Building a model of the isoprene polymerization process in the presence of microheterogeneous neodimiumcatalytic systems

           Production of polymer materials takes one of the leading places in the modern chemical and petrochemical industry. A significant share in it brings the production of synthetic polyisoprene, which accounts for more than 700 thousand tons of the product in year. Polyisoprene is a product of solution polymerization of isoprene in the presence of microheterogeneous titanium and neodymium catalytic system type Ziegler-Natta, characterized by high stereo specificity and the possibility of obtaining rubber of stamps SKI- 3 and SKI-5 with a complex of necessary consumer properties. Earlier made studies [1] have shown, it’s possible to impact on the dispersion of microheterogeneous catalytic system of the Ziegler-Natta due to local hydrodynamic influence on the reaction mixture by changing the technological scheme of the preparation of the titanium catalyst. Building of the mathematical model taking into account these changes allows not only to predict the properties of the product, but also to optimize the production process.

          The process of isoprene polymerization in rubber production is carried out in a continuous method in a battery of sequentially interconnected polymerizers, by way of which are used the vertical cylindrical apparatus with a volume of 16.6 m3, equipped with four-tier two-vane mixing devices. The power of the electric motor of the mixing device is 30 kW, what provides a mixing speed of 20÷40 rpm. The delivery of the heat carrier to the polymerizers is not carried out, and the temperature of the reaction mixture is regulated by the temperature of the incoming monomer solution and the dosage of the catalyst.

         Particularly the polymerization of isoprene in the presence of a neodymium catalyst in industrial production is carried out using a cascade of three bulk reactors. The initial temperature of the isoprene solution in isopentane is 0-minus 50C, the mass flow rate is 20 t / h. The consumption of neodymium catalyst is 1 mol. NdCl3/10000 mol. isoprene. In order to regulate the molecular weight of the polymer, into the process line is continuously supplied the diisobutylaluminium hydride (DIBAH) .The scheme of the production process is shown in Fig.1

References

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