Polymerization of Aromatic Aldehydes. V. Cationic Cyclopolymerization of o-Vinylbenzaldehyde

Abstract

Polymerization of o-vinylbenzaldehyde was carried out at 0°C with BFaOEt2 catalyst. The polymers obtained as white powders were soluble in common organic solvents, and were not cleaved by treatment with dilute hydrochloric acid. The degree of polymerization was 20-30. The polymer contained approximately 20% of the pendent vinyl group and 5% of the pendent aldehyde group. The rest of the monomer unit was presumably the cyclized unit. On the basis of these structural data, a cationic propagation scheme of o-VBA was proposed, in which the neighboring aldehyde group reacted overwhelmingly with the growing cation to form a cyclic unit and the intramolecular cyclization of the neighboring vinyl group with the cation was competitive with the intermolecular propagation. This scheme was consistent with that expected from the cyclopolymerization schemes of o-divinylbenzene and o-phthalaldehyde.

Controlled cationic copolymerization of benzaldehyde with isobutyl vinyl ether using base‐assisting system

“…These results indicated that the copolymers had no BzA-BzA sequences, and were consistent with previous reports that BzA homopolymerization did not proceed. [10][11][12][13] On the other hand, copolymerization failed in polar solvents such as dichloromethane, at 0 C, and/or in the absence of an added base. In these cases, only IBVE homopolymers were obtained, as confirmed by 1 H NMR analysis.…”

“…[10][11][12] In fact, their homopolymerizations have never been achieved except in the case of benzaldehyde (BzA) derivatives with special structures. 10,12,13 In contrast, polymers were obtained from both BzA and a simple derivative in copolymerizations with styrene (St) or isoprene. 10,11,14 However, no copolymers of BzA and its derivatives with vinyl ethers (VEs), which have high cationic polymerizability, have been obtained, 11 although carbocation from BzA derivatives were proven to initiate living polymerization of alkyl vinyl ethers.…”

Polymerization of Aromatic Aldehydes. VII. Cyclopolymerization of o-FormylphenylacetaIdehyde and Formation of a Cyclic Trimer

“…This presumption was substantiated by the fact that o-vinylbenzaldehyde gave a cyclopolymer with cationic catalysts. 3 formation of the six-membered ring unit. It was of particular interest to compare the reactivities of these aldehyde groups.…”

New Degradable Alternating Copolymers from Naturally Occurring Aldehydes: Well-Controlled Cationic Copolymerization and Complete Degradation

“…22 However, the cationic polymerization of these compounds has rarely been studied due to difficulty in their polymerization as reported decades ago. 23, 24 We recently reported the successful controlled cationic copolymerization of BzAs with alkyl vinyl ethers (VEs) using weak Lewis base-assisting initiating systems for the first time. 25,26 Nearly alternating copolymers with controlled molecular weights and narrow molecular weight distributions (MWDs) were obtained from the appropriate combinations of monomers, i.e., VEs with lower reactivity and aldehydes with larger basicity (Scheme 1).…”