二元稀土催化体系引发的异戊二烯定向聚合

STEREOSPECIFIC POLYMERIZATION OF ISOPRENE BY BINARY LANTHANIDE CATALYST

最早用于共轭双烯烃定向聚合的二元稀土催化体系是LnCl_3-AIR_3,它能引发丁二烯定、向聚合,但催化活性不高。后来,报道了聚合活性较高的氯化稀土催化剂,主要是在二元稀土催化体系中添加适量的醇类试剂。最近。

Nd(OPri)Cl_2 in combination with AlEt_3 is a binary lanthanide catalyst of higher activity for the stereospecific polymerization of isoprene. In this paper, the catalytic activity, as well as the microstruture of the polyisoprene are investigated. The experimental results show that it is a highly effective c talyst for the polymerization of isoprene to produce high cis-1,4 polyisoprene. The catalytic activity and the inherent viscosity [η] of the polyisoprene depend greatly on the amount of catalyst, the molar ratio of Al/Nd as well as the polymerization temperature. The cis-1,4 content of the polyisoprenes obtained is over 93% (determined by IR spectra) and the cis-1,4 level depends slightly on the polymerization conditions.