Iron-doped dmc catalysts, methods for their preparation and use

Abstract

The present application relates to the field of catalysts, in particular to iron-doped DMC catalysts, a preparation method and application thereof.The chemical general formula of the iron-doped DMC catalyst is Zn3[Co(CN)6]2•xFeCl3•yL1•zL2•wH2O, wherein x is 1-2, y is 0.5-1.5, z is 1-2, and w is 2-4;L1 is an organic ligand amino acid;L2 is one or several of organic ligands tert-butyl alcohol, polyethylene glycol and 18-crown ether-6.By optimizing the synergistic effect of Zn-Co-Fe ternary metals, the amount of noble metal cobalt is significantly reduced, and the catalytic activity and selectivity are improved, and by using specific composite organic ligands and a preparation method, the key technical bottlenecks of the existing DMC catalysts, such as strong dependence on noble metals, long induction period, many by-products and poor industrial stability, are solved.

Description

Technical Field

[0001] This invention relates to the field of catalysts, specifically to iron-doped DMC catalysts, their preparation methods, and applications. Background Technology

[0002] Polyether polyols are a core raw material in the polyurethane industry, with a huge global market. The construction industry is the largest consumer market for polyether polyols, accounting for approximately 35% of total consumption. The automotive industry is the second largest application area, accounting for 25% of total consumption. Modern cars use an average of 15-20 kg of polyurethane materials, including high-resilience polyether for seat foam, semi-rigid polyether for dashboards, elastomers for sound insulation materials, and microporous elastomers for bumpers.

[0003] Traditional alkaline catalysts such as potassium hydroxide have been used in the production of polyether polyols for over sixty years. Although the process is mature, its inherent technical limitations are becoming increasingly prominent in today's industrial environment. These limitations manifest in several ways, including harsh reaction conditions, product quality defects, complex post-processing, significant environmental problems, poor economic efficiency, and difficulty in reaction control. Furthermore, the complexity of post-processing is another significant drawback of traditional processes. These processes not only increase production costs but also generate a certain amount of high-concentration waste liquid, and the catalyst cannot be recovered. Economic issues are equally prominent, manifested in low raw material utilization, low product yield, and irreversible loss of metallic potassium. In terms of reaction control, traditional catalyst systems suffer from technical bottlenecks such as high temperature sensitivity, susceptibility to explosive polymerization, large batch-to-batch variations, and imprecise molecular weight control. Compared to emerging bimetallic cyanide (DMC) catalysts, traditional alkaline catalysts are significantly inferior in terms of reaction efficiency (2-3 times longer), product performance, and environmental friendliness, and their cost advantage is gradually being lost. The limitations of traditional catalysts are particularly pronounced in the production of high-value-added products. The combined effect of these technological, economic, and environmental factors has not only constrained the sustainable development of the polyether polyol industry, but also spurred a strong demand for technological innovation, creating a broad market space for the research and application of novel catalytic systems such as bimetallic cyanide (DMC) catalysts.

[0004] Although Zn-Co bimetallic cyanide (DMC) catalysts have been widely used in the industrial production of polyether polyols, their inherent defects have severely restricted the further expansion of their technical economy and application scope.

[0005] First, the high cost of the precious metal cobalt constitutes a significant bottleneck. Global reserves of cobalt are limited, and its price fluctuates wildly, resulting in persistently high catalyst production costs. Second, catalytic efficiency is significantly insufficient. Traditional Zn-Co DMC catalysts generally have long induction periods, with many reactors operating at low efficiency during the start-up phase of some reactions, leading to reduced equipment utilization. Third, product quality defects are prominent. Although improvements have been made compared to alkaline catalysts, existing DMC catalysts still result in high levels of unsaturated end groups in polyether polyols, directly affecting the performance of polyurethane products. Fourth, process adaptability is poor. Existing catalysts have stringent requirements for raw material purity (propylene oxide purity >99%), and the reaction window is narrow (temperature fluctuations of ±5℃ significantly affect activity), making industrial production control difficult. More critically, the utilization rate of the metal components in existing catalysts is less than 60%, and unused cobalt salts are ultimately disposed of as hazardous waste, resulting in both resource waste and increased environmental risks. These technical deficiencies collectively limit the application of existing Zn-Co DMC catalysts in the production of high-end polyether polyols such as medical-grade and food-contact-grade products, making it difficult to meet the downstream industries' demands for upgraded material performance.

[0006] Therefore, developing new and efficient catalyst systems has become an urgent technological requirement for the sustainable development of the polyurethane industry chain. Summary of the Invention

[0007] To address the shortcomings of existing technologies, the present invention aims to provide an iron-doped DMC catalyst that overcomes key technical bottlenecks such as strong dependence on precious metals, long induction period, numerous byproducts, and poor industrial stability of existing DMC catalysts.

[0008] The present invention also provides a preparation method that is simple, easy to implement, and suitable for large-scale production.

[0009] The present invention also provides its applications.

[0010] The iron-doped DMC catalyst of the present invention has the general chemical formula Zn3[Co(CN)6]2•xFeCl3•yL1•zL2•wH2O, where x is 1-2, y is 0.5-1.5, z is 1-2, and w is 2-4.

[0011] L1 is an organic ligand amino acid;

[0012] L2 is one or more of the organic ligands tert-butanol, polyethylene glycol, and 18-crown ether-6.

[0013] Preferably, L2 is the organic ligand tert-butanol.

[0014] More preferably, the molar ratio of tert-butanol to amino acid is 1.5:1.

[0015] The preparation method of the iron-doped DMC catalyst of the present invention comprises the following steps:

[0016] (1) The ZnCl2 solution was mixed with the K3[Co(CN)6] solution to obtain the first precipitate;

[0017] (2) Add FeCl3 solution and organic ligands L1 and L2 to the first precipitate and stir to react;

[0018] (3) The catalyst is obtained by filtration, washing and drying.

[0019] In step (1), the pH is controlled at 5-7 during the mixing process.

[0020] In step (2), the reaction temperature is 40-80℃ and the reaction time is 1-4h.

[0021] The drying in step (2) is spray drying.

[0022] The iron-doped DMC catalyst described in this invention is used as a catalyst in the polymerization of propylene oxide to produce polyether polyols.

[0023] The induction period of the polymerization reaction is less than 30 minutes.

[0024] The conversion rate of propylene oxide in the polymerization reaction is above 99%.

[0025] The unsaturated end group content of the obtained polyether polyol is below 0.02 mmol / g.

[0026] The polymerization reaction is carried out at 80-120℃ and 0.1-0.3MPa.

[0027] The amount of catalyst used is 0.005-0.1% of the total mass of the reactants.

[0028] The innovations of this invention are mainly reflected in four key dimensions: catalyst system design, active center regulation, reaction mechanism optimization, and industrial preparation process. Through systematic technological innovation, a breakthrough improvement in the performance of DMC catalysts has been achieved. Regarding catalyst system design, this invention constructs a Zn-Co-Fe ternary metal synergistic catalytic system, overcoming the limitations of traditional Zn-Co bimetallic catalysts. By precisely controlling the metal ratio, the amount of precious metal cobalt used is significantly reduced. The introduction of Fe not only has cost advantages, but more importantly, through its electronic interaction with Co, it forms a unique coordination channel, enhancing the Lewis acidity of the active center, thereby reducing the adsorption energy of propylene oxide at the active site and ultimately improving catalytic activity. In terms of ligand selection and active center regulation, this invention preferentially uses a tert-butanol / amino acid composite ligand system. Studies have found that tert-butanol can effectively stabilize the active center structure through its steric hindrance effect, while the strong coordination ability of amino acids helps to regulate the metal coordination environment. This composite ligand system produces a significant synergistic effect: on the one hand, it prevents active center deactivation by forming a stable coordination structure; on the other hand, it reduces the activation energy of the reaction by regulating the transition state energy. This ligand system effectively inhibits the β-H elimination reaction pathway, keeping the content of unsaturated end groups below 0.02 mmol / g. Regarding reaction mechanism optimization, the introduction of Fe significantly accelerates the formation of active centers, shortening the induction period to less than 30 min. Furthermore, this catalytic system exhibits high selectivity for propylene oxide ring-opening and effectively suppresses side reactions such as isomerization. By controlling the reaction temperature (80-120℃) and pressure (0.1-0.3 MPa), precise molecular weight control can be achieved to meet the needs of different applications. In terms of industrial preparation processes, this invention develops a scalable and controllable co-precipitation technology. By optimizing the precipitation pH (5-7), reaction temperature (40-80℃), and aging time (1-4 h), the homogeneity of the catalyst precursor is ensured. The use of spray drying avoids catalyst aggregation, and repeated experiments have confirmed the good reproducibility of this preparation process.

[0029] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0030] (1) This invention significantly reduces the amount of precious metal cobalt by optimizing the synergistic effect of Zn-Co-Fe ternary metals, while improving catalytic activity and selectivity. By partially replacing Co with Fe, the amount of Co is greatly reduced, and the catalyst cost is significantly reduced. In the propylene oxide polymerization reaction, the induction period is <30 min and the conversion rate is over 99%, which is significantly better than the traditional Zn-CoDMC catalyst. The optimized catalyst can effectively suppress the formation of unsaturated end groups (such as allyl ether), resulting in a lower content of unsaturated end groups in the product and improving the quality of polyether polyol.

[0031] (2) The present invention uses a specific composite organic ligand and preparation method. The ligand system can effectively inhibit the β-H elimination reaction pathway and control the content of unsaturated end groups below 0.02 mmol / g. The method can ensure high catalyst stability, good batch reproducibility, and compatibility with existing industrial equipment, making it suitable for large-scale production.

[0032] (3) The present invention adopts a co-precipitation method to mix ZnCl2, K3[Co(CN)6], FeCl3 and organic ligands under specific conditions to form a highly active catalyst precursor; control the temperature (40-80℃), pH value (5-7) and aging time (1-4 h) to ensure the catalyst structure is stable and the active sites are evenly distributed; use mild washing and spray drying to avoid catalyst deactivation.

[0033] (4) The polyether polyols produced using the catalyst described in this invention have a narrower molecular weight distribution, lower unsaturated end group content and better mechanical properties, providing the polyurethane industry with a new catalytic solution that combines high performance and low cost, and has important industrial application value and broad market prospects. Attached Figure Description

[0034] Figure 1 The XRD pattern of the catalyst in Example 1 is shown below.

[0035] Figure 2 This is the XPS plot of the catalyst in Example 1. Detailed Implementation

[0036] The present invention will be further described below with reference to the embodiments.

[0037] Unless otherwise specified, all raw materials used in the examples were commercially available.

[0038] Example 1

[0039] The iron-doped DMC catalyst is prepared by the following steps:

[0040] (1) Prepare a 3L reactor, install a mechanical stirrer, thermometer and reflux condenser, and purge the air in the reactor with nitrogen to ensure that the oxygen content is less than 100ppm. Weigh 272g of anhydrous ZnCl2 and place it in a beaker, add 1.5L of deionized water deoxygenated by nitrogen, and stir magnetically for 30min until completely dissolved to obtain a colorless and transparent solution A; separately take 332g of K3[Co(CN)6] and dissolve it in 300mL of deionized water, and sonicate for 15min to obtain solution B; transfer solution A to a three-necked flask, adjust the constant temperature water bath to 25±0.5℃, start mechanical stirring at 500rpm; use a constant pressure dropping funnel to slowly add solution B at a rate of 5.0±0.2mL / min, and adjust the pH with 1M hydrochloric acid solution and 1M sodium hydroxide solution during the dropping process to maintain the pH value at 6.0±0.1 to obtain the first precipitate.

[0041] (2) Add 243g of FeCl3 (dispersed in 200mL of water), 150mL of tert-butanol (tBuOH) and 100g of proline (Pro) to the first precipitate, heat to 60±1℃, adjust the stirring speed to 800rpm, and react for 3.0h.

[0042] (3) After the reaction is completed, filter the filter cake immediately with a sand core funnel. Wash the filter cake three times with a mixture of 100 mL of tert-butanol and water (1:1 volume ratio), stirring for 5 min each time. Redisperse the filter cake in the water tank and inject it into the spray dryer for drying. Instrument parameters: Instrument model QFN-8000S, process parameters are: inlet air temperature 180℃, outlet air temperature 90℃, peristaltic pump feed rate 30 mL / min, atomizing gas (nitrogen) flow rate 40 mm (pressure gauge scale), induced draft fan air volume 100%.

[0043] The final product is a powdered catalyst.

[0044] Catalyst structure calculation method: The metal content was determined by ICP: 0.1000 g of catalyst powder was taken, 5 mL of fuming nitric acid (98 wt.%) was added, stirred at 80 °C for 2 h, cooled and filtered, and the volume was adjusted to 100 mL. The ratio Zn:Co:Fe was determined to be 3:2:1.5.

[0045] Elemental analysis was performed using standard laboratory methods, with a sample size of 5 mg. The relative contents of Pro, tBuOH, and water were calculated. Based on the test results, the catalyst molecular formula is determined as follows:

[0046] Zn3[Co(CN)6]2·1.5FeCl3·1.0Pro·1.5tBuOH·3H2O.

[0047] Test results:

[0048] The catalyst is a reddish-brown solid.

[0049] Karl Fischer moisture content: 0.27%.

[0050] The DMC catalyst prepared in Example 1 was subjected to XRD testing (Cu, Kα radiation), and the results are as follows: Figure 1 As shown: 2θ=15-25° exhibits a typical amorphous broad peak, and the surface metallic valence state is Zn. 2+ Co 3+ and Fe 3+ Mainly.

[0051] The DMC catalyst prepared in Example 1 was subjected to XPS testing (Al, Kα source), and the results are as follows: Figure 2 As shown.

[0052] The DMC catalyst prepared in Example 1 was evaluated for propylene oxide polymerization:

[0053] Weigh 10g of polypropylene glycol (PPG400, hydroxyl value 280mgKOH / g) and a catalyst with a content of 50 ppm, mix and stir thoroughly. Incubate the mixture under vacuum at 150℃ for 1 hour. Then, introduce propylene oxide, maintaining the system pressure between 0.1 and 0.3 MPa. After the reaction starts, continue feeding continuously, controlling the pressure to not exceed 0.1 MPa and maintaining the temperature at 120℃. After feeding is complete, wait for the system pressure to drop below 10 Pa, remove residual small molecules, and finally cool and discharge to obtain the product.

[0054] Formula for calculating the time-of-flight (TOF) of polymerization activity:

[0055] TOF = (Number of moles of reactants converted / Number of moles of active sites) × Reaction time;

[0056] The catalyst's TOF is 2650 h⁻¹. -1 The induction period was 9 min, the conversion rate was 99%, and the content of unsaturated end groups was 0.005 mmol / g.

[0057] Example 2

[0058] The iron-doped DMC catalyst is prepared by the following steps:

[0059] (1) Prepare a 3L reactor, install a mechanical stirrer, thermometer and reflux condenser, and purge the air in the reactor with nitrogen to ensure that the oxygen content is less than 100ppm. Weigh 272g of anhydrous ZnCl2 and place it in a beaker, add 1.5L of deionized water deoxygenated by nitrogen, and stir magnetically for 30min until completely dissolved to obtain a colorless and transparent solution A; separately take 332g of K3[Co(CN)6] and dissolve it in 300mL of deionized water, and sonicate for 15min to obtain solution B; transfer solution A to a three-necked flask, adjust the constant temperature water bath to 25±0.5℃, start mechanical stirring at 500rpm; use a constant pressure dropping funnel to slowly add solution B at a rate of 5.0±0.2mL / min, and adjust the pH with 1M hydrochloric acid solution and 1M sodium hydroxide solution during the dropping process to maintain the pH value at 6.0±0.1 to obtain the first precipitate.

[0060] (2) Add 162g of FeCl3 (dispersed in 200mL of water), 150mL of tert-butanol (tBuOH) and 100g of proline (Pro) to the first precipitate, heat to 60±1℃, adjust the stirring speed to 800rpm, and react for 3.0h.

[0061] (3) After the reaction is complete, filter the filter cake immediately with a sand core funnel. Wash the filter cake three times with a mixture of 100 mL tert-butanol and water (1:1 volume ratio), stirring for 5 min each time. Redisperse the filter cake in a water tank and inject it into a spray dryer to dry.

[0062] The final product was a powdered catalyst. Based on the test results, the molecular formula of the catalyst was determined as follows: Zn3[Co(CN)6]2·1.0FeCl3·1.0Pro·1.5tBuOH·3H2O.

[0063] Test results:

[0064] The catalyst is a reddish-brown solid.

[0065] Karl Fischer moisture content: 0.29%.

[0066] The catalyst's TOF is 2520 h. -1 The induction period was 11 min, the conversion rate was 99%, and the content of unsaturated end groups was 0.007 mmol / g.

[0067] Example 3

[0068] The iron-doped DMC catalyst is prepared by the following steps:

[0069] (1) Prepare a 3L reactor, install a mechanical stirrer, thermometer and reflux condenser, and purge the air in the reactor with nitrogen to ensure that the oxygen content is less than 100ppm. Weigh 272g of anhydrous ZnCl2 and place it in a beaker, add 1.5L of deionized water deoxygenated by nitrogen, and stir magnetically for 30min until completely dissolved to obtain a colorless and transparent solution A; separately take 332g of K3[Co(CN)6] and dissolve it in 300mL of deionized water, and sonicate for 15min to obtain solution B; transfer solution A to a three-necked flask, adjust the constant temperature water bath to 25±0.5℃, start mechanical stirring at 500rpm; use a constant pressure dropping funnel to slowly add solution B at a rate of 5.0±0.2mL / min, and adjust the pH with 1M hydrochloric acid solution and 1M sodium hydroxide solution during the dropping process to maintain the pH value at 6.0±0.1 to obtain the first precipitate.

[0070] (2) Add 324g of FeCl3 (dispersed in 200mL of water), 150mL of tert-butanol (tBuOH) and 100g of proline (Pro) to the first precipitate, heat to 60±1℃, adjust the stirring speed to 800rpm, and react for 3.0h.

[0071] (3) After the reaction is complete, filter the filter cake immediately with a sand core funnel. Wash the filter cake three times with a mixture of 100 mL tert-butanol and water (1:1 volume ratio), stirring for 5 min each time. Redisperse the filter cake in a water tank and inject it into a spray dryer to dry.

[0072] The final product was a powdered catalyst. Based on the test results, the molecular formula of the catalyst was determined as follows: Zn3[Co(CN)6]2·2.0FeCl3·1.0Pro·1.5tBuOH·3H2O.

[0073] Test results:

[0074] The catalyst is a reddish-brown solid.

[0075] Karl Fischer moisture content: 0.32%.

[0076] The catalyst's TOF is 2450 h⁻¹. -1 The induction period was 13 min, the conversion rate was 99%, and the content of unsaturated end groups was controlled at 0.009 mmol / g.

[0077] Example 4

[0078] The iron-doped DMC catalyst is prepared by the following steps:

[0079] (1) Prepare a 3L reactor, install a mechanical stirrer, thermometer and reflux condenser, and purge the air in the reactor with nitrogen to ensure that the oxygen content is less than 100ppm. Weigh 272g of anhydrous ZnCl2 and place it in a beaker, add 1.5L of deionized water deoxygenated by nitrogen, and stir magnetically for 30min until completely dissolved to obtain a colorless and transparent solution A; separately take 332g of K3[Co(CN)6] and dissolve it in 300mL of deionized water, and sonicate for 15min to obtain solution B; transfer solution A to a three-necked flask, adjust the constant temperature water bath to 25±0.5℃, start mechanical stirring at 500rpm; use a constant pressure dropping funnel to slowly add solution B at a rate of 5.0±0.2mL / min, and adjust the pH with 1M hydrochloric acid solution and 1M sodium hydroxide solution during the dropping process to maintain the pH value at 6.0±0.1 to obtain the first precipitate.

[0080] (2) Add 243g of FeCl3 (dispersed in 200mL of water), 150mL of tert-butanol (tBuOH) and 50g of proline (Pro) to the first precipitate, heat to 60±1℃, adjust the stirring speed to 800rpm, and react for 3.0h.

[0081] (3) After the reaction is complete, filter the filter cake immediately with a sand core funnel. Wash the filter cake three times with a mixture of 100 mL tert-butanol and water (1:1 volume ratio), stirring for 5 min each time. Redisperse the filter cake in a water tank and inject it into a spray dryer to dry.

[0082] The final product was a powdered catalyst. Based on the test results, the molecular formula of the catalyst was determined as follows: Zn3[Co(CN)6]2·1.5FeCl3·0.5Pro·1.5tBuOH·3H2O.

[0083] Test results:

[0084] The catalyst is a reddish-brown solid.

[0085] Karl Fischer moisture content: 0.31%.

[0086] The catalyst's TOF is 2590 h. -1 The induction period was 13 min, the conversion rate was 99%, and the content of unsaturated end groups was controlled below 0.008 mmol / g.

[0087] Example 5

[0088] The iron-doped DMC catalyst is prepared by the following steps:

[0089] (1) Prepare a 3L reactor, install a mechanical stirrer, thermometer and reflux condenser, and purge the air in the reactor with nitrogen to ensure that the oxygen content is less than 100ppm. Weigh 272g of anhydrous ZnCl2 and place it in a beaker, add 1.5L of deionized water deoxygenated by nitrogen, and stir magnetically for 30min until completely dissolved to obtain a colorless and transparent solution A; separately take 332g of K3[Co(CN)6] and dissolve it in 300mL of deionized water, and sonicate for 15min to obtain solution B; transfer solution A to a three-necked flask, adjust the constant temperature water bath to 25±0.5℃, start mechanical stirring at 500rpm; use a constant pressure dropping funnel to slowly add solution B at a rate of 5.0±0.2mL / min, and adjust the pH with 1M hydrochloric acid solution and 1M sodium hydroxide solution during the dropping process to maintain the pH value at 6.0±0.1 to obtain the first precipitate.

[0090] (2) Add 243g of FeCl3 (dispersed in 200mL of water), 150mL of tert-butanol (tBuOH) and 150g of proline (Pro) to the first precipitate, heat to 60±1℃, adjust the stirring speed to 800rpm, and react for 3.0h.

[0091] (3) After the reaction is complete, filter the filter cake immediately with a sand core funnel. Wash the filter cake three times with a mixture of 100 mL of tert-butanol and water (1:1), stirring for 5 min each time. Redisperse the filter cake in a water tank and inject it into a spray dryer to dry.

[0092] The final product was a powdered catalyst. Based on the test results, the molecular formula of the catalyst was determined as follows: Zn3[Co(CN)6]2·1.5FeCl3·1.5Pro·1.5tBuOH·3H2O.

[0093] Test results:

[0094] The catalyst is a reddish-brown solid.

[0095] Karl Fischer moisture content: 0.31%.

[0096] The catalyst's TOF is 2590 h. -1 The induction period was 13 min, the conversion rate was 99%, and the content of unsaturated end groups was 0.009 mmol / g.

[0097] Example 6

[0098] The iron-doped DMC catalyst is prepared by the following steps:

[0099] (1) Prepare a 3L reactor, install a mechanical stirrer, thermometer and reflux condenser, and purge the air in the reactor with nitrogen to ensure that the oxygen content is less than 100ppm. Weigh 272g of anhydrous ZnCl2 and place it in a beaker, add 1.5L of deionized water deoxygenated by nitrogen, and stir magnetically for 30min until completely dissolved to obtain a colorless and transparent solution A; separately take 332g of K3[Co(CN)6] and dissolve it in 300mL of deionized water, and sonicate for 15min to obtain solution B; transfer solution A to a three-necked flask, adjust the constant temperature water bath to 25±0.5℃, start mechanical stirring at 500rpm; use a constant pressure dropping funnel to slowly add solution B at a rate of 5.0±0.2mL / min, and adjust the pH with 1M hydrochloric acid solution and 1M sodium hydroxide solution during the dropping process to maintain the pH value at 6.0±0.1 to obtain the first precipitate.

[0100] (2) Add 243g of FeCl3 (dispersed in 200mL of water), 100mL of tert-butanol (tBuOH) and 100g of proline (Pro) to the first precipitate, heat to 60±1℃, adjust the stirring speed to 800rpm, and react for 3.0h.

[0101] (3) After the reaction is complete, filter the filter cake immediately with a sand core funnel. Wash the filter cake three times with a mixture of 100 mL tert-butanol and water (1:1 volume ratio), stirring for 5 min each time. Redisperse the filter cake in a water tank and inject it into a spray dryer to dry.

[0102] The final product was a powdered catalyst. Based on the test results, the molecular formula of the catalyst was determined as follows: Zn3[Co(CN)6]2·1.5FeCl3·1.0Pro·1.0tBuOH·3H2O.

[0103] Test results:

[0104] The catalyst is a reddish-brown solid.

[0105] Karl Fischer moisture content: 0.35%.

[0106] The catalyst's TOF is 2420 h⁻¹. -1 The induction period was 17 min, the conversion rate was 99%, and the content of unsaturated end groups was 0.012 mmol / g.

[0107] Example 7

[0108] The iron-doped DMC catalyst is prepared by the following steps:

[0109] (1) Prepare a 3L reactor, install a mechanical stirrer, thermometer and reflux condenser, and purge the air in the reactor with nitrogen to ensure that the oxygen content is less than 100ppm. Weigh 272g of anhydrous ZnCl2 and place it in a beaker, add 1.5L of deionized water deoxygenated by nitrogen, and stir magnetically for 30min until completely dissolved to obtain a colorless and transparent solution A; separately take 332g of K3[Co(CN)6] and dissolve it in 300mL of deionized water, and sonicate for 15min to obtain solution B; transfer solution A to a three-necked flask, adjust the constant temperature water bath to 25±0.5℃, start mechanical stirring at 500rpm; use a constant pressure dropping funnel to slowly add solution B at a rate of 5.0±0.2mL / min, and adjust the pH with 1M hydrochloric acid solution and 1M sodium hydroxide solution during the dropping process to maintain the pH value at 6.0±0.1 to obtain the first precipitate.

[0110] (2) Add 243g of FeCl3 (dispersed in 200mL of water), 200mL of tert-butanol (tBuOH) and 100g of proline (Pro) to the first precipitate, heat to 60±1℃, adjust the stirring speed to 800rpm, and react for 3.0h.

[0111] (3) After the reaction is complete, filter the filter cake immediately with a sand core funnel. Wash the filter cake three times with a mixture of 100 mL tert-butanol and water (1:1 volume ratio), stirring for 5 min each time. Redisperse the filter cake in a water tank and inject it into a spray dryer to dry.

[0112] The final product was a powdered catalyst. Based on the test results, the molecular formula of the catalyst was determined as follows: Zn3[Co(CN)6]2·1.5FeCl3·1.0Pro·2.0tBuOH·3H2O.

[0113] Test results:

[0114] The catalyst is a reddish-brown solid.

[0115] Karl Fischer moisture content: 0.37%.

[0116] The catalyst's TOF is 2258 h. -1 The induction period was 22 min, the conversion rate was 99%, and the content of unsaturated end groups was 0.015 mmol / g.

[0117] Example 8

[0118] The iron-doped DMC catalyst is prepared by the following steps:

[0119] (1) Prepare a 3L reactor, install a mechanical stirrer, thermometer and reflux condenser, and purge the air in the reactor with nitrogen to ensure that the oxygen content is less than 100ppm. Weigh 272g of anhydrous ZnCl2 and place it in a beaker, add 1.5L of deionized water deoxygenated by nitrogen, and stir magnetically for 30min until completely dissolved to obtain a colorless and transparent solution A; separately take 332g of K3[Co(CN)6] and dissolve it in 300mL of deionized water, and sonicate for 15min to obtain solution B; transfer solution A to a three-necked flask, adjust the constant temperature water bath to 25±0.5℃, start mechanical stirring at 500rpm; use a constant pressure dropping funnel to slowly add solution B at a rate of 5.0±0.2mL / min, and adjust the pH with 1M hydrochloric acid solution and 1M sodium hydroxide solution during the dropping process to maintain the pH value at 5.0±0.1 to obtain the first precipitate.

[0120] (2) Add 243g of FeCl3 (dispersed in 200mL of water), 150mL of tert-butanol (tBuOH) and 100g of proline (Pro) to the first precipitate, heat to 60±1℃, adjust the stirring speed to 800rpm, and react for 3.0h.

[0121] (3) After the reaction is complete, filter the filter cake immediately with a sand core funnel. Wash the filter cake three times with a mixture of 100 mL tert-butanol and water (1:1 volume ratio), stirring for 5 min each time. Redisperse the filter cake in a water tank and inject it into a spray dryer to dry.

[0122] The final product was a powdered catalyst. Based on the test results, the catalyst molecular formula was determined as follows: Zn3[Co(CN)6]2·1.8FeCl3·1.0Pro·1.5tBuOH·3H2O. Changes in pH affect the FeCl3 content.

[0123] Test results:

[0124] The catalyst is a reddish-brown solid.

[0125] Karl Fischer moisture content: 0.31%.

[0126] The catalyst's TOF is 2398 h. -1 The induction period was 15 min, the conversion rate was 99%, and the content of unsaturated end groups was 0.017 mmol / g.

[0127] Example 9

[0128] The iron-doped DMC catalyst is prepared by the following steps:

[0129] (1) Prepare a 3L reactor, install a mechanical stirrer, thermometer and reflux condenser, and purge the air in the reactor with nitrogen to ensure that the oxygen content is less than 100ppm. Weigh 272g of anhydrous ZnCl2 and place it in a beaker, add 1.5L of deionized water deoxygenated by nitrogen, and stir magnetically for 30min until completely dissolved to obtain a colorless and transparent solution A; separately take 332g of K3[Co(CN)6] and dissolve it in 300mL of deionized water, and sonicate for 15min to obtain solution B; transfer solution A to a three-necked flask, adjust the constant temperature water bath to 25±0.5℃, start mechanical stirring at 500rpm; use a constant pressure dropping funnel to slowly add solution B at a rate of 5.0±0.2mL / min, and adjust the pH with 1M hydrochloric acid solution and 1M sodium hydroxide solution during the dropping process to maintain the pH value at 7.0±0.1 to obtain the first precipitate.

[0130] (2) Add 243g of FeCl3 (dispersed in 200mL of water), 150mL of tert-butanol (tBuOH) and 100g of proline (Pro) to the first precipitate, heat to 60±1℃, adjust the stirring speed to 800rpm, and react for 3.0h.

[0131] (3) After the reaction is complete, filter the filter cake immediately with a sand core funnel. Wash the filter cake three times with a mixture of 100 mL tert-butanol and water (1:1 volume ratio), stirring for 5 min each time. Redisperse the filter cake in a water tank and inject it into a spray dryer to dry.

[0132] The final product was a powdered catalyst. Based on the test results, the catalyst molecular formula was determined as follows: Zn3[Co(CN)6]2·1.3FeCl3·1.0Pro·1.5tBuOH·3H2O. Changes in pH affect the FeCl3 content.

[0133] Test results:

[0134] The catalyst is a reddish-brown solid.

[0135] Karl Fischer moisture content: 0.38%.

[0136] The catalyst's TOF is 2256 h⁻¹. -1 The induction period was 25 min, the conversion rate was 99%, and the content of unsaturated end groups was 0.019 mmol / g.

[0137] Example 10

[0138] The iron-doped DMC catalyst is prepared by the following steps:

[0139] (1) Prepare a 3L reactor, install a mechanical stirrer, thermometer and reflux condenser, and purge the air in the reactor with nitrogen to ensure that the oxygen content is less than 100ppm. Weigh 272g of anhydrous ZnCl2 and place it in a beaker, add 1.5L of deionized water deoxygenated by nitrogen, and stir magnetically for 30min until completely dissolved to obtain a colorless and transparent solution A; separately take 332g of K3[Co(CN)6] and dissolve it in 300mL of deionized water, and sonicate for 15min to obtain solution B; transfer solution A to a three-necked flask, adjust the constant temperature water bath to 25±0.5℃, start mechanical stirring at 500rpm; use a constant pressure dropping funnel to slowly add solution B at a rate of 5.0±0.2mL / min, and adjust the pH with 1M hydrochloric acid solution and 1M sodium hydroxide solution during the dropping process to maintain the pH value at 6.0±0.1 to obtain the first precipitate.

[0140] (2) Add 243g of FeCl3 (dispersed in 200mL of water), 150mL of tert-butanol (tBuOH) and 100g of proline (Pro) to the first precipitate, heat to 40±1℃, adjust the stirring speed to 800rpm, and react for 3.0h.

[0141] (3) After the reaction is complete, filter the filter cake immediately with a sand core funnel. Wash the filter cake three times with a mixture of 100 mL tert-butanol and water (1:1 volume ratio), stirring for 5 min each time. Redisperse the filter cake in a water tank and inject it into a spray dryer to dry.

[0142] The final product was a powdered catalyst. Based on the test results, the catalyst molecular formula was determined as follows: Zn3[Co(CN)6]2·1.6FeCl3·1.0Pro·1.5tBuOH·3H2O. Temperature changes affect the crystallinity of the polymerization, leading to variations in the FeCl3 content.

[0143] Test results:

[0144] The catalyst is a reddish-brown solid.

[0145] Karl Fischer moisture content: 0.31%.

[0146] The catalyst's TOF is 2370 h⁻¹. -1 The induction period was 30 min, the conversion rate was 99%, and the content of unsaturated end groups was 0.02 mmol / g.

[0147] Example 11

[0148] The iron-doped DMC catalyst is prepared by the following steps:

[0149] (1) Prepare a 3L reactor, install a mechanical stirrer, thermometer and reflux condenser, and purge the air in the reactor with nitrogen to ensure that the oxygen content is less than 100ppm. Weigh 272g of anhydrous ZnCl2 and place it in a beaker, add 1.5L of deionized water deoxygenated by nitrogen, and stir magnetically for 30min until completely dissolved to obtain a colorless and transparent solution A; separately take 332g of K3[Co(CN)6] and dissolve it in 300mL of deionized water, and sonicate for 15min to obtain solution B; transfer solution A to a three-necked flask, adjust the constant temperature water bath to 25±0.5℃, start mechanical stirring at 500rpm; use a constant pressure dropping funnel to slowly add solution B at a rate of 5.0±0.2mL / min, and adjust the pH with 1M hydrochloric acid solution and 1M sodium hydroxide solution during the dropping process to maintain the pH value at 6.0±0.1 to obtain the first precipitate.

[0150] (2) Add 243g of FeCl3 (dispersed in 200mL of water), 150mL of tert-butanol (tBuOH) and 100g of proline (Pro) to the first precipitate, heat to 80±1℃, adjust the stirring speed to 800rpm, and react for 3.0h.

[0151] (3) After the reaction is complete, filter the filter cake immediately with a sand core funnel. Wash the filter cake three times with a mixture of 100 mL tert-butanol and water (1:1 volume ratio), stirring for 5 min each time. Redisperse the filter cake in a water tank and inject it into a spray dryer to dry.

[0152] The final product was a powdered catalyst. Based on the test results, the molecular formula of the catalyst was determined as follows: Zn3[Co(CN)6]2·1.4FeCl3·1.0Pro·1.5tBuOH·2H2O.

[0153] Test results:

[0154] The catalyst is a reddish-brown solid.

[0155] Karl Fischer moisture content: 0.35%.

[0156] The catalyst's TOF is 2311 h⁻¹. -1 The induction period was 26 min, the conversion rate was 99%, and the content of unsaturated end groups was 0.019 mmol / g.

[0157] Example 12

[0158] The iron-doped DMC catalyst is prepared by the following steps:

[0159] (1) Prepare a 3L reactor, install a mechanical stirrer, thermometer and reflux condenser, and purge the air in the reactor with nitrogen to ensure that the oxygen content is less than 100ppm. Weigh 272g of anhydrous ZnCl2 and place it in a beaker, add 1.5L of deionized water deoxygenated by nitrogen, and stir magnetically for 30min until completely dissolved to obtain a colorless and transparent solution A; separately take 332g of K3[Co(CN)6] and dissolve it in 300mL of deionized water, and sonicate for 15min to obtain solution B; transfer solution A to a three-necked flask, adjust the constant temperature water bath to 25±0.5℃, start mechanical stirring at 500rpm; use a constant pressure dropping funnel to slowly add solution B at a rate of 5.0±0.2mL / min, and adjust the pH with 1M hydrochloric acid solution and 1M sodium hydroxide solution during the dropping process to maintain the pH value at 6.0±0.1 to obtain the first precipitate.

[0160] (2) Add 243g of FeCl3 (dispersed in 200mL of water), 150mL of tert-butanol (tBuOH) and 100g of proline (Pro) to the first precipitate, heat to 80±1℃, adjust the stirring speed to 800rpm, and react for 1.0h.

[0161] (3) After the reaction is complete, filter the filter cake immediately with a sand core funnel. Wash the filter cake three times with a mixture of 100 mL tert-butanol and water (1:1 volume ratio), stirring for 5 min each time. Redisperse the filter cake in a water tank and inject it into a spray dryer to dry.

[0162] The final product was a powdered catalyst. Based on the test results, the catalyst molecular formula was determined as follows: Zn3[Co(CN)6]2·1.0FeCl3·0.5Pro·1.0tBuOH·2H2O. The reaction time affects the component ratio and structure.

[0163] Test results:

[0164] The catalyst is a reddish-brown solid.

[0165] Karl Fischer moisture content: 0.46%.

[0166] The catalyst's TOF is 2113 h. -1 The induction period was 23 min, the conversion rate was 99%, and the content of unsaturated end groups was 0.02 mmol / g.

[0167] Example 13

[0168] The iron-doped DMC catalyst is prepared by the following steps:

[0169] (1) Prepare a 3L reactor, install a mechanical stirrer, thermometer and reflux condenser, and purge the air in the reactor with nitrogen to ensure that the oxygen content is less than 100ppm. Weigh 272g of anhydrous ZnCl2 and place it in a beaker, add 1.5L of deionized water deoxygenated by nitrogen, and stir magnetically for 30min until completely dissolved to obtain a colorless and transparent solution A; separately take 332g of K3[Co(CN)6] and dissolve it in 300mL of deionized water, and sonicate for 15min to obtain solution B; transfer solution A to a three-necked flask, adjust the constant temperature water bath to 25±0.5℃, start mechanical stirring at 500rpm; use a constant pressure dropping funnel to slowly add solution B at a rate of 5.0±0.2mL / min, and adjust the pH with 1M hydrochloric acid solution and 1M sodium hydroxide solution during the dropping process to maintain the pH value at 6.0±0.1 to obtain the first precipitate.

[0170] (2) Add 243g of FeCl3 (dispersed in 200mL of water), 150mL of tert-butanol (tBuOH) and 100g of proline (Pro) to the first precipitate, heat to 80±1℃, adjust the stirring speed to 800rpm, and react for 4.0h.

[0171] (3) After the reaction is complete, filter the filter cake immediately with a sand core funnel. Wash the filter cake three times with a mixture of 100 mL tert-butanol and water (1:1 volume ratio), stirring for 5 min each time. Redisperse the filter cake in a water tank and inject it into a spray dryer to dry.

[0172] The final product was a powdered catalyst. Based on the test results, the molecular formula of the catalyst was determined as follows: Zn3[Co(CN)6]2·1.5FeCl3·1.0Pro·1.5tBuOH·4H2O.

[0173] Test results:

[0174] The catalyst is a reddish-brown solid.

[0175] Karl Fischer moisture content: 0.31%.

[0176] The catalyst's TOF is 2580 h⁻¹. -1 The induction period was 13 min, the conversion rate was 99%, and the content of unsaturated end groups was 0.006 mmol / g.

[0177] Example 14

[0178] Same as Example 1, except that polyethylene glycol and 18-crown ether-6 were used instead of tert-butanol. The TOF values ​​of the different catalysts prepared are shown in Table 1 below:

[0179] Table 1. TOF values ​​of different catalysts

[0180]

[0181] Example 15

[0182] Same as Example 1, except that a different amino acid is used instead of Pro.

[0183] The TOF values ​​of the different catalysts obtained are shown in Table 2 below:

[0184] Table 2. TOF values ​​of different catalysts

[0185]

[0186] Example 16

[0187] Same as Example 1, except that the pH during the catalyst synthesis process is 4.0 ± 0.1.

[0188] The final product was a powdered catalyst. Based on the test results, the catalyst molecular formula was determined as follows: Zn3[Co(CN)6]2·1.1FeCl3·1.3Pro·1.9tBuOH·3H2O. Drastic changes in pH can affect the crystallization process of the catalyst, thus affecting the content of each component.

[0189] Test results:

[0190] The catalyst is a reddish-brown solid.

[0191] Karl Fischer moisture content: 0.43%.

[0192] The catalyst's TOF is 2230 h⁻¹. -1 The induction period was 28 min, the conversion rate was 98%, and the content of unsaturated end groups was 0.02 mmol / g.

[0193] Example 17

[0194] Same as Example 1, except that the pH during the catalyst synthesis process is 8.0 ± 0.1.

[0195] The final product was a powdered catalyst. Based on the test results, the catalyst molecular formula was determined as follows: Zn3[Co(CN)6]2·2.0FeCl3·1.5Pro·1.3tBuOH·4H2O. Drastic changes in pH can affect the crystallization process of the catalyst, thus affecting the content of each component.

[0196] Test results:

[0197] The catalyst is a reddish-brown solid.

[0198] Karl Fischer moisture content: 0.49%.

[0199] The catalyst's TOF is 2380 h⁻¹. -1 The induction period was 25 min, the conversion rate was 98%, and the content of unsaturated end groups was 0.02 mmol / g.

[0200] Example 18

[0201] Same as Example 1, except that a vacuum oven is used to dry the catalyst (60 °C).

[0202] The final product was a powdered catalyst. Based on the test results, the molecular formula of the catalyst was determined as follows: Zn3[Co(CN)6]2·1.5FeCl3·1.0Pro·1.5tBuOH·3H2O.

[0203] Test results:

[0204] The catalyst is a reddish-brown solid (with relatively large particles).

[0205] Karl Fischer moisture content: 0.96%.

[0206] The catalyst's TOF is 2215 h⁻¹. -1 The induction period was 49 min, the conversion rate was 96%, and the content of unsaturated end groups was 0.01 mmol / g.

[0207] Comparative Example 1

[0208] Same as Example 1, except that Pro is not used in the synthesis process.

[0209] The final product was a powdered catalyst. Based on the test results, the molecular formula of the catalyst was determined as follows: Zn3[Co(CN)6]2·1.5FeCl3·3tBuOH·3H2O.

[0210] Test results:

[0211] The catalyst is a reddish-brown solid.

[0212] Karl Fischer moisture content: 0.53%.

[0213] The catalyst's TOF is 1127 h⁻¹. -1 The induction period was 50 min, the conversion rate was 71%, and the content of unsaturated end groups was 0.05 mmol / g.

[0214] Comparative Example 2

[0215] Same as Example 1, except that 405g of FeCl3 was used.

[0216] The final product was a powdered catalyst. Based on the test results, the molecular formula of the catalyst was determined as follows: Zn3[Co(CN)6]2·2.5FeCl3·1.2Pro·1.8tBuOH·3H2O.

[0217] Test results:

[0218] The catalyst is a reddish-brown solid.

[0219] Karl Fischer moisture content: 0.51%.

[0220] The catalyst is inactive.

[0221] Comparative Example 3

[0222] Same as Example 1, except that 30g of FeCl3 is used.

[0223] The final product was a powdered catalyst. Based on the test results, the molecular formula of the catalyst was determined as follows: Zn3[Co(CN)6]2·0.2FeCl3·1.1Pro·1.3tBuOH·3H2O.

[0224] Test results:

[0225] The catalyst is a reddish-brown solid.

[0226] Karl Fischer moisture content: 0.51%.

[0227] The catalyst's TOF is 405 h⁻¹. -1 The induction period was 38 min, the conversion rate was 75%, and the content of unsaturated end groups was 0.04 mmol / g.

Claims

1. An iron-doped DMC catalyst, characterized in that, Its general chemical formula is Zn3[Co(CN)6]2•xFeCl3•yL1•zL2•wH2O, where x is 1-2, y is 0.5-1.5, z is 1-2, and w is 2-4; L1 is the organic ligand proline; L2 is the organic ligand tert-butanol; The iron-doped DMC catalyst is prepared by the following steps: (1) The ZnCl2 solution was mixed with the K3[Co(CN)6] solution to obtain the first precipitate; (2) Add FeCl3 solution and organic ligands L1 and L2 to the first precipitate and stir to react; (3) The catalyst is obtained by filtration, washing and spray drying.

2. The iron-doped DMC catalyst according to claim 1, characterized in that, The molar ratio of tert-butanol to proline is 1.5:

1.

3. A method for preparing the iron-doped DMC catalyst according to any one of claims 1-2, characterized in that, It is prepared by the following steps: (1) The ZnCl2 solution was mixed with the K3[Co(CN)6] solution to obtain the first precipitate; (2) Add FeCl3 solution and organic ligands L1 and L2 to the first precipitate and stir to react; (3) The catalyst is obtained by filtration, washing and spray drying.

4. The method for preparing the iron-doped DMC catalyst according to claim 3, characterized in that, In step (1), the pH is controlled at 5-7 during the mixing process.

5. The method for preparing the iron-doped DMC catalyst according to claim 3, characterized in that, In step (2), the reaction temperature is 40-80℃ and the reaction time is 1-4h.

6. The application of the iron-doped DMC catalyst according to any one of claims 1-2, characterized in that, It is used as a catalyst in the polymerization of propylene oxide to produce polyether polyols.

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