Study On Catalytic Performance Of Hyperbranched Metal Complexes For The Polymerization Of Alkenes And Alkylation In Series

In this paper,hyperbranched imine pyridine ligand was synthetized from 1.0-generation poly(amidoamine)hyperbranched macromoelcule and 2-carbaldehyde via Schiff base condensation,and then the hyperbranched imine pyridine ligand was reacted with nickel chloride hexahydrate to obtain hyperbranched imine pyridine nickel complex;The structures of hyperbranched imine pyridine ligand and hyperbranched imine pyridine nickel complex were characterized by FT-IR,UV,1H-NMR,13C-NMR and ESI-MS.Based on the synthesis and characterization of hyperbranched imine pyridine nickel catalyst,the Friedel-Crafts alkylation of ethylene oligomerization in series and the Friedel-Crafts alkylation of ethylene/1-hexene copolymerization were studied.The study investigated the effects of reaction temperature,ethylene pressure,Al/Ni ratio and reaction time on the catalytic activity and product distribution.In addition,the performance of the hyperbranched salicylaldimine nickel catalyst for the synthesis of ethylene oligomerization and Friedel-Crafts alkylation in series and the Friedel-Crafts alkylation of ethylene/1-hexene copolymerization in series were also investigated in this dissertation.Using toluene as solvent,the performance of oligomerization of hyperbranched imine pyridine nickel catalyst was investigated using methylaluminoxane(MAO),diethylaluminum dichloride(Et2Al Cl)and ethylaluminum dichloride(Et Al Cl2)as cocatalysts.The results showed that,under the same polymerization conditions,the order of the activity from high to low using different cocatalysts was: Et Al Cl2> Et2 Al Cl> MAO,and when Et2 Al Cl and Et Al Cl2 were used as cocatalysts,the products were mixed alkylbenzenes.At the reaction temperature of 25 °C,the ethylene pressure of 0.5 MPa,the Al/Ni ratio of 500 and the reaction time of 30 min,the catalytic activity was 8015 kg/(mol·Ni·h)with Et Al Cl2 as cocatalyst.The products were C4,C6 and alkylbenzenes with different substituents,with an olefin content of 1.3% and the alkylbenzenes content of 98.7%.When using Et2 Al Cl as cocatalyst,the catalytic activity was 4015 kg/(mol·Ni·h),and the oligomerization products were C4,C6,C8 and alkylbenzenes with different substituents,in which the olefin content was 92.8% and the content of alkylbenzenes was 7.2%.Under the same reaction conditions,when the Et Al Cl2 was used as cocatalyst,the oligomerization activity of ethylene of hyperbranched salicylaldimine nickel catalyst with different ligand structure was 7011 kg/(mol·Ni·h),and the oligomerization products were alkylbenzenes(93.6%)while containing a small amount of C4 and C6(6.6%).Hyperbranched imine pyridine nickel complex and hyperbranched salicylaldimine nickelcomplex were the main catalysts,Et Al Cl2 was the co-catalyst,and toluene was used as the reaction solvent,the catalytic performance of the two catalysts in the copolymerization of ethylene/1-hexene were explored.The results showed that both hyperbranched imine nickel catalysts could catalyze the ethylene/1-hexene copolymerization and Friedel-Crafts alkylation in series.Under the same reaction conditions,the catalytic activity of hyperbranched imine pyridine nickel catalyst was higher than that of hyperbranched salicylaldimine nickel catalyst,and the products were C4,C6,C8 and mixed alkylbenzenes.