CN1039587C - Preparation method of aluminoxane compound - Google Patents

Abstract

The present invention provides a method for preparing aluminoxane compound, which is prepared by hydrolyzing alkyl aluminum by using crystal water and absorbed water contained in cyclodextrin, and the obtained product has good stability, can be stored for a long time, is used for olefin polymerization, and has high catalytic activity.

Description

A kind of preparation method of aluminium alkoxide compound

The invention belongs to a kind of preparation method who contains the oxygen organo-aluminium compound.

As everyone knows, occurred a kind of novel high-activity metalloscene catalyst in recent years in the field of olefin polymerisation, this catalyzer must use with a kind of special organo-aluminium compound, and this organo-aluminium compound is aluminium alkoxide compound.

At present, the method for synthetic aluminium alkoxide compound has tens kinds, mainly is the route of taking alkyl aluminum hydrolysis, and difference is to be used for the water source difference of aluminum alkyls of hydrolysis, and can reduce following a few class: (1) is that the water source prepares aikyiaiurnirsoxan beta with the hydrated metal salt; (2) the direct and aluminum alkyls effect of water; (3) be water source hydrolysis aluminum alkyls with the silica gel that do not dewater; (4) dehydration and aluminum alkyls effect in the compound molecule.

Usually, it is more to adopt the hydrated metal inorganic salt to be that the water source prepares the method for alkyl aikyiaiurnirsoxan beta, and used hydrated metal inorganic salt have CuSO ₄5H ₂O, FeSO ₄7H ₂O, MgSO ₄7H ₂O, LiOHH ₂O, Al ₂(SO ₄) 18H ₂O, ZrO (NO ₃) ₂2H ₂O etc.The US4 of Germany Hoechst AG company, 544,762 patent disclosures a kind of preparation method of aikyiaiurnirsoxan beta, it is by trimethyl aluminium Al (CH ₃) ₃In toluene or heptane solvent with Al ₂(SO ₄) ₃18H ₂O or Al ₂(SO ₄) ₃16H ₂O effect, temperature of reaction are 25～40 ℃, and the reaction times is 20～40 hours.

U.S.'s ethyl corporation is at its patent US4, discloses in 968,827 a kind ofly in the inertia aromatic solvent, and temperature of reaction is-80～-10 ℃, with distilled deionized water and aluminum alkyls effect and make the method for the aluminium alkoxide compound of high reactivity, high yield.

The less stable of the alkyl aikyiaiurnirsoxan beta that above method makes can not long storage.After depositing for some time, gelatinous precipitate can occur in the aluminoxanes solution, catalytic activity descends when being used for olefinic polymerization.In addition, it is longer to prepare the needed reaction times of alkyl aikyiaiurnirsoxan beta with the hydrated metal salt hydrolysis, generally more than 20 hours.And water is direct and the method for aluminum alkyls effect, and its temperature of reaction requires very low ,-10～-80 ℃, generally wayward.

Mitsubishi changes into Co., Ltd. and opens in the flat 4-359002 patent the spy, discloses a kind of production method of olefin polymer, is to utilize hydroxyl and trialkylaluminium reaction in the cyclodextrin one compounds molecule, and the product of reaction directly is used as the catalyst component of olefinic polymerization.The non-crystal water that utilizes cyclodextrin and comprise water and come hydrolysis alkyl aluminum to be equipped with aluminium alkoxide compound.

The objective of the invention is to overcome the shortcoming that aikyiaiurnirsoxan beta preparation method in the above-mentioned prior art exists, create a kind of easy, easily-controlled reaction conditions, novel method that product stability is good of preparing.

The inventor is through research repeatedly, proposed a kind ofly to utilize the crystal water in the cyclodextrin and comprise water part hydrolyzable alkoxy base aluminium in inert media, and prepares the method for stable aluminium alkoxide compound.Wherein the cyclodextrine as hydrolytic reagent can have α, β, three kinds of homologues of γ, i.e. α-hydration cyclodextrin, β-hydration cyclodextrin, γ-hydration cyclodextrin.This cyclodextrin be by several glucose units by the interconnective organic compound that contains some crystal water of α-1.4 key ring-type, this molecule has the special construction of tubbiness.

The method of the invention comprises the steps:

(1) mix with inert solvent with cyclodextrin, preparation contains the suspension of cyclodextrin;

(2) mix with inert solvent with aluminum alkyls, preparation contains the solution of aluminum alkyls;

(3) under-20～10 ℃, in the nitrogen atmosphere above-mentioned alkyl aluminum solutions is added dropwise in the above-mentioned cyclodextrin suspension, be heated to 10～80 ℃ then and continue reaction, the reaction times is 2～50 hours;

(4) reaction product of step (3) is filtered, removes residue, obtain aluminoxanes solution, also can with this solution further by conventional concentrate, method such as drying, obtain the aluminoxanes solution or the solid aluminium siloxane compound of high density;

Above-mentioned inert solvent is aromatic hydrocarbons or aliphatic hydrocarbon, and the mol ratio of water is 1: 0.8～2 in reactant aluminum alkyls and the cyclodextrin.

The used raw material aluminum alkyls of the present invention can be selected trimethyl aluminium, triethyl aluminum, tri-propyl aluminum, tri-butyl aluminum or triisobutyl aluminium, is best with the trimethyl aluminium.

Inert solvent used in the present invention can be selected aromatic hydrocarbons or aliphatic hydrocarbon, and aromatic hydrocarbons comprises benzene,toluene,xylene, ethylbenzene etc., and aliphatic hydrocarbon comprises hexane, heptane, hexanaphthene etc., is the best to select toluene or heptane.

Reaction mechanism of the present invention is: aluminum alkyls in inert solvent with cyclodextrin in contained water effect generate aikyiaiurnirsoxan beta, hydroxyl on the cyclodextrin of minimal amounts of dissolved in inert solvent further is connected on the aikyiaiurnirsoxan beta molecular chain with the aikyiaiurnirsoxan beta reaction, because cyclodextrine is the macromole of barrel-like structure, thereby stoped the autohemagglutination of aikyiaiurnirsoxan beta own to form the tendency of gelatinous precipitate, formed stable aluminium alkoxide compound.Can be represented by the formula beta-cyclodextrin (β-CD12H ₂O) and the reaction formula of aluminum alkyls effect: $+x[\mathrm{\β}-\mathrm{CD}(12-\frac{m}{2x})\·H_{2}O]$

In the formula: n=2～40 are preferably 10～20; R is C ₁～C ₆Alkyl is preferably methyl: x=0.06n～0.17n is preferably 0.14n.

When product is the line style aikyiaiurnirsoxan beta, m=2n

When product is the ring-type aikyiaiurnirsoxan beta, m=2n+1

Concrete method for making of the present invention is as follows: have in the reactor of agitator through the abundant metathetical of nitrogen at one, the cyclodextrin and the inert solvent that add specified amount, stirred under the room temperature 0.5～1 hour, be cooled to 0～-10 ℃ then, the mol ratio 1 of water in aluminum alkyls and the cyclodextrin: (0.8～2), the best are 1: (1.3～1.8).Dropwise, under 10～80 ℃, be preferably 20～50 ℃, continue reaction 2～50 hours, be preferably 2～10 hours.Reaction finishes, and solution is filtered in loft drier, filters out solid residue, washs residue 1～4 time with inert solvent again, removes residue and stays filtrate, and is last, obtains the water white aluminoxanes solution that is dissolved in inert solvent.Also can with this solution further by conventional concentrate, method such as drying, obtain the aluminoxanes solution or the solid aluminium siloxane compound of high density.

With the aluminoxanes solution of reaction gained is promotor, and metalloscene catalyst such as bis cyclopentadienyl zirconium dichloride are that Primary Catalysts is used for olefinic polymerization, and catalyst activity is improved.As when being used for ethylene homo, activity can reach (1～10) * 10 ⁶Ten thousand gPE/gZrh.

Advantage of the present invention and characteristics:

1. when the aikyiaiurnirsoxan beta that makes of the present invention is used for olefinic polymerization active high, yield is high.By zirconium, catalytic activity is (1～10) * 10 ⁶Ten thousand gPE/gZrh, by aluminium, the catalyst activity performance reaches 10 ³GPE/gAlh.Reduced the ash content of polymkeric substance widely.In the prior art, use hydrated metal salt, have the part metals component to enter in the reaction product unavoidably, thereby influence activity of such catalysts and ash content as in the hydrolytic reagent reaction.

2. the product long term storage stability that obtains of the present invention is good, gelatinous precipitate do not occur.After storing half a year, be used for olefinic polymerization, catalyst activity does not reduce.

3. the reaction conditions of the present invention's employing is easily grasped, and the reaction times is short, and temperature of reaction is not really low, easily control.The present invention is because the cyclodextrin that adopts is one to have the special construction organism, compare with hydrolytic reagent hydrated metal salt of the prior art, easily and the aluminum alkyls reaction that is hydrolyzed, reaction times is shorter, usually, react and just can obtain active higher aluminium alkoxide compound in 4 hours, and when adopting hydrated metal salt, then need the reaction times more than 20 hours as hydrolytic reagent.The preparation method who in the present invention and the prior art with the free-water is hydrolytic reagent compares, and reaction is mild, only needs to drip aluminum alkyls and get final product about 0 ℃, and during as hydrolytic reagent, then need lower temperature of reaction with free-water, is generally-60～-80 ℃.

4. the waste residue of gained of the present invention is easily handled, and does not have environmental pollution problem.Because the present invention uses cyclodextrin as hydrolytic reagent, the waste residue that has reacted the back generation is the dehydration cyclodextrin, and this material is biodegradable, therefore, environment is not polluted.

Embodiment

Example 1: in three mouthfuls of glass flask that have stirring through nitrogen abundant metathetical, add 48.5g β one cyclodextrin (β-CD12H ₂O) and 62.5 milliliters of toluene, stirred 0.5 hour under the room temperature, and be cooled to 0～-10 ℃, under this temperature, slowly drip trimethyl aluminium toluene solution (24.1 milliliters of trimethyl aluminiums are dissolved in 62.5 milliliters of toluene), be attended by methane gas and emit, controlled temperature is about 0 ℃.Dropwise, slowly be warming up to 30 ℃, continue reaction 4 hours.Reaction product is filtered in a loft drier that fills nitrogen, the unreacted solid residue of elimination, and, remove residue with toluene wash residue 2 times, obtain required water white methylaluminoxane solution, its aluminium content 3.5% (wt), productive rate 45%.

In 1 liter of autoclave that stirring is housed, earlier with nitrogen again with air in the ethene displacement still, add 400ml toluene then, the methylaluminoxane toluene solution (6.5 * 10 of the above-mentioned gained of 10ml ^-3The aluminium of mol), and O.5ml contain 6.5 * 10 ^-7Bis cyclopentadienyl zirconium dichloride (the Cp of mole ₂ZrCl ₂) toluene solution.When being warming up to 80 ℃, feed ethene in still, 85 ℃ of temperature, O.3MPa pressure for descending polyreaction 4.6 minutes.Reaction end, cooling, release.The polymkeric substance that obtains is through filtration, dry, acquisition 15 gram polyethylene.Calculation result: catalytic activity is 3.28 * 10 ⁶GPE/g.Zr.h.

Zhi Bei methylaluminoxane solution as stated above, store half a year after, being used for the vinyl polymerization catalytic activity is 3.10 * 10 ⁶GPE/gZr.h.

Comparative example: change the cyclodextrin of example 1 into adding 16gAl ₂(SO ₄) ₃18H ₂O, the remaining reaction condition is with example 1, and it is 1.6 * 10 that the gained aluminoxanes solution is used for ethylene polymerization activity ⁶GPE/gZr.h after this aluminoxanes solution is deposited 2 months, floss occurs in the solution, repeat the vinyl polymerization test, and activity only is 8 * 10 ⁵GPE/gZr.h.After storing half a year, a large amount of gelatinous precipitates appear in solution, carry out vinyl polymerization, non-activity again.

Example 2: except that 30 ℃ of reaction times were extended for 6 hours with 4 hours, the remaining reaction condition is used for vinyl polymerization with the aluminoxanes solution of example 1. gained in the example 1, and activity is 1.81 * 10 ⁶GPE/gZrh.

Example 3: except that the temperature of reaction of cyclodextrin and aluminum alkyls is brought up to 50 ℃ from 30 ℃, the remaining reaction condition is with example 1 in the example 1, and the aluminoxanes solution of gained is used for vinyl polymerization, and activity is 1.12 * 10 ⁶GPE/gZrh.

Claims (5)

1, a kind of aluminium alkoxide compound The preparation method, it is by cyclodextrin and aluminum alkyls effect and make, product is line style aikyiaiurnirsoxan beta or ring-type aikyiaiurnirsoxan beta, R is C in the formula ₁～C ₆Alkyl, n is 2～40, this method comprises the steps:

(1) mix with inert solvent with cyclodextrin, preparation contains the suspension of cyclodextrin;

(2) mix with inert solvent with aluminum alkyls, preparation contains the solution of aluminum alkyls;

(3) under-20～10 ℃, in the nitrogen atmosphere above-mentioned alkyl aluminum solutions is added dropwise in the above-mentioned cyclodextrin suspension, be heated to 10～80 ℃ then and continue reaction, the reaction times is 2～50 hours;

(4) reaction product of step (3) is filtered, removes residue, obtain aluminoxanes solution, also can with this solution further by conventional concentrate, method such as drying, obtain the aluminoxanes solution or the solid aluminium siloxane compound of high density;

Above-mentioned inert solvent is aromatic hydrocarbons or aliphatic hydrocarbon, and the mol ratio of water is 1: 0.8～2 in reactant aluminum alkyls and the cyclodextrin.

2, method according to claim 1, wherein the reactant cyclodextrin is a kind of hydration cyclodextrin that contains some crystal water and bag water receiving, is selected from α-hydration cyclodextrin, β-hydration cyclodextrin and γ-hydration cyclodextrin, or their mixture.

3, method according to claim 1, wherein aluminum alkyls is selected from trimethyl aluminium, triethyl aluminum, tri-propyl aluminum, tri-butyl aluminum or triisobutyl aluminium.

4, method according to claim 1, wherein aromatic hydrocarbons is selected from toluene, dimethylbenzene, ethylbenzene.

5, method according to claim 1, wherein aliphatic hydrocarbon is selected from hexane, heptane, hexanaphthene.