Synthesis Of (Salicylaldiminate) Palladium (Ⅱ) Complexes And Their Catalysis For Olefin Polymerization

Two types of late transition metal complexes:mono-(salicylaldiminate)palladium(II) complexes and bis-(salicylaldiminate)palladium(Ⅱ) complexes were synthesized. With these complexes as catalysts, the polymerizations of ethylene, MMA, and NBE were investigated systematically.Based on our previous research results, three substituted salicylaldiminato ligands L1-L3 were prepared by Shiff base condensation reaction, and characterized by 1H NMR and IR. Three mono-(salicylaldiminate)palladium(Ⅱ) complexes D-Pd-C1,D-Pd-C2,and D-Pd-C3 were obtained by reaction of L1-L3 with trans-[Pd(Ph)(Br)(PPh3)2];Three bis-(salicylaldiminate)nickel(Ⅱ) complexes S-Pd-C4, S-Pd-C5 and S-Pd-C6 were obtained by reaction of L1-L3 with Pd(CH3COO)2. All their structures were analyzed by'H NMR,IR,MS and EA. D-Pd-C2, D-Pd-C3, S-Pd-C5 and S-Pd-C6 were new complexes.With the S-Pd-C4-S-Pd-C6 as the catalyst and MAO as the cocatalyst, the polymerization of ethylene, MMA and NBE were investigated. The effects of diffient polymerization conditions on catalysts activities were discussed, such as the amount of catalyst, polymerization temperature, polymerization time and the structure of complexes. It was found that when we use S-Pd-C4 and S-Pd-C6 as the catalysts, we got C6 and more than C6 oligomers. when we use S-Pd-C5 as the catalyst, we got less than C6 oligomers. And bis-(salicylaldiminate)palladium(Ⅱ) complexes also have good activities for MMA and NBE.The polymerization of NBE was investigated by using the D-Pd-C1/MAO. The effects of polymerization conditions on catalysts activities were discussed, such as the amount of catalyst, monomer concentration, the amount of cocatalyst, polymerization temperature, polymerization time. It was found that when the condition was the catalyst=20μmol,[M]= 1 mol/L, Al/Pd=150,T=60℃,t=0.5hr,the polymerization was the best.With S-Ni-C1, S-Ni-C2 and S-Ni-C3 as the catalysts and MAO as the cocatalyst, the polymerization of ethylene was investigated systematically. The effects of diffient polymerization conditions were discussed, such as catalyst concentration, polymerization temperature, polymerization time and polymerization pressure. It was found that we got not only high molecula polymer but also oligomers, such as butylene and hexane.