Catalyst system for in-situ copolymerizing linear low-density polyethylene

A copolymerization catalyst and a linear low-density technology are applied in the field of catalyst systems for in-situ copolymerization to prepare linear low-density polyethylene, and can solve the problem of high cost of copolymerization catalysts

Inactive Publication Date: 2007-03-28
INST OF CHEM CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] Based on the above-mentioned technical background, the purpose of the present invention is to provide a catalyst system for preparing linear low density polyethylene (LLDPE) by in-situ copolymerization. Aminopyridine iron complexes and alkylaluminoxanes are oligomerization catalyst systems (α-olefin selectivity > 94%, carbon number distribution is C 4 ~C 30 , mainly C 4 ~C 14 ), magnesium chloride-supported titanium tetrachloride and alkylaluminum or alkylaluminoxane as a copolymerization catalyst system, using ethylene as the only raw material to generate α-olefins in situ, and then complete the in situ copolymerization reaction with ethylene to prepare Produced linear low-density polyethylene (LLDPE), not only the prepared LLDPE maintained the original structural characteristics, but also solved the problem of high cost of copolymerization catalysts previously studied

Method used

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  • Catalyst system for in-situ copolymerizing linear low-density polyethylene
  • Catalyst system for in-situ copolymerizing linear low-density polyethylene
  • Catalyst system for in-situ copolymerizing linear low-density polyethylene

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0030] 1) All operations are carried out under anhydrous and oxygen-free conditions, and all solvents require dehydration and deoxygenation treatment.

[0031] 2) A: Oligomerization catalyst

[0032]

[0033] B: The oligomerization cocatalyst is MAO

[0034] C: Copolymerization catalyst TiCl 4 / MgCl 2 (Ti=4.5%)

[0035] D: Co-catalyst triethylaluminum (TEA)

[0036] 3) Replace a 5L stainless steel reactor with anchor stirring with nitrogen and ethylene respectively, add 2L of hexane under the protection of ethylene, add MAO [Al / Fe=1500:1 (molar ratio)] under stirring, and stir for 1 minute , adding 5.0×10 -6 mol oligomerization catalyst A, react at 20°C for 4 minutes.

[0037] 4) Add TEA (Al / Ti=50) and 95.8 mg (90×10 -6 mol) Copolymerization of the main catalyst C, after heating up to 70°C, feed hydrogen until the pressure of the reactor rises by 0.15MPa, then start to feed ethylene into the reactor to 0.4MPa, and use ethylene to maintain the pressure in the reactor,...

Embodiment 2

[0043] 1) All operations are performed under anhydrous and oxygen-free conditions, and all solvents require dehydration and deoxidation treatment.

[0044] 2) A: Oligomerization procatalyst supported by montmorillonite

[0045]

[0046] B: oligomerization promoter MAO

[0047] C: Copolymerization main catalyst TiCl 4 / MgCl 2 (Ti=4.5%)

[0048] D: Co-catalyst triethylaluminum (TEA)

[0049] 3) A 5L stainless steel reactor with anchor stirring was replaced with nitrogen and ethylene respectively, 2L of hexane was added under the protection of ethylene, MAO [Al / Fe=1000:1 (molar ratio)] was added under stirring, and after stirring for 1 minute, Add 0.2g (5.0×10 -6 mol) oligomerization catalyst A, react at 20°C for 10 minutes.

[0050] 4) Add TEA (Al / Ti=50) and 95.8 mg (90×10 -6 mol) Copolymerize the main catalyst C. After the temperature is raised to 70°C, hydrogen is introduced until the pressure of the reactor rises by 0.15 MPa. Then, ethylene is introduced into the re...

Embodiment 3

[0055] 1) All operations are carried out under anhydrous and oxygen-free conditions, and all solvents require dehydration and deoxygenation treatment.

[0056] 2) A: Oligomerization catalyst

[0057]

[0058] B: oligomerization promoter MAO

[0059] C: Copolymerization main catalyst TiCl 4 / MgCl 2 (Ti=5.6%)

[0060] D: co-catalyst TEA

[0061] 3) A 5L stainless steel reactor with anchor stirring was replaced with nitrogen and ethylene respectively, 2L of hexane was added under the protection of ethylene, MAO [Al / Fe=2000:1 (molar ratio)] was added under stirring, and after stirring for 1 minute, Join 8.0×10 -6 mol oligomerization catalyst A, react at 20°C for 8 minutes.

[0062] 4) Add TEA (Al / Ti=75) and 42.8mg (50×10 -6 mol) Copolymerization of the main catalyst C, after heating up to 70°C, feed hydrogen until the pressure of the reactor rises by 0.10MPa, then start to feed ethylene into the reactor to 0.4MPa, and use ethylene to maintain the pressure in the reactor,...

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Abstract

The invention relates to a catalyst system used to prepare linear low density polyethylene by in situ copolymerization. The catalyst system is made up of oligomerization catalyst formed by homogeneous phase or loading type alpha-bi-imine pyridine iron series catalyst and aluminum alkyl-aluminoxane promoter, and copolymerization catalyst formed by titanium serious catalyst and alkyl aluminum or alkyl-aluminoxane promoter. The invention uses ethylene as the only monomer, makes it oligomerize to generate alpha-olefin, and process in situ copolymerization at the same time to prepare linear low density polyethylene in the same reactor which has the features of low melt pointing, low density, high mutual monomer inserting ratio, different length for side chain. And this method can simplify production technology, greatly reduce production cost.

Description

technical field [0001] The invention relates to a catalyst system, in particular to a catalyst system for preparing linear low-density polyethylene (LLDPE) by in-situ copolymerization. Background technique [0002] Ethylene and butene are copolymerized under the action of Ziegler-Natta catalyst to produce LLDPE (Linear Low Density Polyethylene). The required butene is usually produced by dimerization of ethylene. The dimerization catalyst and the copolymerization catalyst can make ethylene dimerize to generate 1-butene and then copolymerize with ethylene to generate LLDPE in situ, which can simplify the production process and reduce the production cost. [J.Polym.Sci, Polym.Chem..Ed.22,3027(1984); 24,1069(1986; Petrochemical Industry, 23,491(1994)].The dimerization catalysts adopted are mostly titanium series catalysts, It is mainly Ti(OBu)4-AlR3. The disadvantage of this catalytic system is that the dimerization catalyst can only oligomerize ethylene to generate 1-butene, a...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08F210/02C08F4/645
Inventor 胡友良吕占霞张志成吴春红李化毅
Owner INST OF CHEM CHINESE ACAD OF SCI
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