Synthesis Of PN~3 Cobalt Complexes And Catalytic Polymerization Of Conjugated Dienes

A series of PN³ and PN³=O cobalt complexes were synthesized.The polymerization has studied such as butadiene,isoprene and myrcene.The PN³ cobalt complex catalyzed polymerization of isoprene has controlled molecular weight polymerization.1.The PN³?L1-L3?and PN³=O?L4-L6?ligand was designed and synthesized,and the corresponding cobalt complex was prepared.Catalytic polymerization of isoprene has high activity and cis-1,4 selectivity by with PN³ cobalt catalyst.The PN³ complex has the effect of controlled molecular weight polymerization in the range of 0-50 ^oC.The number average molecular weight increases linearly with the increase of reaction time?1.26×10⁴-1.64×10⁵ g/mol?,and the molecular weight distribution?M_w/M_n=1.0-1.4?,presenting first-order kinetic results.The PN³ complex polymerizes isoprene and maintains catalytic activity at 0 ^oC and 80 ^oC.The single crystal diffraction pattern showed that the Co-O bond length was short and the bond energy large,which led to the incompatibility of Co-O.2.The synthesis of PN³ cobalt complex polymerized butadiene,CoBr₂-PPh₃-MAO and CoCl₂-PPh₃-MAO system polymerization 1,2-structure butadiene that 1,2 is 79.5%and the syndiotactic degree of 66%.CoBr₂-CS₂-AlⁱBu₃ and CoCl₂-CS₂-AlⁱBu₃ system have polymerized1,2-structured butadiene that melting temperature is 209 ^oC,and crystallinity at 93%.When [Al]/[Co]is 40,the crystallinity of 90%;when[Al]/[Co]is 80,the crystallinity of 76%;the crystallinity main influencing factors is[Al]/[Co]ratios.3.The preparation of the PN³ cobalt complex polymerized myrcene has a high selectivity.The polystyrene cis-1,4 structure can reach 82.7%,and the 3,4 structure is 17.3%.This kind of catalyst polymerizes butadiene,CS₂ electron donor is the key to polymerization;there is no sign of polymerization when no electron donor is added,and there is no sign of polymerization after re-adding electron donor after 24h.Adding TPP to electron donor for CoCl2 catalyzed polymerization of butadiene,the polymerization yield can reach 70%;adding TPP to electron donor for PN³ cobalt complex catalyzed polymerization of butadiene system,the polymerization yield can reach 100%;TPP The electron donor functions as a PN³ ligand.