Polymerizations by Diethylpicolylaluminum

Abstract

We have prepared diethyl -α- picolylaluminum (α-PA) by the reaction of diethylaluminum chloride with α-picolyllithium, and examined the catalytic activity of α-PA for the polymerization of various monomers. Like triethylaluminum, α-PA is slightly active for the polymerization of vinyl monomers, cyclic ethers, lactones and ketenes. However, α-PA is more active than triethylaluminum in the polymerization of acetaldehyde, yielding crystalline polyacetaldehyde in better yield than triethylaluminum. α-PA-TiCl₄ system induces the polymerization of ethylene, although the catalytic activity of the system is lower tham that of Et₃Al-TiCl₄ system. The catalytic activity of α-PA-α-TiCl₃ system is nearly equal to that of Et₃Al-TiCl₃ system for the polymerization of propylene, but α-PA-α-TiCl₃ system gives isotactic polypropylene in better yield.