CN1325165C - Process for continuously preparing double metal cyanide complex catalyst - Google Patents

Abstract

The present invention discloses a technology of a continuous method for preparing bimetal cyanide (DMC) catalysts. The steps for preparing the catalyst comprise material mix reaction, filtration, wash, water replacement, concentration, functional polymer addition in a continuous process. The catalyst adopts a three-stage drying step, and pulverization is carried out in the drying process. The catalyst used for synthesizing polyether glycol has the advantages of high reactivity, short induction period and very low unsaturation degree of the prepared polyether glycol, and the technology period of the present invention is within 36 hours.

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 catalysts) 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^(VI)、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, sulfides or mixtures thereof, typically with tert-butanol (TBA) as complexing agent, are known in the art.

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 have to be removed before an active DMC catalyst is obtained. Almost all DMC catalyst patents state that metal ions, acid ions, etc. from the above ranges are suitable in their DMC catalysts, but the examples essentially conform to the following expressions:

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:

2K₃[Co(CN)₆]+3ZnCl₂→Zn₃[Co(CN)₆]₂↓+6KCl

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}→ the repeated separation of slurry is generally by filtration, centrifugation, dialysis or pouring of supernatant, and the addition of the functional polymer L after washing₂After a certain period of strong stirring, separating into 'wet cake', drying (crushing) and obtaining the active DMC catalyst.

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 catalyst of USP5158922(Arco Corp.) with L₁Essentially 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, the product is washed directly (no longer returns to slurry state), and naturally dried in air at normal temperature and normal pressure, and the product is characterized by high crystalline content (> 35%) and low activity, and is called traditional DMC catalyst. The method for preparing the DMC catalyst by USP5470813(Acro company) 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 the DMC catalyst precipitate, a mixture is formed which contains the DMC catalyst, and the DMC catalyst is then separated off 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 intimate mixing may be achieved by homogenizing, impact mixing, high shear mixing, etc. to produce an amorphous catalyst (crystalline DMC compound < 1% wt) compared to a high crystalline catalyst (crystalline DMC compound > 35% M) produced by simple stirring, and the process for synthesizing polyether polyols is carried out simultaneously with the formation of the amorphous catalystThe activity is 65% higher when the sample is 100ppm (relative to a final product, the same below), and 200% higher when the sample is 130-250 ppm. USP5482908 and USP5536883 (Arco) contain polyether (M) in which DMC catalyst is composed of TBA as complexing agent_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 the DMC catalyst 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 relatively low shear rate, which is believed to cause thickening and agglomeration of the mixture, increasing the difficulty of separation, and also reducing the activity of the resulting catalyst. Then, after separation by filtration, centrifugation, etc., a 40-70 wt% complexing agent solution (preferably containing 2-8 wt% polyether) is used for slurry^{Separation of}The method comprises the following steps of washing the slurry repeatedly for the first time with a pure complexing agent or a mixture of the complexing agent and polyether, and drying the slurry at 40-90 ℃ in vacuum (vacuum pressure of-0.09 to-0.1 MPa) to reach a constant weight, wherein the method better in the patent is to simplify the washing process, namely the slurry does not need to be returned during washing, and the slurry is directly washed to obtain the wet cake, so that the catalyst activity is better: 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) in which a DMC catalyst uses TBA as a complexing agent and contains 5-80% by weight of polyether polyol having a tertiary hydroxyl group, the reaction and washing processes are substantially the same as those of USP5482908 and USP5536883, the washing solution may contain 0.5-8% by weight of such polyether polyol, the catalyst is dried to a constant weight in vacuum (vacuum pressure-0.1 MPa, 50 ℃ C. in the example), and the catalyst activity: preparation of polyoxypropylene triol (M)_n6000), with 70g of polyoxypropylene triol (M)_n700) as starter, 100ppm of catalyst, at 105 ℃ (reaction pressure 0.07MPa), maximum rate of 29.4g PO/min, and degree of unsaturation of 0.0043mol/kg usp5891818(Arco corporation) in the preparation of DMC catalyst in view of the high shear in the process for high activity of the catalyst in the prior patentDuring mixing, a reaction kettle generates a great amount of foam, a great amount of low-activity solid exists in the foam, impurities cannot be effectively washed away, the foam cannot fully contact a complexing agent in a continuous phase, the foam is easily adhered to the wall of the kettle, the yield is reduced, the activity of the prepared catalyst is reduced, therefore, the continuous phase of a reactant is circularly sprayed into the top space of the reaction kettle, the foam is reduced, furthermore, a high-shear mixer is arranged in a circulating pipeline, the effect is better (even if the kettle is provided with strong mixing equipment), the generated particles are smaller, the activity is better, a wet cake obtained in the separation and washing process contains about 15-25 wt% of the catalyst, slurry is formed in a pure complexing agent again, the solid content is 10-30 wt%, drying is carried out after centrifugation or filtration, and the washing and solid/liquid separation in the whole production period accounts for 80%, the wet cake contains 75-85 wt% of impurity-containing mother liquor, and the solid content is increased to 50% by proper pressure filtration before washing, so that the washing times are reduced, the composition of the prepared catalyst is the same as that of USP5482908, and the polyoxypropylene trihydric alcohol (M) is prepared_n6000), 70g of polyoxypropylene triol (M)_n700) as initiator, 100ppm catalyst, reaction rate (under 0.07MPa pressure) 31.0PO/min at 105 ℃ reaction; 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 catalyst is stable in storage, when the catalyst 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 comprises forming a slurry of the catalyst in a volatile complexing agent, replacing the conventional centrifugation and pulverization processes by spraying or freeze-drying in a non-aggregating manner, and removing the excess complexing agent to directly obtain catalyst fine particles, wherein the process takes 76h (108 h is common) at a yield of 135Kg per batch, in the example, K₃[Co(CN)₆]And ZnCl₂After being mixed and reacted strongly in TBA solution, the mixture is subjected to two processes of washing, centrifugal separation/slurry re-returning and then freeze drying or spray drying to obtain the catalystAgent versus ordinary vacuum drying: freeze drying catalyst 25ppm at 130 deg.C to obtain M_n8000 pieces of polyoxypropylene diol, 0.0061 (common method 0.0067) mol/Kg of unsaturation degree, 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) g PO/min, unsaturation 0.0032 (common method 0.0034) mol/Kg. USP6204357 (Bayer) prepared DMC catalyst containing functional polymer cyclodextrin and TBA as complexing agent, in which the catalyst comprises crystalline, amorphous or partially crystalline state, in which the agitation is carried out in a high-speed homogeneous manner, and washed once, the preferred catalyst example is M_n3800 polyoxypropylene diol, as M_n1000 parts by weight of polyoxypropylene diol was used as a starter, the amount of the catalyst was 20ppm, the induction time was 197min at 105 ℃, and the unsaturation degree of the resulting polyether was 0.008 mol/kg. USP6291388 (Bayer) DMC catalyst containing a functional polymer M with TBA as complexing agent_nThe polyoxyethylene ether with the catalyst more than 500 comprises crystalline state, amorphous state and partial crystalline state, the stirring is carried out in a high-speed homogeneous mode, the washing is still one time, and in a better example, the polyoxypropylene diol (M) with the hydroxyl value of 29.8mgKOH/g is prepared_n3810), cat 15ppm, 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 catalyst, 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 ℃ polyoxypropylene diol 508, 105 ℃, cat 15ppm, induction time 80min, reaction time 335min, polyether hydroxyl value 27.4mgKOH/g, viscosity 1084mpa.s (25 ℃).

In general, in the preparation of DMC catalystsFrom 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 KCl) 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 again is adopted, and the 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 complex process of an intermittent washing method used for removing by-product impurities in the catalyst preparation process and solve the defect of unstable product performance caused by the complex 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 method for drying the catalyst.

(1) The invention provides a process for preparing a Double Metal Cyanide (DMC) complex catalyst by a continuous method aiming at the double metal cyanide complex catalyst, which comprises the following steps: firstly, mixing reaction materials in the process of preparing the DMC catalyst for reaction, filtering and washing catalyst slurry to remove by-product impurities, replacing water, concentrating, adding functional polymers and the like to form the slurry required by the integral structure of the catalyst, wherein the steps are carried out in a continuous process and are finished; secondly, the steps are carried out in a reaction kettle with a membrane separation device and two or more than two circulating pipelines, and each pipeline is internally provided with a power pump; thirdly, pressing or sucking the slurry into a filter after the steps are finished, and performing pressure filtration; fourthly, the pasty catalyst formed after the filter pressing is transferred into a vacuum drier for grading drying until the weight is constant, and the smashing is carried out in the process.

Wherein the general formula of the catalyst is as follows: 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^(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 preparation process of the DMC catalyst, the effects of reducing foam generation, easily filtering catalyst slurry, easily drying the filtered pasty catalyst and easily crushing the catalyst slurry are achieved. The activity and temperature resistance are obviously improved, the prepared polyether polyol has extremely low unsaturation degree, and the content of A in the catalyst 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)_cConcentration range 10Percent to 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. And after the reaction, a membrane device is used for washing, the membrane device is placed in a circulating pipeline, the membrane device has the pore diameter of 0.1-50 mu m, the solution with the too small pore diameter is not easy to pass through, and is easy to be blocked by the catalyst fine particles, so that the washing effect is influenced, the process time is prolonged, the activity of the catalyst is greatly reduced, the solution with the too large pore diameter can quickly pass through, but the catalyst fine particles can 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 the membrane device, the slurry circulates through the membrane tube under the pressure of 0.1-0.4 MPa, the water-soluble salt is discharged out of the membrane, and the DMC. 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)⁺Concentrations of less than 500ppm, preferably less than 300ppm, more preferably less than 200 ppm) by replacing part of the water content of the slurry with an organic complexing agent to a water content of less than 20% wt, more preferably less than 15% wt, most preferably less than 5% wt, excess water content making drying of the catalyst difficult and also affecting the catalyst crush performance; 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 the pasty catalyst with the 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 catalyst 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, drying the mixture in vacuum at 40-80 ℃, preferably 45-65 ℃ to constant weight (the catalyst 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 catalyst drying method, which avoids the problem that the catalyst activity is easy to damage when the catalyst is dried by a common process; the catalyst obtained by the method has high yield, the process consumes less time, and the activity is greatly improved compared with the activity of the common process.

The catalyst 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

EXAMPLE 1 preparation of catalyst 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), and part of water in the slurry is replaced by 200L of pure TBA for 3h, membrane separation is continued, and the slurry is concentrated to 300L (the water content of the filtrate is 10 percent by sampling). 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; secondly, drying the mixture in vacuum at 30-35 ℃ for 3 hours until the solid content is reached80 percent; 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 a catalyst A

(yield greater than 95% from theoretical). The process takes about 36 hours.

Catalyst Zn prepared in comparative example 1₃[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), followed by reslurrying in 300mL of a 10% TBA aqueous solution and adding 0.6g of a polyoxypropylene triol

(M_n3000) and 1.8gA (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 catalyst B8.0 g.

Comparative example 2

A small amount of the catalyst before drying in example 1 was taken and dried by the method of comparative example 1 to obtain catalyst 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

In the same wayExample 1, however, 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 the catalyst E8.5Kg.

Preparation of polyether polyols

70g of polyoxypropylene diol (M)_n416) and 8-30ppm of catalyst (relative to the theoretical molecular weight polyol prepared), placing the catalyst in a 2L pressure kettle, stirring, vacuumizing for 30min at 105 ℃, removing trace moisture, adding propylene oxide, keeping the pressure of the residual propylene oxide at a certain pressure after 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 ℃, obtaining 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 catalyst A (15ppm)_n＝4000)

The polyol was prepared by the above procedure at 105 ℃ under 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 catalyst B, the same conditions, the results 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 catalyst C, the same conditions, the results are as follows:

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)

With catalyst D, the conditions were as above, with the following results:

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 catalyst E, the conditions were as above, with the following results:

induction period (min): 40mia

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 for 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 (17)

1. A process for preparing a double metal cyanide complex catalyst by a continuous method is characterized in that: 1) the reaction materials in the process of preparing the DMC catalyst are mixed and reacted, the catalyst slurry is filtered and washed to remove by-product impurities, water is replaced, the catalyst slurry is concentrated, the functional polymer is added to form a catalyst integral structure, and all steps for treating the slurry are required to be carried out and finished in a continuous process; 2, the steps are carried out in a reaction kettle with a membrane separation device and two or more than two circulation pipelines, and each circulation pipeline is internally provided with a power pump; 3) pressing or sucking the slurry into a filter after the steps are finished, and performing pressure filtration; 4) the pasty catalyst formed after filter pressing is transferred into a vacuum drier for grading drying until the weight is constant, and the crushing is carried out in the process.

2. The process as claimed in claim 1, wherein the double metal cyanide complex catalyst satisfies the following 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)One or more than one of the above-mentioned (a),

M²is at least one transition metal ion selected from: fe^(III)、Co^(III)，

M³Is at least one metal ion selected from: zn^(II)、Fe^(III)、Ni^(II)One or more than one of the above-mentioned (a),

x is selected from Cl^-、SO₄ ^2-One or both of the above-mentioned (b) are,

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

t is tertiary butyl alcohol, and the mixture is,

p is polyether polyol selected from polyoxypropylene and polyoxypropylene-oxyethylene copolymer polyol, the functionality of which is 2-8, the molecular weight is 500-100000,

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

wherein R is₁、R₂、R₃、R₁Is alkyl selected from methyl, ethyl, propyl, butyl, R₁、R₂、R₃、R₁May be the same or different; the 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, and the content of P in the double metal cyanide catalyst is 0-5 wt%, z is 0.01-2.5, and the content of A in the double metal cyanide catalyst is 2-70 wt%.

3. The process as set forth in claim 1, wherein the uniform mixing of the reaction materials in the reaction vessel is carried out by circulating the reaction vessel bottom material which is pumped out by a high-speed circulating pump and placed in the upper part of the reaction vessel.

4. The process as claimed in claim 1, wherein the filtration is carried out by pumping the crude slurry after the mixing as claimed in claim 3 through a circulation line into a membrane separation apparatus to wash and separate a filtrate with an aqueous solution of t-butanol to obtain K in the wash liquid^-1And 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 process as claimed in claim 3, wherein a high-speed circulating pump is used, and the ratio of the volume of the material passing through the pump per minute to the total volume of the material is greater than or equal to 1: 2.

10. The process according to 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 vacuum drying process, and the first stage is performed at a low temperature of 0-30 ℃; the second stage is 15-60 ℃; and the third stage is 40-80 ℃.

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

15. The process as claimed in claim 2, wherein M in A is M in double metal cyanide complex catalyst²Is Co^(m)。

16. The process as claimed in claim 2, wherein M in A is M in double metal cyanide complex catalyst³Is Zn^(II)。

17. The process as claimed in claim 2, wherein X in the double metal cyanide complex catalyst is Cl^-。

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