MA Zhi, SUN Wenhua, WANG Hang, YAN Weidong, HU Youliang. STUDY ON ETHYLENE OLIGOMERIZATION WITH A NEW DIIMINE PYRIDINE IRON-BASED CATALYST[J]. Acta Polymerica Sinica, 2002,(5):703-706.
MA Zhi, SUN Wenhua, WANG Hang, YAN Weidong, HU Youliang. STUDY ON ETHYLENE OLIGOMERIZATION WITH A NEW DIIMINE PYRIDINE IRON-BASED CATALYST[J]. Acta Polymerica Sinica, 2002,(5):703-706.DOI:
6-bis[(1-fluorenylimino)ethyl] pyridine iron dicloride (2) was synthesized via Shift base condensation with 2
6-diacetylpyridine and 9-aminofluorene hydrochloride under formic acid as catalyst.Ethylene oligomerizations were carried out using this new catalyst and methylaluminoxane as cocatalyst under various conditions.The effects of Al/Fe molar ratio
reaction temperature and ethylene pressure on catalytic activity and product distribution were investigated.This novel catalyst had a good activity for ethylene oligomerization (e.g.4.21×106g oligomers·mol-1 Fe·h-1
Al/Fe molar ratio=2000
reaction temperature=40℃
ethylene pressure=1.5 MPa). The catalytic activity increased with the increasing concentration of MAO.The tendency to produce more C4~C10 olefins was attributed to the more chain transfer reactions to MAO.The higher the reaction temperature
the lower catalytic activity was present. The reasonable explanation was the combination of the accelerated catalyst’S deactivation and the decrease in ethylene concentration in solvent due to the elevated temperature.Under such condition
however
the oligomerization of ethylene produced more short chain olefins which are adapted to act as comonomers for preparation of linear low density polyethylene materials.Ethylene pressure in autoclave also had an important influence on catalytic activity and carbon-number distribution of product. The catalytic activity increased sharply with the elevated ethylene pressure.However
the proportion of C4~C10 olefins in product decreased in higher pressure due to the enhanced chain propagation reaction. The research work indicated that the control of catalytic activity and product distribution can be realized by the variation of oligomerization conditions such as Al/Fe molar ratio
reaction temperature and ethylene pressure.The results also showed that the ethylene oligomerization employing this novel iron-based catalyst mainly produces the C4~C10 olefins with high selectivity for linear C4~C10 α-olefin (>98%).