Mercury catalyst added with silver element as well as preparation method and application of mercury catalyst
By adding silver elements to the mercury catalyst to form a stable mercury-silver complex, the problem of volatility of traditional mercury catalysts at high temperatures is solved, and more efficient and environmentally friendly PVC production is achieved.
Patent Information
- Application Number
- CN202510313239.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-17
- Publication Date
- 2025-07-08
AI Technical Summary
Traditional mercury catalysts are prone to volatilization under high temperature conditions, resulting in environmental pollution and short service life, making it difficult to achieve stable and efficient catalytic effects in the production of calcium carbide PVC.
By adding silver elements to the mercury catalyst, a stable mercury-silver complex is formed, and an improved catalyst is prepared to inhibit mercury volatility and improve the stability and reaction efficiency of the catalyst.
Significantly reduce mercury volatility, extend the service life of the catalyst, improve catalytic reaction efficiency, reduce environmental pollution risks, and provide a greener and more efficient PVC production solution.
Smart Images
Figure CN120268394A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of polyvinyl chloride production, and in particular to a mercury catalyst added with silver element, and a preparation method and application thereof. Background Art
[0002] Polyvinyl chloride (PVC), as one of the synthetic resins with the largest global production and the widest application, plays an irreplaceable role in many fields such as building materials, decoration, pipe manufacturing, daily necessities production, fiber industry, electronics industry and automobile industry. The production process of PVC is mainly divided into two types: ethylene method and calcium carbide method. Among them, the calcium carbide method has become the mainstream method of PVC production due to its advantages of abundant raw material resources and low production cost.
[0003] In short, the process of producing PVC by the calcium carbide method is to first use calcium carbide (i.e. calcium carbide) to react with water to generate acetylene gas; then, acetylene reacts with hydrogen chloride under specific conditions to generate vinyl chloride monomer; finally, vinyl chloride monomer is polymerized to eventually generate PVC. In this series of chemical reactions, mercury-containing catalysts play a vital role. Among these catalysts, the content of mercuric chloride is usually as high as 10%-12%, and its catalytic mechanism mainly relies on the interaction between the mercury element and the carbon atoms on the surface of the activated carbon to form a catalytic complex, thereby effectively promoting the reaction process of acetylene and hydrogen chloride.
[0004] However, in the process of producing PVC by calcium carbide method, the performance of traditional mercury catalysts in high-temperature reaction environment is not satisfactory. Specifically, mercury is easy to volatilize under high temperature conditions, which not only causes air and water pollution, but also seriously limits the service life of the catalyst. The volatilization of mercury not only increases the risk of environmental pollution, but also makes the continuous and stable use of catalysts extremely difficult, which in turn poses a severe challenge to the economy and sustainability of PVC production.
[0005] In order to solve this bottleneck problem that restricts the green development of calcium carbide-based PVC production, researchers have conducted a lot of exploration and attempts. They tried to effectively inhibit the volatilization of mercury by improving the formulation and preparation process of the catalyst. Unfortunately, however, most of the current solutions have not yet made a breakthrough in this issue. While improving the catalytic effect, they often cannot take into account the solution of environmental pollution problems, leaving the environmental problems of mercury catalysts still unresolved. Therefore, finding a catalyst that is both efficient and environmentally friendly has become a key issue that needs to be urgently addressed in the field of calcium carbide-based PVC production. Summary of the invention
[0006] In order to solve the above problems, the present invention provides a mercury catalyst by adding silver element and a preparation method and application thereof.
[0007] In a first aspect, the present invention provides a method for preparing a mercury catalyst by adding silver element, and the preparation method includes the following steps:
[0008] Obtain a graphene support;
[0009] Impregnate solution A containing a silver source on the graphene support, and then perform a first drying to obtain a catalyst precursor;
[0010] Impregnate solution B containing a mercury source on the catalyst precursor, and then perform a second drying to obtain the mercury catalyst.
[0011] Furthermore, the step of obtaining the graphene support includes the following process:
[0012] Mix graphite, melamine powder and glacial acetic acid, perform a first ball milling, let it stand and then perform a second ball milling to obtain a mixture;
[0013] Add the mixture into a mixed solution of deionized water and acetone and perform ultrasonic treatment at room temperature, transfer the upper clear liquid for centrifugal separation to obtain a precipitate product;
[0014] Dry the precipitate product to obtain graphene;
[0015] Place the graphene in an alumina sol-gel, stir and mix, and then perform drying and grinding to obtain the graphene support.
[0016] Furthermore, the weight-to-volume ratio of the graphite, the melamine powder and the glacial acetic acid is (450 - 550) g : (1450 - 1550) g : (1900 - 2100) ml; the weight ratio of the graphene and the alumina sol-gel is (60% - 80%) : (20% - 40%).
[0017] Furthermore, the working condition parameters of the first ball milling include: ball milling for 7 - 9 hours under the condition that the rotation speed of the ball milling is set to 250 - 350 revolutions per minute; the working condition parameters of the second ball milling include: ball milling for 22 - 26 hours under the condition that the rotation speed of the ball milling is set to 250 - 350 revolutions per minute.
[0018] Furthermore, the weight ratio of the silver source and the graphene support is (7.89 - 15.74) : 500.
[0019] Furthermore, the weight ratio of the mercury source and the catalyst precursor is (67.6 - 135.1) : 500.
[0020] Furthermore, the silver source includes silver nitrate, and the mercury source includes mercury chloride.
[0021] Second aspect, based on the same inventive concept, the present invention provides a mercury catalyst by adding silver element, and the mercury catalyst by adding silver element is prepared by the preparation method described in any item of the first aspect.
[0022] Third aspect, based on the same inventive concept, the present invention provides an application of the mercury catalyst by adding silver element described in any item of the second aspect in the production of polyvinyl chloride by the calcium carbide method.
[0023] The above technical solutions provided by the embodiments of the present invention have at least the following advantages compared with the prior art:
[0024] The embodiments of the present invention provide a mercury catalyst by adding silver element, its preparation method and application. The present invention provides an improved catalyst prepared by adding silver (Ag) element to a mercury-containing catalyst, which can effectively inhibit the volatilization of mercury, and at the same time improve the stability and reaction efficiency of the catalyst. By adding silver element, a stable mercury-silver complex is formed between silver and mercury. This complex not only significantly reduces the volatilization of mercury, but also enhances the efficiency of the catalytic reaction and prolongs the service life of the catalyst. Compared with the traditional mercury catalyst, the catalyst of the present invention has better catalytic stability and can maintain a high catalytic effect during a long-term use process. This catalyst provides a greener and more efficient solution for the production of PVC. Specifically:
[0025] 1. Improve catalytic efficiency: The addition of silver (Ag) element effectively improves the speed and selectivity of the catalytic reaction, and significantly improves the overall efficiency of PVC production.
[0026] 2. Reduce mercury volatilization: Silver element forms a stable mercury-silver complex by interacting with mercury, significantly inhibiting the volatilization of mercury and reducing the risk of environmental pollution.
[0027] 3. Prolong the service life of the catalyst: The improved catalyst shows a longer service life under high-temperature conditions, reduces the replacement frequency of the catalyst, and reduces the production cost.
[0028] 4. Green and environmentally friendly: By reducing the volatilization of mercury, the catalyst of the present invention helps to reduce environmental pollution and promote the green development of the PVC production process. Description of the Drawings
[0029] The drawings here are incorporated into the specification and form a part of this specification, showing embodiments in line with the present invention, and are used together with the specification to explain the principles of the present invention.
[0030] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the accompanying drawings required for the description of the embodiments or the prior art. Obviously, for those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.
[0031] Figure 1 It is a schematic flow chart of a preparation method of a mercury catalyst by adding silver element provided by an embodiment of the present invention. Specific embodiments
[0032] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.
[0033] Unless otherwise specifically stated, various raw materials, reagents, instruments, and equipment used in the present invention can be obtained through market purchases or can be prepared by existing methods.
[0034] In a first aspect, the present invention provides a preparation method of a mercury catalyst by adding silver element, as Figure 1 shown, the preparation method includes the following steps:
[0035] Obtain a graphene support;
[0036] Impregnate solution A containing a silver source on the graphene support, and then perform a first drying to obtain a catalyst precursor;
[0037] Impregnate solution B containing a mercury source on the catalyst precursor, and then perform a second drying to obtain the mercury catalyst.
[0038] The embodiments of the present invention provide a preparation method of a mercury catalyst by adding silver element. The present invention provides an improved catalyst prepared by adding silver (Ag) element to a mercury-containing catalyst, which can effectively inhibit the volatilization of mercury, and at the same time improve the stability and reaction efficiency of the catalyst. By adding silver element, a stable mercury-silver complex is formed between silver and mercury. This complex not only significantly reduces the volatilization of mercury, but also enhances the efficiency of the catalytic reaction and extends the service life of the catalyst. Compared with the traditional mercury catalyst, the catalyst of the present invention has better catalytic stability and can maintain a higher catalytic effect during a long-term use process. This catalyst provides a greener and more efficient solution for the production of PVC.
[0039] In some specific embodiments, the step of obtaining the graphene support includes the following process:
[0040] Mix graphite, melamine powder, and glacial acetic acid, then conduct the first ball milling, let it stand, and then conduct the second ball milling to obtain a mixture.
[0041] Add the mixture to a mixed solution of deionized water and acetone and ultrasonically treat it at room temperature. Transfer the supernatant and conduct centrifugal separation to obtain a precipitate product.
[0042] Dry the precipitate product to obtain graphene.
[0043] Place the graphene in an alumina sol-gel, stir and mix, then conduct drying and grinding to obtain the graphene support.
[0044] In some specific embodiments, the weight-to-volume ratio of the graphite, the melamine powder, and the glacial acetic acid is (450 - 550) g : (1450 - 1550) g : (1900 - 2100) ml; the weight ratio of the graphene and the alumina sol-gel is (60% - 80%) : (20% - 40%).
[0045] In some specific embodiments, the working condition parameters of the first ball milling include: ball milling for 7 - 9 hours under the condition that the rotation speed of the ball milling is set at 250 - 350 revolutions per minute; the working condition parameters of the second ball milling include: ball milling for 22 - 26 hours under the condition that the rotation speed of the ball milling is set at 250 - 350 revolutions per minute.
[0046] In some specific embodiments, the weight ratio of the silver source and the graphene support is (7.89 - 15.74) : 500.
[0047] In some specific embodiments, the weight ratio of the mercury source and the catalyst precursor is (67.6 - 135.1) : 500.
[0048] In some specific embodiments, the silver source includes silver nitrate, and the mercury source includes mercury chloride.
[0049] In a second aspect, based on the same inventive concept, the present invention provides a mercury catalyst with added silver elements, and the mercury catalyst with added silver elements is prepared by using the preparation method described in any item of the first aspect.
[0050] In a third aspect, based on the same inventive concept, the present invention provides an application of the mercury catalyst with added silver elements described in any item of the second aspect in the production of polyvinyl chloride by the calcium carbide method.
[0051] It should be noted that for the component raw materials involved in the mercury catalyst provided by the embodiments of the present invention by adding silver elements, its preparation method and application, if there is no special limitation or specific description, commercially available products can be directly used or prepared by oneself using existing publicly disclosed preparation methods; at the same time, for the steps and parameters involved, if there is no special limitation or specific description, they can be carried out according to the preparation process steps and parameters disclosed in the prior art or directly used according to the operation instructions of existing equipment, and the present invention document will not elaborate one by one.
[0052] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and not to limit the scope of the present invention. The experimental methods without specific conditions in the following embodiments are usually determined according to national standards. If there is no corresponding national standard, they are carried out according to general international standards, conventional conditions, or the conditions recommended by the manufacturer.
[0053] Example 1
[0054] This example provides a mercury catalyst by adding silver elements. The preparation method of the mercury catalyst by adding silver elements includes the following steps:
[0055] Preparation of graphene support:
[0056] Mix 500 g of graphite, 1500 g of melamine powder and 2000 mL of glacial acetic acid, and add them into a silicon nitride ball milling tank. The rotation speed of ball milling is set at 300 revolutions per minute, and ball milling is carried out for 8 hours. Subsequently, the sample is taken out and ground for 20 minutes, and then left standing in air for 48 hours to volatilize glacial acetic acid. Then weigh the composite material obtained in the previous step and further ball mill it at a ball milling rate of 300 revolutions per minute for 24 hours. Then put the obtained mixture into a mixed solution of deionized water and acetone (volume ratio of deionized water / acetone is 1:3), and perform ultrasonic treatment for 2 hours at room temperature. The sample after ultrasonic treatment is centrifuged at 3000 revolutions per minute for 10 minutes. Pipette the supernatant, and centrifuge the supernatant at a speed of 8000 revolutions per minute for 5 minutes. Retain the precipitate product of the second centrifugation, and dry it in a vacuum dryer at room temperature (vacuum degree is 0.5 MPa) to finally obtain graphene. Place 500 g of graphene in 100 g of alumina sol-gel, stir and mix, dry, and grind to obtain a graphene support.
[0057] Weigh 7.89 grams of silver nitrate (Ag(NO3)2) and add it to 400 mL of deionized water. Stir until completely dissolved to obtain Solution A. Immerse it on 500 g of the carrier and dry it at 120 °C under nitrogen protection for 24 hours to obtain the catalyst precursor. Weigh 67.6 grams of mercury chloride HgCl2, add it to 400 mL of deionized water, and stir until completely dissolved to obtain Solution B. Immerse Solution B on the above-mentioned 500 g of catalyst precursor and dry it at 120 °C for 4 hours to improve the activity of the catalyst. Denote it as: RPVC-1.
[0058] Example 2
[0059] Support preparation: Please refer to Example 1.
[0060] Weigh 11.7 grams of silver nitrate and add it to 400 mL of deionized water. Stir until completely dissolved to obtain Solution A. Immerse it on 500 g of the carrier and dry it at 120 °C under nitrogen protection for 24 hours to obtain the catalyst precursor. Weigh 67.6 grams of mercury chloride HgCl2, add it to 400 mL of deionized water, and stir until completely dissolved to obtain Solution B. Immerse Solution B on the above-mentioned catalyst precursor and dry it at 120 °C for 4 hours to improve the activity of the catalyst. Denote it as: RPVC-2.
[0061] Example 3
[0062] Support preparation: Please refer to Example 1.
[0063] Weigh 15.74 grams of silver nitrate and add it to 400 mL of deionized water. Stir until completely dissolved to obtain Solution A. Immerse it on 500 g of the carrier and dry it at 120 °C under nitrogen protection for 24 hours to obtain the catalyst precursor. Weigh 67.6 grams of mercury chloride HgCl2, add it to 400 mL of deionized water, and stir until completely dissolved to obtain Solution B. Immerse Solution B on the above-mentioned catalyst precursor and dry it at 120 °C for 4 hours to improve the activity of the catalyst. Denote it as: RPVC-3.
[0064] Example 4
[0065] Support preparation: Please refer to Example 1.
[0066] Weigh 11.7 grams of silver nitrate and add it to 400 mL of deionized water. Stir until completely dissolved to obtain Solution A. Immerse it on 500 g of the carrier and dry it at 120 °C under nitrogen protection for 24 hours to obtain the catalyst precursor. Weigh 101.5 grams of mercury chloride HgCl2, add it to 400 mL of deionized water, and stir until completely dissolved to obtain Solution B. Immerse Solution B on the above-mentioned catalyst precursor and dry it at 120 °C for 4 hours to improve the activity of the catalyst. Denote it as: RPVC-4.
[0067] Example 5
[0068] Support preparation: Refer to Example 1
[0069] Weigh 11.7 g of silver nitrate and add it to 400 mL of deionized water. Stir until completely dissolved to obtain Solution A. Immerse it on 500 g of the support, and under the conditions of 120 °C and nitrogen protection, dry it for 24 hours to obtain the catalyst precursor. Weigh 135.1 g of mercury chloride HgCl2, add it to 400 mL of deionized water, stir until completely dissolved to obtain Solution B. Immerse Solution B on the above-mentioned catalyst precursor and dry it at 120 °C for 4 hours to improve the activity of the catalyst. Denote it as: RPVC-5.
[0070] Example 6
[0071] Support preparation: Refer to Example 1
[0072] Weigh 101.5 g of mercury chloride HgCl2, add it to 400 mL of deionized water, stir until completely dissolved to obtain Solution B. Immerse Solution B on the above-mentioned catalyst precursor and dry it at 120 °C for 4 hours to improve the activity of the catalyst. Denote it as: RPVC-6.
[0073] Example 7
[0074] The support used is commercially available coconut shell activated carbon. Weigh 11.7 g of silver nitrate and add it to 400 mL of deionized water. Stir until completely dissolved to obtain Solution A. Immerse it on 500 g of the support, and under the conditions of 120 °C and nitrogen protection, dry it for 24 hours to obtain the catalyst precursor. Weigh 101.5 g of mercury chloride HgCl2, add it to 400 mL of deionized water, stir until completely dissolved to obtain Solution B. Immerse Solution B on the above-mentioned catalyst precursor and dry it at 120 °C for 4 hours to improve the activity of the catalyst. Denote it as: RPVC-7.
[0075] Test Example
[0076] Catalyst evaluation method: It is used for the preparation of vinyl chloride by the hydrochlorination of acetylene. The acetylene space velocity is 120 h-1, the reaction temperature is 140 °C, V(HCl):V(C2H2) = 1.15, at atmospheric pressure, and it runs continuously for 20 h. Measure the average conversion rate and stability of acetylene. The results are shown in Table 1 and Table 2.
[0077] Table 1
[0078] Reaction time RPVC-1 RPVC-2 RPVC-3 RPVC-4 RPVC-5 RPVC-6 RPVC-7 10h 93.12％ 98.32％ 92.15％ 99.12％ 97.16％ 93.32％ 76.73％ 20h 83.28％ 92.52％ 86.15％ 99.45％ 88.45％ 89.65％ 75.67％
[0079] Table 2 Mercury content of the catalyst after 20 hours of reaction
[0080]
[0081] In summary, the embodiments of the present invention provide a mercury catalyst prepared by adding silver element, its preparation method and application. The present invention provides an improved catalyst prepared by adding silver (Ag) element to a mercury-containing catalyst, which can effectively inhibit the volatilization of mercury, and at the same time improve the stability and reaction efficiency of the catalyst. By adding silver element, a stable mercury-silver complex is formed between silver and mercury. This complex not only significantly reduces the volatilization of mercury, but also enhances the efficiency of the catalytic reaction and extends the service life of the catalyst. Compared with the traditional mercury catalyst, the catalyst of the present invention has better catalytic stability and can maintain a high catalytic effect during a long-term use. This catalyst provides a greener and more efficient solution for the production of PVC.
[0082] The various embodiments of the present invention may exist in the form of a range; it should be understood that the description in the form of a range is only for convenience and brevity and should not be construed as a rigid limitation on the scope of the present invention; therefore, it should be considered that the described range description has specifically disclosed all possible sub-ranges and individual values within that range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and individual numbers within the range, such as 1, 2, 3, 4, 5, and 6, and this applies regardless of the range. Additionally, whenever a numerical range is indicated herein, it means including any cited number (fraction or integer) within the indicated range.
[0083] The above are only specific embodiments of the present invention, enabling those skilled in the art to understand or implement the present invention. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to these embodiments shown herein, but rather will conform to the broadest scope consistent with the principles and novel features claimed herein.
Claims
1. A preparation method of a mercury catalyst by adding silver element, characterized in that, The preparation method comprises the following steps: Obtain a graphene support; Immerse solution A containing a silver source on the graphene support, and then perform first drying to obtain a catalyst precursor; Immerse solution B containing a mercury source on the catalyst precursor, and then perform second drying to obtain the mercury catalyst.
2. The preparation method of the mercury catalyst by adding silver element according to claim 1, characterized in that, The step of obtaining the graphene support comprises the following process: Mix graphite, melamine powder and glacial acetic acid, perform first ball milling, let it stand, and then perform second ball milling to obtain a mixture; Add the mixture into a mixed solution of deionized water and acetone, perform ultrasonic treatment at room temperature, transfer the upper clear liquid and perform centrifugal separation to obtain a precipitate product; Dry the precipitate product to obtain graphene; Place the graphene in an alumina sol-gel, stir and mix, and then perform drying and grinding to obtain the graphene support.
3. The preparation method of the mercury catalyst by adding silver element according to claim 2, characterized in that, The weight-to-volume ratio of the graphite, the melamine powder and the glacial acetic acid is (450-550) g:(1450-1550) g:(1900-2100) ml; the weight ratio of the graphene and the alumina sol-gel is (60%-80%):(20%-40%).
4. The preparation method of the mercury catalyst by adding silver element according to claim 2, characterized in that, The working condition parameters of the first ball milling include: ball milling for 7-9 hours under the condition that the rotation speed of the ball milling is set at 250-350 revolutions per minute; the working condition parameters of the second ball milling include: ball milling for 22-26 hours under the condition that the rotation speed of the ball milling is set at 250-350 revolutions per minute.
5. The preparation method of the mercury catalyst by adding silver element according to claim 1, characterized in that, The weight ratio of the silver source and the graphene support is (7.89-15.74):
500.
6. The preparation method of the mercury catalyst by adding silver element according to claim 1, characterized in that, The weight ratio of the mercury source and the catalyst precursor is (67.6-135.1):
500.
7. The preparation method of the mercury catalyst by adding silver element according to claim 1, characterized in that The silver source includes silver nitrate, and the mercury source includes mercuric chloride.
8. A mercury catalyst with silver element added, characterized in that, The mercury catalyst with silver element added is prepared by using the preparation method according to any one of claims 1-7.
9. Use of the mercury catalyst with silver element added according to claim 8 in the production of polyvinyl chloride by the calcium carbide method.