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A suspension of commercial WCl 4 initiates rapid polymerization of norbornene and norbornadiene under mild conditions. If norbornenyl acetate is used as a substrate, WCl 4 is dissolved and homogeneous polymerization occurs. In both cases polymers ( M w = about 80 000 ), the structure of which corresponds to the ring-opening metathesis mode of polymerization, were prepared. WCl 4 has also been found to polymerize monosubstituted acetylenes (benzene, 50°C). Poly( t -butylacetylene) of M w = 600 000 , poly(phenylacetylene) of M w = 200 000 and poly(1-hexyne) of M w = 14 000 were prepared in high yields. When WCl 4 was dissolved in the reaction with oxygen-containing compounds (e.g. methyl acetate, acetylacetone, acetophenone) before substrate addition, catalyst activity increased significantly. WCl 4 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 w = 400 000 . |
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