Catalyst composition for ethylene oligomerization and preparation method and application thereof

Abstract

The invention provides a catalyst composition for ethylene oligomerization as well as a preparation method and application thereof, and relates to the field of ethylene oligomerization catalysis. The catalyst composition comprises a self-supported metal complex and an aluminum alkyl cocatalyst, the self-supported metal complex is generated through a coordination reaction of a self-supported phosphine-nitrogen ligand and a transition metal, and the self-supported phosphine-nitrogen ligand is obtained by copolymerization of a phosphine-nitrogen ligand monomer containing terminal double bonds and styrene. The invention further discloses an ethylene oligomerization method using the catalyst composition, a three-kettle series oligomerization process is adopted, appropriate reaction conditions are adopted according to the characteristics of different catalysis stages, the retention time of the catalyst is effectively prolonged, and the content of high polymers is reduced. The catalyst is easy to separate from a reaction system, high in temperature tolerance and long in high activity duration, the activity of the catalyst reaches up to 12.5 * 10 < 6 > g / (mol Cr.h), and the total selectivity of 1-hexene and 1-octene exceeds 90%.

Description

technical field

[0001] The invention relates to the field of ethylene oligomerization catalysis, in particular to a catalyst composition for ethylene oligomerization and its preparation method and application. Background technique

[0002] Linear α-olefins are very important organic raw materials and chemical intermediates, and are widely used in the synthesis of copolymerized polyethylene, surfactants, advanced synthetic lubricants (polyα-olefins), plasticizers and other fine chemicals.

[0003] Among them, 1-hexene and 1-octene are mainly used as comonomers for polyethylene, and 1-octene is also used as a raw material for polyalphaolefin (PAO). With the increasing demand of polyolefin elastomer (POE) and synthetic lubricating oil (poly-α-olefin), 1-hexene and 1-octene have become the main growth points of the α-olefin market, accounting for 30% of the total demand %above. At present, 1-hexene and 1-octene are mainly produced by ethylene oligomerization in industry. [0...

Examples

Embodiment 1

[0042] Preparation of self-supporting chromium complexes:

[0043] (1) under nitrogen protection, utilize basic alumina column to remove the polymerization inhibitor in styrene;

[0044] (2) Under anhydrous and oxygen-free conditions, using N,N-dimethylformamide (DMF) as a solvent, the phosphine nitrogen ligand monomer containing terminal double bonds, styrene and initiator azobisisobutyronitrile (AIBN) mixed at 1:0.1:0.005;

[0045] (3) Heating at 100°C for 24 hours, removing the solvent under reduced pressure to form a solid powder, washing and vacuum drying to obtain a self-supported phosphine nitrogen ligand;

[0046] (4) Combine the self-supported phosphine nitrogen ligand with CrCl 3 (THF) 3 Mix in toluene, react at 60°C for 24 hours, filter in a glove box, and vacuum dry to obtain the target complex, the structure of which is shown in formula III.

[0047] Catalyst configuration: freshly prepare 20 mL of toluene solution of the self-supporting metal complex shown in...

Embodiment 2

[0054] Preparation of self-supporting chromium complex: same as Example 1.

[0055] Catalyst configuration: with embodiment 1.

[0056] Ethylene oligomerization: the amount of co-catalyst methylaluminoxane was reduced to 5000 μmol (10 wt% toluene solution), and other conditions were the same as in Example 1. The catalyst activity calculated by the internal standard method was 12.3×10 6 g / (mol Cr h), the product composition is recorded in Table 1, and the gas chromatographic analysis of the product is shown in the attached figure 1 .

Embodiment 3

[0058] Preparation of self-supporting chromium complex: same as Example 1.

[0059] Catalyst configuration: with embodiment 1.

[0060] Ethylene oligomerization: the amount of co-catalyst methylaluminoxane was reduced to 4000 μmol (10 wt% toluene solution), and other conditions were the same as in Example 1. The catalyst activity calculated by the internal standard method was 8.5×10 6 g / (mol Cr h), the product composition is recorded in Table 1.

technical field

[0001] The invention relates to the field of ethylene oligomerization catalysis, in particular to a catalyst composition for ethylene oligomerization and its preparation method and application. Background technique

[0002] Linear α-olefins are very important organic raw materials and chemical intermediates, and are widely used in the synthesis of copolymerized polyethylene, surfactants, advanced synthetic lubricants (polyα-olefins), plasticizers and other fine chemicals.

[0003] Among them, 1-hexene and 1-octene are mainly used as comonomers for polyethylene, and 1-octene is also used as a raw material for polyalphaolefin (PAO). With the increasing demand of polyolefin elastomer (POE) and synthetic lubricating oil (poly-α-olefin), 1-hexene and 1-octene have become the main growth points of the α-olefin market, accounting for 30% of the total demand %above. At present, 1-hexene and 1-octene are mainly produced by ethylene oligomerization in industry. [0...

Examples

Embodiment 1

[0042] Preparation of self-supporting chromium complexes:

[0043] (1) under nitrogen protection, utilize basic alumina column to remove the polymerization inhibitor in styrene;

[0044] (2) Under anhydrous and oxygen-free conditions, using N,N-dimethylformamide (DMF) as a solvent, the phosphine nitrogen ligand monomer containing terminal double bonds, styrene and initiator azobisisobutyronitrile (AIBN) mixed at 1:0.1:0.005;

[0045] (3) Heating at 100°C for 24 hours, removing the solvent under reduced pressure to form a solid powder, washing and vacuum drying to obtain a self-supported phosphine nitrogen ligand;

[0046] (4) Combine the self-supported phosphine nitrogen ligand with CrCl 3 (THF) 3 Mix in toluene, react at 60°C for 24 hours, filter in a glove box, and vacuum dry to obtain the target complex, the structure of which is shown in formula III.

[0047] Catalyst configuration: freshly prepare 20 mL of toluene solution of the self-supporting metal complex shown in...

Embodiment 2

[0054] Preparation of self-supporting chromium complex: same as Example 1.

[0055] Catalyst configuration: with embodiment 1.

[0056] Ethylene oligomerization: the amount of co-catalyst methylaluminoxane was reduced to 5000 μmol (10 wt% toluene solution), and other conditions were the same as in Example 1. The catalyst activity calculated by the internal standard method was 12.3×10 6 g / (mol Cr h), the product composition is recorded in Table 1, and the gas chromatographic analysis of the product is shown in the attached figure 1 .

Embodiment 3

[0058] Preparation of self-supporting chromium complex: same as Example 1.

[0059] Catalyst configuration: with embodiment 1.

[0060] Ethylene oligomerization: the amount of co-catalyst methylaluminoxane was reduced to 4000 μmol (10 wt% toluene solution), and other conditions were the same as in Example 1. The catalyst activity calculated by the internal standard method was 8.5×10 6 g / (mol Cr h), the product composition is recorded in Table 1.

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