HIGH-REACTIVITY LOW-MOLECULAR POLYISOBUTYLENE PRODUCTION Russian patent published in 2003 - IPC

FIELD: polymer production. SUBSTANCE: high-reactivity low-molecular polyisobutylene is prepared by two-step polymerization of isobutylene or isobutylene-containing hydrocarbon fraction in presence of Friedel-Crafts catalyst and rate regulator. In the first step, gaseous hydrocarbon feedstock and boron trifluoride are introduced into reactor, said boron trifluoride having general formula BF₃×ROH, in which R can be hydrogen and, in case of isobutylene-containing hydrocarbon fraction, isopropyl, n-butyl, or phenyl radicals, at molar ratio BF₃/ROH varying between 1:0.01 and 1:3. Indicated complex is used in amounts corresponding to 0.05-0.2% BF₃ based on the weight of isobutylene. Polymerization is carried out at temperature from +10 to -20 C until isobutylene conversion attains 10-30%. In the second step, oligoisobutylene with molecular weight 200-300 is added to reaction mixture as rate regulator in amounts 1 to 10% of the weight of isobutylene and polymerization of residual isobutylene is continued at temperature from -10 to -20 C to give at least 90% conversion. Method of industry can find use in synthetic rubber industry and polyisobutylene obtained by this method can be used as base material for succinimide and thickening additives. EFFECT: enabled production of polyisobutylene with elevated content of terminal vinylidene bonds and narrow molecular weight distribution. 1 tbl, 5 ex