Kinetics of Isoprene Polymerization in the Presence of a Gadolinium Catalyst: Effect of the Chemical Composition and Particle Size of the Isopropanol Solvate of Gadolinium Chloride

Lanthanide catalysts are used in the industrial production of stereoregular rubbers. It is believed that the activity of solvate complexes of lanthanide chlorides increases with decreasing size of their particles and increasing content of the solvating ligand. The kinetics of isoprene polymerization catalyzed by the isopropanol solvates of gadolinium chloride GdCl3 center dot n(i-PrOH), which were obtained by various methods (conventional mechanical stirring, hydrodynamic exposure, ultrasonic irradiation), was studied. A correlation between the particle size and composition of the solvate complex and the activity of the catalyst was found whatever the method the solvate complex was obtained. At the same time, the resulting data show that, at comparable particle size and composition of the complex, its activity in the polymerization of isoprene nevertheless depends on the method of synthesis. It was shown that the gadolinium catalysts exhibit the highest activity in isoprene polymerization, when the solvate complexes are subjected to hydrodynamic treatment after preliminary solvation for 4-8 h.