Nekhaeva L.A.1, Maksimov A.L.1, Reshetnikov D.M.1, Boyunkov A.I.2, Vinogradova M.E.2
Establishment of the Russian Academy of Sciences of the Order of the Red Banner of Labor AV A.V. Topchieva Institute of Petrochemical Synthesis, Russian Academy of Sciences, Moscow, Russia 2Redkinsky Pilot Plant, Redkino, Tver Region., Russia
The outstanding event in the chemistry of poly-olefins was the discovery of highly homogeneous catalysts consisting of derivatives of zirconcenes and methylaluminoxane (MAO) [1-4]. The use of metallocenes with different ligand environment allows obtain new types of polymers with technically important properties. Over the past three decades, a host of publications on the catalytic properties of systems of this type of polymerization and oligomerization processes, their mechanism of action, and the range of catalytic systems has been greatly expanded both at the expense of other transition metals and other compounds, as well as through the involvement of homologues of MAO . We have shown that using alkyl-alumoxanes the stereospecific polymerization of not only olefins and styrene can be carried out, but also of conjugated dienes with high activity. Results of experiments on the polymerization of butadiene and isoprene, conducted by Catalyst systems, based on compounds of Co, Ti, V, Nd with different ligands in combination with alkyl-alumoxanes, showed that in addition to steric hindrance and donor-acceptor interaction, arising due to ligand environment around the transition metal, the nature of the metal and aluminoxane also affect the stereospecificity of the catalytic system. Catalytic systems, based on compounds Co and MAO, allow obtain cis-1 ,4-PB with the content of cis-units more than 95%. Replacement of MAO in isobutylalyumoxane results in crystalline syndiotactic 1,2-PB. Used methyl-, ethyl-and isobutylalumoxane were obtained on a pilot plant Tehnoroz, their properties and structure were study. Optimal conditions for obtaining alkyl-alumoxanes in the laboratory and reactor of 15 l with a stirrer were laid in the basis of regulations on the design of installation on Redkino pilot plant. The process is carried out in the unbroken pattern of T-shaped reactor (500l).