Recovery and regeneration method of palladium acetate
The problem of low palladium acetate recovery rate was solved by using activated carbon decolorization and sulfide metathesis reaction, achieving efficient palladium acetate recovery and regeneration while maintaining the catalytic activity of the regenerated palladium acetate.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- ANHUI RUISAI BIOCHEM TECH
- Filing Date
- 2025-04-30
- Publication Date
- 2026-05-01
AI Technical Summary
In existing technologies, palladium acetate has a low recovery rate and cannot be regenerated, resulting in high production costs.
The mother liquor after decolorization with activated carbon was then reacted with an aqueous sulfide solution to generate palladium sulfide, which was then reacted with acetic acid in a metathesis reaction to obtain palladium acetate.
High recovery and regeneration of palladium acetate were achieved, with a recovery rate of over 80%, and the catalytic activity of the regenerated palladium acetate was comparable to that of the original palladium acetate.
Abstract
Description
A method for the recovery and regeneration of palladium acetate Technical Field
[0001] This invention belongs to the field of metal recycling technology, specifically relating to a method for the recovery and regeneration of palladium acetate. Background Technology
[0002] 5-Acetyl-3-chloroiminodibenzyl is an important pharmaceutical intermediate. Its synthesis primarily involves a chlorination reaction in an organic solution between 5-acetyliminodibenzyl and chlorosuccinimide in the presence of palladium acetate as a catalyst, yielding 5-acetyl-3-chloroiminodibenzyl. Palladium acetate, being a precious metal catalyst, is relatively expensive. Therefore, recovering and reusing palladium acetate from the mother liquor after the reaction can reduce production costs. Current technologies for recovering precious metals mainly employ biosorption and electrochemical methods. However, these methods not only have low recovery rates but also fail to regenerate palladium acetate. Therefore, a high-recovery-rate method for the recovery and regeneration of palladium acetate is urgently needed. Summary of the Invention
[0003] The purpose of this invention is to provide a method for the recovery and regeneration of palladium acetate. The method provided by this invention has a high recovery rate and can regenerate palladium acetate.
[0004] To achieve the above-mentioned objectives, the present invention provides the following technical solution:
[0005] This invention provides a method for the recovery and regeneration of palladium acetate, comprising the following steps:
[0006] (1) The mother liquor after the reaction of palladium acetate catalyzing the synthesis of 5-acetyl-3-chloroiminodibenzyl was mixed with activated carbon and decolorized to obtain the decolorized mother liquor.
[0007] (2) The decolorized mother liquor obtained in step (1) is mixed with an aqueous solution of sulfide to carry out a precipitation reaction to obtain palladium sulfide;
[0008] (3) The palladium sulfide obtained in step (2) is mixed with acetic acid and subjected to a metathesis reaction to obtain palladium acetate.
[0009] Preferably, in step (1), the ratio of the mass of activated carbon to the volume of the mother liquor after the reaction is (1-1.5) g: 500 mL.
[0010] Preferably, the decolorization temperature in step (1) is 20-45°C and the decolorization time is 1-2.5h.
[0011] Preferably, the sulfide in the aqueous solution of the sulfide in step (2) includes one or more of sodium sulfide, potassium sulfide and ammonium sulfide.
[0012] Preferably, the mass concentration of the aqueous solution of sulfide in step (2) is 10-30%.
[0013] Preferably, the volume ratio of the mother liquor after the reaction in step (1) to the aqueous solution of sulfide in step (2) is 500:(10-20).
[0014] Preferably, the temperature of the precipitation reaction in step (2) is 20–35°C.
[0015] Preferably, the mass concentration of acetic acid in step (3) is 25-35%.
[0016] Preferably, in step (3), the mass ratio of palladium sulfide to acetic acid is (0.138-0.145) g: 20 mL.
[0017] Preferably, the temperature of the metathesis reaction in step (3) is 30-60°C, and the reaction time is 2-3 hours.
[0018] This invention provides a method for the recovery and regeneration of palladium acetate, comprising the following steps: (1) mixing the mother liquor from the catalytic synthesis of 5-acetyl-3-chloroiminodibenzyl acetate with activated carbon for decolorization to obtain a decolorized mother liquor; (2) mixing the decolorized mother liquor obtained in step (1) with an aqueous solution of sulfide for precipitation to obtain palladium sulfide; (3) mixing the palladium sulfide obtained in step (2) with acetic acid for metathesis reaction to obtain palladium acetate. This invention first decolorizes the mother liquor after the reaction, then adds sulfide to precipitate palladium sulfide, and then adds acetic acid to react the palladium sulfide with acetic acid to generate palladium acetate, thereby achieving the recovery and regeneration of palladium acetate. The recovery rate of palladium acetate is high, and the catalytic activity of the regenerated palladium acetate is comparable to that of the original palladium acetate. The results of the examples show that the recovery rate of palladium acetate using the method of this invention is above 80%. Detailed Implementation
[0019] This invention provides a method for the recovery and regeneration of palladium acetate, comprising the following steps:
[0020] (1) The mother liquor after the reaction of palladium acetate catalyzing the synthesis of 5-acetyl-3-chloroiminodibenzyl was mixed with activated carbon and decolorized to obtain the decolorized mother liquor.
[0021] (2) The decolorized mother liquor obtained in step (1) is mixed with an aqueous solution of sulfide to carry out a precipitation reaction to obtain palladium sulfide;
[0022] (3) The palladium sulfide obtained in step (2) is mixed with acetic acid and subjected to a metathesis reaction to obtain palladium acetate.
[0023] Unless otherwise specified, the present invention does not impose any special restrictions on the source of the raw materials, and commercially available products well known to those skilled in the art can be used.
[0024] In this invention, the mother liquor from the reaction of palladium acetate catalytic synthesis of 5-acetyl-3-chloroiminodibenzyl is mixed with activated carbon and decolorized to obtain a decolorized mother liquor.
[0025] The present invention does not have any particular limitation on the source of the mother liquor after the reaction of the palladium acetate-catalyzed synthesis of 5-acetyl-3-chloroiminodibenzyl, and any mother liquor after the reaction of the palladium acetate-catalyzed synthesis of 5-acetyl-3-chloroiminodibenzyl that is well known to those skilled in the art can be used. In an embodiment of the present invention, the mother liquor following the reaction of the palladium acetate-catalyzed synthesis of 5-acetyl-3-chloroiminodibenzyl is specifically prepared as follows: 1 mol of iminodibenzyl, 4 mol of acetic acid, 1.2 mol of acetic anhydride and 0.002 mol of perchloric acid are added to a three-necked flask equipped with a reflux device, heated at a uniform rate to 105°C, held at this temperature for 2 hours, and then cooled to 20°C to obtain an acetic acid solution of 5-acetyliminodibenzyl; 0.001 mol of palladium acetate and 1.3 mol of N-chlorosuccinimide are added to the acetic acid solution of 5-acetyliminodibenzyl, heated to 105°C and held at this temperature for 10 hours, then cooled to 25°C, 1.5 mol of water is added, stirred for 1 hour, and then cooled to 5°C. The mixture is then filtered to obtain 500 mL of the mother liquor following the reaction.
[0026] In this invention, the activated carbon is preferably 767 type medical-grade activated carbon. The activated carbon used in this invention has a better decolorization effect. This invention does not have a special limitation on the source of the activated carbon; commercially available products well known to those skilled in the art can be used. In the embodiments of this invention, the 767 type medical-grade activated carbon was purchased from Shanghai Xingchang Activated Carbon Co., Ltd.
[0027] In this invention, the preferred mass ratio of the activated carbon to the volume of the mother liquor after the reaction is (1-1.5) g: 500 mL. As one embodiment, the specific mass ratio of the activated carbon to the volume of the mother liquor after the reaction can be 1 g: 500 mL, 1.1 g: 500 mL, 1.2 g: 500 mL, 1.3 g: 500 mL, 1.4 g: 500 mL, or 1.5 g: 500 mL.
[0028] The present invention does not have any special limitations on the mixing of the mother liquor and activated carbon after the reaction of palladium acetate catalytic synthesis of 5-acetyl-3-chloroiminodibenzyl, and any material mixing technology known to those skilled in the art can be used.
[0029] In this invention, the temperature of the decolorization treatment is preferably 20–45°C. As one embodiment, the temperature of the decolorization treatment can specifically be 20°C, 25°C, 30°C, 35°C, 40°C, or 45°C.
[0030] In this invention, the decolorization treatment time is preferably 1 to 2.5 hours. As one embodiment, the decolorization treatment time can be specifically 1 hour, 1.5 hours, 2 hours, or 2.5 hours.
[0031] In this invention, the decolorization treatment is preferably carried out under stirring conditions. This invention does not impose any particular limitations on the stirring method and rate; any stirring technique well-known to those skilled in the art can be used. By controlling the type and amount of activated carbon, the temperature and time of the decolorization treatment within the aforementioned ranges, this invention can further improve the decolorization effect and avoid adverse effects on the performance of the subsequently recovered palladium acetate.
[0032] After the decolorization process is completed, the present invention preferably filters the product of the decolorization process to obtain a filtrate, and then concentrates the filtrate to obtain a decolorized mother liquor.
[0033] In this invention, the filtration is preferably performed by vacuum filtration. This invention does not impose any special limitations on the operation of the vacuum filtration; any vacuum filtration technique well-known to those skilled in the art can be used to separate the solid and liquid.
[0034] In this invention, the concentrated volume of the mother liquor after decolorization is preferably 1 / 3 to 1 / 2 of the filtrate volume. This invention does not impose any special limitations on the concentration operation; concentration techniques well-known to those skilled in the art can be used.
[0035] After obtaining the decolorized mother liquor, the present invention mixes the decolorized mother liquor with an aqueous solution of sulfide to carry out a precipitation reaction to obtain palladium sulfide.
[0036] In this invention, the sulfide in the aqueous solution of the sulfide preferably includes one or more of sodium sulfide, potassium sulfide and ammonium sulfide, and more preferably sodium sulfide.
[0037] In this invention, the mass concentration of the aqueous solution of the sulfide is preferably 10-30%. As one embodiment, the mass concentration of the aqueous solution of the sulfide may specifically be 10%, 15%, 20%, 25%, or 30%.
[0038] In this invention, the volume ratio of the mother liquor after reaction to the aqueous solution of the sulfide is preferably 500:(10-20). As one embodiment, the volume ratio of the mother liquor after reaction to the aqueous solution of the sulfide can be specifically 500:10, 500:15, or 500:20.
[0039] The present invention does not have any special limitations on the mixing operation of the decolorized mother liquor and the aqueous solution of sulfide; any material mixing technology known to those skilled in the art can be used.
[0040] In this invention, the preferred temperature for the precipitation reaction is 20–35°C; the preferred time for the precipitation reaction is 2–2.5 h. In this invention, during the precipitation reaction, palladium in the decolorized mother liquor reacts with sulfur in the sulfide to form palladium sulfide precipitate. By controlling the amount of sulfide, the temperature, and the time of the precipitation reaction within the above-mentioned ranges, this invention ensures complete palladium precipitation and improves the recovery rate of palladium acetate.
[0041] After the precipitation reaction is completed, the product of the precipitation reaction is preferably filtered to obtain a solid, and then the solid is washed and dried to obtain palladium sulfide.
[0042] The present invention does not impose any special limitations on the filtering, washing and drying operations, and any technical solutions known to those skilled in the art can be used.
[0043] After obtaining palladium sulfide, the present invention mixes the palladium sulfide with acetic acid and performs a metathesis reaction to obtain palladium acetate.
[0044] In this invention, the mass concentration of the acetic acid is preferably 25-35%. As one embodiment, the mass concentration of the acetic acid may specifically be 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, or 35%.
[0045] In this invention, the preferred mass ratio of palladium sulfide to acetic acid is (0.138–0.145) g:20 mL. As one embodiment, the specific mass ratio of palladium sulfide to acetic acid can be 0.138 g:20 mL, 0.139 g:20 mL, 0.140 g:20 mL, 0.141 g:20 mL, 0.142 g:20 mL, 0.143 g:20 mL, 0.144 g:20 mL, or 0.145 g:20 mL.
[0046] In this invention, the temperature of the metathesis reaction is preferably 30–60°C. As one embodiment, the temperature of the metathesis reaction can specifically be 30°C, 35°C, 40°C, 45°C, 50°C, 55°C, or 60°C.
[0047] In this invention, the metathesis reaction time is preferably 2-3 hours. As one embodiment, the metathesis reaction time can specifically be 2 hours, 2.2 hours, 2.5 hours, 2.8 hours, or 3 hours. By controlling the amount of each raw material, the temperature and time of the metathesis reaction within the above ranges, this invention ensures that palladium sulfide reacts fully to form palladium acetate, thereby improving the recovery rate of palladium acetate.
[0048] After the metathesis reaction is completed, the product of the metathesis reaction is preferably concentrated, cooled and crystallized, centrifuged, washed with water and dried in sequence to obtain palladium acetate.
[0049] In this invention, the volume of the concentrated solution is preferably 1 / 4 to 1 / 2 of the volume of the solution before concentration.
[0050] In this invention, the preferred temperature for cooling crystallization is 5 to 10°C; the preferred time for cooling crystallization is 2 to 2.5 hours.
[0051] The present invention does not impose any special limitations on the centrifugation, washing and drying operations, and any technical solutions known to those skilled in the art can be used.
[0052] This invention first decolorizes the mother liquor after the reaction, then adds sulfide to form palladium sulfide precipitate, and then adds acetic acid to react with palladium sulfide to form palladium acetate. This achieves the recovery and regeneration of palladium acetate. By controlling the process parameters such as the amount of each raw material, reaction temperature and time during the recovery and regeneration process, the recovery rate of palladium acetate is high and the catalytic activity of the regenerated palladium acetate is comparable to that of the original palladium acetate.
[0053] The technical solutions of this invention will be clearly and completely described below with reference to the embodiments thereof. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.
[0054] In each embodiment, the mother liquor after the reaction of palladium acetate-catalyzed synthesis of 5-acetyl-3-chloroiminodibenzyl was specifically prepared as follows: 1 mol of iminodibenzyl, 4 mol of acetic acid, 1.2 mol of acetic anhydride and 0.002 mol of perchloric acid were added to a three-necked flask equipped with a reflux device, heated at a uniform rate to 105°C, held at this temperature for 2 hours, and then cooled to 20°C to obtain an acetic acid solution of 5-acetyliminodibenzyl; 0.001 mol of palladium acetate and 1.3 mol of N-chlorosuccinimide were added to the acetic acid solution of 5-acetyliminodibenzyl, heated to 105°C and held at this temperature for 10 hours, then cooled to 25°C, 1.5 mol of water was added, stirred for 1 hour, and then cooled to 5°C. The mixture was then filtered to obtain 500 mL of the mother liquor after the reaction.
[0055] Example 1
[0056] A method for recovering and regenerating palladium acetate: (1) Take 500 mL of the mother liquor after the reaction of palladium acetate catalytic synthesis of 5-acetyl-3-chloroiminodibenzyl, add 1.2 g of activated carbon (767 type medical grade activated carbon), stir and decolorize at 25 °C for 2 h, filter and concentrate to 1 / 2 of the original solution volume to obtain the decolorized mother liquor;
[0057] (2) Add 15 mL of sodium sulfide aqueous solution with a mass concentration of 20% to the mother liquor obtained in step (1). Under stirring at room temperature, a gray-brown palladium sulfide precipitate is generated. After filtration, washing and drying, 0.138 g of palladium sulfide is obtained.
[0058] (3) The palladium sulfide 0.138g obtained in step (2) was mixed with 20mL of acetic acid with a mass concentration of 30%, reacted at 40℃ for 2h, concentrated to 1 / 2 of the original solution volume, cooled at 7℃ for 2.2h for crystallization, centrifuged, washed with water and dried to obtain brownish-yellow regenerated palladium acetate 0.180g, with a recovery rate of 80.20%.
[0059] The palladium acetate obtained in Example 1 has a melting point of 204.4–204.7 °C, and its catalytic activity is comparable to that of the initial palladium acetate.
[0060] Example 2
[0061] A method for recovering and regenerating palladium acetate: (1) Take 500 mL of the mother liquor after the reaction of palladium acetate catalytic synthesis of 5-acetyl-3-chloroiminodibenzyl, add 1.5 g of activated carbon (767 type medical grade activated carbon), stir and decolorize at 40 °C for 1.5 h, filter and concentrate to 1 / 2 of the original solution volume to obtain the decolorized mother liquor;
[0062] (2) Add 20 mL of sodium sulfide aqueous solution with a mass concentration of 10% to the mother liquor obtained in step (1). Under stirring at room temperature, a gray-brown palladium sulfide precipitate is generated. After filtration, washing and drying, 0.145 g of palladium sulfide is obtained.
[0063] (3) The palladium sulfide 0.145g obtained in step (2) was mixed with 20mL of acetic acid with a mass concentration of 30%, reacted at 45℃ for 2h, concentrated to 1 / 4 of the original solution volume, cooled and crystallized at 6℃ for 2.5h, separated by centrifugation, washed with water and dried to obtain 0.191g of brownish-yellow regenerated palladium acetate with a recovery rate of 85.21%.
[0064] The palladium acetate obtained in Example 2 has a melting point of 204.6–204.8 °C, and its catalytic activity is comparable to that of the initial palladium acetate.
[0065] Example 3
[0066] A method for recovering and regenerating palladium acetate: (1) Take 500 mL of the mother liquor after the reaction of palladium acetate catalytic synthesis of 5-acetyl-3-chloroiminodibenzyl, add 1.0 g of activated carbon (767 type medical grade activated carbon), stir and decolorize at 35°C for 1.5 h, filter and concentrate to 1 / 3 of the original solution volume to obtain the decolorized mother liquor;
[0067] (2) Add 15 mL of sodium sulfide aqueous solution with a mass concentration of 10% to the mother liquor obtained in step (1). Under stirring at room temperature, a gray-brown palladium sulfide precipitate is generated. After filtration, washing and drying, 0.140 g of palladium sulfide is obtained.
[0068] (3) The palladium sulfide 0.140 g obtained in step (2) was mixed with 20 mL of acetic acid with a mass concentration of 30%, reacted at 55 °C for 2 h, concentrated to 1 / 4 of the original solution volume, cooled and crystallized at 5 °C for 2 h, centrifuged, washed with water and dried to obtain 0.185 g of brownish-yellow regenerated palladium acetate with a recovery rate of 82.20%.
[0069] The palladium acetate obtained in Example 3 has a melting point of 204.6–204.8 °C, and its catalytic activity is comparable to that of the initial palladium acetate.
[0070] In summary, the method of this invention achieves the recovery and regeneration of palladium acetate, with a high recovery rate and the catalytic activity of the regenerated palladium acetate being comparable to that of the original palladium acetate.
[0071] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.
Claims
1. A method for recovering and regenerating palladium acetate, comprising the following steps: (1) The mother liquor after the catalytic synthesis of palladium acetate into 5-acetyl-3-chloroiminodibenzyl was mixed with activated carbon and decolorized to obtain a decolorized mother liquor; (2) The decolorized mother liquor obtained in step (1) was mixed with an aqueous solution of sulfide and a precipitation reaction was carried out to obtain palladium sulfide; (3) The palladium sulfide obtained in step (2) was mixed with acetic acid and a metathesis reaction was carried out to obtain palladium acetate.
2. The method for recovering and regenerating palladium acetate according to claim 1, characterized in that, In step (1), the ratio of the mass of activated carbon to the volume of the mother liquor after the reaction is (1-1.5) g: 500 mL.
3. The method for recovering and regenerating palladium acetate according to claim 1, characterized in that, The decolorization process in step (1) is carried out at a temperature of 20–45°C for 1–2.5 hours.
4. The method for recovering and regenerating palladium acetate according to claim 1, characterized in that, The sulfides in the aqueous solution of the sulfides in step (2) include one or more of sodium sulfide, potassium sulfide and ammonium sulfide.
5. The method for recovering and regenerating palladium acetate according to claim 1, characterized in that, The mass concentration of the aqueous solution of sulfide in step (2) is 10-30%.
6. The method for recovering and regenerating palladium acetate according to claim 5, characterized in that, The volume ratio of the mother liquor after the reaction in step (1) to the aqueous solution of sulfide in step (2) is 500:(10-20).
7. The method for recovering and regenerating palladium acetate according to claim 1, characterized in that, The precipitation reaction in step (2) is carried out at a temperature of 20–35°C.
8. The method for recovering and regenerating palladium acetate according to claim 1, characterized in that, In step (3), the mass concentration of acetic acid is 25-35%.
9. The method for recovering and regenerating palladium acetate according to claim 8, characterized in that, In step (3), the mass ratio of palladium sulfide to acetic acid is (0.138-0.145) g: 20 mL.
10. The method for recovering and regenerating palladium acetate according to claim 1, characterized in that, The temperature of the metathesis reaction in step (3) is 30-60℃, and the reaction time is 2-3h.