Polymerization of β-Acetoxypropionaldehyde

Abstract

High crystalline and high molecular weight poly[(acetoxyethyl)oxymethylene] was prepared from .S-acetoxypropionaldehyde with use of triethylaluminum and diethylaluminum chloride at low temperature. It was also established by infrared, NMR, and X-ray analyses that even protonic acid such as sulfuric acid could produce the crystalline, isotactic poly[(acetoxyethyl)oxymethylene] at -78°C. It is suggested that the polar acetoxy group participates in the steric control of polymerization and the mechanism is presumed.KEY WORDS .S-Acetoxypropionaldehyde / Stereospecific Polymerization / Crystalline Poly[(acetoxyethyl)oxymethylene] / Polar Substituent / Protonic Acid/ Organoaluminum / As part of the studies on polar-substituted poly-( oxymethylene)s, 1-3 the present paper describes an attempt of polymerizing .S-acetoxypropionaldehyde at low temperature and of characterizing the resulting polymer. It was found that crystalline isotactic poly[(acetoxyethyl)oxymethylene] is produced by organoaluminum and protonic acid. It is noticeable that a protonic acid such as sulfuric acid could produce the crystalline polymer and attention should be drawn to the role of polar substituents in the stereospecific polymerization.