PROCEDURE FOR OBTAINING POLYISOBUTYLENE LOW MOLECULAR WEIGHT, HIGHLY REACTIVE.

摘要

Process for obtaining low molecular weight polyisobutylene, highly reactive, with an average molecular weight Mn of 500 to 5000 Dalton and a content of double terminal bonds of more than 80% in mol, by polymerization of isobutene or hydrocarbon streams containing isobutene, in the liquid phase, and with the help of a catalyst based on a complex of boron trifluoride, at temperatures from 40 to + 20º C and at a pressure of 1 to 20 bar, characterized in that a) the polymerization is carried out up to a remaining content in the reaction mixture of less than 2% by weight of isobutene, based on the total amount of the feedstock streams, or removed near the end of the remaining isobutene polymerization until the remaining content is less than 2% by weight, b) the catalyst is enriched based on a complex of boron trifluoride, which is obtained in the form of drops above, in the dispersed and / or coherent phase, c) they are recycled the complex-rich phases to the polymerization, d) the losses of catalyst are compensated by the addition of boron trifluoride and, if necessary, of complexing agents.