| 摘要 |
<p>The invention relates to a method for continuously or discontinuously producing tetrahydrofuran polymers by homopolymerization of tetrahydrofuran, alkyl-substituted tetrahydrofurans and/or alkylene oxides in the presence of carboxylic acid anhydrides or compounds containing reactive hydrogen using an optionally non-acidified or acid-activated calcined and granular natural amorphous aluminum silicate catalyst. The inventive method provides a means for substantially suppressing the formation of cyclic ethers and for obtaining a polymer with a narrow molecular weight distribution by keeping the concentration of carboxylic acid anhydrides or alkylene oxide constantly below 1 wt.-% during polymerization. The catalysts have a long shelf-life and lead to polymers that are characterized by highly uniform properties and a narrow molecular weight distribution even if a fairly impure monomer is used. The catalysts are characterized in their granulated form by a previously unknown activity and they form polymers having a very narrow molecular weight distribution and low color index and acid number.</p> |
