A method for regenerating a carbon-supported gold-based catalyst for vinyl chloride production

Abstract

The present application relates to a kind of regeneration methods of carbon-supported gold-based catalyst for vinyl chloride production, belong to catalyst regeneration technical field.The carbon-supported gold-based catalyst deactivated after being used for vinyl chloride production is calcined under inert atmosphere to obtain calcined gold-loaded carbon;The obtained calcined gold-loaded carbon is added to organic aqua regia and impregnated under pressure stirring for 3-8h, after impregnation is completed, the treated activated carbon A and gold-containing leaching solution are separated;The obtained activated carbon is passed into high-pressure steam and oxygen and kept warm;Then stop passing into high-pressure steam, continue to pass into oxygen, keep warm for 1-5h, naturally cool to room temperature, obtain the activated carbon B after reactivation;A certain proportion of ionic liquid is added to gold-containing leaching solution to configure new impregnation solution, the obtained activated carbon B after reactivation is vacuum impregnated in new impregnation solution, solvent is evaporated, and regenerated gold-based catalyst is obtained after drying.The present application does not produce any waste during the whole process, and the process is simple, which realizes the green cycle of the carbon-supported gold-based catalyst deactivated after being used for vinyl chloride production.

Description

Technical Field

[0001] This invention relates to a method for regenerating a carbon-supported gold-based catalyst used in vinyl chloride production, belonging to the field of catalyst regeneration technology. Background Technology

[0002] China is a major producer and the largest consumer of vinyl chloride. Due to uneven energy distribution—poor in oil, rich in coal, and scarce in natural gas—the country primarily uses the calcium carbide acetylene process to produce vinyl chloride. Carbon-supported mercury catalysts are commonly used in vinyl chloride production and are employed by the vast majority of factories in China. However, the drawbacks of these highly efficient mercury chloride catalysts have become apparent: the active components are prone to volatilization and loss, they have poor renewability, and they cause significant harm to the ecological environment. From a sustainable development perspective, there is an urgent need to find environmentally friendly mercury-free catalysts to replace mercury catalysts and address the current bottlenecks in the PVC industry.

[0003] Currently, domestic researchers have conducted extensive experimental studies using precious metals such as gold, palladium, platinum, and ruthenium as active components. Among them, gold catalysts have the best effect. However, their cost is very high, and they also suffer from deactivation.

[0004] The main reasons for the deactivation of gold-based catalysts include the following three aspects: (1) the active component Au 3+ Or Au + Reduced to Au 0 (2) Carbon deposits are generated, and the active components are covered by carbon deposits; (3) Au particles and clusters aggregate. During the reaction, these three reasons may occur simultaneously. (Research progress on gold-based mercury-free catalysts for acetylene hydrochlorination, Zeng Junjian).

[0005] Application number 2022115783899 discloses a method for regenerating a deactivated gold-based acetylene hydrochlorination catalyst. It presents a method combining ultrasonic washing with polar and non-polar solvents under ultrasonic conditions with microwave heating under inert gas protection to regenerate the gold-based acetylene hydrochlorination catalyst. This method primarily addresses the issue that solvents A and B can dissolve and wash out the self-polymerized organic matter in the deactivated gold-based catalyst, restoring and expanding the specific surface area and pore size of the activated carbon support. However, how to better solve the three main problems of gold-based catalyst deactivation remains a challenge. Summary of the Invention

[0006] To address the problems and shortcomings of the existing technology, this invention provides a method for regenerating a carbon-supported gold-based catalyst for vinyl chloride production. This invention involves calcining the deactivated carbon-supported gold-based catalyst under an inert atmosphere, then leaching it with organic aqua regia. The gold-leached activated carbon is then activated by a combination of high-pressure steam and oxygen, followed by additional oxygen. Finally, the reactivated activated carbon B is vacuum impregnated, evaporated, and dried in a newly prepared gold-containing impregnation solution to obtain the regenerated gold-based catalyst. This invention is achieved through the following technical solution.

[0007] A method for regenerating a carbon-supported gold-based catalyst for vinyl chloride production, comprising the following steps:

[0008] (1) The deactivated carbon-supported gold-based catalyst after use in vinyl chloride production is calcined at 600℃-1000℃ for 1-8h under an inert atmosphere to obtain calcined gold-supported carbon.

[0009] (2) Add the calcined gold-loaded carbon obtained in step (1) to organic aqua regia and impregnate under pressure and stirring for 3-8 hours. After impregnation, separate the treated activated carbon A and the gold-containing leachate.

[0010] (3) The activated carbon obtained in step (2) is passed through high-pressure steam and oxygen and kept at 110-300℃ for 2-12 hours; then the high-pressure steam is stopped and oxygen is continuously passed through and kept at 100-180℃ for 1-5 hours, and then naturally cooled to room temperature to obtain reactivated activated carbon B.

[0011] (4) Add the corresponding amount of ionic liquid to the gold-containing leaching solution obtained in step (2) to obtain a new impregnation solution. Add the reactivated activated carbon B obtained in step (3) to the new impregnation solution for vacuum impregnation. Impregnate at an impregnation temperature of 26-100℃ for 6-12 hours. Evaporate the solvent and dry to obtain the regenerated gold-based catalyst.

[0012] In step (2), the organic aqua regia is prepared by mixing thionyl chloride and a polar aprotic organic solvent in a volume ratio of 1:5 to 1:30.

[0013] The polar aprotic organic solvent is one or more organic solvents in any proportion, such as acetone, pyridine, nitromethane, N,N-dimethylformamide, and acetonitrile.

[0014] In step (2), the pressure is 0.2-0.8 MPa.

[0015] In step (3), the high-pressure steam pressure is 0.1-0.5 MPa and the flow rate is 10-50 mL / min; the oxygen pressure is 0.05-0.5 MPa and the flow rate is 5-20 mL / min.

[0016] The ionic liquid in step (4) is one or more of the following: containing a P-ligand, containing an S-ligand, and containing an N-ligand. The P-ligand is one or more of the following: hexamethylphosphonic acid triamide, hydroxyethylidene diphosphonic acid, aminotrimethylene phosphonic acid, triphenylphosphine, and tetraphenylphosphine bromide. The S-ligand is one or more of the following: 1-ethyl-3-methylimidazolium thiocyanate, 3-methyl-1-[6-(N,N-dibutyldithiocarbamate)-hexyl]-imidazolium hexafluorophosphate, 4,5-methylenedisulfide-1,3-disulfide-2-thione, and 2-mercaptobenzimidazole. The N-ligand is one or more of the following: 2,5-dimethylaniline, tetrabutylammonium hydroxide, and 4-(5-chloro-2-pyridinium azo)-1,3-diaminobenzene. The ionic liquid is added to the gold-containing leaching solution at a mass ratio of 1-5:1-30 to obtain a new leaching solution.

[0017] In step (4), the drying process involves drying at 120°C for 2-8 hours.

[0018] The beneficial effects of this invention are:

[0019] (1) The present invention obtains a regenerated gold-based catalyst by inert calcination of deactivated carbon-supported gold-based catalyst, leaching gold with organic aqua regia, activation by combination of activated carbon and vacuum impregnation with a new impregnation solution prepared by ionic liquid. This not only exposes the active sites covered by carbon deposits, but also increases the active components.

[0020] (2) The present invention uses organic aqua regia to leach gold from activated carbon, avoiding the potential risks of using strong acid in ordinary aqua regia; and by adjusting the ratio of thionyl chloride and different polar aprotic organic solvents, the dissolution effect of gold in different carbon-supported gold-based catalysts is the best during the gold leaching process.

[0021] (3) The organic aqua regia gold-containing leachate obtained in the gold leaching process of the present invention does not require further recovery. After adding ionic liquid, it can be directly configured into a new impregnation solution. The reactivated activated carbon B is then impregnated in the new impregnation solution to achieve gold loading. The entire process does not generate any waste, the process is simple, and it realizes the green recycling of carbon-supported gold-based catalysts that are deactivated after use in vinyl chloride production. Attached Figure Description

[0022] Figure 1 This is a photograph of the deactivated carbon-supported gold-based catalyst from Example 1 of this invention.

[0023] Figure 2 This is a photograph of the regenerated gold-based catalyst after regeneration in Example 1 of the present invention. Detailed Implementation

[0024] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0025] Example 1

[0026] The regeneration method for the carbon-supported gold-based catalyst used in vinyl chloride production includes the following specific steps:

[0027] (1) 20g of deactivated carbon-supported gold-based catalyst after use in vinyl chloride production was calcined at 800℃ for 3h under an inert atmosphere (nitrogen atmosphere) to obtain calcined gold-supported carbon.

[0028] (2) Add 10g of the calcined gold-loaded carbon obtained in step (1) to 15mL of organic aqua regia (thionyl chloride + N,N-dimethylformamide at a volume ratio of 1:10) and pressurize and stir for 3h. After impregnation, separate the treated activated carbon A and the gold-containing leachate; the pressure is 0.4Mpa.

[0029] (3) The activated carbon obtained in step (2) is passed through high-pressure steam (pressure of 0.15 MPa, flow rate of 15 mL / min) and oxygen (pressure of 0.05 MPa, flow rate of 10 mL / min) and kept at 200℃ for 3 h; then the high-pressure steam is stopped and oxygen (pressure of 0.05 MPa, flow rate of 10 mL / min) is continuously passed through and kept at 150℃ for 1 h, and then naturally cooled to room temperature to obtain reactivated activated carbon B;

[0030] (4) Add 1g of 4-(5-chloro-2-pyridiniazo)-1,3-diaminobenzene to the gold-containing leaching solution obtained in step (2) to reconfigure a new impregnation solution. Vacuum impregnate 5g of the reactivated activated carbon B obtained in step (3) in 10mL of the new impregnation solution (vacuum degree is -0.1MPa). Impregnate at 60℃ for 8h. Evaporate the solvent and dry at 120℃ for 8h to obtain the regenerated gold-based catalyst.

[0031] Example 2

[0032] The regeneration method for the carbon-supported gold-based catalyst used in vinyl chloride production includes the following specific steps:

[0033] (1) 20g of deactivated carbon-supported gold-based catalyst after use in vinyl chloride production was calcined at 800℃ for 3h under an inert atmosphere (nitrogen atmosphere) to obtain calcined gold-supported carbon.

[0034] (2) 10g of the calcined gold-loaded carbon obtained in step (1) was added to 15mL of organic aqua regia (thionyl chloride + N,N-dimethylformamide at a mass ratio of 1:15) and impregnated under pressure and stirring for 3h. After impregnation, the treated activated carbon A and the gold-containing leachate were separated; the pressure was 0.4Mpa.

[0035] (3) The activated carbon obtained in step (2) is passed through high-pressure steam (pressure of 0.15 MPa, flow rate of 15 mL / min) and oxygen (pressure of 0.05 MPa, flow rate of 10 mL / min) and kept at 200℃ for 3 hours; then the high-pressure steam is stopped and oxygen (pressure of 0.05 MPa, flow rate of 10 mL / min) is continuously passed through and kept at 150℃ for 1 hour, and then naturally cooled to room temperature to obtain reactivated activated carbon B;

[0036] (4) Add 1g of 4-(5-chloro-2-pyridiniazo)-1,3-diaminobenzene to the gold-containing leaching solution obtained in step (2) to reconfigure a new impregnation solution. Vacuum impregnate 5g of the reactivated activated carbon B obtained in step (3) in 10mL of the new impregnation solution (vacuum degree is -0.1MPa). Impregnate at 60℃ for 8h. Evaporate the solvent and dry at 120℃ for 8h to obtain the regenerated gold-based catalyst.

[0037] Example 3

[0038] The regeneration method for the carbon-supported gold-based catalyst used in vinyl chloride production includes the following specific steps:

[0039] (1) 20g of deactivated carbon-supported gold-based catalyst after use in vinyl chloride production was calcined at 800℃ for 3h under an inert atmosphere (nitrogen atmosphere) to obtain calcined gold-supported carbon.

[0040] (2) Add 10g of the calcined gold-loaded carbon obtained in step (1) to 15mL of organic aqua regia (thionyl chloride + pyridine at a mass ratio of 1:10) and pressurize and stir for 3h. After impregnation, separate the treated activated carbon A and the gold-containing leachate; the pressurization is 0.4Mpa.

[0041] (3) The activated carbon obtained in step (2) is passed through high-pressure steam (pressure of 0.15 MPa, flow rate of 15 mL / min) and oxygen (pressure of 0.05 MPa, flow rate of 10 mL / min) and kept at 200℃ for 3 h; then the high-pressure steam is stopped and oxygen (pressure of 0.05 MPa, flow rate of 10 mL / min) is continuously passed through and kept at 150℃ for 1 h, and then naturally cooled to room temperature to obtain reactivated activated carbon B;

[0042] (4) Add 1g of 4-(5-chloro-2-pyridiniazo)-1,3-diaminobenzene to the gold-containing leaching solution obtained in step (2) to reconfigure a new impregnation solution. Vacuum impregnate 5g of the reactivated activated carbon B obtained in step (3) in 10mL of the new impregnation solution (vacuum degree is -0.1MPa). Impregnate at 60℃ for 8h. Evaporate the solvent and dry at 120℃ for 8h to obtain the regenerated gold-based catalyst.

[0043] Example 4

[0044] The regeneration method for the carbon-supported gold-based catalyst used in vinyl chloride production includes the following specific steps:

[0045] (1) 20g of deactivated carbon-supported gold-based catalyst after use in vinyl chloride production was calcined at 800℃ for 3h under an inert atmosphere (nitrogen atmosphere) to obtain calcined gold-supported carbon.

[0046] (2) Add 10g of the calcined gold-loaded carbon obtained in step (1) to 15mL of organic aqua regia (thionyl chloride + pyridine at a mass ratio of 1:15) and pressurize and stir for 3h. After impregnation, separate the treated activated carbon A and the gold-containing leachate; the pressurization is 0.4Mpa.

[0047] (3) The activated carbon obtained in step (2) is passed through high-pressure steam (pressure of 0.15 MPa, flow rate of 15 mL / min) and oxygen (pressure of 0.05 MPa, flow rate of 10 mL / min) and kept at 200℃ for 3 h; then the high-pressure steam is stopped and oxygen (pressure of 0.05 MPa, flow rate of 10 mL / min) is continuously passed through and kept at 150℃ for 1 h, and then naturally cooled to room temperature to obtain reactivated activated carbon B;

[0048] (4) Add 1g of 4-(5-chloro-2-pyridiniazo)-1,3-diaminobenzene to the gold-containing leaching solution obtained in step (2) to reconfigure a new impregnation solution. Vacuum impregnate 5g of the reactivated activated carbon B obtained in step (3) in 10mL of the new impregnation solution (vacuum degree is -0.1MPa). Impregnate at 60℃ for 8h. Evaporate the solvent and dry at 120℃ for 8h to obtain the regenerated gold-based catalyst.

[0049] To further demonstrate the catalytic effect of the catalyst prepared in this invention, the regenerated gold-based catalyst obtained in Examples 1 to 4 above, the fresh catalyst, and the deactivated catalyst were tested in a fixed-bed acetylene hydrochlorination reactor. The test was conducted at an acetylene volume hourly space velocity of 1000 h⁻¹. -1 The reaction was carried out at a flow rate ratio of 1.1:1 for hydrogen chloride and acetylene, and at a temperature of 150℃. The reaction products were absorbed by alkaline solution and then entered a gas chromatograph for online evaluation and analysis. The results are shown in Table 1.

[0050] Table 1

[0051]

[0052]

[0053] As can be seen from Table 1, the performance of the regenerated catalyst obtained by the present invention is very close to that of the unused fresh catalyst.

[0054] Example 5

[0055] The regeneration method for the carbon-supported gold-based catalyst used in vinyl chloride production includes the following specific steps:

[0056] (1) 20g of deactivated carbon-supported gold-based catalyst after use in vinyl chloride production was calcined at 600℃ for 8h under an inert atmosphere (nitrogen atmosphere) to obtain calcined gold-supported carbon.

[0057] (2) Add 10g of the calcined gold-loaded carbon obtained in step (1) to 15mL of organic aqua regia (thionyl chloride + nitromethane in a mass ratio of 1:5) and pressurize and stir for 8h. After impregnation, separate the treated activated carbon A and the gold-containing leachate; the pressurization is 0.2Mpa.

[0058] (3) The activated carbon obtained in step (2) is passed through high-pressure steam (pressure of 0.1 MPa, flow rate of 10 mL / min) and oxygen (pressure of 0.5 MPa, flow rate of 5 mL / min) and kept at 110℃ for 12 h; then the high-pressure steam is stopped and oxygen (pressure of 0.5 MPa, flow rate of 10 mL / min) is continuously passed through and kept at 100℃ for 5 h, and then naturally cooled to room temperature to obtain reactivated activated carbon B;

[0059] (4) Add 4,5-methylenedithio-1,3-dithio-2-thionone to the gold-containing leaching solution obtained in step (2) at a mass ratio of 1:5 to reconfigure a new impregnation solution. Vacuum impregnate 5g of the reactivated activated carbon B obtained in step (3) in 10mL of the new impregnation solution (vacuum degree is -0.1MPa). Impregnate at 60℃ for 6h, evaporate the solvent, and dry at 120℃ for 8h to obtain the regenerated gold-based catalyst.

[0060] Example 6

[0061] The regeneration method for the carbon-supported gold-based catalyst used in vinyl chloride production includes the following specific steps:

[0062] (1) 20g of deactivated carbon-supported gold-based catalyst after use in vinyl chloride production was calcined at 1000℃ for 1h under an inert atmosphere (nitrogen atmosphere) to obtain calcined gold-supported carbon.

[0063] (2) Add 10g of the calcined gold-loaded carbon obtained in step (1) to 15mL of organic aqua regia (thionyl chloride + acetonitrile in a mass ratio of 1:30) and pressurize and stir for 6h. After impregnation, separate the treated activated carbon A and the gold-containing leachate; the pressurization is 0.8Mpa.

[0064] (3) The activated carbon obtained in step (2) was passed through high-pressure steam (pressure of 0.5 MPa, flow rate of 50 mL / min) and oxygen (pressure of 0.1 MPa, flow rate of 20 mL / min) and kept at 300℃ for 12 h; then the high-pressure steam was stopped and oxygen (pressure of 0.1 MPa, flow rate of 20 mL / min) was continuously passed through and kept at 180℃ for 3 h, and then naturally cooled to room temperature to obtain reactivated activated carbon B;

[0065] (4) Add a mixed ionic liquid of hexamethylphosphotriamide and hydroxyethylidene diphosphonic acid in a volume ratio of 1:1 (the mass ratio of the gold leaching solution to the mixed ionic liquid is 3:18) to the gold leaching solution obtained in step (2) to reconfigure a new impregnation solution. Vacuum impregnate 5g of the reactivated activated carbon B obtained in step (3) in 10mL of the new impregnation solution (vacuum degree is -0.1MPa). Impregnate at 60℃ for 8h, evaporate the solvent, and dry at 120℃ for 8h to obtain the regenerated gold-based catalyst.

[0066] The specific embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. A method for regenerating a carbon-supported gold-based catalyst for vinyl chloride production, characterized in that... The specific steps include: (1) The deactivated carbon-supported gold-based catalyst after use in vinyl chloride production is calcined at 600℃-1000℃ for 1-8h under an inert atmosphere to obtain calcined gold-supported carbon. (2) Add the calcined gold-loaded carbon obtained in step (1) to organic aqua regia and impregnate under pressure and stirring for 3-8 hours. After impregnation, separate the treated activated carbon A and the gold-containing leachate. (3) Pass the activated carbon obtained in step (2) through high-pressure steam and oxygen, and keep it at a temperature of 110-300℃ for 2-12 hours; then stop passing high-pressure steam, continue to pass oxygen, keep it at a temperature of 100-180℃ for 1-5 hours, and cool it naturally to room temperature to obtain reactivated activated carbon B. (4) Add ionic liquid to the gold-containing leaching solution obtained in step (2) to obtain a new impregnation solution. Add the reactivated activated carbon B obtained in step (3) to the new impregnation solution for vacuum impregnation. The impregnation temperature is 26-100℃, and the impregnation time is 6-12h. Evaporate the solvent and dry to obtain the regenerated gold-based catalyst. In step (2), the organic aqua regia is prepared by mixing thionyl chloride and a polar aprotic organic solvent in a volume ratio of 1:2 to 1:

20. The polar aprotic organic solvent is one or more organic solvents in any proportion of acetone, pyridine, nitromethane, N,N-dimethylformamide, and acetonitrile. The ionic liquid in step (4) is one or more of the following: containing a P-ligand, containing an S-ligand, and containing an N-ligand. The P-ligand is one or more of the following: hexamethylphosphonic acid triamide, hydroxyethylidene diphosphonic acid, aminotrimethylene phosphonic acid, triphenylphosphine, and tetraphenylphosphine bromide. The S-ligand is one or more of the following: 1-ethyl-3-methylimidazolium thiocyanate, 3-methyl-1-[6-(N,N-dibutyldithiocarbamate)-hexyl]-imidazolium hexafluorophosphate, 4,5-methylenedisulfide-1,3-disulfide-2-thione, and 2-mercaptobenzimidazole. The N-ligand is one or more of the following: 2,5-dimethylaniline, tetrabutylammonium hydroxide, and 4-(5-chloro-2-pyridinium azo)-1,3-diaminobenzene. The ionic liquid is added to the gold-containing leaching solution at a mass ratio of 1-5:1-30 to obtain a new leaching solution.

2. The method for regenerating the carbon-supported gold-based catalyst for vinyl chloride production according to claim 1, characterized in that: In step (2), the pressure is 0.2-0.8 MPa.

3. The method for regenerating the carbon-supported gold-based catalyst for vinyl chloride production according to claim 1, characterized in that: In step (3), the high-pressure steam pressure is 0.1-0.5 MPa and the flow rate is 10-50 mL / min; the oxygen pressure is 0.05-0.5 MPa and the flow rate is 5-20 mL / min.

4. The method for regenerating the carbon-supported gold-based catalyst for vinyl chloride production according to claim 3, characterized in that: In step (4), the drying process involves drying at 120°C for 2-8 hours.

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