CN1109058C - Composite catalyst bimetal cyanide and its preparing process and application - Google Patents

Abstract

The invention discloses an improved double metal cyanide compound catalyst and its preparation method and application. The catalyst comprises a DMC compound, an organic complexing agent and a sulfate with a molar ratio of 0.5-5.0 based on DMC. Compared with the known DMC catalyst, the catalyst of the invention is simple to prepare, has high yield, and the cost of the corresponding catalyst is reduced. When used as a catalyst in the production process of polyether polyols, the catalyst greatly shortens the induction period of addition polymerization of epoxides to initiators containing hydrogen atoms, and exhibits high reactivity, making it sufficient to It can be used at a low concentration (<25ppm), which can avoid the post-refinement process, realize the pollution-free process of 'zero discharge', shorten the production cycle, save energy and material consumption.

Description

Double metal cyanide composite catalyst and its preparation method and application

Field:

The invention relates to a double metal cyanide (DMC) catalyst for epoxide polymerization, a preparation method thereof, and a method for producing polyether polyol from the catalyst.

Background technique:

Double metal cyanide complexes are well known as effective catalysts for the addition polymerization of alkylene oxides to starting compounds containing active hydrogen atoms and can be used to prepare a number of polymer products including polyethers, polyesters and polyetherester polyols. The polyol can be widely used in polyurethane coatings, elastomers, sealants, foams and adhesives, and exhibits extremely superior properties (see US patents: 5 223 583; 5 145 883; 4 472 560; 3 900 518) . Therefore, the preparation of polyether polyols with DMC catalysts has become a direction for the development of polyether products.

Usually double metal cyanide complexes are prepared by reacting metal salts with aqueous metal cyanide salt solutions to form DMC compound precipitates. It includes a low molecular weight water-soluble organic complexing agent that promotes catalyst activity. Known DMC catalyst preparation method (referring to U.S. Patent: 5 158 922; 4 477 589; 3 829 505; 3 427 334 and Japanese Patent Application Publication No. 4-145123) include: (1) in the presence of organic complexing agent In this case, an excess of the metal salt is used and the metal cyanide salt is fully reacted in aqueous solution to produce a catalyst slurry. The organic complexing agent can also be included in the aqueous solution of these two salts, or the metal salt and the metal cyanide salt solution are added simultaneously under stirring in the organic complexing agent to form a catalyst precipitate; (2) adopt any conventional separation Methods, such as filtration, centrifugation, sedimentation or the like, are used to separate the solid catalyst from the catalyst slurry; (3) washing the separated solid catalyst with an aqueous solution containing an organic complexing agent. That is: the catalyst is re-made into a slurry in an aqueous solution of an organic complexing agent, and then the catalyst is separated. This washing step serves to remove impurities that would deactivate the catalyst. The content of the organic complexing agent in the washing liquid is about 40-80%; (4) washing the solid catalyst in the pure organic complexing agent again for pulping. The solid catalyst obtained after separation was dried in vacuum at 60° C. to a constant weight, and pulverized to obtain a powder catalyst.

The metal salt is a water-soluble metal salt with the general formula M(X)n, where M can be selected from Zn(II), Fe(II), Ni(II), Co(II), Al(III) and the like. X is selected from anionic halogens, hydroxides, sulfates, oxalates, and the like. The value of n needs to be determined according to the valence state of M, and the preferred metal salts are zinc chloride and zinc bromide.

The metal cyanide salt is a water-soluble salt with a general formula _Ma [M'(CN) ₆ ] _b , where M is an alkali metal ion or an alkaline earth metal ion. M' is Co(II), Co(III), Fe(II), Fe(III), etc., and a and b are integers of equilibrium valence. Preferred water-soluble metal cyanide salts are potassium hexacyanocobaltate, potassium hexacyanoferrate.

Appropriate organic complexing agents are the key to preparing high-performance double metal cyanide complex catalysts. The manner in which the complexing agent is introduced into the DMC complex is also extremely important. The selected complexing agent is a water-soluble heteroatom-containing organic compound capable of complexing with double metal cyanide. Including alcohols, ethers, esters, etc. Diethylene glycol dimethyl ether and tert-butanol are preferred.

DMC catalysts as described in the above-mentioned patents have higher reactivity for epoxide polymerization and are more effective with double metal cyanide catalysts than conventional similar polyols made using base (KOH) catalysts. The occurrence of side reactions of chain transfer can be effectively suppressed, and the prepared polyether polyol has the characteristics of low unsaturation, high average functionality and good molecular regularity. At the same time, the catalyst can produce polyether polyols with high molecular weight (the equivalent weight of the KOH catalyst system is less than 2200, while the equivalent weight of the DMC catalyst system can reach 5000 or higher). However, because the raw materials used in the DMC catalyst are more expensive, the cost of the corresponding catalyst is higher. Catalysts with improved activity are therefore desired, allowing for reduced catalyst usage. In addition, no matter whether KOH or DMC catalyst is used to prepare polyether polyol, a catalyst separation step is inevitably required. When using KOH to prepare polyether polyols, the crude product generally needs to be adsorbed with an adsorbent such as magnesium silicate, washed with water or ion-exchanged in order to remove the residual potassium ions in the polyol (“polyurethane resin” Li Shaoxiong, Zhu Lumin Edited by Jiangsu Science and Technology Press). Methods for removing DMC catalysts from polyols are also generally cumbersome, most of which involve chemical treatments (see US patents: 5 248 833; 4 877 906; 4 355188). Since the DMC catalyst is quite expensive, in addition, the separation method of any catalyst is time-consuming, labor-intensive, and requires handling of materials, resulting in waste. Catalysts with improved activity are therefore desired, allowing the production of polyether polyols to use less catalyst and eliminate the need for catalyst separation.

Another feature of the DMC catalyst is that when the epoxide is added to the reactor, it does not react immediately, but there is an obvious latent state, that is, the "induction period". The "induction period" can be determined by the rapid drop in reactor pressure after the initial amount of epoxide has been added. Its length is closely related to the manufacturing process and structural composition of the DMC catalyst. The "induction period" is too long, which directly affects the cycle time of the production process and the economy of the process. Although the "induction period" can be shortened by increasing the temperature, it has an adverse effect on the performance of the final product. The "induction period" is generally several hours to more than ten hours.

In summary, although the activity of DMC catalyst is higher than that of traditional KOH, its cost is much higher. In addition, expensive and time-consuming purification methods are required due to the presence of large amounts of transition metal ions, especially cobalt and zinc, in the initial polyether product. At the same time, the longer "induction period" directly affects the production cycle and economy of the process. U.S. Patent No. 5 158 922 discloses higher activity DMC catalyst, and its consumption (by the weight of polyol product) is 250-500ppm, makes catalyst cost itself close to traditional KOH catalyst cost, but the cost of removing residual catalyst from product still hinders its large-scale commercial production.

Invention content:

The first purpose of the present invention is to develop a double metal cyanide composite catalyst with high activity, low consumption, low cost, short induction period and no need to be separated from the final product.

A second object of the present invention is to develop a process for the preparation of the above-mentioned catalyst.

The 3rd object of the present invention is to develop a kind of application method that above-mentioned catalyst is synthesized in polyether polyol, and in this method, the consumption of catalyst is few, cost is low, need not separate catalyst from product.

The first object of the present invention is achieved in this way: the double metal cyanide composite catalyst, including double metal cyanide and organic complexing agent, is characterized in that adding H ₂ SO ₄ based on the double metal cyanide molar ratio of 0.5-5.0 or sulfates;

Among them, the double metal cyanide is potassium hexacyanocobaltate, potassium hexacyanocobaltate, calcium hexacyanocobaltate, and the organic complexing agent is ethanol, isobutanol, n-butanol, tert-butanol, diethylene glycol dimethyl ether .

The sulfate is zinc sulfate, magnesium sulfate, aluminum sulfate or cerium sulfate, preferably ZnSO ₄ . The second purpose of the present invention is achieved in that compared with previous catalyst preparation methods, an important feature of the inventive method is to add a certain amount of sulfuric acid or sulfuric acid in the (3) step of the above-mentioned catalyst preparation process Salt; That is: in the solid catalyst filter cake process that slurry is separated by (2) step, contain sulfate radical ion in the slurry liquid, its consumption and water-soluble metal cyanide consumption molar ratio are: metal cyanide salt : Sulfuric acid or sulfate = 1:0.5～1:5.0. This preparation method increases the yield of the catalyst (based on the expensive metal cyanide salt), and correspondingly reduces the cost of the catalyst.

The 3rd object of the present invention is achieved like this: in the production low unsaturation polyether polyol method disclosed in U.S. Patent No. 5,158,922, add the catalyst of the present invention that is less than or equal to 25ppm, exempt post-refining treatment process.

The steps are as follows:

(1) Adding in the reactor should not be less than 400 for the starter molecular weight of difunctionality product, should be not less than the low molecular weight starter of 600 and be equivalent to the catalyst of the present invention of final product 25ppm or lower for trifunctionality product molecular weight ;

(2) Under stirring, vacuumize at a temperature of 100-120 ° C, N ₂ bubbling, replacement, about 0.5-1.0 hours, to remove possible traces of water and air;

(3) Under negative pressure or normal pressure, pre-dosing 5-10% of the total amount of alkylene oxide required to the reactor, and controlling the temperature at 105±5°C to enter the “induction period”;

(4) Carefully monitor the pressure of the reactor. When the reactor pressure suddenly drops rapidly, it indicates that the catalyst has been activated and the "induction period" ends;

(5) Continuously input the remaining alkylene oxide compound to reach the required molecular weight product; the feeding speed generally depends on the possible heat removal degree of the reactor structure; Control below 0.2MPa, for normal pressure feed should be controlled below 0.3MPa;

(6) After the feeding is completed, carry out the internal pressure reaction at 105±5°C, when the pressure is basically constant, vacuumize at 90°C to remove unreacted monomers, then cool the reaction product and discharge it to obtain the product .

Catalyst of the present invention and preparation method thereof and the application in producing polyether polyol of low degree of unsaturation, obvious advantage is as follows:

1. Due to the high activity of the catalyst of the present invention, the consumption is only 25ppm or lower based on the polyether polyol product, thus reducing the cost of the catalyst; the residue does not need to be separated from the final product, thereby reducing the cost in the production process Greatly reduced.

2. Since the "induction period" of the catalyst of the present invention is greatly shortened in the production application, the production benefit is obviously improved.

3. The preparation of the catalyst adopts the method of the prior art, and only the inexpensive sulfuric acid or its salts are added, which does not significantly increase the cost of the catalyst.

Detailed ways:

Catalyst preparation:

Example 1

Preparation of Zinc Hexacyanocobaltate/Zinc Sulfate Catalyst Improved with Different Amounts of Zinc Sulfate Using Diethylene Glycol Dimethyl Ether as Organic Ligand

Solution (1): Dissolve 15g of potassium hexacyanocobaltate in 270ml of deionized water;

Solution (2): the zinc chloride of 45g is dissolved in the deionized water of 75ml;

Solution (3): a mixture of 180 ml diethylene glycol dimethyl ether and 180 ml deionized water.

1. After mixing solution (1) and solution (2) under high-speed stirring, immediately add solution (3) to obtain a milky white suspension, continue stirring for 30 minutes, and separate the solid by filtration;

2. Divide the solid evenly into three parts A, B and C, slurry with the mixture solution containing zinc sulfate, stir for 20 minutes, and filter.

Slurry solution A: 105ml diethylene glycol dimethyl ether + 45ml deionized water + 12g zinc sulfate

   Potassium zinc hexacyanocobaltate: zinc sulfate = 1:5

Slurry solution B: 105ml diethylene glycol dimethyl ether + 45ml deionized water + 6g zinc sulfate

  Potassium zinc hexacyanocobaltate: zinc sulfate = 1: 2.47

Slurry solution C: 105ml diethylene glycol dimethyl ether + 45ml deionized water + 1.2g zinc sulfate

  Potassium zinc hexacyanocobaltate: zinc sulfate = 1:0.5

3. The resulting filter cakes A, B, and C were reslurried with 150 ml of diethylene glycol dimethyl ether, filtered, and dried to constant weight under vacuum at 60° C., and ground to obtain a powdery catalyst.

A: 9.2% B: 8.8g C: 6.0g

The catalyst yields are (g catalyst/g potassium hexacyanocobaltate × 100%)

A: 184% B: 176% C: 120%.

Example 2

Zinc hexacyanocobaltate/magnesium sulfate catalyst improved by magnesium sulfate using tert-butanol as organic complexing agent

(1) Mix the solution of potassium hexacyanocobaltate (5.0g) dissolved in 90ml of deionized water with the solution of 15g of zinc chloride dissolved in 25ml of deionized water under vigorous stirring, and immediately mix 60ml of tert-butanol and 60ml of deionized water The mixture was added to the resulting suspension, the mixture was then stirred for 30 min, and the solids were separated by filtration;

(2) The resulting filter cake was slurried in a mixed solution of 105ml tert-butanol+45ml deionized water+4g magnesium sulfate (zinc hexacyanocobaltate:magnesium sulfate=1:2.21 molar ratio) for 20min, and then filtered;

(3) Gained filter cake is re-slurried and washed in 150ml tert-butanol solution for 20min, then filtered, vacuum-dried at 60°C to constant weight, pulverized to obtain powdered catalyst D: 8.5g, and the catalyst yield is 170% catalyst/ g Potassium zinc hexacyanocobaltate.

Example 3

Prepare respectively the catalyst improved through sulfuric acid, aluminum sulfate, cerium sulfate by the method for embodiment 2

Catalyst E: zinc hexacyanocobaltate/sulfuric acid (1:1 molar ratio), yield 150%;

Catalyst F: zinc hexacyanocobaltate/aluminum sulfate (molar ratio is 1:1.5), yield 166%;

Catalyst G: zinc hexacyanocobaltate/cerium sulfate (molar ratio 1:0.8), yield 160%.

Embodiment 4 (comparative example)

Preparation of DMC Catalyst Using Diethylene Glycol Dimethyl Ether as Organic Ligand

Solution (1): Dissolve 10g of potassium hexacyanocobaltate in 180ml of deionized water;

Solution (2): the zinc chloride of 43g is dissolved in the deionized water of 50ml;

Solution (3): a mixture of 120 ml diethylene glycol dimethyl ether and 120 ml deionized water.

1. After mixing solution (1) and solution (2) under high-speed stirring, immediately add solution (3) to obtain a milky white suspension, continue stirring for 30 minutes, and separate the solid matter by filtration;

2. Slurry the solid filter cake in a mixture of 210ml diethylene glycol dimethyl ether and 90ml deionized water, stir for 20min, and filter;

3. Slurry the solid filter cake in 300ml diethylene glycol dimethyl ether again, stir for 20min, and then filter;

4. Dry the solid filter cake under vacuum at 60° C. to constant weight, and grind to obtain powdered catalyst H: 11.0 g. The catalyst yield is 110 g catalyst/g potassium zinc hexacyanocobaltate.

Preparation of polyether polyols

Example 1

Synthesis of 3000 Molecular Weight Polyoxypropylene Triol

Charge 45g polyoxypropylene triol (molecular weight is 700) initiator and double metal cyanide complex catalyst 0.0193g (catalyst content 100ppm in the final polyol) in 1 liter of band stirring reactor. The mixture was stirred and heated to 105°C, vacuumed and replaced by nitrogen bubbling to remove trace water in the trihydric alcohol starter and oxygen in the reactor, and when the reactor was filled with nitrogen to normal pressure, 12g of propylene oxide was pre-cast , Enter the "induction period" of the catalyst, the pressure of the reactor is 0.28MPa, and then pay attention to the pressure of the reactor. Catalyst activation is indicated when there is an accelerated pressure drop in the reactor - the end of the "induction period". The reaction temperature was controlled at 105° C., and the remaining 180 g of propylene oxide was gradually added at a rate of 150 g/hr. After the feeding of propylene oxide is completed, the internal pressure is reacted to a constant pressure at 105°C. Unreacted monomers are then removed from the polyol product under vacuum, and discharged after cooling. In addition to the "induction period", the activity of the catalyst can also be judged from the pressure of the reactor during the reaction. A, B, C, D, E, F, G are the catalysts of the present invention, and H is the catalyst of the comparative example. The comparison shows that the induction period of the catalyst of the present invention is short, the pressure is low, and the activity is high.

The reaction results of different catalysts are shown in Table 1 catalyst Cat(ppm) Induction period (min) Reaction pressure (MPa) Unsaturation (meq/g) The molecular weight distribution A 100 70 0.16 0.007 1.12 B 100 45 0.12 0.005 1.06 C 100 73 0.15 0.007 1.10 D. 100 90 0.18 0.009 1.08 E. 100 55 0.12 0.005 1.10 f 100 65 0.15 0.008 1.12 G 100 78 0.16 0.007 1.11 h 100 180 0.22 0.009 1.16

Example 2

Preparation of 3000 molecular weight polyoxypropylene triol using a catalyst concentration of 25 ppm

Under the reaction device and reaction condition described in embodiment 1, only the consumption of changing catalyst is 0.0048g, and reaction result is shown in Table 2. catalyst Cat(ppm) Induction period (min) Reaction pressure (MPa) Unsaturation (meq/g) The molecular weight distribution B 25 90 0.18 0.008 1.16 h 25 500 0.35 0.018 1.49

Example 3

Preparation of 4000 molecular weight polyoxypropylene diol using a catalyst concentration of 20 ppm

Under the reaction device described in embodiment 1 and reaction conditions, starting material adopts 45g molecular weight to be the polyoxypropylene diol of 400, and the consumption of catalyst B is 0.009g, and the total charging capacity of propylene oxide is 405g, and reaction result is: "Induction period": 60min Pressure during reaction: <1.8Kg/cm ²

Product unsaturation: 0.0046meq/g Molecular weight distribution: 1.11.

Claims (8)

1. a composite catalyst bimetal cyanide comprises double metal cyanide and organic complexing agent, it is characterized in that having added the H based on double metal cyanide mol ratio 0.5-5.0 ₂SO ₄Or Sulfates;

Wherein double metal cyanide is Cobalt Potassium Cyanide, potassium hexacynoferrate, hexacyanocobaltate acid calcium, and organic complexing agent is ethanol, isopropylcarbinol, propyl carbinol, the trimethyl carbinol, diethylene glycol dimethyl ether.

Vitriol is zinc sulfate, sal epsom, Tai-Ace S 150 or cerous sulfate.

2. catalyzer as claimed in claim 1 is characterized in that described organic complexing agent is the diethylene glycol dimethyl ether or the trimethyl carbinol.

3. catalyzer as claimed in claim 1 is characterized in that described double metal cyanide is a Cobalt Potassium Cyanide.

4. catalyzer as claimed in claim 1 is characterized in that described double metal cyanide is the hexacyanocobaltate acid zn cpds.

5. catalyzer as claimed in claim 2 is characterized in that described vitriol is zinc sulfate.

6. as each described Preparation of catalysts method among the claim 1-5, it is characterized in that:

(1) the thorough mixing reaction in the presence of organic complexing agent with the excess water soluble metal-salt and the metal cyanides aqueous solution generates catalyst pulp;

(2) solid catalyst in the separating slurry;

(3) aqueous mixture with the organic complexing agent that contains sulfuric acid or vitriol washs this solid catalyst, the Separation and Recovery solid catalyst;

(4) solid catalyst is with organic complexing agent pulp again, washing, separation, and drying promptly;

Described water-soluble metal salt is zinc chloride, zinc bromide, zinc acetate, zinc nitrate.

7. Preparation of catalysts method as claimed in claim 6 is characterized in that described water-soluble metal salt is a zinc chloride

8. an application rights requires the method for each Catalyst Production polyether glycol among the 1-5, it is characterized in that:

(1) adding should be not less than 400 for two functionality product starter molecules amounts in the reactor, should be not less than 600 lower molecular weight initiator and be equivalent to the finished product 25ppm or lower catalyzer of the present invention for the three-functionality-degree molecular weight of product;

(2) under whipped state, temperature 100-120 ℃ vacuumizes N ₂Bubbling, displacement, about 0.5-1.0 hour, to remove the micro-water and air that may exist;

(3) under negative pressure or atmospheric pressure state, throw the 5-10% of oxirane total requiremants in advance to reactor, controlled temperature enters " inductive phase " for 105 ± 5 ℃;

(4) carefully monitor the pressure of reactor, when reactor pressure unexpected acceleration occurs and descends, show that catalyzer is activated, " inductive phase " finishes;

(5) drop into the residual epoxide hydride compounds continuously, reach required molecular weight products; Feed rate generally depend on structure of reactor possible move hot degree; Temperature of reaction is controlled at 105-120 ℃, and reaction pressure should be controlled at below the 0.2MPa for the negative pressure fill process, should be controlled at below the 0.3MPa for the normal pressure charging;

(6) feed intake finish after, press reaction under 105 ± 5 ℃, carrying out, when the pressure substantially constant, under 90 ℃, vacuumize to remove unreacted monomer, with reaction product cooling, blowing, promptly get product then.