: γ-ray irradiation > cationic catalysts ≥ anionic catalysts > coordination catalysts. Cyclopoly-mers of phthalaldehyde obtained by cationic polymerization had high cis content. The mechanism of this arrangement is discussed in more detail. © 1969, American Chemical Society. All rights reserved.