CRCU

Chemical Research in Chinese Universities ›› 2011, Vol. 27 ›› Issue (6): 1014-1018.

• Articles • Previous Articles     Next Articles

Highly Active New α-Diimine Nickel Catalyst for Polymerization of Ethylene

YUAN Jian-chao*, LIU Yu-feng, MEI Tong-jian and WANG Xue-hu   

  1. Key Laboratory of Eco-Environment-Related Polymer Materials, Ministry of Education, Gansu Key Laboratory of Polymer Materials, College of Chemistry and Chemical Engineering, Northwest Normal University, Lanzhou 730070, P. R. China
  • Received:2011-03-10 Revised:2011-07-27 Online:2011-11-25 Published:2011-11-07
  • Contact: YUAN Jian-chao E-mail:jianchaoyuan@nwnu.edu.cn
  • Supported by:

    Supported by the National Natural Science Foundation of China(No.20964003).

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Abstract: A new α-diimine ligand 1a, bis[N,N'-(4-tert-butyl-2,6-dimethylphenyl)imino]-2,3-butanediylidene and its corresponding Ni(II) complex 2a, {bis[N,N'-(4-tert-butyl-2,6-dimethylphenyl)imino]-2,3-butanediylidene}dibromo- nickel were successfully synthesized, and characterized by 1H NMR, 13C NMR, Fourier transform infrared spectroscope(FTIR), elemental analysis and X-ray photoelectron spectroscopy(XPS). α-Diimine ligand 1b, bis[N,N'-(2,6-  dimethylphenyl)imino]-2,3-butanediylidene and its corresponding Ni(II) complex 2b, {bis[N,N'-(2,6-dimethyl- phenyl)imino]-2,3-butanediylidene}dibromonickel were also synthesized and characterized for comparison. The pre-catalyst 2a with sterically bulky, electron-donating group tert-butyl, activated by diethylaluminum chloride (DEAC) and tested in the polymerization of ethylene, was very highly active[2.01×107 g PE/(mol Ni·h·0.1 MPa)] and led to a very highly branched polyethylene(ca. 35―103 branches/1000 C). The state of the polyethylene obtained varied from plastic, elastomer polymers to the oil-like hyperbranched polymers.

Key words: α-Diimine nickel(II) complex, Diethylaluminium chloride, Late transition metal catalyst, Ethylene polymerization