Polymerization of acrolein and methyl vinyl ketone induced by amine–water and pyridine–phenol systems

It was reported that acrolein (AL) in tetrahydrofuran (THF) polymerizes at temperatures below 0°C in the presence of pyridine (Py) and water. To clarify this polymerization mechanism the polymerization of AL and methyl vinyl ketone (MVK) by an initiation system such as Py–water, triethylamine (Et₃N)–water, or Py–phenol(Ph) was carried out. The polymerization rate (R_p) of MVK in the Et₃N–water system was expressed by the same equation, R_p = k Et₃N] H₂O] MVK]², used for AL in the Py–water system. Meanwhile, β-hydroxypropionaldehyde, β-phenoxypropionaldehyde, γ-ketobutanol, and β-phenoxy-1-methylpropionketone were obtained as the initial addition products. The polymer of AL obtained was composed of polymer units of vinyl and aldehyde polymerization, but the structure of MVK polymer obtained by the Py–water system was composed of only vinyl polymerization units. The polymerization of MVK by the Py–Ph system did not occur, however. These results were discussed in terms of the initiation and propagation mechanisms.