Study On The Synthesis Of ?-decene By Ethylene(CO)polymerization

A salicylaldimine nickel catalyst was prepared by Schiff base reaction and Complexation reaction using ethylenediamine,salicylaldehyde and NiCl₂·6H₂O as raw materials.The structures of ligand and complex were characterized by elemental analysis,FT-IR,UV,¹H-NMR,ESI-MS and Elemental analysis,and the results showed that the actual structure had achieved the goal for devised structure.Based on the systhesis and characterization of salicylaldimine nickel catalyst,the catalytic performances for ethylene oligomerization were researched,and the effects of phenolic compounds and 1-dodecanethiol on their catalytic properties and their mechanism were investigated.The results showed that the salicylaldimine nickel catalyst had catalytic activity,reaching up to 689 kg·?mol Ni?^-1·h^-1,with MAO as cocatalyst and cyclohexane as solvent,when the molar ratio of Al/Ni was 275,the temperature was 50?,the pressure was 4MPa,and the reaction time was 30 min,and the oligomerization production was widely distributed(C₄^C₂₈),contained a large amount of insoluble polymers.After phenolic compounds and 1-dodecanethiol were introduced as modifiers for the production of linear?-olefins,the content of insoluble polymer decreased,and the?-C₁₀0 content increases,and with the increase of the amount of regulator and its steric hindrance,the content of insoluble polymer decreased.Using 4-tert-butylphenol as a modifier,when the molar ratio of[-OH]/[Al]was 0.2,the salicylaldimine nickel-based catalyst still has good catalytic activity,and the content of?-C₁₀0 could reach 9.67 wt%.The 1-dodecanethiol was used as modifier,when the[-SH]/[Al]molar ratio was 0.3,the the content of?-C₁₀0 in the product obtained by ethylene oligomerization could reach 12.70 wt%.Based on the Cr?A+B+C+D?catalyst provided by Daqing Chemical Research Center,the copolymerization performances of ethylene and 1-hexene was researched.The results showed that the catalyst concentration,catalyst ratio,feed mode,reaction temperature,reaction pressure,Al/Cr molar ratio and other factors had a great influence on the copolymerization properties of ethylene and 1-hexene.The catalytic activity could reach to5400 kg·?mol Cr?^-1·h^-1,the selectivity of 1-decene could reach more than 70%,when the reaction pressure was 2.0 MPa,the reaction temperature was 110?,the catalyst concentration was 40 mg/kg,the molar ratio of Al/Cr was 150,residence time was 45 min.