CN1457928A - Process for continuously preparing double metal cyanide complex catalyst - Google Patents

Abstract

The continuous process of preparing double metal cyanide catalyst includes the steps of: mixing reaction of the materials, filtering and washing, replacement of water, concentration and addition of functional polymer. The catalyst is used in synthesis of polyether polyol and has high reaction activity and short inducing period. The prepared polyether polyol has very low unsaturation degree. The present invention has a technological period within 36 hr.

Description

Process for preparing double metal cyanide complex catalyst by continuous method

Technical Field

The present invention relates to a process for the manufacture of Double Metal Cyanide (DMC) complex catalysts

Background

Double metal cyanide complex catalysts (DMC cat) are well known for epoxide ring opening polymerization and generally have the composition:

M_a ¹[M²(CN)_b(G)_c]_d·xM³(X)_e·wH₂O·yL₁·zL₂formula I

M¹Is at least one metal ion selected from: zn^(II)、Fe^(II)、Fe^(III)、Co^(II)、Ni^(II)、Mo^(IV)、Sn^(II)、Cu^(II)、Pb^(II)、Mo^(VI)、Al^(III)、V^(IV)、V^(V)、Sr^(II)、W^(IV)、W^(VI)、Mn^(II)And Cr^(III)

M²Is at least one transition metal ion selected from: fe^(II)、Fe^(III)、Co^(II)、Co^(III)、Cr^(II)、Cr^(III)、Mn^(II)、Mn^(III)、V^(IV)、V^(V)、Ir^(III)、Rh^(III)、Ni^(II)、Ru^(II)

M³Represents M¹And/or M²

G. X is CN^-、F^-、Cl^-、Br^-、I^-、OH^-、NO₂ ^-、CO₃ ^2-、NO₃ ^-、SO₄ ^2-、CNO^-、C₂O₄ ^2-、CNS^-、

NCO^-、NCS^-And carboxylate radical RCOO^-(ii) a G. X may be the same or different

a. b, c, d, e satisfy the condition that positive and negative charges are equal

L₁Represents water-soluble heteroatom organic complexing agents (complexing agents) such as: alcohols, aldehydes, ketones, ethers, esters, amides, nitriles, sulphurization

The use of tert-butyl alcohol (TBA) as complexing agent, typically is known.

L₂Represents a functional polymer

The main reaction is formed by M¹In M as a water-soluble salt of³(X)_eIn the presence of (or at an appropriate time after) M¹May be equal to M³(X)_e]And M²Alkali metal cyanide salt reaction (L in solution)₁。L₂May be added at appropriate times) to form a precipitate of double metal cyanide and a water-soluble alkali metal salt as a by-product. The by-products and other excess water soluble salts must be removed before an active DMC cat is obtained. Almost all DMC cat patents claim that metal ions, acid ions, etc. from the above-mentioned range are suitable in their DMC cat, but the examples essentially conform to the following expression:

Zn₃[Co(CN)₆]₂·xZnCl₂·wH₂O·yL₁·zL₂formula II

Wherein L is₁Essentially organic alcohols, L₂Being functional polymers

Wherein Zn is₃[Co(CN)₆]₂Is made of ZnCl₂With alkali metal cyanides, typically K₃[Co(CN)₆]And then the reaction is carried out. The reaction formula is as follows:

reaction at L₁Optionally added with L₂By-products KCl and excess ZnCl₂By using L₁Optionally has L₂Is repeatedly washed to remove the aqueous solution, usually reactant slurry-^{Separation of}Repeated repetition of → wet cake- → slurry separation method is generally filtration, centrifugation, dialysis or supernatant pouring method, and functional polymer L is added after washing₂After a certain period of strong stirring, separating into 'wet cake', drying (crushing) and obtaining the active DMC cat.

USP4843054 (Arco) adds filter aid particles to the reaction mixture to facilitate separation, but obviously the active is diluted and the process is not practical. DMC cat of USP5158922(Arco Corp.) with L₁Substantially Glyme (dimethoxyethane) or Diglyme (diethylene glycol dimethyl ether) without L₂Emphasis is placed on M³(X)_eAdding M into the solution (at the temperature of 30-75℃)²The catalyst (cat) particles formed in this order are considered to be easily filterable (for unknown reasons) and the slurry can be immediately filtered or left to stand for less than 24 hours, avoiding excessive washing with water during washing to prevent unreacted M³(X)_e(example ZnCl)₂) Excessive washing away, affecting the activity, in the case of slurry-^{Separation of}After → wet cake, directly washed (no longer returning to slurry state), naturally dried in air at normal temperature and pressure, and they are characterized by high crystalline content (>35%) of cat and low activity, and are called traditional DMC cat. The process for preparing DMC cat by USP5470813(Arco Corp.) comprises two steps: first, a water-soluble metal salt and a water-soluble metal cyanide salt solution are intimately mixed together in a complexing agent L₁In the presence of a DMC cat precipitate,the DMC cat is then isolated and dried. The complexing agent may be included in one or both of the solutions first, or may be added immediately after the precipitate is formed, the former being preferred. The methods for achieving intimate mixing include homogenization, impact mixing, high shear mixing, etc. to obtain amorphous cat (crystalline DMC compound<1% wt), which is 65% more active at100ppm (relative to the final product, the same applies hereinafter) and 200% more active at 130-250 ppm, than the highly crystalline cat (crystalline DMC compound>35% wt) obtained by simple stirring. In USP5482908 and USP5536883 (Arco) the DMC cat uses TBA as complexing agent and contains polyether (M)_n>500) by intimately mixing a water-soluble metal salt and a water-soluble metal cyanide salt solution with a homogenizer or high-shear mixer to form a mixture containing a precipitate of DMC cat in the presence of a complexing agent (TBA), which may be initially contained in one or both of the solutions or added immediately after the precipitate has formed, preferably the former, and then a polyether (M)_n>500) is added to the resulting slurry and stirred at a lower shear rate, it is believed that excessive stirring will thicken and coagulate the mixture, increasing the difficulty of separation, and also reducing the resulting cat activity. Then, the mixture is separated by filtration, centrifugation and the like, and then is mixed with 40 to 70 wt% of complexing agent solution (preferably containing 2 to 8 wt% of complexing agent solution)t polyether) slurry^{Separation of}Repeated washing of the slurry is → wet cake- → repeated washing of the slurry for a plurality of times, the first washing can be carried out by using pure complexing agent or mixture of complexing agent and polyether, and finally the drying is carried out to balance weight in vacuum (vacuum pressure-0.09-0.1 MPa) and at 40-90 ℃, the better method of the patent is to simplify the washing process, namely the slurry is not required to return during the washing, the wet cake is directly washed, and the better cat activity: for example, production of polyoxypropylene triol (M)_n6000), 100ppm, reaction rate at 105 ℃ (under 0.07MPa pressure) 6.69kg Propylene Oxide (PO)/gCo/min, unsaturation 0.0042 mol/kg. USP5545601 (corresponding to CN application No. 96119923), USP 56327673 (Arco) uses TBA as complexing agent, contains 5-80 wt% of polyether polyol with tertiary hydroxyl group, the reaction and washing process is basically the same as that of USP5482908 and USP5536883, the washing solution can contain 0.5-8 wt% of polyether polyol, the cat is dried to balance weight in vacuum (vacuum pressure-0.1 MPa, 50 ℃ in the example), the cat activity: preparation of polyoxypropylene triol (M)_n6000), with 70g of polyoxypropylene triol (M)_n700) as initiator, cat100ppm, at 105 ℃ (reaction pressure 0.07MPa), maximum rate 29.4g PO/min, obtained polyether unsaturation 0.0043 mol/kg; USP5891818(Arco company) is prepared DMC cat, in view of the fact that in the previous patent, in order to make cat reach high activity, the reaction kettle produces a great amount of foam when high shear mixing is used in the process, a great amount of low activity solid is inevitably present in the foam, impurities contained in the foam can not be effectively washed away, the impurities can not fully contact with complexing agents in a continuous phase, and the foam is easily adhered to the kettle wall, so that the yield is reduced, the activity of the prepared cat is reduced, therefore, the continuous phase of reactants is circularly sprayed into the top space of the reaction kettle, so that the foam is reduced, furthermore, a high shear mixer arranged in a circulating pipeline has better effect (even if the kettle is provided with strong mixing equipment), the produced particles are smaller, the activity is better, a 'wet cake' obtained in the separation and washing processes contains about 15-25 wt% cat, slurry is formed in pure complexing agents again, the solid content is 10-30 wt%, drying after centrifugation or filtration, wherein washing and solid/liquid separation account for 80% of the time in the whole production cycle, and the wet cake contains 75-85 wt% of impurity-containing mother liquorThe solid content was increased to 50% by pressure filtration to reduce the number of washings, the cat composition prepared in the example was the same as USP5482908, to prepare polyoxypropylene triols (M)_n6000), 70g of polyoxypropylene triol (M)_n700) as initiator, cat100ppm, reaction rate at 105 ℃ (under pressure of 0.07MPa) 31.0 gPO/min; the processes for preparing DMC cat by USP5900384 and USP5998672(Arco company) adopt spray drying or freeze drying, directly obtain fine particles of cat without strong pulverization, the obtained cat is stable in storage, when the process is used for preparing polyether polyol, a reaction kettle has little dirt, the product has low degree of unsaturation, the molecular weight distribution is narrow, the conventional commercial scale production process takes 100 hours, 88 percent of the time is spent on separation, drying and pulverization, and the activity is reduced due to the change of the particle surface in the pulverization process. The process directly obtains cat fine particles by forming a slurry of cat in a volatile complexing agent, replacing the ordinary centrifugal separation and pulverization processes by non-aggregation means including spray or freeze drying, and removing the excessive complexing agent, wherein the process takes 76h (108 h is normally needed) when the yield per batch is 135Kg, in the example, K is used₃[Co(CN)₆]And ZnCl₂After being mixed and reacted strongly in TBA solution, after washing, centrifugal separation/slurry re-returning twice, freeze drying or spray drying, the cat obtained is compared with the ordinary vacuum drying: freeze drying cat25ppm at 130 deg.C to obtain M_n8000 pieces of polyoxypropylene diol, 0.0061 (common method 0.0067) mol/Kg of unsaturationdegree, polydispersity M_w/M_n1.19 (common method 1.23), viscosity (25 ℃)3940 (common method 4150) mpa · s; preparation of M from cat obtained by spray drying method_n6000 polyoxypropylene triol (no conditions given), reaction rate 21.7 (common method 20.0) gPO/min, unsaturation 0.0032 (common method 0.0034) mol/Kg. USP6204357(Bayer Corp.)The DMC cat obtained uses TBA as complexing agent, cyclodextrin containing functional polymer, the cat of which comprises crystalline, amorphous or partially crystalline state, in which case the stirring is carried out in a high-speed homogeneous manner and the washing is carried out once, the preferred cat is M_n3800 polyoxypropylene diol, as M_n1000 parts by weight of polyoxypropylene diol as initiator, 20ppm of cat, an induction time of 197min at 105 ℃ and a polyether unsaturation of 0.008 mol/kg. DMC cat from USP6291388 (Bayer) containing a functional polymer M, TBA as complexing agent_nMore than 500 polyoxyethylene ether, the cat of which comprises crystalline state, amorphous state and partially crystalline state, is stirred in a high-speed homogeneous mode, and the washing is still one time, in a better example, polyoxypropylene diol (M) with a hydroxyl value of 29.8mgKOH/g is prepared_n3810), cat15ppm, at 105 ℃ reaction temperature, with 50g of polyoxypropylene diol (M)_n1000) as starter, total reaction time 395min, resulting polyether unsaturation 0.011mol/kg, viscosity (25 ℃)935mpa · s.

USP6323375 (Bayer) for preparing substantially crystalline DMC cat, TBA as complexing agent, which contains a functional polymer, water 1-10 wt%, water-soluble salt (ZnCl)₂) 5-25 wt%, in the examples, a high-speed homogenization mode is adopted, the washing process is only one time, and the cat activity test obtained in one ideal example is as follows: initiator M_n1000 g of polyoxypropylene diol, the reaction temperatureis 105 ℃, the cat is 15ppm, the induction time is 80min, the reaction time is 335min, the hydroxyl value of the obtained polyether is 27.4mgKOH/g, and the viscosity is 1084mpa · s (25 ℃).

In general, DMC cat is prepared from water-soluble metal salts (e.g., ZnCl)₂) And water-soluble metal cyanides (e.g. K)₃[Co(CN)₆]) DMC is generated by reaction, and the byproduct alkali metal salt (such as KCI) generated at the same time is inactive and must be removed, and generally, a batch method of separating by slurry centrifugation, filtration and the like to form wet cakes, then forming slurry by a washing solution and then separating into wet cakes is adopted, and the batch method is repeated for a plurality of times, and meanwhile, a generally accepted method with obvious effect is not provided in a drying mode.

Disclosure of Invention

The invention aims to simplify the troublesome process of an intermittent washing method used when removing by-product impurities in the cat preparation process and solve the defect of unstable product performance caused by the complicated process; another object of the present invention is to solve the problem of the high amount of foam generated at the liquid surface by the intensive mixing of the reaction mixture in the previous patents; it is a further object of the present invention to provide a more efficient cat drying process.

(1) A process for preparing the double-metal cyanide (DMC) complex catalyst by continuous method includes such steps as ① mixing the reactants for reaction, filtering the slurry of catalyst to remove impurities, displacing water, concentrating, adding functional polymer, etc, preparing the slurry, ② in a reactor with membrane separator and two or more circulating pipelines, each of which has power pump, ③ pressing the slurry in or sucking it in filter, pressure filtering, ④ drying to constant weight, and pulverizing_a ¹[M²(CN)_b]_d·xM³(X)_c·wH₂O·yT·jP·zA

Wherein:

M¹is at least one metal ion selected from: zn^(II)、Fe^(II)、Fe^(III)、Co^(II)、Ni^(II)、Mo^(IV)、Sn^(II)、Cu^(II)、Pb^(II)、Mo^(VI)、Al^(III)、V^(IV)、V^(V)、Sr^(II)、W^(IV)、W^(VI)、Mn^(II)And Cr^(III). Preferably selected from Zn^(II)、Fe^(III)、Ni^(II)And one or more than one of them, and Zn^(II)Mainly comprises the following steps.

M²Is at least one transition metal ion selected from: fe^(II)、Fe^(III)、Co^(II)、Co^(III)、Cr^(II)、Cr^(III)、Mn^(II)、Mn^(III)、V^(IV)、V^(V)、Ir^(III)、Rh^(III)、Ru^(II)、Ni^(II)Preferably selected from Fe^(III)、Co^(III)And with Co^(III)Mainly comprises the following steps.

M³Represents M¹And&Or M²Preferably Zn, in the presence of one or more of^(II)。

X is selected from CN^-、F^-、Cl^-、Br^-、I^-、OH^-、NO₂ ^2-、CO₃ ^2-、NO₃ ^-、SO₄ ^2-、CNO-、C₂O₄ ^2-、CNS^-、NCO^-、NCS^-And carboxylate radical RCOO^-Preferably Cl^-、SO4^2-One or two of them, preferably Cl^-。

a. b, c, d, e satisfy the condition that positive and negative charges are equal

T is selected from water-soluble heteroatom organic complexing agents such as: alcohols, aldehydes, ketones, ethers, esters, amides, nitriles, sulfides or mixtures thereof, preferably tert-butanol (TBA), dimethoxyethane (Glyme), diethylene glycol dimethyl ether (digyme), tert-amyl alcohol (TPA), most preferably tert-butanol (TBA).

P is polyether polyol including polyoxypropylene and polyoxypropylene ethylene oxide copolymer polyol, the functionality of the polyether polyol is 2-8, preferably 2-3, the molecular weight is 500-10000, preferably 2000-4000,

x is 0.1-10, w is 0.1-1, y is 0.1-1, j is 0-0.15 (satisfying P content in cat 0-5 wt%), z is 0.01-2.5 (satisfying A content in cat 2-70 wt%).

A is an organosiloxane containing Si-C chains, and the molecular formula of the organosiloxane is as follows:

wherein R is₁、R₂、R₃、R₄Is selected from methyl, ethyl, propyl, butyl, R₁、R₂、R₃、R₄May be the same or different. The molecular weight is 300-6000, preferably 1000-4000.

After a proper amount of A is added in the process of preparing DMC cat, the foaming is reduced, the cat slurry is easy to filter, and the pasty cat after filtering is easy to dry and crush. The activity and temperature resistance are obviously improved, the prepared polyether polyol has extremely low unsaturation degree, and the content of A in cat is 2-70 wt%, preferably 5-50 wt%, and most preferably 10-40 wt%. The P content is limited to 0 to 5% by weight, preferably 2 to 5% by weight. (2) Process for the preparation of a catalyst

a.Water soluble salt M³(X)_cSolutions, typically with ZnCl₂The organic complexing agent contains water-soluble heteroatom organic complexing agent, preferably tertiary butanol, the concentration of the organic complexing agent ranges from 10% to 80% by weight, and P and/or A can be optionally contained. P is 0.05 to 1 wt%, A is 0.1 to 5 wt%. Water-soluble salt M³(X)_cThe concentration range is 10% -saturation.

b. Complexing alkali metal hexacyanocobaltate typically K₃[Co(CN)₆]The solution may optionally be supplemented with a water-soluble heteroatom-containing organic complexing agent, preferably TBA, in a concentration range of 10-80 wt%, K₃[Co(CN)₆]The concentration range of the solution is 1 to saturation, and K can be added optionally₃[Fe(CN)₆]Amount is K₃[Co(CN)₆]0 to 20% by weight, preferably 0 to 10% by weight of (A).

c. Alternatively, the solution in "a" is added to the solution in "b" or vice versa, M³(X)_c/K₃[Co(CN)₆]The mass ratio is 1: 1-7: 1, the reaction is carried out in a reaction kettle with two or more than two circulating pipelines, and a high-rotation-speed power pump is arranged in each pipeline and rotates at 1000-10000 rpm. The materials are circulated at high speed through a circulating pipeline during reaction to generate M_a ¹[M²(CN)_b]_dTypically Zn₃[Co(CN)₆]₂And a byproduct water-soluble potassium salt, typically KCl.

d. Removing Zn₃[Co(CN)₆]₂Other DMC compounds than DMC may alternatively be present in Zn₃[Co(CN)₆]₂Added after formation, the other DMC compounds referred to are: ni₃[Co(CN)₆]₂、Fe[Co(CN)₆]、Zn₃[Fe(CN)₆]、Fe[Fe(CN)₆]、Ni₃[Fe(CN)₆]One or more of them, the total amount of which is relative to Zn₃[Co(CN)₆]₂Is 0 to 20% by weight, preferably 0 to 10% by weight.

e. After the reaction, a membrane device is used for washing, the membrane device is placed in a circulating pipeline, the aperture of the membrane is 0.1-50 mu m, a solution with an undersized aperture is not easy to pass through, and is easy to be blocked by cat fine particles, so that the washing effect is influenced, the process time is prolonged, and the cat activity is greatly reduced; the solution with overlarge pore diameter can quickly pass through, but the cat fine particles can also partially run off, the pore diameter of the membrane is preferably 2-15 mu m, reaction byproducts and excessive water-soluble salt are continuously washed by a membrane device, the slurry is circulated through a membrane tube under the pressure of 0.1-0.4 MPa, the water-soluble salt is discharged out of the membrane, and the DMC compound still remains in the membrane. In order to prevent the membrane pores from being blocked, compressed gas is used for timed reverse pressurization, the concentration range of an organic complexing agent used in the washing process is 10-80 wt%, washing liquid optionally contains 0.1-5 wt% of A and 0.05-1 wt% of P, the A content is helpful for the homogenization of slurry, and the A and P are both added to be helpful for improving the activity of the catalyst.

f. After the washing has ended (to detect alkali metal ions, typically K, in the separation liquid)⁺The concentration is less than 500ppm, preferably 300ppmBelow, preferably below 200 ppm) by replacing part of the water in the slurry with an organic complexing agent to a water content of<20% wt, preferably<15% wt, more preferably<5% wt, too much water making drying of the catdifficult and also affecting the pulverization performance of the cat; and adding P and A, wherein the adding amount is larger than the actual content of the final catalyst and is at least 50% excessive, and the excessive part is the amount of P and A carried in the solution finally separated from the slurry. Circulating at high speed (660L/min) for 0.5-5 h, preferably 1-3 h.

g. The slurry is subjected to solid-liquid separation, centrifugal separation, filter pressing and other modes can be used, a multi-membrane tube-containing multi-layer filter is preferably adopted, and the membrane aperture is 2-15 mu m, so that the slurry filtering device has the advantages that the slurry outside the membrane can be pressurized in the filtering process, the pressure is 0.1-0.4 MPa, and the vacuum pumping in the membrane is combined, so that the filtering efficiency is high; the other advantage is that the inside of the membrane can be pressurized, so that the cat coated on the membrane tube can fall off and can not form a filtering barrier layer. Obtaining pasty cat with solid content of 10-30%, preferably 15-25%.

h. The pasty cat is dried naturally or under negative pressure at the temperature of 0-80 ℃, and is preferably dried in vacuum, a rotary vacuum dryer with a built-in blade is preferably adopted in the invention, and the advantage is that the volatilization surface of the cat is continuously increased in the drying process, so that the drying speed is accelerated. And secondly, drying the mixture in vacuum at 15-60 ℃, preferably 30-50 ℃ until the solid content is 40-95%, preferably 60-90%. And thirdly, vacuum drying at 40-80 ℃, preferably 45-65 ℃ to constant weight (cat crushing is completed in the process).

Effects of the invention

In the cat preparation process, by-product impurities are removed by a continuous process, so that the defect of unstable product performance caused by an intermittent method is overcome; the invention solves the problem that the final cat activity is reduced because of the high-efficiency circulation of the materials in the kettle and the addition of a proper amount of A, which is caused by the intense mixing method of the reaction mixture in the previous patent, the liquid surface generates a large amount of foam; the invention provides a more effective cat drying method, which avoids the problem that the cat activity is easy to damage when the cat is dried by a common process; the cat obtained by the method has high yield, less process time consumption and greatly improved activity compared with the common process.

The cat obtained by the process is used for preparing polyether polyol, the activity is high, the obtained polyether polyol has ultralow unsaturation degree, can reach the range of 0.001-0.005 mol/kg, and can be used for preparing high molecular weight products such as M_nWhen the content is 6000 to 10000, the cat is 30ppm or less, and the unsaturation degree can still satisfy the range.

The device and the drying method used in the process are suitable for preparing any catalyst meeting the formula I, and the effect is obviously improved.

Drawings

FIG. 1 is a schematic diagram of a catalyst slurry preparation process

1. Reaction: and placing the prepared reaction solution into a reaction kettle, and generating DMC and a byproduct water-soluble alkali metal salt by high-speed circulation through a circulation pipeline by using a high-speed power pump.

2. Washing: the reaction by-product and excessive water-soluble salt are continuously washed by a membrane separation device, the slurry is circulated by a pump through a membrane tube, the water-soluble salt is discharged out of the membrane, DMC is remained in the membrane, and the pressure is regularly and reversely increased by using compressed gas to prevent the membrane hole from being blocked.

3. And (3) replacement: part of the water in the slurry was replaced with an organic complexing agent in the same manner as in the washing.

4. Addition of functional polymers a and P: in the same way as the reaction, the slurry is fully mixed by high-speed circulation.

Figure 2 schematic filter-pressing of the catalyst slurry. The slurry outside the membrane can be pressurized and the inside of the membrane can be vacuumized in the filter pressing process.

FIG. 3 schematic diagram of drying of a paste catalyst

The method is a vacuum drier with the functions of refrigerating and heating the pasty catalyst for controlling the temperature so as to implement a three-stage drying method.

Detailed description of the preferred embodimentexample 1 preparation of cat Zn₃[Co(CN)₆]₂·ZnCl₂·0.5H₂In a compounding kettle of O.0.15 TBA.0.015 P.0.092A, 24kg ZnCl is added₂Dissolving in 50L TBA/90L deionized water, adding into a reaction kettle, adding into another compounding kettle, and adding 6kg K₃[Co(CN)₆]Dissolving in 90L deionized water, adding the latter solution into reaction kettle within 30min, starting high-speed circulation pump for mixing reaction, circulating for 1.5 hr, circulating in membrane, mixing TBA with deionized water to obtain 50% TBA solution (with 0.1% A), and washing with 300L for 5 hr (detecting K in eluate)⁺About 300ppm), replacing partial water in the slurry with 200L of pure TBA3h, continuing membrane separation, and concentrating to 300L of slurry (water in filtrate is sampled and measured)Content 10%). 0.6kg of polyoxypropylene triol (M) was added_n3000) and 1.8kg of A (M)_n2000) and circulating for 2 hours, transferring the slurry into a multi-membrane tube multi-layer filter, performing pressure filtration for 7-8 hours until the solid content is 16-20%, and performing vacuum drying at 5-10 ℃ for 4.5 hours until the solid content is 40% in the first step; step two, vacuum drying is carried out for 3 hours at the temperature of 30-35 ℃ until the solid content is 80%; and thirdly, drying at 45-50 ℃ for 5.5h in vacuum until the weight is constant (in the process, the cat is crushed). To obtain cat A8.5kg (byTheoretical yield greater than 95%). The process takes about 36 hours. Comparative example 1 preparation of cat Zn₃[Co(CN)₆]₂·ZnCl₂·0.5H₂O.0.15 TBA.0.015 P.0.092A used the same raw material ratio, but prepared in a batch method laboratory: in a beaker, 24g of ZnCl₂Dissolved in 50mL TBA/90mL deionized water (solution 1) in another beaker, 6g K₃[Co(CN)₆]Dissolving in 90L deionized water (solution 2), mixing TBA with deionized water to obtain 50% TBA solution (with 0.1% A), homogenizing with homogenizer for 2 hr while adding solution 1 into solution 2, separating solid from the mixture under pressure by 5 μ filter, homogenizing the solid cake in 150mL of solution 3 for 30min, filtering, and washing (detecting K in filtrate)⁺300ppm or less), then reslurried in 300mL of 10% aqueous TBA and 0.6g of polyoxypropylene triol (M) added_n3000) and 1.8g A (M)_n2000), homogenizing for 2h, press-filtering to solid content of 18%, vacuum-drying at 50 deg.C to constant weight to obtain dry powder cat B8.0 g. Comparative example 2

A small amount of cat before drying in example 1 was dried by the method of comparative example 1 to obtain cat C, comparative example 3

The procedure of example 1, but without A, is followed by an extension of the wash time to 6.5h (detection of K in the eluate)⁺About 300ppm), and finally 2.4Kg of P is added to obtain cat D8.3Kg

EXAMPLE 3 preparation of { Zn₃[Co(CN)₆]₂+0.06Ni₃[Co(CN)₆]₂+0.06Fe[Co(CN)₆]}·ZnCl₂·0.5H₂O·0.15TBA·0.015P·0.092A

Same as example 1, but ZnCl₂Is 22Kg, K₃[Co(CN)₆]5.5Kg, 0.33Kg of Ni was added at the beginning of washing at the time of membrane separation₃[Co(CN)₆]₂And 0.15Kg of Fe [ Co (CN)₆]Obtain cat E8.5Kg. Preparation of polyether polyols

70g of polyoxypropylene diol (M)_n416), cat8-30ppm (relative to the theoretical molecular weight of the polyol prepared), placing in a 2L autoclave, stirring, evacuating at 105 ℃ for 30min, removing trace water, adding propylene oxide at about 20g pressure of 0.07And (4) MPa, when the pressure is sharply reduced, adding the residual propylene oxide at a certain reaction temperature, consuming all propylene oxide in the kettle in a post-reaction period, removing volatile matters at 90 ℃ to obtain the polyol, and measuring the hydroxyl value, the double bond content, the viscosity and the like. Example A preparation of a polyoxypropylene diol (M) with cat A (15ppm)_n＝4000)

The polyol was prepared in the above procedure at 105 ℃ and 0.07MPa with the following results:

induction period (min): 55

Total reaction time (min): 300

Maximum reaction rate (g PO/min): 10

Polyol:

hydroxyl number (mg KOH/g): 29.1

Double bond content (mol/Kg): 0.0040

Viscosity (25 ℃, mpa · s): 950 comparative example A (1) with catB, conditions are as follows:

induction period (min): 160min

Total reaction time (min): 510

Maximum reaction rate (g PO/min): 5g/min

Polyol:

hydroxyl number (mg KOH/g): 30.50

Double bond content (mol/Kg): 0.0085

Viscosity (25 ℃, mpa · s): 1450 comparative example A (2) with catC, conditions are as above, with the following results:

induction period (min): 65

Total reaction time (min): 340

Maximum reaction rate (g PO/min): 9.0g/min polyol:

hydroxyl number (mg KOH/g): 29.20

Double bond content (mol/Kg): 0.0045

Viscosity (25 ℃, mpa · s): 1020 comparative example A (3)

At cat.d, conditions are as above, the results are as follows:

induction period (min): 130min

Total reaction time (min): 450

Maximum reaction rate (g PO/min): 6.0g/min

Polyol:

hydroxyl number (mg KOH/g): 30.0

Double bond content (mol/Kg): 0.0080

Viscosity (25 ℃, mpa · s): 1350

Examples

With cat E, the conditions are as above, the results are as follows:

induction period (min): 40min

Total reaction time (min): 240

Maximum reaction rate (g PO/min): 12g/min

Polyol:

hydroxyl number (mg KOH/g): 28.1

Double bond content (mol/Kg): 0.0015

Viscosity (25 ℃, mpa · s): 757 example of Process stability of the continuous Process of the invention

The same procedure as in example 1 was used to prepare different batches of catalysts, and polyoxypropylene diol (M) was prepared as in example A_n4000) the results were as follows:

batch stability comparative example of catalyst prepared in batch Process laboratory

A different batch of catalyst was prepared according to the procedure of comparative example 1, and polyoxypropylene diol (M) was prepared according to example A_n4000) the results were as follows:

Claims (14)

1. a process for preparing the complex catalyst of Double Metal Cyanide (DMC) by continuous method includes such steps as mixing the reaction materials in ① process, filtering and washing the slurry of catalyst to remove impurities, water displacement, concentrating, adding functional polymer to form the whole catalyst structure, continuous reaction, ② in a reactor with membrane separator and two or more circulating pipelines, each of which has power pump, ③ in a filter, pressure filtering, ④ in which the paste catalyst is obtained after filter pressing, vacuum drying, classifying and drying.

2. The process of claim 1, wherein the DMC complex catalyst satisfies the general formula:

M_a ¹[M²(CN)_b]_d·xM³(X)_c·wH₂O·yT·jP·zA

wherein:

M¹is at least one metal ion selected from: zn^(II)、Fe^(III)、Ni^(II)And/or one or more than one of them, and

Zn^(II)mainly comprises the following steps of;

M²is at least one transition metal ion selected from: fe^(III)、Co^(III)And with Co^(III)Mainly comprises the following steps of;

M³is at least one metal ion selected from: zn^(II)、Fe^(III)、Ni^(II)And one or more than one of them, and Zn^(II)Mainly comprises the following steps of;

x is selected from Cl^-、SO₄ ^2-One or two of them, and with Cl^-Mainly comprises the following steps of;

a. b, c and d meet the condition that positive and negative charges are equal;

t is tert-butyl alcohol (TBA);

p is polyether polyol including polyoxypropylene and polyoxypropylene ethylene oxide copolymer polyol, the functionality of the polyether polyol is 2-8, and the molecular weight of the polyether polyol is 500-10000;

a is an organosiloxane containing a Si-C chain, satisfying the following general formula:

wherein R is₁、R₂、R₃、R₄Is alkyl selected from methyl, ethyl, propyl, butyl, R₁、R₂、R₃、R₄The molecular weight of A is 300-6000

x is 0.1-10, w is 0.1-1, y is 0.1-1, j is 0-0.15 (satisfying P content in cat 0-5 wt%), z is 0.01-2.5 (satisfying A content in catalyst 2-70 wt%).

3. The process as claimed in claim 1, wherein: the materials at the bottom of the reaction kettle are pumped out by a high-speed circulating pump and are placed at the upper part of the reaction kettle to finish the reciprocating circulation.

4. The process as claimed in claim 1, wherein: the washing and filtering are that after the mixing of claim 3 is finished, the crude slurry is pumped into a membrane separation device through a circulating line to be washed and separated by tertiary butanol aqueous solution to obtain filtrate, and K in the filtrate is treated⁺And washing is completed when the concentration is 300ppm or less.

5. The process according to claim 4, wherein the concentration of the aqueous solution of tert-butanol used for washing is 10 to 99%.

6. The process as claimed in claim 4 or 5, wherein the aqueous tert-butanol solution used contains A in a concentration of 0.1 to 5%.

7. The process as set forth in claim 1, characterized in that the displacer used in the step of displacing the water is used in a concentration of t-butanol of 80% or more, and is completed when the water content of the slurry is less than 25%.

8. The process as claimed in claim 1, wherein the functional polymers P and A are added to the reactor and then mixed homogeneously after being circulated through the circulation line.

9. The processas claimed in claim 3, wherein the ratio of the volume of the material passing through the high-speed circulating pump per minute to the total volume of the material is 1: 2 or more.

10. The process as claimed in claim 1, 3 or 4, wherein the membrane separation apparatus is used in which the membrane has a pore size of 0.1 to 50 μm.

11. The process as claimed in claim 1, wherein the slurry is transferred to a filter for filtration, and the slurry is filtered to a solid content of 10-30%.

12. The process as claimed in claim 1, wherein a rotary vacuum drier with built-in blades is used in the vacuum drying process.

13. The process as claimed in claim 1 or 12, wherein a three-stage vacuum drying method is adopted in the drying process: the first-stage low temperature is 0-30 ℃; the second stage is 15-60 ℃; and the third stage is 40-80 ℃.

14. The process as claimed in claim 12 or 13, wherein in the three-stage vacuum drying method, the termination time of each stage is: the first stage is to a solid content of 25-60%; the second stage is carried out until the solid content is 40-95%; and drying the third stage to constant weight.

Images