| 摘要 |
A process for preparing low molecular weight, highly reactive polyisobutylene having an average molecular weight Mn of from 500 to 5000 Dalton and a terminal double bond content of more than 80 mol % by polymerization in the liquid phase of isobutene or hydrocarbon streams comprising isobutane [sic] with the aid of a boron trifluoride complex catalyst at from -40 to 20° C. and at from 1 to 20 bar comprisesa) polymerizing until the residual isobutene content of the reaction mixture is less than 2% by weight, based on isobutene introduced, or removing residual isobutene towards the end of the polymerization until the residual isobutene content is less than 2% by weight,b) enriching the boron trifluoride complex catalyst which is obtained in the form of droplets in the disperse and/or coherent phase,c) recycling the complex-enriched phases to the polymerization andd) compensating for catalyst losses by adding boron trifluoride and, if necessary, complexing agents. |
