CN1583807A - Multinuclear acenaphthene diimine nickle catalyst for synthesis of branched polyethylene - Google Patents

Abstract

The invention relates to a polynuclear acenaphthylenediimide nickel chloride catalyst for synthesizing branched polyethylene and a preparation method thereof. The catalyst uses polynuclear acenaphthylenediimide nickel complex supported on a SiO ₂ -MgCl ₂ composite carrier as the main catalyst, and AlEt ₂ Cl as the co-catalyst. The preparation method adopts the impregnation reaction method. The obtained catalyst has the shape of spherical particles, and the high-branched low-density polyethylene plastic body and elastomer can be prepared without MAO catalyzing single ethylene polymerization.

Description

Polynuclear nickel (II) acenaphthenequinonedcatalyst catalyst of synthesizing branched polyethylene and preparation method thereof

Technical field

The present invention relates to a kind of synthesizing branched polyethylene plastomer, elastomeric multinuclear acenaphthene diimine nickelous chloride composition catalyst and preparation method thereof.

Background technology

Reaction has catalytic activity preferably to traditional Z-N (Z-N) catalyzer to ethene and alpha-olefin copolymer, can make the different degrees of branching in, new LDPE (film grade); But its body can not make polyethylene produce side chain, obtain branched polyethylene, just needs to use expensive alpha-olefin, and this has increased poly cost, simultaneously, also is difficult to obtain the polyethylene of the high degree of branching with this class catalyzer.The diimine ligand compound of the rear transition metal nickel of middle nineteen nineties in last century discovery, palladium etc. can be from the polyethylene plastomers and the elastomerics of single ethylene oligomerisation, the synthetic various high degrees of branching of in-situ copolymerization at the catalyst system that makes with methylaluminoxane (MAO) or boron compound, this has opened up a frontier for olefinic polymerization, have important application prospects (J.K.Johnson is arranged, C.M.Killian and M.Brookhart, J Am.Chem.Soc, 1995,117:6414).Yet this catalyzer need adopt expensive MAO or boron compound to make promotor, and cost is higher; And the prepared product degree of branching is wayward, and product form is irregular, promotes the use of in industrial production and still has bigger difficulty.

Summary of the invention

The purpose of this invention is to provide a kind of setting out and prepare supported catalyst---the multinuclear acenaphthene diimine nickelous chloride composition catalyst of branched polyethylene by single ethylene.This catalyzer only need be with general AlEt ₂Cl makes promotor, need not to use expensive MAO or boron compound, can the poly-polymerization of catalysis single ethylene make high degree of branching polyethylene plastomers of low density and elastomerics.Contain branch chain of different length in the polymer molecular chain, help improving the over-all properties of polymkeric substance.The preparation of this series catalyst is simple, is easy to suitability for industrialized production, and some technical problems that above-mentioned prior art is existed can solve preferably.

Catalyzer of the present invention, its component comprises Primary Catalysts and promotor; Load on MgCl with multinuclear acenaphthene diimine nickelous chloride title complex ₂, SiO ₂On the complex carrier, constitute compound primary catalysts; With AlEt ₂Cl is a promotor; Multinuclear acenaphthene diimine nickelous chloride title complex is (Ni) _N+2LCl _{2 (n+2)}, wherein L is a multinuclear acenaphthene diimine compound, is selected from L shown in the following structural formula I ₁To L ₄In arbitrary compound:

Among the formula I: n is 2～10;

L ₁: R ₁=R ₂=R ₃=sec.-propyl;

L ₂: R ₁=R ₂=ethyl, R ₃=sec.-propyl;

L ₃: R ₁=ethyl, R ₂=R ₃=sec.-propyl;

L ₄: R ₁=H, R ₂=methoxyl group, R ₃=sec.-propyl;

Corresponding multinuclear acenaphthene diimine nickelous chloride complex structure is as shown in the formula shown in the II:

N is 2～10 among the formula II.

The catalyzer of the invention described above, the each component proportioning is generally by weight: MgCl ₂: SiO ₂: (Ni) _N+2LCl _{2 (n+2)}=1: (2～8): (0.5～3), all the other each components are with (Ni) _N+2LCl _{2 (n+2)}Mole number calculate its mol ratio and be: (Ni) _N+2LCl _{2 (n+2)}: AlEt ₂Cl=1.0: (20～200).

The used multinuclear acenaphthene diimine nickelous chloride title complex of the invention described above catalyzer can obtain by the following method: under nitrogen protection; anhydrous chlorides of rase nickel was dissolved in dehydrated alcohol 2～3 hours; after waiting to have dissolved, join the CH that is dissolved with multinuclear acenaphthene diimine compounds L ₂Cl ₂In the solution, back flow reaction 12～16 hours is drained and is sloughed solvent, and with the anhydrous diethyl ether washing, vacuum-drying promptly gets required multinuclear acenaphthene diimine nickel complex (Ni) _N+2LCl _{2 (n+2)}

The invention described above catalyzer can adopt dipping-reaction method preparation, and concrete steps are as follows:

(1) with microspheroidal SiO ₂Place tube furnace, the heating down of logical nitrogen is warming up to 600 ℃, and 4～6 hours postcooling of calcining at constant temperature in the nitrogen protection bottom discharge, place reaction flask again, add 10 times of SiO ₂The heptane of volume, nitrogen protection and stirring add and contain AlR down ₃Hexane solution, maintain 25～30 ℃ the reaction 30 minutes, vacuumize drying and remove heptane, pre-treatment SiO ₂AlR ₃Middle R is C ₂～C ₄Alkyl contains AlR ₃Hexane solution concentration be 2.5mol/L AlR ₃

Under (2) 60～65 ℃, with MgCl ₂Be dissolved in alcohol, the ether mixing solutions, stir mother liquor; Wherein alcohol is ethanol, and ether is tetrahydrofuran (THF), MgCl ₂: alcohol=1: (3～5), MgCl ₂: ether=1: (24～40);

(3) N ₂Protection is following, above-mentioned mother liquor is added enter pretreated SiO ₂In, 60～65 ℃ of stirring reaction 1～2h remove by filter mother liquor, 50～60 ℃ of controlled temperature, and vacuum tightness 30～35kPa drains liquid, gets active SiO ₂-MgCl ₂Complex carrier;

(4) N ₂Protection adds alkane down in (3) products therefrom, be warming up to 60～70 ℃, adds title complex (Ni) under agitation condition _N+2LCl _{2 (n+2)}CH ₂Cl ₂Solution, reaction 1.5～3h; Used alkane is hexane, heptane or octane, and consumption is every gram complex carrier 8～15ml alkane; (Ni) _N+2LCl _{2 (n+2)}: CH ₂Cl ₂=1: (10～20) W/W;

(5)) solvent in above-mentioned (4) reactant is drained, with alkane washing three times, vacuum is drained under 60 ℃ condition again, promptly gets Primary Catalysts; Wherein, (Ni) _N+2LCl _{2 (n+2)}: CH ₂Cl ₂=1: (10～20) W/W; Alkane is hexane or heptane, and consumption is every gram complex carrier 8～15ml; Primary Catalysts and promotor AlEt ₂Cl forms the poly composite catalyst of ethylene polymerization for preparing branched, and its mol ratio is: (Ni) _N+2LCl _{2 (n+2)}: AlEt ₂Cl=1: (20～200).

The present invention is by (Ni) _N+2LCl _{2 (n+2)}Component and above-mentioned specific dipping reaction method for preparing make the catalyzer that makes only need general AlEt ₂Cl makes promotor, need not expensive MAO or boron compound, can the highly active catalytic vinyl polymerization, make high degree of branching new LDPE (film grade) plastomer and elastomerics; Owing to adopt MgCl ₂, SiO ₂Form complex carrier, make to make polyethylene product and have good particle form.Catalyzer of the present invention has above-mentioned excellent comprehensive performance, is beneficial to aborning and promotes the use of, and has significant superiority.

Catalyzer of the present invention is 106.7kPa at pressure, 50～60 ℃ of polymerization temperatures, and slurry polymerization 1.5 hours, to vinyl polymerization, catalytic efficiency is 45～58kgLLDPE/molNi, making density is 0.879～0.912g/cm ³, the degree of branching is 18.9～86.4 polyethylene plastomers and elastomerics.

Embodiment

The invention will be further described below by embodiment:

Embodiment one:

1. nickel complex (Ni) _N+2L ₁Cl _{2 (n+2)}Preparation: multinuclear acenaphthene diimine nickel complex can obtain by the following method: under nitrogen protection; 0.5354g (4.14mmol) anhydrous chlorides of rase nickel was dissolved in the 20ml dehydrated alcohol 2～3 hours; after waiting to have dissolved, join and be dissolved with 2.005g (4.14mmol) ligand L ₁30 the gram CH ₂Cl ₂In the solution, back flow reaction 12～16 hours is drained and is sloughed solvent, and with 30ml anhydrous diethyl ether washing three times, vacuum-drying promptly gets required nickel complex (Ni) _N+2L ₁Cl _{2 (n+2)}

2. Preparation of Catalyst:

2-1. with 5 gram microspheroidal SiO ₂Put in the tube furnace, the heating down of logical nitrogen is warming up to 600 ℃, the calcining at constant temperature dehydration, and 6 hours postcooling get 4 gram SiO in the nitrogen protection bottom discharge ₂, place reaction flask, add the 40ml heptane, under nitrogen protection and under constantly stirring, add and contain 2.5mol/L AlEt ₃Hexane solution 3ml, maintain 25～30 ℃ the reaction 30 minutes, vacuumize drying and remove heptane, pre-treatment SiO ₂

2-2. with 1.2 gram MgCl ₂Be dissolved in alcohol, the ether mixing solutions, stir mother liquor.Wherein alcohol is ethanol, and ether is tetrahydrofuran (THF), MgCl ₂: alcohol=1: 3, MgCl ₂: ether=1: (24～40).

2-3. at N ₂Protection is following, above-mentioned mother liquor is added enter pretreated SiO ₂In, 60～65 ℃ of stirring reaction 2h remove by filter mother liquor, 50～60 ℃ of controlled temperature, and vacuum tightness 30～35kPa drains liquid, promptly gets active SiO ₂-MgCl ₂Complex carrier.

2-4. at N ₂Under the protection, with SiO ₂-MgCl ₂Complex carrier is added in the reaction flask, adds alkane again, is warming up to 60～70 ℃, adds 1.624g nickel complex (Ni) under agitation condition _N+2L ₁Cl _{2 (n+2)}CH ₂Cl ₂Solution, reaction 1.5h.Used alkane can be hexane, heptane or octane, and consumption is every gram complex carrier 8～15ml alkane.

2-5. solvent is drained, use hexane wash three times, vacuum is drained under 60 ℃ condition again, promptly gets body of catalyst.Wherein the hexane consumption is every gram complex carrier 8～15ml.Body of catalyst and AlEt ₂Cl forms ethylene rolymerization catalyst.

3. the ethene slurry polymerization prepares low-density branched polyethylene:

Reaction flask was vacuumized under 100 ℃ dry 1 hour, use N ₂Replace three times, at N ₂Protection down, add 50ml exsiccant toluene and by Al/Ni than the AlR that are 100 calculating ₂Cl, under agitation add 0.5～15mg Primary Catalysts then, after continuation is stirred and catalyzer was uniformly dispersed in 5 minutes, feeding ethylene gas, is under the 106.7kPa at the pressure that keeps ethylene gas, is warming up to 30 ℃, carry out polyreaction, write down the ethene of polyreaction consumption in per 5 minutes, reaction 1.5h, stopped reaction.With acidic alcohol mixing solutions termination reaction thing, use washing with alcohol again, weigh after the drying, calculate catalyst efficiency.

Under above-mentioned polymerizing condition, the density of gained branched polyethylene is 0.881g/cm ³, be the degree of branching (elastomerics of number of branches/1000C) that is 69.4.The catalytic efficiency of catalyzer is 63kgLLDPE/molNi.

Embodiment two:

1. in embodiment one step 1, with the 4.14mmol ligand L ₁Change the 4.14mmol ligand L into ₂, the remaining reaction condition is identical, gets title complex (Ni) _N+2L ₂Cl _{2 (n+2)}

2. in embodiment one step 2-4, will add 1.624g nickel complex (Ni) _N+2L ₁Cl _{2 (n+2)}CH ₂Cl ₂Solution changes adding 1.486g (Ni) into _N+2L ₂Cl _{2 (n+2)}CH ₂Cl ₂Solution, all the other conditions and operation are with embodiment one, and the catalyzer that makes is polyreaction under embodiment one the same terms.

The density of gained branched polyethylene is 0.894g/cm under above-mentioned polymerizing condition ³, the degree of branching is 68.0 elastomericss.The catalytic efficiency of catalyzer is 65kgLLDPE/molNi.

Embodiment three:

1. in embodiment one step 1, with 2.005g (4.14mmol) ligand L ₁Change 1.788 (4.14mmol) ligand L into ₃, the remaining reaction condition is identical, gets title complex (Ni) _N+2L ₃Cl _{2 (n+2)}

2. in embodiment one step 2-4, with 1.624g nickel complex (Ni) _N+2L ₁Cl _{2 (n+2)}Change 1.577g (Ni) into _N+2L ₃Cl _{2 (n+2)}, all the other conditions and operation are with embodiment one, and the catalyzer that makes is polyreaction under embodiment one the same terms.

Under above-mentioned polymerizing condition the density of prepared branched polyethylene be, 0.887g/cm ³, the degree of branching is 50.2 elastomericss.The catalytic efficiency of catalyzer is 65kgLLDPE/molNi.

Embodiment four

1. in embodiment one step 1, with 2.005g (4.14mmol) ligand L ₁Change 1.788 (4.14mmol) ligand L into ₄, the remaining reaction condition is identical, gets title complex (Ni) _N+2L ₄Cl _{2 (n+2)}

2. in embodiment one step 2-4, with 1.624g nickel complex (Ni) _N+2L ₁Cl _{2 (n+2)}Change 1.455g (Ni) into _N+2L ₄Cl _{2 (n+2)}, all the other conditions and operation are with embodiment one, and the catalyzer that makes is polyreaction under embodiment one the same terms.

The density of prepared branched polyethylene is 0.915g/cm under above-mentioned polymerizing condition ³, the degree of branching is 18.9 plastomeies.The catalytic efficiency of catalyzer is 13kgLLDPE/molNi.

Claims (4)

1. A multinuclear acenaphthylenediimide nickel chloride complex catalyst for synthesizing branched polyethylene, comprising a main catalyst and a cocatalyst; it is characterized in that the multinuclear acenaphthylenediimide nickel chloride complex is supported on MgCl ₂ , SiO ₂ A composite main catalyst is formed on a composite carrier; AlEt ₂ Cl is used as a cocatalyst; the polynuclear acenaphthylenediimide nickel chloride complex is (Ni) _n+2 LCl _2(n+2) , wherein L is selected from the following structural formula I A polynuclear acenaphthylenebisimide compound of one of the compounds _L1 to _L4 shown: In formula I: n is 2-10; L ₁ : R ₁ =R ₂ =R ₃ =isopropyl; L ₂ : R ₁ = R ₂ = ethyl, R ₃ = isopropyl; L ₃ : R ₁ = ethyl, R ₂ = R ₃ = isopropyl; L ₄ : R ₁ =H, R ₂ =methoxy, R ₃ =isopropyl; The structure of the corresponding polynuclear acenaphthylenediimide nickel chloride complex is shown in the following formula II:

In formula II, n is 2-10. 2. according to the described catalyzer of claim 1, it is characterized in that described polynuclear acenaphthylenediimide nickel chloride complex is obtained by the following method: under nitrogen protection, anhydrous nickel chloride is dissolved in dehydrated alcohol Dissolve for 2 to 3 hours. After the dissolution is complete, add it to the CH ₂ Cl ₂ solution in which polynuclear acenaphthylenediimine compound L is dissolved, reflux for 12 to 16 hours, drain to remove the solvent, wash with anhydrous ether, and vacuum After drying, the desired polynuclear acenaphthylenediimide nickel complex (Ni) _n+2 LCl _2(n+2) is obtained. 3. according to the described catalyzer of claim 1 or 2, it is characterized in that each component proportioning is by weight ratio: MgCl ₂ : SiO ₂ : (Ni) _n+2 LCl _{2 (n+2)} =1: (2 ～8): (0.5～3.0), the molar ratio of all other components is calculated based on the moles of (Ni) _n+2 LCl _2(n+2) : (Ni) _n+2 LCl _2(n+2) : AlEt ₂ Cl = 1.0: (20-200). 4. claim 1, the preparation method of the described catalyst of 2 or 3 is characterized in that adopting impregnation reaction method, concrete steps are as follows: (1) Put the microspherical _SiO2 in a tube furnace, heat it under nitrogen, raise the temperature to 600°C, calcine at a constant temperature for 4 to 6 hours, cool it down, discharge it under the protection of nitrogen, put it in a reaction flask, add 10 Heptane with twice the volume of SiO ₂ , under nitrogen protection and stirring, add the hexane solution containing AlR ₃ , maintain the reaction at 25-30°C for 30 minutes, and remove the heptane by vacuum drying to obtain pretreated SiO ₂ ; R in AlR ₃ It is a C ₂ -C ₄ alkyl group, and the concentration of the hexane solution containing AlR ₃ is 2.5mol/L AlR ₃ ; (2) At 60-65°C, dissolve MgCl ₂ in the mixed solution of alcohol and ether, and stir evenly to obtain the mother liquor; where the alcohol is ethanol, the ether is tetrahydrofuran, MgCl ₂ : alcohol = 1: (3-5), MgCl ₂ : ether=1: (24～40); (3) Under the protection of _N2 , add the above mother liquor into the pretreated _SiO2 , stir and react at 60~65°C for 1~2h, filter and remove the mother liquor, control the temperature at 50~60°C, vacuum degree 30~35kPa, and drain Liquid, get active SiO ₂ -MgCl ₂ composite carrier; (4) Under the protection of N ₂ , add alkanes to the product obtained in (3), raise the temperature to 60-70°C, and add the CH ₂ Cl ₂ of the complex (Ni) _n+2 LCl _{2 (n+2)} under stirring conditions solution, reacted for 1.5-3 hours; the alkane used is hexane, heptane or octane, and the dosage is 8-15ml alkane per gram of composite carrier; (Ni) _n+2 LCl _2(n+2) : CH ₂ Cl ₂ =1 : (10～20)W/W; (5)) The solvent in the above-mentioned (4) reactant is drained, washed three times with alkane, and then vacuum-dried under the condition of 60° C. to obtain the main catalyst; wherein, the alkane is hexane or heptane, and the consumption is 8-15ml of composite carrier; main catalyst, co-catalyst aluminum alkyl and AlEt ₂ Cl to form a composite catalyst for ethylene polymerization to prepare branched polyethylene, the molar ratio of which is: (Ni) _n+2 LCl _{2 (n+2)} : AlEt ₂ Cl = 1: (20-200).