Apparatus and Method for Microwave-Ultrasonic Co-distillation Recovery of Depleted Homogeneous Catalysts

Abstract

This invention discloses an apparatus and method for recovering exhausted homogeneous catalysts by microwave-ultrasound synergistic distillation, relating to the field of exhausted homogeneous catalyst recovery technology. The apparatus includes a multi-stage distillation reaction chamber comprising a primary distillation chamber, a secondary distillation chamber, and a tertiary distillation chamber connected sequentially from top to bottom. Each of the primary, secondary, and tertiary distillation chambers is equipped with a microwave generating module and an ultrasonic oscillation module. This microwave-ultrasound synergistic distillation apparatus and method for recovering exhausted homogeneous catalysts, through a combination of microwave-ultrasound synergistic multi-field enhancement and three-stage temperature-controlled distillation, enables stepwise orderly vaporization and precise separation of alcohols, aldehydes, and high-boiling-point organic impurities in the exhausted catalyst. It solves the problems of low separation efficiency and severe component mixing in traditional single distillation methods, resulting in more thorough removal of organic impurities and higher separation purity, laying a good foundation for subsequent rhodium catalyst purification.

Description

Technical Field

[0001] This invention relates to the field of spent homogeneous catalyst recovery technology, and particularly to an apparatus and method for recovering spent homogeneous catalysts by microwave-ultrasonic synergistic distillation. Background Technology

[0002] Rhodium-based homogeneous catalysts are widely used in petrochemical and fine chemical fields such as hydrogenation, carbonylation, and organic synthesis due to their excellent catalytic activity and selectivity. However, these catalysts gradually deactivate over long-term use due to factors such as raw material contamination, accumulation of reaction byproducts, and destruction of the active center structure. Even after deactivation, the system still retains rhodium active components with high recovery value, while simultaneously containing a large amount of reaction residues and byproduct organic impurities such as alcohols and aldehydes, forming a complex mixed system.

[0003] Current methods for recovering exhausted homogeneous catalysts mainly rely on single microwave distillation, single ultrasound-assisted distillation, or traditional extraction methods. These methods generally suffer from the technical problem of simultaneously achieving efficient separation of organic impurities and low-loss recovery of rhodium active components. Single heating or intensification methods cannot break the encapsulation of organic impurities on rhodium active components, which can easily lead to incomplete separation of organic impurities. At the same time, the oxidation, volatilization, and mechanical entrainment loss of rhodium active components cannot be effectively controlled during the distillation process, resulting in low rhodium recovery rates and insufficient purity of regenerated catalysts.

[0004] Therefore, it is necessary to propose an apparatus and method for recovering failed homogeneous catalysts by microwave-ultrasound synergistic distillation to solve the above problems. Summary of the Invention

[0005] The purpose of this invention is to provide an apparatus and method for recovering failed homogeneous catalysts by microwave-ultrasound synergistic distillation, so as to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: an apparatus for recovering exhausted homogeneous catalysts by microwave-ultrasound synergistic distillation, comprising: The multi-stage distillation reaction chamber includes a primary distillation chamber, a secondary distillation chamber, and a tertiary distillation chamber connected sequentially from top to bottom. Each of the primary, secondary, and tertiary distillation chambers is equipped with a microwave generation module and an ultrasonic oscillation module. The condensation recovery module includes a primary anti-entrapment serpentine condenser and a primary dedicated sealed collection tank connected in sequence to the primary distillation chamber; a secondary anti-entrapment serpentine condenser and a secondary dedicated sealed collection tank connected in sequence to the secondary distillation chamber; and a tertiary anti-entrapment serpentine condenser and a tertiary dedicated sealed collection tank connected in sequence to the tertiary distillation chamber. The catalyst separation and purification module is located at the outlet of the multi-stage distillation reaction chamber and includes filters, rhodium-specific filtration polyethersulfone membranes, and centrifuges arranged sequentially from the inside to the outside. The precise temperature and pressure monitoring module is installed in the primary, secondary, and tertiary distillation chambers, and includes temperature and pressure sensors.

[0007] Preferably, the microwave generating module includes a microwave radiator, the power adjustment range of which is 500-1500W, and the angle adjustment range of which is 0-360°.

[0008] Preferably, the ultrasonic oscillation module includes an ultrasonic transducer with an adjustable frequency range of 20-60 kHz and an oscillation intensity of 0.1-0.5. .

[0009] This invention also discloses a method for recovering failed homogeneous catalysts by microwave-ultrasound synergistic distillation. The apparatus for recovering failed homogeneous catalysts by microwave-ultrasound synergistic distillation described above further includes the following steps: S1. Pretreatment: The mixed exhausted homogeneous rhodium-containing catalyst and ethanol aqueous solution are stirred under closed conditions. After stirring, the mixture is filtered through a filter screen to remove solid impurities, and the mixture to be distilled is obtained. S2. Microwave-ultrasound synergistic enhancement of multi-stage distillation: The mixture to be distilled is sent into the multi-stage distillation reaction chamber, and nitrogen or argon is introduced into the chamber to replace the internal air to form an inert atmosphere. The material is subjected to three-stage temperature-controlled distillation by using microwave and ultrasound synergistic action. S3. Staged condensation and recovery: The organic gas phase components generated in each stage of the distillation chamber are condensed independently, and the liquid phase components obtained from the condensation are collected in stages. S4. Rhodium catalyst separation and purification: The residual concentrated material discharged from the multi-stage distillation reaction chamber is sequentially filtered through two stages to remove impurities, then retained and enriched by a rhodium-specific retention membrane, and finally centrifuged to obtain a high-purity rhodium-containing concentrate. S5. In-situ compounding and stabilization of rhodium active components: The rhodium-enriched material is placed in a reactor, and triphenylphosphine ligand is added to the reactor. The complexation reaction is carried out under an inert atmosphere and low temperature. After the complexation reaction is completed, the temperature is lowered and the mixture is stirred to fully stabilize the rhodium-phosphine complex.

[0010] Preferably, in S1, the mass fraction of the ethanol aqueous solution is 10% to 15%; The mass ratio of ethanol solution to degraded homogeneous rhodium-containing catalyst is 2:1 to 4:1.

[0011] Preferably, in step S2, the purity of nitrogen or argon is ≥99.99%, the gas replacement time is 10-15 min, and the gas flow rate is 0.3-0.6 L / min.

[0012] Preferably, in step S2, the temperature of the primary distillation chamber is 60–80°C, and the distillation time is 0.5–1 hour. The temperature of the secondary distillation chamber is 100–120℃, and the distillation time is 0.5–1 hour. The temperature of the three-stage distillation chamber is 200–260℃, and the distillation time is 2–4 hours; the chamber pressure is maintained at a negative pressure of 0.01–0.1 MPa.

[0013] Preferably, in step S3, the first-stage condensation temperature is 40–50°C, the second-stage condensation temperature is 60–80°C, and the third-stage condensation temperature is 160–180°C.

[0014] Preferably, in step S4, the centrifugation speed is 8000 r / min and the centrifugation time is 10-15 min.

[0015] Preferably, in step S5, the purity of the triphenylphosphine ligand is ≥99.5%, and the molar ratio of the triphenylphosphine ligand to the rhodium element in the rhodium-enriched material is controlled to be 3:1 to 6:1.

[0016] The technical effects and advantages of this invention are as follows: 1. By combining microwave-ultrasound synergistic multi-field enhancement with three-stage temperature-controlled distillation, it is possible to achieve stepwise orderly vaporization and precise separation of alcohols, aldehydes and high-boiling-point organic impurities in the depleted catalyst. This solves the problems of low separation efficiency and severe component mixing in traditional single distillation methods. Organic impurities are removed more thoroughly and the separation purity is higher, laying a good foundation for the subsequent purification of rhodium catalysts. 2. By using inert gas protection, uniform microwave heating throughout the entire process, and low-temperature negative pressure conditions, the oxidation and volatilization pathways of rhodium active components can be effectively blocked throughout the distillation process, avoiding rhodium loss caused by local overheating. At the same time, the ultrasonic intensity is controlled to prevent rhodium particles from being suspended and entrained, thus achieving comprehensive control over the three major loss pathways of rhodium: oxidation, volatilization, and mechanical entrainment, thereby improving the stability of rhodium recovery. 3. Through the design of staged independent condensation and anti-entrainment serpentine condenser tube structure, the gas phase flow rate is effectively reduced while achieving rapid and complete condensation of organic gas phase. This reduces the risk of trace amounts of rhodium active components being entrained into the condensate by the gas phase, and enables the staged collection of organic impurities and the prevention and control of rhodium loss to be completed simultaneously, thereby improving the overall resource utilization rate and economic benefits of the process. 4. By in-situ compounding and low-temperature complexation stabilization of rhodium active components, the damaged rhodium-phosphine coordination structure in the failed catalyst is repaired, and the free and particulate rhodium is converted into coordinated rhodium with high chemical stability, which is not easy to lose or volatilize. This blocks secondary loss at the structural level and improves the activity and recycling performance of the regenerated catalyst. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the device structure for recovering failed homogeneous catalysts by microwave-ultrasound synergistic distillation according to the present invention.

[0018] Figure 2 This is a flowchart of the microwave-ultrasonic synergistic distillation method for recovering failed homogeneous catalysts according to the present invention.

[0019] In the diagram: 1. Microwave generating module; 2. Microwave radiating head; 3. Ultrasonic oscillation module; 4. Primary distillation chamber; 5. Secondary distillation chamber; 6. Tertiary distillation chamber; 7. Primary anti-entrapment serpentine condenser tube; 8. Primary dedicated sealed collection tank; 9. Secondary anti-entrapment serpentine condenser tube; 10. Secondary dedicated sealed collection tank; 11. Tertiary anti-entrapment serpentine condenser tube; 12. Tertiary dedicated sealed collection tank. Detailed Implementation

[0020] This invention provides, for example Figure 1 The device shown for recovering exhausted homogeneous catalysts by microwave-ultrasonic synergistic distillation includes a multi-stage distillation reaction chamber, a condensation recovery module, a catalyst separation and purification module, and a precise temperature and pressure monitoring module. The modules work together to form an integrated recovery system that can be adapted to the entire process requirements of microwave-ultrasonic synergistic enhancement, staged temperature-controlled distillation, inert atmosphere protection, and precise retention of rhodium components.

[0021] The multi-stage distillation reaction chamber includes a first-stage distillation chamber 4, a second-stage distillation chamber 5, and a third-stage distillation chamber 6 connected sequentially from top to bottom. Each of the first-stage distillation chamber 4, the second-stage distillation chamber 5, and the third-stage distillation chamber 6 is equipped with a microwave generation module 1 and an ultrasonic oscillation module 3, which enables independent multi-field enhancement of the three chambers and meets the requirements for stepwise vaporization and separation of organic impurities with different boiling points.

[0022] The microwave generating module 1 includes a microwave radiator 2, the power of which is adjustable from 500 to 1500W and the angle of which is adjustable from 0 to 360°. This allows for uniform heating of the material over its entire surface, preventing local overheating that could cause oxidation and volatilization of the rhodium active components.

[0023] The ultrasonic oscillation module 3 includes an ultrasonic transducer with an adjustable frequency range of 20-60kHz and an oscillation intensity of 0.1-0.5. While enhancing mass transfer and impurity vaporization, it avoids the suspension and entrainment of rhodium particles caused by high-intensity cavitation.

[0024] The condensation recovery module includes a primary anti-entrapment serpentine condenser 7 and a primary dedicated sealed collection tank 8 connected in sequence to the primary distillation chamber 4; a secondary anti-entrapment serpentine condenser 9 and a secondary dedicated sealed collection tank 10 connected in sequence to the secondary distillation chamber 5; and a tertiary anti-entrapment serpentine condenser 11 and a tertiary dedicated sealed collection tank 12 connected in sequence to the tertiary distillation chamber 6. This enables independent condensation and graded collection of each stage of gas phase components, preventing cross-mixing of organic components and loss of rhodium particles.

[0025] The catalyst separation and purification module is located at the outlet of the multi-stage distillation reaction chamber, i.e., at the bottom of the three-stage distillation chamber 6. Specifically, it includes a filter, a rhodium-specific retention polyethersulfone membrane, and a centrifuge distributed sequentially from the inside to the outside. It can complete the step-by-step removal of impurities, directional retention of rhodium components, and solid-liquid separation to obtain high-purity rhodium-containing concentrates.

[0026] The temperature and pressure precision monitoring module is set up in three sets, which are respectively set on the first-stage distillation chamber 4, the second-stage distillation chamber 5 and the third-stage distillation chamber 6. It includes temperature sensors and pressure sensors, which collect and stably control the temperature and pressure of each chamber in real time to ensure that the distillation conditions are below the volatilization threshold of the rhodium active component.

[0027] This invention also discloses, as follows Figure 2 The microwave-ultrasonic synergistic distillation method for recovering failed homogeneous catalysts, as shown, employs a five-stage continuous process: pretreatment, multi-stage microwave-ultrasonic synergistic distillation, staged condensation recovery, catalyst separation and purification, in-situ compounding of rhodium active components, and anti-loss stabilization. This achieves stepwise separation of organic impurities and low-loss recovery of rhodium active components, effectively controlling the three major loss pathways of rhodium: oxidation, volatilization, and mechanical entrainment. It is suitable for the resource recycling of failed homogeneous rhodium-containing catalysts in the petrochemical and fine chemical industries. The specific operation steps are as follows: S1. Pretreatment of Defective Homogeneous Catalyst Take the failed homogeneous rhodium-containing catalyst to be recovered and add it to the pretreatment reactor. Add an ethanol aqueous solution with a mass fraction of 10% to 15% as a pretreatment solvent to the reactor. Control the mass ratio of ethanol solution to failed homogeneous catalyst to be 2:1 to 4:1 to form a mixture.

[0028] Keep the reactor sealed and maintain the temperature of the mixture at 20–45°C. Continue to process the mixture at low speed for 1–3 hours to ensure that the mixture is fully dispersed. The residual organic impurities in the catalyst are directionally dissolved by ethanol, which weakens the encapsulation and entrainment effect of organic impurities on the rhodium active component in the catalyst.

[0029] After pretreatment, the mixture is filtered through a primary filter to remove mechanical impurities, flocculent insoluble matter, and other solid particles, resulting in a uniformly dispersed mixture free of large particles for distillation.

[0030] S2, Microwave-Ultrasonic Synergistic Enhanced Multistage Distillation The mixture to be distilled prepared in S1 is smoothly fed into the multi-stage distillation reaction chamber through the feed inlet. The feed inlet is then closed for sealing to ensure that the chamber is completely sealed and there is no gas leakage.

[0031] Nitrogen or argon gas with a purity of ≥99.99% is continuously introduced into the cavity to fully replace the air inside the cavity. The replacement time is 10-15 minutes and the gas flow rate is 0.3-0.6 L / min. After the replacement is completed, a slightly positive pressure inert atmosphere is maintained to block the high-temperature oxidation path of the rhodium active component in the catalyst.

[0032] Microwave and ultrasonic oscillation treatment was performed, with a microwave output power of 500–1500W, an ultrasonic frequency of 20–60kHz, and an oscillation intensity stabilized at 0.1–0.5. By employing synchronous or alternating action modes and controlling the duty cycle at 50%–70%, the synergistic enhancement of microwave thermal effect and ultrasonic cavitation effect is achieved.

[0033] The multi-stage distillation reaction chamber adopts a three-stage series, independently temperature-controlled structure, as detailed below: Primary distillation chamber: The temperature is stably controlled at 60-80℃, and constant temperature distillation is carried out for 0.5-1h to achieve stepwise vaporization and separation of low-boiling-point alcohol impurities; Secondary distillation chamber: The temperature is stably controlled at 100-120℃, and constant temperature distillation is carried out for 0.5-1h to achieve directional vaporization and separation of medium-boiling-point organic impurities; Three-stage distillation chamber: The temperature is stably controlled at 200-260℃, and constant temperature distillation is carried out for 2-4 hours to achieve deep separation of high-boiling-point, non-volatile organic impurities; Furthermore, the chamber pressure of the multi-stage distillation reaction chamber is maintained at a negative pressure of 0.01 to 0.1 MPa, which reduces the vaporization boiling point of organic impurities, shortens the high-temperature residence time, and inhibits the volatilization loss of rhodium active components in the catalyst.

[0034] S3, Staged Condensation Recovery The organic gaseous components generated in each distillation chamber are condensed separately to achieve staged condensation of gaseous components without cross-mixing.

[0035] All stages of condensation use anti-entrainment serpentine condenser tubes with a tube diameter of 8–12 mm and an effective condensation section length of 50–80 cm. This increases the heat exchange area and reduces the gas flow rate, minimizing the loss of trace amounts of rhodium active components entrained in the gas phase.

[0036] Each condensing temperature stage is independently and precisely controlled, with specific parameters as follows: The primary condensation temperature is controlled at 40-50℃ to completely condense the low-boiling-point organic gas phase produced by the primary distillation into a liquid phase. The secondary condensation temperature is controlled at 60-80℃ to completely condense the medium-boiling-point organic gas phase produced by the secondary distillation into a liquid phase. The tertiary condensation temperature is controlled at 160–180°C to completely condense the high-boiling-point organic gas phase produced by the tertiary distillation into a liquid phase.

[0037] The liquid organic components obtained from condensation flow into corresponding dedicated sealed collection tanks to achieve graded collection and purification of organic impurities. The non-condensable gases generated during the condensation process are collected centrally and treated to render them harmless before being discharged.

[0038] S4, Rhodium catalyst separation and purification After multi-stage distillation is completed, the residual concentrated material discharged from the main outlet of the multi-stage distillation reaction chamber is separated and purified.

[0039] The material is first passed through a two-stage precision filtration structure for step-by-step impurity removal: the first stage uses a 0.2μm precision filter to remove large suspended impurities from the material; the second stage uses a 0.05μm precision filter to remove fine micron-sized impurities from the material.

[0040] After two-stage filtration, the material is further passed through a rhodium-specific polyethersulfone membrane with a retention accuracy of 0.1 μm to efficiently retain and enrich trace amounts of rhodium active components in the material, preventing rhodium from being lost with the filtrate.

[0041] The enriched material was centrifuged at a speed of 8000 r / min for 10–15 min to ensure complete separation of the solid and liquid phases. After centrifugation, the solid phase was removed to obtain a high-purity rhodium-containing enrichment.

[0042] S5, in-situ compounding and anti-loss stabilization treatment of rhodium active components The rhodium-containing concentrate obtained from S4 was transferred into a reactor, and triphenylphosphine ligands with a purity ≥99.5% were added to the reactor. The molar ratio of triphenylphosphine ligands to rhodium in the rhodium-containing concentrate was controlled at 3:1 to 6:1.

[0043] Nitrogen or argon gas with a purity of ≥99.99% is introduced into the reactor for protection, maintaining a slightly positive pressure inert atmosphere inside the reactor. The material temperature is controlled to be stable at 40-70℃, and the reaction is continued for 1-2 hours with low-speed stirring at a stirring rate of 80-150 r / min. This allows the rhodium active component in the material to undergo low-temperature in-situ complexation with the triphenylphosphine ligand, repairing the damaged rhodium-phosphine coordination structure in the failed catalyst.

[0044] After the complexation reaction is complete, the material temperature is lowered to 20-30℃, and stirring is continued for 20-40 minutes to fully stabilize the rhodium-phosphine complex, forming a rhodium active center complex with high chemical stability, low volatility, and low entrainment.

[0045] After this step, the free and particulate rhodium components are directionally converted into stable coordinated rhodium, thus blocking the risk of secondary rhodium loss at the chemical structure level and further improving the total rhodium recovery rate.

[0046] The method for recovering exhausted homogeneous catalysts by microwave-ultrasound synergistic distillation includes the following examples: Example 1: S1. Pretreatment of Defective Homogeneous Catalyst Take the failed homogeneous rhodium-containing catalyst to be recovered and add it to the pretreatment reactor. Add a 10% (w / w) aqueous ethanol solution to the reactor as a pretreatment solvent and control the mass ratio of the ethanol solution to the failed homogeneous catalyst to be 2:1 to form a mixture.

[0047] Keep the reactor sealed and maintain the temperature of the mixture at 20°C. Continue to process the mixture at low speed for 1 hour to ensure that the mixture is fully dispersed. The residual organic impurities in the catalyst are directionally dissolved by ethanol, which weakens the encapsulation and entrainment effect of organic impurities on the rhodium active component in the catalyst.

[0048] After pretreatment, the mixture is filtered through a primary filter to remove mechanical impurities, flocculent insoluble matter, and other solid particles, resulting in a uniformly dispersed mixture free of large particles for distillation.

[0049] S2, Microwave-Ultrasonic Synergistic Enhanced Multistage Distillation The mixture to be distilled prepared in S1 is smoothly fed into the multi-stage distillation reaction chamber through the feed inlet. The feed inlet is then closed for sealing to ensure that the chamber is completely sealed and there is no gas leakage.

[0050] Nitrogen gas with a purity of ≥99.99% was continuously introduced into the chamber for 10 minutes at a flow rate of 0.3 L / min. After the replacement was completed, a slightly positive pressure inert atmosphere was maintained to block the high-temperature oxidation pathway of the rhodium active component in the catalyst.

[0051] Microwave and ultrasonic oscillation treatment was performed, with a microwave output power of 500W, an ultrasonic frequency of 20kHz, and an oscillation intensity stabilized at 0.1. By adopting a synchronous action mode and controlling the duty cycle at 50%, the synergistic enhancement of microwave thermal effect and ultrasonic cavitation effect is achieved.

[0052] The multi-stage distillation reaction chamber adopts a three-stage series, independently temperature-controlled structure, as detailed below: Primary distillation chamber: The temperature is stably controlled at 60℃, and constant temperature distillation is carried out for 0.5 hours to achieve stepwise vaporization and separation of low-boiling-point alcohol impurities; Secondary distillation chamber: The temperature is stably controlled at 100℃, and constant temperature distillation is carried out for 0.5h to achieve directional vaporization and separation of medium-boiling-point organic impurities; Three-stage distillation chamber: The temperature is stably controlled at 200℃, and constant temperature distillation is carried out for 2 hours to achieve deep separation of high-boiling-point, non-volatile organic impurities; Furthermore, the chamber pressure of the multi-stage distillation reaction chamber is maintained at a negative pressure of 0.01 MPa, which reduces the vaporization boiling point of organic impurities, shortens the high-temperature residence time, and inhibits the volatilization loss of rhodium active components in the catalyst.

[0053] S3, Staged Condensation Recovery The organic gaseous components generated in each distillation chamber are condensed separately to achieve staged condensation of gaseous components without cross-mixing.

[0054] All stages of condensation use anti-entrainment serpentine condenser tubes with a tube diameter of 8mm and an effective condensation section length of 50cm. This increases the heat exchange area and reduces the gas phase flow rate, thereby reducing the loss of trace amounts of rhodium active components entrained in the gas phase.

[0055] Each condensing temperature stage is independently and precisely controlled, with specific parameters as follows: The primary condensation temperature is controlled at 40℃ to completely condense the low-boiling-point organic gas phase produced by the primary distillation into a liquid phase. The secondary condensation temperature is controlled at 60℃ to completely condense the medium-boiling-point organic gas phase produced by the secondary distillation into a liquid phase. The three-stage condensation temperature is controlled at 160℃ to completely condense the high-boiling-point organic gas phase produced by the three-stage distillation into a liquid phase.

[0056] The liquid organic components obtained from condensation flow into corresponding dedicated sealed collection tanks to achieve graded collection and purification of organic impurities. The non-condensable gases generated during the condensation process are collected centrally and treated to render them harmless before being discharged.

[0057] S4, Rhodium catalyst separation and purification After multi-stage distillation is completed, the residual concentrated material discharged from the main outlet of the multi-stage distillation reaction chamber is separated and purified.

[0058] The material is first passed through a two-stage precision filtration structure for step-by-step impurity removal: the first stage uses a 0.2μm precision filter to remove large suspended impurities from the material; the second stage uses a 0.05μm precision filter to remove fine micron-sized impurities from the material.

[0059] After two-stage filtration, the material is further passed through a rhodium-specific polyethersulfone membrane with a retention accuracy of 0.1 μm to efficiently retain and enrich trace amounts of rhodium active components in the material, preventing rhodium from being lost with the filtrate.

[0060] The enriched material was centrifuged at a speed of 8000 r / min for 10 min to ensure complete separation of the solid and liquid phases. After centrifugation, the solid phase was removed to obtain a high-purity rhodium-containing enrichment.

[0061] S5, in-situ compounding and anti-loss stabilization treatment of rhodium active components The rhodium-containing concentrate obtained from S4 was transferred into a reactor, and triphenylphosphine ligands with a purity ≥99.5% were added to the reactor. The molar ratio of triphenylphosphine ligands to rhodium in the rhodium-containing concentrate was controlled at 3:1.

[0062] Nitrogen gas with a purity of ≥99.99% was introduced into the reactor to maintain a slightly positive pressure inert atmosphere and keep the material temperature stable at 40℃. The reaction was carried out continuously for 1 hour with low-speed stirring at a stirring rate of 80r / min, so that the rhodium active component in the material could undergo low-temperature in-situ complexation with the triphenylphosphine ligand, thus repairing the damaged rhodium-phosphine coordination structure in the failed catalyst.

[0063] After the complexation reaction is complete, the material temperature is lowered to 20°C and stirred for another 20 minutes to allow the rhodium-phosphine complex to fully solidify, forming a rhodium active center complex with high chemical stability, low volatility, and low entrainment.

[0064] In this example: the total rhodium recovery rate was 92.1%, the organic impurity removal rate was 91.3%, and the regenerated catalyst activity retention rate was 94.8%.

[0065] Example 2: S1. Pretreatment of Defective Homogeneous Catalyst Take the failed homogeneous rhodium-containing catalyst to be recovered and add it to the pretreatment reactor. Add a 12.5% ​​(w / w) aqueous ethanol solution to the reactor as a pretreatment solvent. Control the mass ratio of the ethanol solution to the failed homogeneous catalyst to be 3:1 to form a mixture.

[0066] Keep the reactor sealed and maintain the temperature of the mixture at 32°C. Continue to process the mixture at low speed for 2 hours to ensure that the mixture is fully dispersed. The residual organic impurities in the catalyst are directionally dissolved by ethanol, which weakens the encapsulation and entrainment effect of organic impurities on the rhodium active component in the catalyst.

[0067] After pretreatment, the mixture is filtered through a primary filter to remove mechanical impurities, flocculent insoluble matter, and other solid particles, resulting in a uniformly dispersed mixture free of large particles for distillation.

[0068] S2, Microwave-Ultrasonic Synergistic Enhanced Multistage Distillation The mixture to be distilled prepared in S1 is smoothly fed into the multi-stage distillation reaction chamber through the feed inlet. The feed inlet is then closed for sealing to ensure that the chamber is completely sealed and there is no gas leakage.

[0069] Argon gas with a purity of ≥99.99% was continuously introduced into the cavity for 12.5 min at a flow rate of 0.45 L / min. After the replacement was completed, a slightly positive pressure inert atmosphere was maintained to block the high-temperature oxidation pathway of the rhodium active component in the catalyst.

[0070] Microwave and ultrasonic oscillation treatment was performed, with a microwave output power of 1000W, an ultrasonic frequency of 40kHz, and an oscillation intensity stabilized at 0.3. By employing synchronous or alternating action modes and controlling the duty cycle at 60%, the synergistic enhancement of microwave thermal effect and ultrasonic cavitation effect is achieved.

[0071] The multi-stage distillation reaction chamber adopts a three-stage series, independently temperature-controlled structure, as detailed below: Primary distillation chamber: The temperature is stably controlled at 70℃, and constant temperature distillation is carried out for 0.75 hours to achieve stepwise vaporization and separation of low-boiling-point alcohol impurities; Secondary distillation chamber: The temperature is stably controlled at 110℃, and constant temperature distillation is carried out for 0.75h to achieve directional vaporization and separation of medium-boiling-point organic impurities; Three-stage distillation chamber: The temperature is stably controlled at 230℃, and constant temperature distillation is carried out for 3 hours to achieve deep separation of high-boiling-point, non-volatile organic impurities; Furthermore, the chamber pressure of the multi-stage distillation reaction chamber is maintained at a negative pressure of 0.055 MPa, which reduces the vaporization boiling point of organic impurities, shortens the high-temperature residence time, and inhibits the volatilization loss of rhodium active components in the catalyst.

[0072] S3, Staged Condensation Recovery The organic gaseous components generated in each distillation chamber are condensed separately to achieve staged condensation of gaseous components without cross-mixing.

[0073] All stages of condensation use anti-entrainment serpentine condenser tubes with a tube diameter of 10mm and an effective condensation section length of 65cm. This increases the heat exchange area and reduces the gas phase flow rate, minimizing the loss of trace amounts of rhodium active components entrained in the gas phase.

[0074] Each condensing temperature stage is independently and precisely controlled, with specific parameters as follows: The primary condensation temperature is controlled at 45℃ to completely condense the low-boiling-point organic gas phase produced by the primary distillation into a liquid phase. The secondary condensation temperature is controlled at 70℃ to completely condense the medium-boiling-point organic gas phase produced by the secondary distillation into a liquid phase. The tertiary condensation temperature is controlled at 170℃ to completely condense the high-boiling-point organic gas phase produced by the tertiary distillation into a liquid phase.

[0075] The liquid organic components obtained from condensation flow into corresponding dedicated sealed collection tanks to achieve graded collection and purification of organic impurities. The non-condensable gases generated during the condensation process are collected centrally and treated to render them harmless before being discharged.

[0076] S4, Rhodium catalyst separation and purification After multi-stage distillation is completed, the residual concentrated material discharged from the main outlet of the multi-stage distillation reaction chamber is separated and purified.

[0077] The material is first passed through a two-stage precision filtration structure for step-by-step impurity removal: the first stage uses a 0.2μm precision filter to remove large suspended impurities from the material; the second stage uses a 0.05μm precision filter to remove fine micron-sized impurities from the material.

[0078] After two-stage filtration, the material is further passed through a rhodium-specific polyethersulfone membrane with a retention accuracy of 0.1 μm to efficiently retain and enrich trace amounts of rhodium active components in the material, preventing rhodium from being lost with the filtrate.

[0079] The enriched material was centrifuged at a speed of 8000 r / min for 12.5 min to ensure complete separation of the solid and liquid phases. After centrifugation, the solid phase was removed to obtain a high-purity rhodium-containing enrichment.

[0080] S5, in-situ compounding and anti-loss stabilization treatment of rhodium active components The rhodium-containing concentrate obtained from S4 was transferred into a reactor, and triphenylphosphine ligands with a purity ≥99.5% were added to the reactor. The molar ratio of triphenylphosphine ligands to rhodium in the rhodium-containing concentrate was controlled at 4.5:1.

[0081] Argon gas with a purity of ≥99.99% was introduced into the reactor for protection, maintaining a slightly positive pressure inert atmosphere inside the reactor. The material temperature was controlled to be stable at 55℃, and the reaction was carried out continuously for 1.5 hours with low-speed stirring at a stirring rate of 115 r / min. This allowed the rhodium active component in the material to undergo low-temperature in-situ complexation with the triphenylphosphine ligand, repairing the damaged rhodium-phosphine coordination structure in the failed catalyst.

[0082] After the complexation reaction is complete, the material temperature is lowered to 25°C and stirred for another 30 minutes to allow the rhodium-phosphine complex to fully solidify, forming a rhodium active center complex with high chemical stability, low volatility, and low entrainment.

[0083] In this example: the total rhodium recovery rate was 95.6%, the organic impurity removal rate was 95.4%, and the regenerated catalyst activity retention rate was 98.1%.

[0084] Example 3: S1. Pretreatment of Defective Homogeneous Catalyst Take the failed homogeneous rhodium-containing catalyst to be recovered and add it to the pretreatment reactor. Add a 15% (w / w) aqueous ethanol solution to the reactor as a pretreatment solvent. Control the mass ratio of the ethanol solution to the failed homogeneous catalyst to be 4:1 to form a mixture.

[0085] Keep the reactor sealed and maintain the temperature of the mixture at 45°C. Continue to process the mixture at low speed for 3 hours to ensure that the mixture is fully dispersed. The residual organic impurities in the catalyst are directionally dissolved by ethanol, which weakens the encapsulation and entrainment effect of organic impurities on the rhodium active component in the catalyst.

[0086] After pretreatment, the mixture is filtered through a primary filter to remove mechanical impurities, flocculent insoluble matter, and other solid particles, resulting in a uniformly dispersed mixture free of large particles for distillation.

[0087] S2, Microwave-Ultrasonic Synergistic Enhanced Multistage Distillation The mixture to be distilled prepared in S1 is smoothly fed into the multi-stage distillation reaction chamber through the feed inlet. The feed inlet is then closed for sealing to ensure that the chamber is completely sealed and there is no gas leakage.

[0088] Nitrogen gas with a purity of ≥99.99% was continuously introduced into the chamber for 15 minutes at a flow rate of 0.6 L / min. After the replacement was completed, a slightly positive pressure inert atmosphere was maintained to block the high-temperature oxidation pathway of the rhodium active component in the catalyst.

[0089] Microwave and ultrasonic oscillation treatment was performed, with a microwave output power of 1500W, an ultrasonic frequency of 60kHz, and an oscillation intensity stabilized at 0.5. It adopts an alternating action mode with a duty cycle controlled at 70% to achieve synergistic enhancement of microwave thermal effect and ultrasonic cavitation effect.

[0090] The multi-stage distillation reaction chamber adopts a three-stage series, independently temperature-controlled structure, as detailed below: Primary distillation chamber: The temperature is stably controlled at 80℃, and constant temperature distillation is carried out for 1 hour to achieve stepwise vaporization and separation of low-boiling-point alcohol impurities; Secondary distillation chamber: The temperature is stably controlled at 120℃, and constant temperature distillation is carried out for 1 hour to achieve directional vaporization and separation of medium-boiling-point organic impurities; Three-stage distillation chamber: The temperature is stably controlled at 260℃, and constant temperature distillation is carried out for 4 hours to achieve deep separation of high-boiling-point, non-volatile organic impurities; Furthermore, the chamber pressure of the multi-stage distillation reaction chamber is maintained at a negative pressure of 0.1 MPa, which reduces the vaporization boiling point of organic impurities, shortens the high-temperature residence time, and inhibits the volatilization loss of rhodium active components in the catalyst.

[0091] S3, Staged Condensation Recovery The organic gaseous components generated in each distillation chamber are condensed separately to achieve staged condensation of gaseous components without cross-mixing.

[0092] All stages of condensation use anti-entrainment serpentine condenser tubes with a tube diameter of 12mm and an effective condensation section length of 80cm. This increases the heat exchange area and reduces the gas phase flow rate, thereby reducing the loss of trace amounts of rhodium active components entrained in the gas phase.

[0093] Each condensing temperature stage is independently and precisely controlled, with specific parameters as follows: The primary condensation temperature is controlled at 50℃ to completely condense the low-boiling-point organic gas phase produced by the primary distillation into a liquid phase. The secondary condensation temperature is controlled at 80℃ to completely condense the medium-boiling-point organic gas phase produced by the secondary distillation into a liquid phase. The tertiary condensation temperature is controlled at 180℃ to completely condense the high-boiling-point organic gas phase produced by the tertiary distillation into a liquid phase.

[0094] The liquid organic components obtained from condensation flow into corresponding dedicated sealed collection tanks to achieve graded collection and purification of organic impurities. The non-condensable gases generated during the condensation process are collected centrally and treated to render them harmless before being discharged.

[0095] S4, Rhodium catalyst separation and purification After multi-stage distillation is completed, the residual concentrated material discharged from the main outlet of the multi-stage distillation reaction chamber is separated and purified.

[0096] The material is first passed through a two-stage precision filtration structure for step-by-step impurity removal: the first stage uses a 0.2μm precision filter to remove large suspended impurities from the material; the second stage uses a 0.05μm precision filter to remove fine micron-sized impurities from the material.

[0097] After two-stage filtration, the material is further passed through a rhodium-specific polyethersulfone membrane with a retention accuracy of 0.1 μm to efficiently retain and enrich trace amounts of rhodium active components in the material, preventing rhodium from being lost with the filtrate.

[0098] The enriched material was centrifuged at a speed of 8000 r / min for 15 min to ensure complete separation of the solid and liquid phases. After centrifugation, the solid phase was removed to obtain a high-purity rhodium-containing enrichment.

[0099] S5, in-situ compounding and anti-loss stabilization treatment of rhodium active components The rhodium-containing concentrate obtained from S4 was transferred into a reactor, and triphenylphosphine ligands with a purity ≥99.5% were added to the reactor. The molar ratio of triphenylphosphine ligands to rhodium in the rhodium-containing concentrate was controlled at 6:1.

[0100] Nitrogen gas with a purity of ≥99.99% was introduced into the reactor to maintain a slightly positive pressure inert atmosphere and keep the material temperature stable at 70℃. The reaction was carried out for 2 hours with low-speed stirring at a stirring rate of 150r / min, so that the rhodium active component in the material could undergo low-temperature in-situ complexation with the triphenylphosphine ligand, thus repairing the damaged rhodium-phosphine coordination structure in the failed catalyst.

[0101] After the complexation reaction is complete, the material temperature is lowered to 30℃ and stirred for another 40 minutes to allow the rhodium-phosphine complex to fully solidify, forming a rhodium active center complex with high chemical stability, low volatility, and low entrainment.

[0102] In this example: the total rhodium recovery rate was 93.5%, the organic impurity removal rate was 92.7%, and the regenerated catalyst activity retention rate was 96.2%.

Claims

1. An apparatus for recovering exhausted homogeneous catalysts by microwave-ultrasonic synergistic distillation, characterized in that, include: The multi-stage distillation reaction chamber includes a first-stage distillation chamber (4), a second-stage distillation chamber (5), and a third-stage distillation chamber (6) connected sequentially from top to bottom. Each of the first-stage distillation chamber (4), the second-stage distillation chamber (5), and the third-stage distillation chamber (6) is equipped with a microwave generating module (1) and an ultrasonic oscillation module (3). The condensation recovery module includes a primary anti-entrapment serpentine condenser tube (7) and a primary dedicated sealed collection tank (8) connected in sequence to the primary distillation chamber (4); a secondary anti-entrapment serpentine condenser tube (9) and a secondary dedicated sealed collection tank (10) connected in sequence to the secondary distillation chamber (5); and a tertiary anti-entrapment serpentine condenser tube (11) and a tertiary dedicated sealed collection tank (12) connected in sequence to the tertiary distillation chamber (6). The catalyst separation and purification module is located at the outlet of the multi-stage distillation reaction chamber and includes filters, rhodium-specific filtration polyethersulfone membranes, and centrifuges arranged sequentially from the inside to the outside. A precise temperature and pressure monitoring module is installed on the primary distillation chamber (4), the secondary distillation chamber (5), and the tertiary distillation chamber (6), and includes a temperature sensor and a pressure sensor.

2. The apparatus for recovering depleted homogeneous catalyst by microwave-ultrasonic synergistic distillation according to claim 1, characterized in that, The microwave generating module (1) includes a microwave radiator (2), the power adjustment range of which is 500-1500W, and the angle adjustment range of which is 0-360°.

3. The apparatus for recovering failed homogeneous catalysts by microwave-ultrasonic synergistic distillation according to claim 1, characterized in that, The ultrasonic oscillation module (3) includes an ultrasonic transducer with an adjustable frequency range of 20-60kHz and an oscillation intensity of 0.1-0.

5. .

4. A method for recovering a failed homogeneous catalyst by microwave-ultrasonic synergistic distillation, characterized in that, using the apparatus for recovering a failed homogeneous catalyst by microwave-ultrasonic synergistic distillation as described in any one of claims 1 to 3, it further includes the following operational steps: S1. Pretreatment: The mixed exhausted homogeneous rhodium-containing catalyst and ethanol aqueous solution are stirred under closed conditions. After stirring, the mixture is filtered through a filter screen to remove solid impurities, and the mixture to be distilled is obtained. S2. Microwave-ultrasound synergistic enhancement of multi-stage distillation: The mixture to be distilled is sent into the multi-stage distillation reaction chamber, and nitrogen or argon is introduced into the chamber to replace the internal air to form an inert atmosphere. The material is subjected to three-stage temperature-controlled distillation by using microwave and ultrasound synergistic action. S3. Staged condensation and recovery: The organic gas phase components generated in each stage of the distillation chamber are condensed independently, and the liquid phase components obtained from the condensation are collected in stages. S4. Rhodium catalyst separation and purification: The residual concentrated material discharged from the multi-stage distillation reaction chamber is sequentially filtered through two stages to remove impurities, then retained and enriched by a rhodium-specific retention membrane, and finally centrifuged to obtain a high-purity rhodium-containing concentrate. S5. In-situ compounding and stabilization of rhodium active components: The rhodium-enriched material is placed in a reactor, and triphenylphosphine ligand is added to the reactor. The complexation reaction is carried out under an inert atmosphere and low temperature. After the complexation reaction is completed, the temperature is lowered and the mixture is stirred to fully stabilize the rhodium-phosphine complex.

5. The method for recovering failed homogeneous catalysts by microwave-ultrasound synergistic distillation according to claim 4, characterized in that, In S1, the mass fraction of the ethanol aqueous solution is 10% to 15%; The mass ratio of ethanol solution to degraded homogeneous rhodium-containing catalyst is 2:1 to 4:

1.

6. The method for recovering failed homogeneous catalysts by microwave-ultrasonic synergistic distillation according to claim 4, characterized in that, In S2, the purity of nitrogen or argon is ≥99.99%, the gas replacement time is 10-15 min, and the gas flow rate is 0.3-0.6 L / min.

7. The method for recovering failed homogeneous catalysts by microwave-ultrasonic synergistic distillation according to claim 4, characterized in that, In S2, the temperature of the primary distillation chamber is 60–80°C, and the distillation time is 0.5–1 hour. The temperature of the secondary distillation chamber is 100–120℃, and the distillation time is 0.5–1 hour. The temperature of the three-stage distillation chamber is 200–260℃, and the distillation time is 2–4 hours; the chamber pressure is maintained at a negative pressure of 0.01–0.1 MPa.

8. The method for recovering failed homogeneous catalysts by microwave-ultrasonic synergistic distillation according to claim 4, characterized in that, In S3, the first-stage condensation temperature is 40–50°C, the second-stage condensation temperature is 60–80°C, and the third-stage condensation temperature is 160–180°C.

9. The method for recovering failed homogeneous catalysts by microwave-ultrasonic synergistic distillation according to claim 4, characterized in that, In step S4, the centrifugation speed is 8000 r / min, and the centrifugation time is 10–15 min.

10. The method for recovering failed homogeneous catalysts by microwave-ultrasonic synergistic distillation according to claim 4, characterized in that, In S5, the purity of the triphenylphosphine ligand is ≥99.5%, and the molar ratio of the triphenylphosphine ligand to the rhodium element in the rhodium-enriched material is controlled to be 3:1 to 6:1.

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