A kind of method of ethylene oligomerization

Abstract

The present invention relates to a method for ethylene oligomerization, comprising carrying out ethylene oligomerization reaction in the presence of a main catalyst represented by formula (I), a cocatalyst, an organic solvent and water; wherein, the 4 Rs present may be the same or different, Each is independently selected from alkyl, cycloalkyl and aromatic groups, preferably phenyl or substituted phenyl; R' and R" are different, and each independently selects hydrogen and tert-butyl, M is a transition metal, X selected from halogen, and n is an integer of 1-3.

Description

technical field

[0001] The invention relates to a method for ethylene oligomerization, in particular to a method for continuous reaction of ethylene trimerization and tetramerization. Background technique

[0002] The oligomerization of olefins, mainly α-olefins, using chromium-based catalysts has been extensively studied. Among them, the trimerization of ethylene into 1-hexene and the tetramerization of ethylene into 1-octene have special significance. The linear low-density polyethylene (LLDPE) produced by the copolymerization of 1-hexene or 1-octene and ethylene can significantly improve the properties of PE, especially the mechanical properties, optical properties, tear strength and impact resistance of polyethylene. The strength has been significantly improved, and it is very suitable for packaging films and agricultural covering films such as greenhouses and greenhouses. At the same time, 1-hexene and 1-octene are also used as plasticizers, fatty acids, alcohols for d...

Examples

Embodiment 1

[0033] The ethylene oligomerization reaction specifically comprises the steps:

[0034] (1) In a continuous reaction device, water-containing ethylene, solvent n-heptane, metal procatalyst solution (concentration is 2.5 μ mol / mL, such as formula I, wherein 4 Rs are all phenyl groups, M is chromium, and X is chlorine , n=3), cocatalyst trimethylaluminum solution (concentration is 1mmol / mL) enters reactor respectively, and its flow rate is 80g / h, 160g / h, 3.5g / h, 2.6g / h, keeps in the reaction system Al / Cr mol ratio is 500, and the residence time that keeps reaction material in reactor is 30 minutes;

[0035] (2) The reaction pressure is 5MPa and the reaction temperature is 80°C, wherein, based on ethylene, the mass content of water is 400 mg / Kg (ppm);

[0036] (3) Carry out gas chromatography (GC) analysis to the reaction outlet material. See attached table 1 for the data.

Embodiment 2

[0038] The specific steps are the same as in Example 1, except that the cocatalyst is a mixed solution of 300 equivalents of trimethylaluminum and 300 equivalents of diethylaluminum chloride, the Al / Cr ratio is 600, and the ethylene water content is 300 mg / Kg. The results of ethylene oligomerization are shown in Table 1.

Embodiment 3

[0040] The specific steps are the same as in Example 1, the cocatalyst is triethylaluminum, the Al / Cr ratio is 500, the reaction temperature is 50° C., the pressure is 4.0 MPa, the ethylene water content is 500 mg / Kg, and the reaction time is 20 minutes. The results of ethylene oligomerization are shown in Table 1.

technical field

[0001] The invention relates to a method for ethylene oligomerization, in particular to a method for continuous reaction of ethylene trimerization and tetramerization. Background technique

[0002] The oligomerization of olefins, mainly α-olefins, using chromium-based catalysts has been extensively studied. Among them, the trimerization of ethylene into 1-hexene and the tetramerization of ethylene into 1-octene have special significance. The linear low-density polyethylene (LLDPE) produced by the copolymerization of 1-hexene or 1-octene and ethylene can significantly improve the properties of PE, especially the mechanical properties, optical properties, tear strength and impact resistance of polyethylene. The strength has been significantly improved, and it is very suitable for packaging films and agricultural covering films such as greenhouses and greenhouses. At the same time, 1-hexene and 1-octene are also used as plasticizers, fatty acids, alcohols for d...

Examples

Embodiment 1

[0033] The ethylene oligomerization reaction specifically comprises the steps:

[0034] (1) In a continuous reaction device, water-containing ethylene, solvent n-heptane, metal procatalyst solution (concentration is 2.5 μ mol / mL, such as formula I, wherein 4 Rs are all phenyl groups, M is chromium, and X is chlorine , n=3), cocatalyst trimethylaluminum solution (concentration is 1mmol / mL) enters reactor respectively, and its flow rate is 80g / h, 160g / h, 3.5g / h, 2.6g / h, keeps in the reaction system Al / Cr mol ratio is 500, and the residence time that keeps reaction material in reactor is 30 minutes;

[0035] (2) The reaction pressure is 5MPa and the reaction temperature is 80°C, wherein, based on ethylene, the mass content of water is 400 mg / Kg (ppm);

[0036] (3) Carry out gas chromatography (GC) analysis to the reaction outlet material. See attached table 1 for the data.

Embodiment 2

[0038] The specific steps are the same as in Example 1, except that the cocatalyst is a mixed solution of 300 equivalents of trimethylaluminum and 300 equivalents of diethylaluminum chloride, the Al / Cr ratio is 600, and the ethylene water content is 300 mg / Kg. The results of ethylene oligomerization are shown in Table 1.

Embodiment 3

[0040] The specific steps are the same as in Example 1, the cocatalyst is triethylaluminum, the Al / Cr ratio is 500, the reaction temperature is 50° C., the pressure is 4.0 MPa, the ethylene water content is 500 mg / Kg, and the reaction time is 20 minutes. The results of ethylene oligomerization are shown in Table 1.

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