Polymerization of higher aldehydes. IV. Crystalline isotactic polyaldehydes: Anionic and cationic polymerization

Low temperature polymerization of aldehydes in solvents of low dielectric constants yields crystalline isotactic polyaldehydes. Alkali metal alkoxides were found to be the best initiators; but alkali metals, alkali metal alkyls, Grignard reagents, lithium aluminum hydride, and aluminum organic compounds also work effectively. Isotactic polyaldehydes were also obtained by cationic initiation (stannic bromide, solid BF 3 etherate). The stereoregularity increases with the increase of the space requirements of the side chain.