Ethylene oligomerization method

Abstract

The invention discloses an ethylene oligomerization method. Ethylene is subjected to oligomerization in a reaction system consisting of n-propiono-substituted-1,10-phenanthroline amine iron (II) which is shown in a formula (I) as described in the specification and is used as a main catalyst, an aluminum-containing cocatalyst, water and an organic solvent. The solvent is alpha-olefin of Cn (n is greater than 4 and no less than 10). In the formula (I), R1 to R5 are independently selected from the group consisting of hydrogen, C1-C6 alkyl groups, halogen, C1-C6 alkoxy groups and a nitro group. The method overcomes technical biases, optimizes ethylene oligomerization process, has high oligomerization activity, enables rapid initiation, stable operation, low toxicity and environmental protection of the ethylene oligomerization process to be realized, allows good balance to be reached between a catalytic effect and cost and has good practicality; moreover, the method enables cost for ethylene oligomerization to be greatly decreased and has wide industrial prospects in overall consideration of the catalytic effect and production cost.

Description

technical field [0001] The invention relates to the field of olefin polymerization, in particular to a method for ethylene oligomerization. Background technique [0002] Linear α-olefins are widely used in the fields of ethylene comonomers, surfactant synthesis intermediates, plasticizer alcohols, synthetic lubricating oils and oil additives. In recent years, with the continuous development of the polyolefin industry, the worldwide demand for α-olefins has grown rapidly. At present, the vast majority of α-olefins are prepared by ethylene oligomerization. The used catalyst of ethylene oligomerization mainly contains nickel series, chromium series, zirconium series and aluminum series etc., in recent years, Brookhart group (Brookhart, the people such as M, J.Am.Chem.Soc.,1998,120,7143-7144 ; WO99 / 02472,1999), Gibson group (Gibson, V.C. et al., Chem.Commun., 1998,849-850; Chem.Eur.J., 2000,2221-2231) found that some Fe(II) and Co The tridentate pyridine imine complex of (II)...

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Problems solved by technology

Whether it is methylalumoxane or modified methylalumoxane, the unit price is relatively high, and when it is used for ethylene oligomerization on a large scale, it will inevitably lead to high production costs

Moreover, the oligomerization reaction has very strict requirements on the initiation environment, and it is strictly required to be carried out in an anhydrous and oxygen-free environment. Due to the special conditions, it is very difficult to achieve, so the reaction initiation, stability and repeatability of the oligomerization process are very poor.

In addition, the solvent used in the oligomerization process is generally toluene. As we all know, toluene is a toxic aromatic hydrocarbon, which is irritating to the skin and mucous membranes and has an anesthetic effect on the central nervous system; and in the oligomerization products, the toluene content is relatively large. Unable to meet the requirements for aromatic hydrocarbon content when used as a comonomer

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