Synthesis And Catalytic Property Of PNSiCP/M Complexes For Ethylene Oligomerization

Linear ?-olefins(linear end olefins above C4 and C4)are among the most important industrial chemical raw materials.They are mainly used as copolymers of polyethylene,alcohols for plasticizers,synthetic lubricant base oils,fatty acids and other intermediates.At present,ethylene oligomerization is an important industrial technology for product linear alpha-olefins.In this process is the most critical technology.In recent years,plenty of the catalysts have been tested for ethylene oligomerization to produce a-olefins.For example,late-transition metal catalysts,especially nickel and palladium complexes,have been extensively developed due to their good stability,mild synthetic conditions,and low cost.In this paper,we have designed and synthesized a series of new silicon-amine-based carbon bridged phosphine ligands with different molecular skeleton.Phosphine ligands(PNSiCP)was emplyed to synthesize a series of metal complexes such as nickel and cobalt complexes.The effects of various reaction conditions on the catalytic performance of catalyst system for ethylene oligomerization were studied.The main works are as follows:(1)A series of PNSiCP-type ligands(L1-L3)were synthesized and characterized by NMR spectroscopy.Bisphosphine nickel catalysts[Ni(L1)Br2](C1),[Ni(L2)Br2](C2)and[Ni(L3)Br2](C3)and bisphosphine cobalt catalysts[Co(L1)Cl2](C4),[Co(L2)Cl2](C5)and[Co(L3)Cl2](C6)were synthesized and characterized by elemental analysis,mass spectrometry and single crystal X-ray diffraction.These center of the catalysts adapt X-ray diffraction analysis indicates that a distorted four-coordinated plane geometry.(2)In the presence of bisphosphine nickel complex(C1-C3),the main products were butene and hexene,with ethylaluminum dichloride(EADC)as co-catalyst and methylcyclohexane as solvent.The catalytic activity of Cl could reach 3.66 x 106 g/(molNi·h)89.5%butene selectivity with 75.8%1-butene fraction under the reaction condition that the temperature was 45?,and the n(Al)/n(Ni)was 500.The catalytic activity of catalyst C2 could reach 3.45 × 107 g/(molNi·h)under the reaction condition that the temperature was 45?,and the n(Al)/n(Ni)was 700.The catalyst C3 could produce 95.6%butene selectivity containing 75.8%1-butene fraction under the reaction condition that the temperature was 30?,reaction time was 30 min and the n(Al)/n(Ni)was 500.(3)The product was butene and the selectivity of butene was 100%,upon with bisphosphine cobalt catalysts(C4-C6)as catalyst,DMAO/Et3Al as co-catalyst and methylcyclohexane as solvent,Under the reaction condition that the temperature was 45?,reaction time was 30 min and the n(Al)/n(Co)was 700,the catalytic activity of catalyst C5 could reach 3.3 × 104 g/(molco·h)with 79.8%1-butene selectivity.Under the reaction condition that the temperature was 45?,reaction time was 30 min and the n(Al)/h(Co)was 500,the catalytic activity of catalyst C6 could reach 8.2 × 104 g/(molCo·h)with 90.8%1-butene selectivity.