Aldehyde Polymerization, Helical Polymers, Macromolecular Asymmetry, and Oligomers

Abstract

A historical development of the polymerization of higher aldehydes is presented. It shows the development of the polymerization of the simplest example, formaldehyde, the very ancient and to some extent incorrect history of other aldehyde polymerizations, and actually starts with the full understanding of this field as of the early 1950s. Much of the early work is incoherent and inconsistent, not surprisingly because of the limited knowledge of polymer chemistry that was available at that time. This contribution tries to correlate the polymerization of formaldehyde, the higher aliphatic aldehydes, and the trihaloacetaldehydes within the framework of a comprehensive understanding of the field of polymer science. The extensive progress in the field of trihaloacetaldehyde polymerization has led to the development of cryotachensic polymerization, the concept of optical activity based on macromolecular asymmetry, ultimately the recognition of the importance of the study of oligomers of stereoregular polymers, and the very essence of the embryonic state of addition polymerization.

Mechanistic Insights on the Anionic Polymerization of Aliphatic Aldehydes

“…Aliphatic aldehydes, and, in particular, acetaldehyde, are known to polymerize in the presence of an acidic glassware surface . An acidic surface acts as a cationic initiator for the polymerization.…”

“…Aliphatic aldehydes, and, in particular, acetaldehyde, are known to polymerize in the presence of an acidic glassware surface. 32 An acidic surface acts as a cationic initiator for the polymerization. The cationic initiation of aldehydes leads to the formation of a mixture of cyclic trimers and of polymers.…”

“…Surface Coating of the Glassware. 32 It was found that polymerization results were erratic when the polymerization was performed in usual glassware. This phenomenon was attributed to the residual acidity of the glassware.…”

Alternating-like Cationic Copolymerization of Styrene Derivatives and Benzaldehyde: Precise Synthesis of Selectively Degradable Copoly(styrenes)

“…Aldehydes with appropriate structures can be polymerized via the cationic or anionic addition reactions of carbonyl groups. − A representative example is the polymerization of formaldehyde into polyoxymethylene, which is an industrially important engineering plastic . Aliphatic aldehydes such as acetaldehyde are also homopolymerizable, although the polymerization reaction needs to be conducted at low temperature due to the low ceiling temperature ( T c ). − However, aromatic aldehydes are generally nonhomopolymerizable although special types such as o -phthalaldehyde are homopolymerizable. − For example, benzaldehyde (BzA) has an extremely low T c , which was estimated to be approximately −160 °C …”