| 摘要 |
<p>An improved process for the preparation of polytetramethylene ether glycol diesters of the formula R-CO-O(CH2-CH2-CH2-CH2-O)n-COR1, in which R and R1 are identical or different and are an alkyl radical or a derivative thereof, by polymerization of tetrahydrofuran in the presence of a fixed-bed polymerization catalyst and in the presence of a carboxylic anhydride. The use of a catalyst selected from amorphous aluminium silicate, acid-activated and calcined kaolin or zeolite instead of the known natural montmorillonite catalysts having a cryptocrystalline three-layer structure means that polymers having more uniform properties and a narrower molecular weight distribution are now accessible at a higher polymerization rate.</p> |
