| 摘要 |
<p>A process is disclosed for producing a low molecular, highly reactive polyisobutylene having a mean molecular weight M n from 500 to 20,000 daltons and containing more than 80 mol.% terminal double bond s. For that purpose, isobutylene or isobutylene-containing hydrocarbon streams are polymerised in the liquid phases with a boron trifluoride complex catalyst at temperatures from -40 .degree.C to 0 .degree .C and pressures from 1 to 20 bars. The polymerisation reaction is carried out in a t least two polymerisation steps. During the first polymerisation step, up to 95 % of the supplied isobutylene is polymerised. The thus obtain ed polyisobutylene is then separated or not and the remaining isobutylene is polymerised in one or several subsequent polymerisation steps .</p> |
