Pure WCl4-catalyst for polymerization of norbornene and monosubstituted acetylenes

A suspension of commercial WCl4 initiates rapid polymerization of norbornene and norbornadiene under mild conditions. If norbornenyl acetate is used as a substrate, WCl4 is dissolved and homogeneous polymerization occurs. In both a cases polymers (<(M)over bar (w)> = about 80 000), the structure of which corresponds to the ring-opening metathesis mode of polymerization, were prepared. WCl4 has also been found to polymerize monosubstituted acetylenes (benzene, 50 degrees C). Poly(t-butylacetylene) of <(M)over bar (w)> = 600 000, poly(phenylacetylene) of <(M)over bar (w)> = 200 000 and poly(1-hexyne) of <(M)over bar (w)> = 14 000 were prepared in high yields. When WCl4 was dissolved in the reaction with oxygen-containing compounds (e.g. methyl acetate, acetylacetone, acetophenone) before substrate addition, catalyst activity increased significantly. WCl4 in 1,4-dioxane was found to be a very active system for phenylacetylene polymerization; it polymerizes this monomer at the monomer-to-catalyst mole ratio equal to 1000 providing polymer of <(M)over bar (w)> = 400 000.