A process for the recovery of low concentration rhodium catalyst from organic heel containing rhodium catalyst

Abstract

The present application relates to the technical field of catalyst recovery, and discloses a method for recovering low-concentration rhodium catalyst from organic residues containing rhodium catalyst, comprising the following steps: (1) adding a modified temperature-sensitive polymer aqueous solution into isopentanal mother liquor, stirring, and layering after standing; (2) heating the water phase obtained after separation, and causing the rhodium-adsorbed polymer to phase change and precipitate, and then filtering and roasting, so as to obtain the recovered rhodium catalyst. The present application realizes the recovery of low-concentration rhodium catalyst from organic residues containing rhodium catalyst, has high recovery rate, is energy-saving and environment-friendly, has mild process conditions, and can effectively expand the application range of rhodium catalyst.

Description

Technical Field

[0001] This invention relates to the field of catalyst recovery technology, and in particular to a method for recovering low-concentration rhodium catalysts from organic by-products containing rhodium catalysts. Background Technology

[0002] The hydroformylation of olefins is an important industrial method for synthesizing aldehydes and alcohols, possessing advantages such as high catalytic activity and good selectivity. Isovaleraldehyde is an important fragrance and pharmaceutical intermediate with wide applications. The hydroformylation of isobutene to produce isopentaldehyde uses rhodium-based catalysts. Although rhodium-based catalysts reduce the production conditions of olefin hydroformylation, offering advantages such as mild reaction conditions, high product yields, and good heat transfer, demonstrating excellent economic benefits, the synthesis of isopentaldehyde and the widespread application of these catalysts are significantly limited due to rhodium's precious metal nature, limited reserves, high price, and difficulty in recovery.

[0003] There are many existing methods for rhodium recovery, including combustion, extraction, precipitation and washing, liquid-phase digestion, adsorption separation, and chemical activation. However, these methods are mainly for the recovery of rhodium from spent catalyst solutions, while neglecting the recovery and utilization of rhodium from organic byproducts of rhodium-containing catalysts, such as reaction waste liquids. Summary of the Invention

[0004] In view of this, the present invention provides a method for recovering low-concentration rhodium catalysts from organic by-products containing rhodium catalysts, in order to solve the problems of difficulty in recovering rhodium catalysts from existing reaction waste liquids and the limited application of such catalysts.

[0005] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0006] A method for recovering low-concentration rhodium catalyst from organic by-products containing rhodium catalysts includes the following steps:

[0007] (1) Add the modified temperature-sensitive polymer aqueous solution to the isovaleraldehyde mother liquor, stir and let stand to separate into layers;

[0008] (2) The aqueous phase obtained after separation is heated, and the polymer adsorbed with rhodium undergoes a phase change and precipitates out. After filtration, the rhodium-containing polymer is separated, dried in a vacuum drying oven, and then transferred to a muffle furnace for high-temperature calcination to obtain the recovered rhodium catalyst.

[0009] Preferably, in the above method, the modified thermosensitive polymer is a thermosensitive polymer with phosphine groups at the end; the amount of the modified thermosensitive polymer aqueous solution added is 1-20 times the mass of the catalyst in the mother liquor, and the concentration of the modified thermosensitive polymer aqueous solution is 1-10 mg / ml.

[0010] Preferably, in the above method, the stirring temperature in step (1) is 34-55℃ and the stirring time is 4-7h.

[0011] Preferably, in the above method, the heating in step (2) is first raised from room temperature to 60-85°C and maintained for 0.5-1.5h to allow the modified thermosensitive polymer to completely coat the rhodium catalyst in the solution; then the temperature is continuously raised to 90-103°C to allow the modified thermosensitive polymer to completely precipitate.

[0012] Specifically, after standing and separating into layers, the aqueous phase is separated, and rhodium metal ions are adsorbed onto the thermosensitive polymer at room temperature. When the temperature is raised from room temperature to 60-85℃, the thermosensitive hydrogel molecular chains shrink and embed the rhodium metal. When the temperature is continuously raised to 90-103℃, the thermosensitive hydrogel molecular chains embedding the rhodium metal precipitate out.

[0013] Preferably, in the above method, the drying temperature in step (2) is 30-50°C and the drying time is 3-6 hours.

[0014] Preferably, in the above method, the roasting temperature in step (2) is 500-600℃ and the roasting time is 5-10h.

[0015] Preferably, in the above method, the modified thermosensitive polymer is prepared as follows:

[0016] A. Dissolve the monomer, initiator, and catalyst in an organic solvent and mix them at low temperature; after mixing, purge with an inert gas 3-5 times, and then heat the mixture under inert gas protection to obtain a thermosensitive polymer.

[0017] B. Continue adding alkylphosphine compounds, and the reaction yields a thermosensitive polymer with phosphine groups at the ends.

[0018] Preferably, in the above method, the mass ratio of the monomer, the initiator, and the catalyst in step A is 1:0.05-0.1:0.01-0.03;

[0019] The monomer includes one or more of 4-methacrylamidoaniline, N-isopropylacrylamide, and ethylene glycol monomethyl ether methacrylic acid;

[0020] The initiator includes one or more of azobisisobutyronitrile, benzoyl peroxide, and azobisisoheptanenitrile;

[0021] The catalyst includes one or more of cuprous chloride, cuprous bromide, cuprous thiocyanate, and cuprous hexafluorophosphate.

[0022] The organic solvent includes one or more of tetrahydrofuran, dichloromethane, diethyl ether, and anhydrous ethanol.

[0023] Preferably, in the above method, the temperature of the low-temperature mixing in step A is 0-10°C, the reaction temperature of the heating reaction is 55-80°C, and the reaction time is 20-30h.

[0024] Preferably, in the above method, the molar ratio of the thermosensitive polymer to the alkylphosphine compound in step B is 1:1.1-1.5.

[0025] This invention provides a method for recovering low-concentration rhodium catalysts from organic by-products containing rhodium catalysts. Compared with existing technologies, its advantages are as follows:

[0026] This invention utilizes a temperature-sensitive polymer for the adsorption and enrichment of rhodium. The enriched rhodium-containing polymer is then incinerated to recover the rhodium catalyst. The remaining rhodium-free mother liquor is distilled to recover isovaleraldehyde before incineration. This invention achieves the recovery of low-concentration rhodium catalyst from organic by-products containing rhodium catalysts, with high recovery rate, energy saving, environmental protection, and mild process conditions, effectively expanding the application range of rhodium catalysts. Detailed Implementation

[0027] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] Example 1

[0029] This embodiment provides a method for preparing a modified thermosensitive polymer, including the following steps:

[0030] (1) Ethylene glycol monomethyl ether methacrylic acid, azobisisobutyronitrile, and cuprous thiocyanate were dissolved in dichloromethane in an organic solvent at a mass ratio of 1:0.05:0.01 and the mixing temperature was 0℃. After mixing, an inert gas was introduced to replace the mixture three times, and then the mixture was heated to 55℃ under inert gas protection and reacted for 30h to obtain a thermosensitive polymer.

[0031] (2) The alkylphosphine compound was added in a ratio of 1:1.1 to the thermosensitive polymer and the alkylphosphine compound to obtain thermosensitive polymer A with phosphine group at the end.

[0032] Example 2

[0033] This embodiment provides a method for preparing a modified thermosensitive polymer, including the following steps:

[0034] (1) 4-methylacrylamidoaniline, azobisisobutyronitrile, and cuprous chloride were dissolved in anhydrous ethanol in an organic solvent at a mass ratio of 1:0.08:0.01 and the mixing temperature was 5℃. After mixing, inert gas was introduced to replace the mixture three times, and then the temperature was raised to 70℃ under inert gas protection for 25h to obtain a thermosensitive polymer.

[0035] (2) The alkylphosphine compound was added in a ratio of 1:1.2 to the thermosensitive polymer and the alkylphosphine compound to obtain thermosensitive polymer B with phosphine group at the end.

[0036] Example 3

[0037] This embodiment provides a method for preparing a modified thermosensitive polymer, including the following steps:

[0038] (1) N-isopropylacrylamide, benzoyl peroxide and cuprous bromide were dissolved in the organic solvent tetrahydrofuran at a mass ratio of 1:0.1:0.01 and the mixing temperature was 10℃. After mixing, inert gas was passed through three times for replacement, and then the temperature was raised to 80℃ under inert gas protection for 20h to obtain a thermosensitive polymer.

[0039] (2) The alkylphosphine compound was added in a ratio of 1:1.5 to the thermosensitive polymer and the alkylphosphine compound to obtain thermosensitive polymer C with phosphine group at the end.

[0040] Example 4

[0041] This embodiment provides a method for preparing a modified thermosensitive polymer, including the following steps:

[0042] (1) 4-methylacrylamidoaniline, azobisisobutyronitrile, and cuprous chloride were dissolved in anhydrous ethanol in an organic solvent at a mass ratio of 1:0.15:0.01 and the mixing temperature was 20℃. After mixing, inert gas was introduced to replace the mixture three times, and then the temperature was raised to 70℃ under inert gas protection for 25h to obtain a thermosensitive polymer.

[0043] (2) The alkylphosphine compound was added in a ratio of 1:1.2 to the thermosensitive polymer and the alkylphosphine compound to obtain thermosensitive polymer D with phosphine group at the end.

[0044] Example 5

[0045] This embodiment provides a method for preparing a modified thermosensitive polymer, including the following steps:

[0046] (1) 4-methylacrylamidoaniline, azobisisobutyronitrile, and cuprous chloride were dissolved in anhydrous ethanol in an organic solvent at a mass ratio of 1:0.08:0.01 and the mixing temperature was 5℃. After mixing, inert gas was introduced to replace the mixture three times, and then the temperature was raised to 50℃ under inert gas protection for 35h to obtain a thermosensitive polymer.

[0047] (2) The alkylphosphine compound was added in a ratio of 1:1.2 to the thermosensitive polymer and the alkylphosphine compound to obtain a thermosensitive polymer E with phosphine groups at the end.

[0048] Example 6

[0049] This embodiment provides a method for preparing a modified thermosensitive polymer, including the following steps:

[0050] (1) 4-methylacrylamidoaniline, azobisisobutyronitrile, and cuprous chloride were dissolved in anhydrous ethanol in an organic solvent at a mass ratio of 1:0.08:0.01 and the mixing temperature was 5℃. After mixing, inert gas was introduced to replace the mixture three times, and then the temperature was raised to 70℃ under inert gas protection for 25h to obtain a thermosensitive polymer.

[0051] (2) The alkylphosphine compound was added in a 1:1 molar ratio of thermosensitive polymer to alkylphosphine compound to obtain thermosensitive polymer F with phosphine group at the end.

[0052] Example 7

[0053] This embodiment provides a method for recovering low-concentration rhodium catalyst from organic by-products containing rhodium catalyst, comprising the following steps:

[0054] (1) Prepare a 0.3% mass fraction of thermosensitive polymer aqueous solution at room temperature. Add 35g of modified thermosensitive polymer A aqueous solution to 350g of isovaleraldehyde mother liquor (catalyst content 50ppm) at 35℃, stir for 6h and let stand to separate into layers.

[0055] (2) After separation of layers, rhodium metal ions adsorbed on the thermosensitive polymer at room temperature. The temperature was raised to 60°C and stirred for 3 hours. When the thermosensitive hydrogel molecular chains contracted and completely embedded the rhodium metal, the thermosensitive hydrogel molecular chains that embedded the rhodium metal began to precipitate when the temperature was raised to 90°C. After the temperature was raised to 100°C and the temperature was raised, no new precipitate was precipitated.

[0056] (3) The rhodium-containing polymer was separated after filtration. The separated rhodium-containing polymer was dried in a vacuum drying oven at 30°C for 6 hours and then transferred to a muffle furnace and calcined at 500°C for 8 hours to obtain the recovered rhodium catalyst. The rhodium catalyst recovery rate was 93.45%.

[0057] Example 8

[0058] This embodiment provides a method for recovering low-concentration rhodium catalyst from organic by-products containing rhodium catalyst, comprising the following steps:

[0059] (1) Prepare a 0.3% mass fraction of thermosensitive polymer aqueous solution at room temperature. Add 100g of modified thermosensitive polymer B aqueous solution to 1000g of isovaleraldehyde mother liquor (catalyst content 50ppm) at 45℃, stir for 7h and let stand to separate into layers.

[0060] (2) After the layers are separated, the rhodium metal ions are adsorbed on the thermosensitive polymer at room temperature. The temperature is raised to 70°C and stirred for 2 hours. When the thermosensitive hydrogel molecular chains shrink and completely encapsulate the rhodium metal, the thermosensitive hydrogel molecular chains encapsulating the rhodium metal begin to precipitate when the temperature is raised to 95°C. After the temperature is raised to 103°C and the temperature is raised, no new precipitate is precipitated.

[0061] (3) The rhodium-containing polymer was separated after filtration. The separated rhodium-containing polymer was dried in a vacuum drying oven at 40°C for 5 hours and then transferred to a muffle furnace and calcined at 550°C for 7 hours to obtain the recovered rhodium catalyst. The rhodium catalyst recovery rate was 94.06%.

[0062] Example 9

[0063] This embodiment provides a method for recovering low-concentration rhodium catalyst from organic by-products containing rhodium catalyst, comprising the following steps:

[0064] (1) Prepare a 0.3% mass fraction of thermosensitive polymer aqueous solution at room temperature, add 85g of modified thermosensitive polymer C aqueous solution to 850g of isovaleraldehyde mother liquor (catalyst content 50ppm) at 55℃, stir for 4h and let stand to separate into layers.

[0065] (2) After separation of layers, rhodium metal ions adsorbed on the thermosensitive polymer at room temperature. The temperature was raised to 85°C and stirred for 1 hour. When the thermosensitive hydrogel molecular chains contracted and completely embedded the rhodium metal, the temperature-sensitive hydrogel molecular chains that embedded the rhodium metal began to precipitate when the temperature was raised to 103°C. After the temperature was raised to 105°C, the temperature was raised again and no new precipitate was precipitated.

[0066] (3) The rhodium-containing polymer was separated after filtration. The separated rhodium-containing polymer was dried at 50°C for 3 hours in a vacuum drying oven and then transferred to a muffle furnace and calcined at 600°C for 5 hours to obtain the recovered rhodium catalyst. The rhodium catalyst recovery rate was 93.08%.

[0067] Example 10

[0068] This embodiment provides a method for recovering low-concentration rhodium catalyst from organic by-products containing rhodium catalyst, comprising the following steps:

[0069] (1) Prepare a 0.3% mass fraction of thermosensitive polymer aqueous solution at room temperature, add 75g of modified thermosensitive polymer D aqueous solution to 850g of isovaleraldehyde mother liquor (catalyst content 50ppm) at 55℃, stir for 4h and let stand to separate into layers.

[0070] (2) After separation of layers, rhodium metal ions adsorbed on the thermosensitive polymer at room temperature. The temperature was raised to 85°C and stirred for 1 hour. When the thermosensitive hydrogel molecular chains contracted and completely embedded the rhodium metal, the temperature-sensitive hydrogel molecular chains that embedded the rhodium metal began to precipitate when the temperature was raised to 103°C. After the temperature was raised to 105°C, the temperature was raised again and no new precipitate was precipitated.

[0071] (3) The rhodium-containing polymer was separated after filtration. The separated rhodium-containing polymer was dried at 50°C for 3 hours in a vacuum drying oven and then transferred to a muffle furnace and calcined at 600°C for 5 hours to obtain the recovered rhodium catalyst. The rhodium catalyst recovery rate was 86.70%.

[0072] Example 11

[0073] This embodiment provides a method for recovering low-concentration rhodium catalyst from organic by-products containing rhodium catalyst, comprising the following steps:

[0074] (1) Prepare a 0.3% mass fraction of thermosensitive polymer aqueous solution at room temperature, add 70g of modified thermosensitive polymer E aqueous solution to 850g of isovaleraldehyde mother liquor (catalyst content 50ppm) at 55℃, stir for 4h and let stand to separate into layers.

[0075] (2) After separation of layers, rhodium metal ions adsorbed on the thermosensitive polymer at room temperature. The temperature was raised to 85°C and stirred for 1 hour. When the thermosensitive hydrogel molecular chains contracted and completely embedded the rhodium metal, the temperature-sensitive hydrogel molecular chains that embedded the rhodium metal began to precipitate when the temperature was raised to 103°C. After the temperature was raised to 105°C, the temperature was raised again and no new precipitate was precipitated.

[0076] (3) The rhodium-containing polymer was separated after filtration. The separated rhodium-containing polymer was dried at 50°C for 3 hours in a vacuum drying oven and then transferred to a muffle furnace and calcined at 600°C for 5 hours to obtain the recovered rhodium catalyst. The rhodium catalyst recovery rate was 83.67%.

[0077] Example 12

[0078] This embodiment provides a method for recovering low-concentration rhodium catalyst from organic by-products containing rhodium catalyst, comprising the following steps:

[0079] (1) Prepare a 0.3% mass fraction of thermosensitive polymer aqueous solution at room temperature, add 50g of modified thermosensitive polymer F aqueous solution to 500g of isovaleraldehyde mother liquor (catalyst content 50ppm) at 55℃, stir for 4h and let stand to separate into layers.

[0080] (2) After separation of layers, rhodium metal ions adsorbed on the thermosensitive polymer at room temperature. The temperature was raised to 85°C and stirred for 1 hour. When the thermosensitive hydrogel molecular chains contracted and completely embedded the rhodium metal, the temperature-sensitive hydrogel molecular chains that embedded the rhodium metal began to precipitate when the temperature was raised to 103°C. After the temperature was raised to 105°C, the temperature was raised again and no new precipitate was precipitated.

[0081] (3) The rhodium-containing polymer was separated after filtration. The separated rhodium-containing polymer was dried at 50°C for 3 hours in a vacuum drying oven and then transferred to a muffle furnace and calcined at 600°C for 5 hours to obtain the recovered rhodium catalyst. The rhodium catalyst recovery rate was 89.01%.

[0082] Example 13

[0083] This embodiment provides a method for recovering low-concentration rhodium catalyst from organic by-products containing rhodium catalyst, comprising the following steps:

[0084] (1) Prepare a 0.3% mass fraction aqueous solution of thermosensitive polymer at room temperature. Add 70g of modified thermosensitive polymer B aqueous solution to 700g of isovaleraldehyde mother liquor (catalyst content 50ppm) at 45℃, stir for 7h and let stand to separate into layers.

[0085] (2) After separation of the aqueous phase, the rhodium-containing polymer was separated by filtration after being heated from room temperature to 95°C. The separated rhodium-containing polymer was dried in a vacuum drying oven at 40°C for 5 hours, and then transferred to a muffle furnace and calcined at 550°C for 7 hours to obtain the recovered rhodium catalyst. The rhodium catalyst recovery rate was 95.39%.

[0086] Example 14

[0087] This embodiment provides a method for recovering low-concentration rhodium catalyst from organic by-products containing rhodium catalyst, comprising the following steps:

[0088] (1) Prepare a 0.3% mass fraction of thermosensitive polymer aqueous solution at room temperature. Add 50g of modified thermosensitive polymer B aqueous solution to 500g of isovaleraldehyde mother liquor (catalyst content 50ppm) at 60℃, stir for 7h and let stand to separate into layers.

[0089] (2) After the layers are separated, the rhodium metal ions are adsorbed on the thermosensitive polymer at room temperature. The temperature is raised to 70°C and stirred for 2 hours. When the thermosensitive hydrogel molecular chains shrink and completely encapsulate the rhodium metal, the thermosensitive hydrogel molecular chains encapsulating the rhodium metal begin to precipitate when the temperature is raised to 95°C. After the temperature is raised to 103°C and the temperature is raised, no new precipitate is precipitated.

[0090] (3) The rhodium-containing polymer was separated after filtration. The separated rhodium-containing polymer was dried in a vacuum drying oven at 40°C for 5 hours and then transferred to a muffle furnace and calcined at 550°C for 7 hours to obtain the recovered rhodium catalyst. The rhodium catalyst recovery rate was 95.27%.

[0091] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. The solutions disclosed in the embodiments are described simply because they correspond to the methods disclosed in the embodiments; relevant parts can be found in the method section.

[0092] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for recovering low-concentration rhodium catalyst from organic by-products containing rhodium catalyst, characterized in that, Includes the following steps: (1) Add the modified temperature-sensitive polymer aqueous solution to the isovaleraldehyde mother liquor, stir and let stand to separate into layers; (2) The aqueous phase obtained after separation is heated, and the polymer adsorbed with rhodium undergoes a phase change and precipitates out. After filtration, drying and calcination, the recovered rhodium catalyst is obtained. The modified thermosensitive polymer is a thermosensitive polymer with phosphine groups at the end.

2. The method for recovering low-concentration rhodium catalyst from organic by-products containing rhodium catalyst according to claim 1, characterized in that, The amount of the modified thermosensitive polymer aqueous solution added is 1-20 times the mass of the catalyst in the mother liquor, and the concentration of the modified thermosensitive polymer aqueous solution is 1-10 mg / ml.

3. The method for recovering low-concentration rhodium catalyst from organic by-products containing rhodium catalyst according to claim 1, characterized in that, The stirring temperature in step (1) is 34-55℃ and the stirring time is 4-7h.

4. The process for recovering low concentration rhodium catalyst from rhodium- containing organic scraps according to claim 1, characterized in that, The heating in step (2) is first raised from room temperature to 60-85°C and maintained for 0.5-1.5 h to allow the modified thermosensitive polymer to completely coat the rhodium catalyst in the solution; then the temperature is continuously raised to 90-103°C to allow the modified thermosensitive polymer to completely precipitate.

5. The method for recovering low-concentration rhodium catalyst from organic by-products containing rhodium catalyst according to claim 1, characterized in that, The drying temperature in step (2) is 30-50℃ and the drying time is 3-6h.

6. The method for recovering low-concentration rhodium catalyst from organic by-products containing rhodium catalyst according to claim 1, characterized in that, The roasting temperature in step (2) is 500-600℃ and the roasting time is 5-10h.

7. The method for recovering low-concentration rhodium catalyst from organic by-products containing rhodium catalyst according to any one of claims 1-6, characterized in that, The modified thermosensitive polymer is prepared as follows: A. The monomer, initiator, and catalyst are dissolved in an organic solvent and mixed at low temperature. After mixing, the mixture is heated under inert gas protection to obtain a thermosensitive polymer. B. Continue adding alkylphosphine compounds, and the reaction yields a thermosensitive polymer with phosphine groups at the ends.

8. The process for recovering low concentration rhodium catalyst from rhodium- containing catalyst-containing organic scraps according to claim 7, characterized by, In step A, the mass ratio of the monomer, the initiator, and the catalyst is 1:0.05-0.1:0.01-0.

03. The monomer includes one or more of 4-methacrylamidoaniline, N-isopropylacrylamide, and ethylene glycol monomethyl ether methacrylic acid; The initiator includes one or more of azobisisobutyronitrile, benzoyl peroxide, and azobisisoheptanenitrile; The catalyst includes one or more of cuprous chloride, cuprous bromide, cuprous thiocyanate, and cuprous hexafluorophosphate. The organic solvent includes one or more of tetrahydrofuran, dichloromethane, diethyl ether, and anhydrous ethanol.

9. The process for recovering low concentration rhodium catalyst from rhodium- containing catalyst-containing organic scraps according to claim 7, characterized by, The low-temperature mixing temperature in step A is 0-10℃, the heating reaction temperature is 55-80℃, and the reaction time is 20-30h.

10. The method for recovering low-concentration rhodium catalyst from organic by-products containing rhodium catalyst according to claim 7, characterized in that, The molar ratio of the thermosensitive polymer to the alkylphosphine compound in step B is 1:1.1-1.5.