| 摘要 |
<p>It is known that an electron donor together with a compound of tetravalent titanium on a magnesium halide carrier is usable if it is a mono- or polyester of an unsaturated polycarboxylic acid in which at least two carboxyl groups are joined to contiguous carbon atoms which form double bonds. It has now been observed that activity and stereospecificity increase if at least one of the said carbon atoms, or a carbon atom joined thereto by a double bond, is substituted by a hydrocarbon group having 1-20 carbon atoms. Maleic and fumaric acid esters substituted with the said hydrocarbon group can be mentioned as examples.</p> |
