Method for regenerating deactivation dmc catalyst based on mechanochemical method, regenerated dmc catalyst and application

Abstract

The present application belongs to the technical field of industrial catalyst recovery, and particularly relates to a regeneration method of deactivated DMC catalyst based on mechanical chemical method, regenerated DMC catalyst and application. The method comprises the following steps: pretreatment cleaning: mixing the deactivated DMC catalyst with a polar organic solvent, ultrasonic treatment, removing surface organic residues, and centrifugal drying; mechanical chemical activation: mixing the pretreated catalyst with a metal salt and a complexing agent, and performing high-energy ball milling under an inert atmosphere; post-treatment drying: washing and vacuum drying the ball-milled product to obtain the regenerated DMC catalyst. Through high-energy ball milling, the crystalline phase of the deactivated catalyst is destroyed, and at the same time, the coordination of tert-butyl alcohol and metal salt is utilized to reconstruct the high-activity amorphous structure, thereby avoiding the metal loss and structure collapse caused by traditional acid pickling or high-temperature calcination; zinc salt is dynamically supplemented during the ball milling process, and Co 2+ is oxidized to Co 3+ , so as to restore the complexing ability of the catalyst to the substrate.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of industrial catalyst recovery, and particularly relates to a method for regenerating deactivated DMC catalyst based on mechanical chemical method, regenerated DMC catalyst and application. BACKGROUND

[0002] Double metal cyanide (DMC) catalyst is a kind of heterogeneous catalyst formed by coordination of transition metal ions and cyanide ligands, such as Zn 2+ , Co 2+ , Co 3+ and [Co(CN)6] 3- . This kind of catalyst was first developed by General Electric Company in the 1960s, and was initially used for the ring-opening polymerization of propylene oxide (PO) and ethylene oxide (EO) to produce polyether polyols (PPG / PEG). Due to its unique coordination structure and the synergistic effect of surface acidic-basic sites, DMC catalysts exhibit extremely high catalytic activity and selectivity, which can precisely control the molecular weight distribution of polymers and effectively inhibit chain transfer and cyclization side reactions. Compared with traditional alkaline catalysts (such as KOH), DMC catalysts have the advantages of high activity, narrow molecular weight distribution, environmental friendliness, etc. After the reaction, there is no need for neutralization treatment, which reduces the discharge of waste salt.

[0003] At present, Zn-Co type DMC catalysts have become the mainstream catalyst for producing low unsaturation polyether polyols (used for high resilience foam, elastomer, etc.) due to their high catalytic efficiency and simplicity. In recent years, with the rise of green chemistry and sustainable chemical philosophy, the application of DMC catalysts has broken through the traditional field and has important applications in the preparation of polycarbonates by CO2 copolymerization, the polymerization of bio-based epoxides and the synthesis of high-performance special polyethers.

[0004] Although DMC catalysts have broad application prospects, their industrialization still faces two major challenges. One is the high industrial cost. The preparation of the catalyst involves noble metals such as Co and complex processes such as coprecipitation and aging, resulting in high cost. The other is the deactivation problem. In the continuous reaction process, the catalyst is easily deactivated due to the deposition of organic matter, crystallization or change of metal valence. For example, the activity of the deactivated catalyst for the polymerization of propylene oxide decreases by more than 50%, and it is difficult to recover through simple regeneration. At present, the treatment of deactivated catalysts in industry is mainly landfill or incineration, which not only causes the loss of metals such as Zn and Co, resulting in resource waste, but also produces cyanide leakage, causing environmental risks. Therefore, the development of efficient and low-cost regeneration technology to realize the recycling of DMC catalysts has become the focus of attention of the academic and industrial circles. From the perspective of technical economy, if the regeneration cost of deactivated catalysts can be controlled within 30% of the preparation cost of newly prepared catalysts, and the activity recovery rate is > 90%, the technology is expected to be widely used in the polyurethane industry, which can reduce tens of thousands of tons of heavy metal waste every year and greatly reduce production costs.

[0005] The deactivation of double metal cyanide catalysts is a complex multi-factor process involving physical, chemical and structural changes. Its deactivation is mainly due to the following aspects: 1) surface organic deposition: in the polymerization reaction of epoxide compounds (such as propylene oxide and ethylene oxide), the growth of polymer chains may not be completely controlled, resulting in the coverage of the active centers on the catalyst surface by the physical adsorption of incompletely dissociated monomers or oligomers. And with the reaction, the polymer chains on the catalyst surface are intertwined to form "dead zones", which hinder the diffusion of new monomers to the active sites, resulting in a significant decrease in reaction rate; 2) change of valence and coordination environment of metal active center: the high activity of DMC catalysts depends on the special electronic configuration of transition metals (such as Zn 2+ -Co 3+ electron pair), but Co 3+ reduction, Zn 2+ coordination imbalance and loss of cyanide ligand may occur during the reaction; 3) crystallization and phase change process: the activity of DMC catalysts is closely related to their amorphous structure, but long-term use will cause local crystallization. In addition, trace impurities (acidic substances and halide ions) in raw materials or reaction environment may cause irreversible damage to the catalyst.

[0006] Patent US048779067 discloses a method for removing double metal cyanide complex catalyst from polyether polyol, using alkali metal compounds and phosphorus compounds to precipitate the residual catalyst, and then removing it by filtration, which requires a filter aid (diatomite) to promote the recovery efficiency of the catalyst. Patent US050990756 discloses a method for removing double metal cyanide complex catalyst residues from polyol, comprising the steps of: (a) contacting the polyol containing catalyst residues with an effective amount of an oxidizing agent, resulting in the formation of insoluble residues of the residues, which are insoluble in polyol; (b) separating the insoluble residues from the polyol. Thus, the separation of DMC catalyst and polyether polyol is achieved. Although the above method can efficiently separate the catalyst from the reaction system, the recovered catalyst cannot be directly reused for catalytic reaction, resulting in a significant increase in the cost of catalytic reaction. Patent DE19809539A1 reports a method for recovering DMC catalyst with the aid of soluble polymers. The core of this method is to use DMC catalyst to react with soluble polymer acid (such as polyacrylic acid) to form insoluble agglomerates, and then separate by filtration. And the agglomerates can be regenerated into active DMC catalyst by acid solution. Patent CN116730401A discloses a method for high-selective adsorption and recovery of cobalt from DMC catalyst sludge. This method uses a "three-leaf clover" structure of high molecular resin adsorbent, combined with an optimized process flow, to achieve efficient and selective recovery of cobalt and zinc from DMC catalyst sludge with specific components. Technical and economic evaluation of the above regeneration methods shows that the biggest problem in the current DMC catalyst recovery and regeneration process is the deactivation of the catalyst. Therefore, how to reactivate the deactivated catalyst is the key problem to be solved at present. SUMMARY

[0007] In view of the deficiencies of the prior art, the purpose of the present application is to provide a method for regenerating deactivated DMC catalyst based on mechanical-chemical method, which uses mechanical-chemical regeneration technology to restore the amorphous structure of the catalyst and regenerate the active sites by controllable ball milling combined with metal salt and complexing agent. This method can reduce the treatment cost and carbon emission, promote the recycling of DMC catalyst, reduce heavy metal waste and improve the production sustainability of the polyurethane industry.

[0008] The principle of mechanical-chemical method is to induce physical and chemical changes of substances by mechanical force. Unlike traditional wet chemical method or high temperature treatment, mechanical-chemical method has three core advantages: first, it requires no or low solvent, greatly reducing waste liquid discharge; second, it is usually carried out at room temperature or under mild conditions, avoiding structural damage caused by high temperature; third, mechanical energy directly acts on chemical bonds, with high energy conversion efficiency.

[0009] The application also provides the regenerated DMC catalyst, and the activity recovery rate of the regenerated DMC catalyst is more than 90%, and the cycle number is increased to 3-5 times.

[0010] The application also provides the application thereof, and the regenerated DMC catalyst can be reused in the polymerization reaction process of the epoxide compound.

[0011] The application provides a regeneration method of the deactivated DMC catalyst based on the mechanical chemical method.

[0012] (1), pretreatment cleaning:

[0013] The deactivated DMC catalyst is mixed with a polar organic solvent, and ultrasonic treatment is carried out for 10-30 minutes, the surface organic residues are removed, and centrifugal drying is carried out.

[0014] (2) mechanical chemical activation:

[0015] The pretreated catalyst is mixed with a metal salt and a complexing agent, high-energy ball milling is carried out in an inert atmosphere, and zinc salt is additionally supplemented in batches during the ball milling process.

[0016] (3) post-treatment drying:

[0017] The ball milling product is washed and vacuum dried to obtain the regenerated DMC catalyst.

[0018] The polar organic solvent in step (1) is at least one of acetone, ethanol or methanol.

[0019] In step (2), the metal salt is a mixture of ZnCl2 and K3[Co(CN)6] with a mass ratio of (1-3):1, and the addition amount is 10%-50% of the mass of the deactivated DMC catalyst; the additional batch supplement of zinc salt is that the zinc salt is added in three times, the total amount of the zinc salt is 10% of the mass of the deactivated DMC catalyst, the additional batch supplement process is accompanied by an inert gas, and the zinc salt is ZnCl2.

[0020] In step (2), the complexing agent is tert-butyl alcohol, and the addition amount is 10%-20% of the mass of the deactivated DMC catalyst.

[0021] In step (2), the rotation speed of the high-energy ball milling is 300-800 rpm, the ball milling time is 2-6 hours, the high-energy ball milling uses a planetary ball mill, and the ball-to-material ratio is 10:1-20:1.

[0022] In step (2), the inert atmosphere is nitrogen (N2) or argon (Ar).

[0023] In step (3), the vacuum drying temperature is 60-80 DEG C, and the drying time is 4-12 hours.

[0024] The washing in step (3) is washing with deionized water and acetone, and the number of washing times is 2-4 times.

[0025] The regenerated DMC catalyst is used in the polymerization reaction of an epoxy compound, including the polymerization of propylene oxide, ethylene oxide or a mixture thereof.

[0026] The catalytic activity of the regenerated DMC catalyst in the polymerization reaction of propylene oxide or ethylene oxide is recovered to more than 90% of that of a fresh catalyst.

[0027] The recyclable regeneration is at least 3 times, and the catalytic activity after each regeneration is still maintained at more than 80% of the initial activity, wherein the activity of the first and second regeneration is more than 90%, and the activity of the third regeneration is more than 80%.

[0028] Compared with the prior art, the present application has the following beneficial effects:

[0029] (1) The present application first applies high-energy ball milling technology and metal salt / complexing agent to DMC catalyst regeneration, establishes a new mechanism of "mechanical force-chemical action" synergistic regeneration, develops a mild regeneration process without strong acid / high temperature, uses polar organic solvents (acetone / ethanol / methanol) to replace traditional hydrochloric acid / sulfuric acid cleaning, completely eliminates heavy metal wastewater pollution, and designs a ball milling system protected by inert atmosphere (N2 / Ar, O2<50ppm) to prevent oxidation of active components.

[0030] (2) The present application selectively destroys the crystalline phase of the catalyst by precisely controlling the ball milling parameters, so that the crystallinity detected by XRD is reduced from 20-30% at the time of deactivation to less than 8%, and the amorphous active structure is restored.

[0031] (3) The present application introduces tert-butyl alcohol as a complexing regulator, which forms a stable Zn 2+ / Co 3+ ternary complex with Zn 2+ - t BuOH-Co 3+ under the action of mechanical force, dynamically protects the active sites, and avoids the structure collapse problem of traditional regeneration methods.

[0032] (4) The present application realizes the synergistic effect of mechanical force cleaning and chemical activation, and simultaneously completes the removal of surface organic matter, mass comparison analysis and ICP analysis show that the removal rate of surface organic matter is >90%, and the catalyst crystal structure is repaired, and the specific surface area is recovered to more than 85% of the initial value.

[0033] (5) The present application selects K3[Co(CN)6] as an oxidation-supplementing dual-function additive, which oxidizes the deactivated Co 2+ to active Co 3+Meanwhile, the cyanide ligand is supplemented to repair coordination defects; through dynamic supplementation of ZnCl2 and mechanical chemical dispersion, the catalyst activity recovery rate of the application is significantly improved compared with traditional pickling methods; the application establishes a quantitative relationship between ball milling energy input (rotation speed 300-800 rpm) and metal valence conversion, realizes precise regulation of the electronic structure of the catalyst, and restores the substrate complexing capacity of the regenerated catalyst to more than 90% of that of the fresh catalyst.

[0034] (6) The washing process of the application improves the drying efficiency of the catalyst, which only needs 4-12 hours, saving the production cost.

[0035] (7) The regenerated DMC catalyst can be regenerated more than 3 times by the regeneration method of the application, and the activity of the regenerated catalyst is more than 90% in the first two times, and the activity of the regenerated catalyst is more than 80% in the third time, which breaks through the technical bottleneck that the regeneration times of the traditional method is not more than 2 times. The TOF value of the regenerated catalyst in the polymerization of propylene oxide reaches 2000h -1 The above completely meets the production requirements of high-end polyether polyol. BRIEF DESCRIPTION OF DRAWINGS

[0036] Figure 1 XRD patterns of the DMC catalyst before regeneration and the DMC catalyst after regeneration of Example 1;

[0037] Figure 2 XPS patterns of the DMC catalyst before regeneration and the DMC catalyst after regeneration of Example 1;

[0038] Figure 3 XRD pattern of the DMC catalyst after regeneration of Example 5;

[0039] Figure 4 XPS pattern of the DMC catalyst after regeneration of Example 5. DETAILED DESCRIPTION

[0040] The application will be further described below in combination with examples.

[0041] All raw materials used in the examples are commercially available, except for special instructions.

[0042] Example 1

[0043] The regeneration method of the deactivated DMC catalyst based on the mechanical chemical method comprises the following steps:

[0044] (1) Pretreatment cleaning:

[0045] Put 100 g of deactivated DMC catalyst into a 500 mL polytetrafluoroethylene beaker, add 300 mL of acetone (water content <0.1%), treat in a 40 kHz ultrasonic cleaner for 20 minutes (ultrasonic frequency 20 kHz, temperature 35°C), remove surface organic residues, transfer the suspension to a centrifuge tube, centrifuge at 4000 rpm for 10 minutes, discard the supernatant, and place the solid in a vacuum drying oven, dry at 80°C for 2 hours (vacuum degree -0.095 MPa);

[0046] (2) Mechanical chemical activation:

[0047] Mix 95.2 g of the pretreated catalyst with 15 g of anhydrous ZnCl2, 10 g of K3[Co(CN)6] (ACS reagent grade), and 15.76 g of tert-butyl alcohol (analytical pure), load the mixture into a 500 mL zirconium oxide ball mill jar, add zirconium oxide grinding balls with a diameter of 5 mm (ball-to-material ratio 15:1), connect the ball mill gas inlet, and replace three times with high-purity nitrogen (99.999%) to ensure that the oxygen content is less than 50 ppm,

[0048] Maintain a positive pressure of 0.05 MPa, run the planetary ball mill at 500 rpm for 4 hours, and add a total of 10 g of anhydrous ZnCl2 in three portions (3.33 g each, with an interval of 20 minutes), and continuously introduce nitrogen into the ball mill during the addition process, and monitor the temperature outside the jar (35±2°C) in real time;

[0049] (3) Post-treatment drying:

[0050] Transfer the ball-milled product to a sand core funnel, wash it once with 200 mL of deionized water, and then wash it twice with 200 mL of acetone, each time stirring for 5 minutes; after washing, place the solid in a vacuum drying oven and dry at 70°C for 10 hours (vacuum degree -0.098 MPa) to obtain the regenerated DMC catalyst.

[0051] Test results:

[0052] The color of the catalyst changes from grayish brown before regeneration to grayish white.

[0053] Caking rate after ball milling: measured by passing through a 2 mm sieve, the mass of solid that does not pass through the sieve / the mass of activated catalyst is the caking rate; the caking rate is 2.1%.

[0054] Karl Fischer moisture test: 0.13%.

[0055] Test and evaluate the effect of pretreatment cleaning to remove organic residues according to step (1):

[0056] Organic matter removal rate = the amount of organic matter tested by the mass comparison method after pretreatment cleaning / the amount of residual organic matter in the deactivated DMC catalyst based on ICP test x 100%.

[0057] The organic removal rate was 91.4%.

[0058] Wherein:

[0059] The deactivated DMC catalyst had a residual organic amount of 12.36 wt.% based on ICP testing;

[0060] The process and calculation method for testing the organic amount of the pretreated and cleaned solid by the mass comparison method:

[0061] The method is to heat and weigh in stages, gradually removing different components. After each step, cool to room temperature (in a nitrogen-filled desiccator, the cooling process is about 30 min), weigh with a high-precision balance (0.0001 mg, Balance XPR2U). Record the weight to 0.0001 mg.

[0062] Step 1: Initial weighing (total weight, including moisture + organic matter + inorganic framework). Place the empty crucible on the balance and zero. Add the sample and evenly distribute it with tweezers. Weigh to get the initial mass m0.

[0063] Step 2: Remove moisture and weakly adsorbed substances (low-temperature stage, <=100°C). Place the sample in a vacuum drying oven and heat to 100°C under a nitrogen atmosphere for 2 h (volatile water and low-boiling-point solvents). Cool and weigh to get m1. Moisture loss = m0−m1.

[0064] Step 3: Remove surface organic matter (medium-temperature stage, 150-400°C). Transfer the sample to a muffle furnace and slowly heat (5°C / min) to 350-400°C under nitrogen protection for 2 h. Cool and weigh to get m2. Organic matter loss = m1−m2.

[0065] Step 4: Verify inorganic residues (high-temperature stage, >500°C). Heat to 500-600°C for 1 h and weigh to get m3. This loss is cyanide, etc., but is not included in the organic residue, only for confirmation of total loss.

[0066] Step 5: Calculate, the formula is as follows:

[0067] The pretreated and cleaned solid was tested for the amount of organic matter (wt.%) = (m1−m2) / m0×100% using the mass comparison method.

[0068] Repeat: The deactivated DMC catalyst and the pretreated and cleaned solid sample were each repeated 3 times in parallel, and the average value was taken.

[0069] The DMC catalyst before regeneration and the DMC catalyst after regeneration were tested by XRD (Cu, Kα radiation), and the results are as follows Figure 1The XRD pattern shows that the catalyst has a typical amorphous broad peak at 2θ = 15-25°, and the surface metal valence is mainly Zn 2+ and Co 3+ The crystallinity degree decreases from 25% before regeneration to 4.8%.

[0070] The fresh DMC catalyst and the regenerated DMC catalyst were subjected to XPS test (Al, Kα source), and the results are shown in Figure 2 .

[0071] The fresh catalyst (DMC bimetallic catalyst of Changzhou Run Tian Yuan New Material Co., Ltd.) and the regenerated catalyst of Example 1 (regenerated according to the method of Example 1 after each use, cyclic test for 3 times, and the same reaction conditions for each evaluation) were respectively subjected to epoxy propane polymerization evaluation:

[0072] Polyoxypropylene glycol (PPG400, hydroxyl value 280 mgKOH / g, 10 g) and catalyst (content 50 ppm) were weighed and mixed and stirred uniformly, vacuumized at 150℃ for 1h. The propylene oxide was introduced to maintain the pressure at 0.1-0.3 MPa, and after the reaction started, continuous feeding was carried out (maintain the pressure ≤0.1 MPa, temperature 150℃). After the feeding stopped, the pressure was ≤10 Pa, the small molecules were removed, and the product was obtained by cooling and discharging.

[0073] The calculation formula of polymerization activity TOF is:

[0074] TOF = the number of moles of converted reactants / the number of moles of active sites × reaction time;

[0075] The TOF and activity recovery rate test results of the fresh catalyst and the regenerated catalyst of Example 1 are shown in Table 1 below:

[0076] Table 1 TOF and activity recovery rate test results of fresh catalyst and regenerated catalyst of Example 1

[0077]

[0078] Example 2

[0079] The said regeneration method of deactivated DMC catalyst based on mechanical chemical method, comprising the following steps:

[0080] (1) Pretreatment cleaning:

[0081] Put 100 g of deactivated DMC catalyst into a 500 mL polytetrafluoroethylene beaker, add 300 mL of anhydrous ethanol (water content <0.1%), treat in a 40 kHz ultrasonic cleaner for 20 minutes (ultrasonic frequency 20 kHz, temperature 35°C), remove surface organic residues, transfer the suspension to a centrifuge tube, centrifuge at 4000 rpm for 10 minutes, discard the supernatant, and place the solid in a vacuum drying oven, dry at 80°C for 2 hours (vacuum degree -0.095 MPa);

[0082] (2) Mechanical chemical activation:

[0083] Mix the pretreated catalyst 95.2 g with 7.5 g of anhydrous ZnCl2, 2.5 g of K3[Co(CN)6] (ACS reagent grade), and 20 g of tert-butanol (analytical pure), load the mixture into a 500 mL zirconium oxide ball mill jar, add zirconium oxide grinding balls with a diameter of 5 mm (ball-to-material ratio 10:1), connect the ball mill gas inlet, and replace three times with high-purity nitrogen (99.999%) to ensure that the oxygen content is less than 50 ppm, maintain a positive pressure of 0.05 MPa, and run in a planetary ball mill at 300 rpm for 6 hours. During the running process, add a total of 10 g of anhydrous ZnCl2 in three times (each time interval is 20 minutes, and each time 3.33 g), and continuously introduce nitrogen into the ball mill during the addition process. Monitor the temperature outside the jar (35±2°C) in real time;

[0084] (3) Post-treatment drying:

[0085] Transfer the ball-milled product to a sand core funnel, wash it once with 200 mL of deionized water, and then wash it once with 200 mL of acetone, each time stirring for 5 minutes. After washing, place the solid in a vacuum drying oven and dry at 60°C for 12 hours (vacuum degree -0.098 MPa) to obtain the regenerated DMC catalyst.

[0086] Test data: activity recovery rate 91.2%, TOF value 2098h -1 .

[0087] Example 3

[0088] The mechanical chemical method-based regeneration method of deactivated DMC catalyst comprises the following steps:

[0089] (1) Pretreatment and cleaning:

[0090] Put 100 g of deactivated DMC catalyst into a 500 mL polytetrafluoroethylene beaker, add 300 mL of methanol (water content <0.1%), treat in a 40 kHz ultrasonic cleaner for 20 minutes (ultrasonic frequency 20 kHz, temperature 35°C), remove surface organic residues, transfer the suspension to a centrifuge tube, centrifuge at 4000 rpm for 10 minutes, discard the supernatant, and place the solid in a vacuum drying oven at 80°C for 2 hours (vacuum degree -0.095 MPa);

[0091] (2) Mechanical chemical activation:

[0092] Mix the pretreated catalyst 95.2 g with 35 g of anhydrous ZnCl2, 15 g of K3[Co(CN)6] (ACS reagent grade), and 15.76 g of tert-butyl alcohol (analytical pure), load the mixture into a 500 mL zirconium oxide ball mill jar, add zirconium oxide grinding balls with a diameter of 5 mm (ball-to-material ratio 20:1), connect the ball mill gas inlet, and replace three times with high-purity nitrogen (99.999%) to ensure that the oxygen content is less than 50 ppm,

[0093] Maintain a positive pressure of 0.05 MPa, run the planetary ball mill at 800 rpm for 2 hours, and add a total of 10 g of anhydrous ZnCl2 in three portions (3.33 g each, with an interval of 20 minutes), and continuously introduce nitrogen into the ball mill during the addition process. Monitor the temperature outside the jar (35±2°C) in real time;

[0094] (3) Post-treatment drying:

[0095] Transfer the ball-milled product to a sand core funnel, wash it once with 200 mL of deionized water, and then wash it three times with 200 mL of acetone, stirring for 5 minutes each time. After washing, place the solid in a vacuum drying oven at 80°C for 4 hours (vacuum degree -0.098 MPa) to obtain the regenerated DMC catalyst.

[0096] Test data: activity recovery rate 91.8%, TOF value 2111 h -1 .

[0097] Example 4

[0098] The same as Example 1, except that the amount of tert-butyl alcohol in step (2) is reduced to 10 g. During the ball milling process, the material shows a slight agglomeration phenomenon.

[0099] Test results:

[0100] The color of the catalyst changes from grayish brown before regeneration to grayish white.

[0101] Caking rate after ball milling: measured by passing through a 2 mm sieve, the mass of solid that does not pass through the sieve / the mass of activated catalyst is the caking rate; the caking rate is 4.9%.

[0102] Propylene oxide polymerization evaluation was same as Example 1, polymerization activity TOF = 2107 h -1 , activity recovery rate 91.6%.

[0103] Example 5

[0104] Same as Example 1, the processing capacity was amplified by 10 times synchronously.

[0105] Test results:

[0106] The regenerated DMC catalyst was tested by XRD (Cu, Kα radiation), and the results are shown in Figure 3 : 2θ = 15-25° presents a typical amorphous broad peak, and the crystallinity decreases from 25% before regeneration to 5.6%.

[0107] The regenerated DMC catalyst was tested by XPS (Al, Kα source), and the results are shown in Figure 4 .

[0108] Caking rate after ball milling: measured by 2 mm screen, the mass of solid not passing through the screen / the mass of activated catalyst is the caking rate; the caking rate is 2.0%.

[0109] Karl Fischer moisture test: 0.15%.

[0110] Propylene oxide polymerization evaluation was same as Example 1, polymerization activity TOF = 2082 h -1 , activity recovery rate 90.5%.

[0111] Example 6

[0112] Same as Example 1, the difference is that the rotation speed in step (2) is 200 rpm.

[0113] Propylene oxide polymerization evaluation was same as Example 1, polymerization activity TOF = 1872 h -1 , activity recovery rate 81.4%.

[0114] Example 7

[0115] Same as Example 1, the difference is that the complexing aid is isopropanol.

[0116] Polymerization activity TOF = 1939 h -1 , activity recovery rate 84.3%.

[0117] Example 8

[0118] Same as Example 1, the difference is that in step (3), deionized water is used for washing 3 times.

[0119] The drying time needs to be extended to 24 hours.

[0120] Caking rate after ball milling: measured by 2mm sieve, the mass of solid not passing through the sieve / the mass of activated catalyst, which is the caking rate; the caking rate is 8.7%.

[0121] The state of the catalyst after passing through the sieve after washing with acetone in Example 1 is like flour, while the catalyst washed with deionized water in this example, after drying, even after passing through the sieve, its form is like sand, which will affect its solubility in the solvent.

[0122] The propylene oxide polymerization evaluation is the same as in Example 1, and the polymerization activity TOF = 1962h -1 , and the activity recovery rate is 85.3%.

[0123] Comparative Example 1

[0124] The same as in Example 1, except that:

[0125] (2) Mechanical-chemical activation:

[0126] 10g of ZnCl2supplemented in batches during ball milling is added to the metal salt mixture:

[0127] 25g of anhydrous ZnCl2, 10g of K3[Co(CN)6] (ACS reagent grade), without batch supplementation.

[0128] The propylene oxide polymerization evaluation is the same as in Example 1, and the polymerization activity TOF = 1990h -1 , and the activity recovery rate is 86.5%.

[0129] Comparative Example 2

[0130] The regeneration method of the deactivated DMC catalyst based on the acid washing method comprises the following steps:

[0131] (1) Pretreatment cleaning:

[0132] 100g of deactivated DMC catalyst is placed in a 500mL polytetrafluoroethylene beaker, 300mL of acetone (water content <0.1%) is added, and it is treated in a 40kHz ultrasonic cleaner for 20 minutes (ultrasonic frequency 20kHz, temperature 35℃), to remove surface organic residues. The suspension is transferred to a centrifuge tube, centrifuged at 4000rpm for 10 minutes, the supernatant is discarded, and the solid is placed in a vacuum drying oven, dried at 80℃ for 2 hours (vacuum degree -0.095MPa);

[0133] (2) Acid washing activation method:

[0134] The pretreated catalyst 95.2 g was mixed with 15.76 g of tert-butyl alcohol (analytical pure) and dissolved in 500 mL of 1 wt.% hydrochloric acid solution. Then 25 g of anhydrous ZnCl2 and 10 g of K3[Co(CN)6] (ACS reagent grade) were added to the above solution. The solution was replaced with high-purity nitrogen (99.999%) for three times to ensure that the oxygen content was less than 50 ppm. Then the solution was stirred (300 rpm) for 60 minutes, and the temperature outside the reactor was monitored in real time (35±2℃).

[0135] (3) Drying after treatment:

[0136] The product after acid washing was transferred to a sand core funnel and washed once with 200 mL of deionized water and twice with 200 mL of acetone, each time stirring for 5 minutes. After washing, the solid was placed in a vacuum drying oven and dried at 70℃ for 10 hours (vacuum degree -0.098 MPa) to obtain the regenerated DMC catalyst.

[0137] The TOF and activity recovery rate test results of the fresh catalyst and the regenerated catalyst of Comparative Example 2 are shown in Table 2 below:

[0138] Table 2 TOF and activity recovery rate test results of fresh catalyst and regenerated catalyst of Comparative Example 2

[0139]

[0140] The activity recovery rate of the catalyst activated by the acid washing method is much lower than that of the catalyst activated by the mechanical-chemical method described in the present application.

Claims

1. A method for regenerating a deactivated double metal cyanide (DMC) catalyst based on a mechanochemical process, characterized in that, The method comprises the following steps: (1) Pretreatment cleaning: Mixing the deactivated DMC catalyst with polar organic solvent, ultrasonic treatment, removing surface organic residues, centrifugal drying; (2) Mechanical chemical activation: Mixing the pretreated catalyst with metal salt and complexing agent, high-energy ball milling under inert atmosphere, additional batch supplementing zinc salt during ball milling; (3) Post-treatment drying: Washing and vacuum drying the ball milling product to obtain regenerated DMC catalyst; The metal salt in step (2) is a mixture of ZnCl2 and K3[Co(CN)6]; The complexing agent in step (2) is tert-butyl alcohol.

2. The regeneration method of the mechanically and chemically based inactivated double metal cyanide (DMC) catalyst according to claim 1, characterized by, The polar organic solvent in step (1) is at least one of acetone, ethanol or methanol.

3. The regeneration method of the mechanically and chemically based inactivated double metal cyanide (DMC) catalyst according to claim 1, characterized by, The addition amount of the metal salt in step (2) is 10%-50% of the mass of the deactivated DMC catalyst; the additional batch supplementing zinc salt is adding zinc salt for three times, the total amount of zinc salt is 10% of the mass of the deactivated DMC catalyst, and the additional batch supplementing process is accompanied by inert gas.

4. The regeneration method of the mechanically and chemically based inactivated double metal cyanide (DMC) catalyst according to claim 1, characterized by, The addition amount of the complexing agent in step (2) is 10%-20% of the mass of the deactivated DMC catalyst.

5. The regeneration method of the mechanically and chemically based inactivated double metal cyanide (DMC) catalyst according to claim 1, characterized by, The rotation speed of the high-energy ball milling in step (2) is 300-800 rpm, the ball milling time is 2-6 hours, the high-energy ball milling uses a planetary ball mill, and the ball-to-material ratio is 10:1-20:

1.

6. The regeneration method of the mechanically and chemically based inactivated double metal cyanide (DMC) catalyst according to claim 1, characterized by, The inert atmosphere in step (2) is nitrogen or argon.

7. The regeneration method of the mechanically and chemically based inactivated double metal cyanide (DMC) catalyst according to claim 1, characterized by, The vacuum drying temperature in step (3) is 60-80℃, and the drying time is 4-12 hours.

8. The regeneration method of the mechanically and chemically based inactivated double metal cyanide (DMC) catalyst according to claim 1, characterized by, The washing in step (3) uses water and acetone, and the washing times are 2-4 times.

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