Verfahren zur Polymerisation von 1, 3-Butadien

摘要

Polybutadiene having at least 80% cis-1, 4-configuration is obtained by polymerizing 1, 3-butadiene in the presence of a stereospecific catalyst, first at a low temperature in the range 20 DEG to 80 DEG F. to obtain at least 40% conversion of the butadiene, and then continuing the polymerization at a higher temperature in the range 80 DEG to 200 DEG F. to at least 80% conversion of the butadiene. Either or both of the low and high temperature polymerization steps can be carried out in stages in either a batch or a continuous operation. The low temperature polymerization step in preferably carried out in two stages, the first at 20 DEG to 60 DEG F. and the second at 60 DEG to 80 DEG F., and the higher temperature polymerization step is preferably carried out in one stage at 80 DEG to 130 DEG F. In the preferred continuous three stage process, the residue time in each reactor may be 30 to 60 minutes. The polymerization is preferably carried out in an inert hydrocarbon diluent. The stereospecific catalyst is preferably selected from (1) R11mM+TiI4 where M is Al, Hg, Zn, Be, Cd, Mg, Na or K and R11 is alkyl, cycloalkyl, aryl, alkaryl, aralkyl, alkylcycloalkyl, arylcycloalkyl or cycloalkylalkyl, and m equals the valence of M; (2) R11nM1+TiCl4+TiI4 where M1 is Al Zn, Mg, P6, Na or K; (3) R113Al, R112Zn or R112Mg+TiXa where X is chlorine or bromine and n is 2, 3 or 4, and elemental iodine; (4) R11xM11+TiX4+M111I6 where M11 is Al, Mg, Zn, Ga, In, Tl, X is Cl or Br and M111 is Be, Zn, Cd, Al, Ga, In, Tl, Si, Ge, Sn, Pb, P, Sb, As and Bi and b is 2, 3, 4 or 5; (5) R11xM11+TiI4+MivXc where Miv is Al, Ga, In, Tl, Ge, Sn, Pb, P, Sb, As or Bi, X is Cl or Br and c is 2, 3, 4 or 5, and (6) R1nM1111 or R12AlH+TiCl4 and/or TiBr4+CaIbHcXd where R1 is alkyl, alkenyl, cycloalkyl, cycloalkenyl or aryl, M1111 is Mg, Al or Zn, 'a' is an integer from 1 to 20, 'b' from 1 to 6, 'c' from 0 to 41, 'd' from 0 to 6 and X is F, Br or Cl. Lists of catalysts are given. A flow sheet is given illustrating the polymerization of butadiene in four reaction zones, the catalyst being triisobutylaluminium, titanium tetrachloride and iodine. There are several examples using the same catalyst.