Composite polymerization inhibitor, preparation method and application thereof
By using composite polymerization inhibitors and precise temperature control technology to suppress the self-polymerization of acrylamide monomers, the problem of unstable product performance and quality in traditional methods has been solved, achieving efficient production and low-cost acrylamide preparation.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- ANHUI TIANRUN CHEM CO LTD
- Filing Date
- 2025-06-12
- Publication Date
- 2026-05-01
AI Technical Summary
Traditional methods for inhibiting the self-polymerization of acrylamide monomers have problems such as affecting product performance and poor control of reaction conditions, resulting in high production costs and unstable product quality.
A composite polymerization inhibitor, including modified chitosan, nanocomposite and N,N-di-n-butyldithiocarbamate, is used to prepare acrylamide through precise temperature control and high-shear emulsification, combined with precision metering pump and equilibrium distillation technology to optimize the acrylamide production process.
It effectively inhibits the self-polymerization of acrylamide monomers, increases purity to 99.9%, reduces the self-polymerization rate to below 0.01%, increases production efficiency by 20-30%, and reduces energy consumption and production costs.
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Figure CN120737446B_ABST
Abstract
Description
A composite polymerization inhibitor, its preparation method and its application Technical Field
[0001] This application relates to the field of acrylamide production technology, and in particular to a composite polymerization inhibitor, its preparation method and its application. Background Technology
[0002] Acrylamide is an important organic chemical raw material widely used in industries such as water treatment, papermaking, and oil extraction. In the production process of acrylamide, monomer self-polymerization is a common and serious problem. Self-polymerization not only reduces the yield of acrylamide monomers and increases production costs, but also leads to unstable product quality, affecting its performance in downstream applications.
[0003] Currently, traditional methods for inhibiting self-polymerization have many shortcomings, such as the impact of adding excessive polymerization inhibitors on product performance and poor self-polymerization inhibition due to inadequate control of reaction conditions. Therefore, developing a high-performance polymerization inhibitor and a method that can precisely inhibit the self-polymerization of acrylamide monomers and optimize production efficiency is of significant practical importance. Summary of the Invention
[0004] This application provides a composite polymerization inhibitor, its preparation method, and its application to effectively suppress monomer self-polymerization during acrylamide production.
[0005] In a first aspect, a composite polymerization inhibitor is provided, comprising:
[0006] 40-60 parts modified chitosan, 40-60 parts nanocomposite, 1-3 parts copper N,N-di-n-butyldithiocarbamate;
[0007] The preparation method of the modified chitosan includes the following steps:
[0008] S101. Chitosan is dissolved in 1 wt% acetic acid solution and stirred at 60°C for 2 h. Dimethylaminosulfonyl chloride is added, the pH is adjusted to 8, and the reaction is carried out for 4 h. After filtration and freeze-drying, an intermediate product is obtained. The mass-volume ratio of chitosan to acetic acid solution is 1 g: 100 mL, and the mass ratio of dimethylaminosulfonyl chloride to chitosan is 1: (4-6).
[0009] S102. The intermediate product is mixed with the modified solution and reacted under nitrogen for 6 hours. The resulting reaction solution is dialyzed for 48 hours and then freeze-dried to obtain modified chitosan. The mass ratio of the intermediate product to the modified solution is 1:(4-6).
[0010] Preferably, the modified solution comprises maleic anhydride, ammonium persulfate, and deionized water in a mass ratio of (2-4):0.1:100.
[0011] Preferably, the preparation method of the nanocomposite includes the following steps:
[0012] S201. Cerium oxide is dispersed in isopropanol and sonicated for 30 min to obtain a cerium oxide suspension. The mass-to-volume ratio of cerium oxide to isopropanol is 1 g: 4000 mL.
[0013] S202. The cerium oxide suspension and the compound solution are mixed at a mass ratio of 20:1, hydroxytyrosol and sorbic acid are added, and the mixture is stirred until completely dissolved. The pH is adjusted to 7 to obtain a nanocomposite. The mass ratio of hydroxytyrosol to sorbic acid is 2:1, and the mass of sorbic acid is 20% of the mass of cerium oxide.
[0014] Preferably, the method for preparing the compound solution includes:
[0015] Lithium stearate was dissolved in isopropanol at 50°C to obtain a first solution, and sophorolipid was dissolved in deionized water at 40°C to obtain a second solution. The first solution and the second solution were mixed to obtain a compound solution.
[0016] The mass ratio of lithium stearate to isopropanol is 1:10, the mass ratio of sophorolipid to deionized water is 1:5, and the mass ratio of lithium stearate to sophorolipid is 2:5.
[0017] Preferably, S202 further includes the addition of N-phenyl-2-naphthylamine, wherein the mass ratio of N-phenyl-2-naphthylamine to hydroxytyrosol is 25:1.
[0018] Secondly, a method for preparing the composite polymerization inhibitor as described above is provided, comprising the following steps:
[0019] Mix 40-60 parts of modified chitosan, 40-60 parts of nanocomposite and 1-3 parts of N,N-di-n-butyldithiocarbamate, and then treat with a high-shear emulsifier at 5000-10000 rpm for 30 min to obtain a composite polymerization inhibitor.
[0020] Thirdly, the application of composite polymerization inhibitors as described above in inhibiting monomer self-polymerization during the acrylamide production process is provided.
[0021] Preferably, the application includes the following steps:
[0022] Step 1: Precision Temperature Control System: Acrylonitrile is added to the reactor, and intelligent temperature control equipment is used to precisely control the reaction temperature within 5-10℃. A high-precision temperature sensor is used to monitor the temperature of the reaction system in real time, and the preheater is automatically adjusted through the feedback control system to ensure that the temperature fluctuation is within ±0.5℃.
[0023] Step 2: Addition of composite polymerization inhibitor: Add composite polymerization inhibitor to the reactor using a precision metering pump. The amount of composite polymerization inhibitor added is 0.08-0.12% of the monomer mass.
[0024] Step 3: Balance distillation: The discharged material enters the balance distillation device and is subjected to balance distillation under vacuum. Unreacted acrylonitrile in the material is recovered to the process water tank for recycling. The material circulation tank is ventilated to keep the material in a boiling state.
[0025] Step 4: Concentration Process: The material enters the concentration tower for further purification, evaporating excess water. The temperature is controlled at 65-70℃, the tower pressure is 16kPa, and the air volume is 20-30m³ / h. 3 / h;
[0026] Step 5: Refining process: After the material temperature is reduced to below 35℃, it is put into a storage tank and the pH value is adjusted to 7-9 to obtain acrylamide.
[0027] Preferably, in the third step, the controlled temperature is 55-60℃ and the vacuum degree is 0.06-0.065MPa.
[0028] The beneficial effects of the technical solution provided in this application include:
[0029] This application provides a composite polymerization inhibitor, its preparation method, and its application. The modified chitosan is modified by introducing a sulfonic acid group, dimethylaminosulfonyl chloride, and combining it with a modification solution to enhance its ability to capture free radicals and prolong the induction period. It is used together with nanocomposites and copper N,N-di-n-butyldithiocarbamate as a composite polymerization inhibitor. Copper N,N-di-n-butyldithiocarbamate is stable at high temperatures and can effectively quench free radicals, thereby improving the purity of acrylamide and meeting application requirements. Attached Figure Description
[0030] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0031] Figure 1 is a flowchart of the preparation method of the modified chitosan provided in this application;
[0032] Figure 2 is a flowchart of the preparation method of the nanocomposite provided in this application. Detailed Implementation
[0033] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.
[0034] Referring to Figures 1 and 2: This application provides a composite polymerization inhibitor, a preparation method and its application. The composite polymerization inhibitor can effectively inhibit monomer self-polymerization in acrylamide production. The composite polymerization inhibitor includes 40-60 parts of modified chitosan and 40-60 parts of nanocomposite.
[0035] Example 1
[0036] The composite polymerization inhibitor provided in this embodiment includes 25g of modified chitosan, 25g of nanocomposite and 1g of N,N-di-n-butyldithiocarbamate copper.
[0037] The composite polymerization inhibitor is prepared by mixing 25g of modified chitosan, 25g of nanocomposite and 1g of N,N-di-n-butyldithiocarbamate, and then treating the mixture at 6000rpm for 30min using a high-shear emulsifier to obtain the composite polymerization inhibitor.
[0038] The method for preparing modified chitosan is as follows:
[0039] S101. Dissolve 50g of chitosan in 5L of 1wt% acetic acid solution, stir at 60℃ for 2h, add 10g of dimethylaminosulfonyl chloride, adjust the pH to 8, react for 4h, filter and freeze dry to obtain intermediate product.
[0040] S102. Mix 40g of intermediate product with 200g of modified solution and react under nitrogen atmosphere for 6h. Dialyze the resulting reaction solution for 48h and freeze-dry to obtain modified chitosan.
[0041] The modified solution consists of 6g maleic anhydride, 0.2g ammonium persulfate, and 200g deionized water.
[0042] The preparation method of the nanocomposite is as follows:
[0043] S201. Disperse 0.05g of cerium oxide in 200mL of isopropanol and sonicate for 30min to obtain a cerium oxide suspension;
[0044] S202. Mix 400g of cerium oxide suspension with 20g of compound solution, then add 0.02g of hydroxytyrosol, 0.01g of sorbic acid and 0.5g of N-phenyl-2-naphthylamine, stir until completely dissolved, and adjust the pH to 7 to obtain the nanocomposite.
[0045] The methods for preparing the compound solution include:
[0046] 2g of lithium stearate was dissolved in 20g of isopropanol at 50℃ to obtain a first solution. 5g of sophorolipid was dissolved in 25g of deionized water at 40℃ to obtain a second solution. The first and second solutions were then mixed to obtain a compound solution.
[0047] Example 2
[0048] The difference between this example and Example 1 is that the composite polymerization inhibitor in this example includes 20g of modified chitosan, 30g of nanocomposite and 1g of N,N-di-n-butyldithiocarbamate.
[0049] Example 3
[0050] The difference between this example and Example 1 is that the composite polymerization inhibitor in this example includes 30g of modified chitosan, 20g of nanocomposite and 1g of N,N-di-n-butyldithiocarbamate.
[0051] Example 4
[0052] The composite polymerization inhibitor provided in this embodiment includes 25g of modified chitosan, 25g of nanocomposite and 1.5g of N,N-di-n-butyldithiocarbamate copper.
[0053] The composite polymerization inhibitor is prepared by mixing 25g of modified chitosan, 25g of nanocomposite and 1.5g of N,N-di-n-butyldithiocarbamate, and then treating the mixture at 5000rpm for 30min using a high-shear emulsifier to obtain the composite polymerization inhibitor.
[0054] The method for preparing modified chitosan is as follows:
[0055] S101. Dissolve 40g of chitosan in 4L of 1wt% acetic acid solution, stir at 60℃ for 2h, add 10g of dimethylaminosulfonyl chloride, adjust the pH to 8, react for 4h, filter and freeze dry to obtain intermediate product.
[0056] S102. Mix 35g of intermediate product with 140g of modified solution and react under nitrogen atmosphere for 6h. Dialyze the resulting reaction solution for 48h and freeze-dry to obtain modified chitosan.
[0057] The modified solution consists of 6g maleic anhydride, 0.2g ammonium persulfate, and 200g deionized water.
[0058] The preparation method of the nanocomposite is as follows:
[0059] S201. Disperse 0.05g of cerium oxide in 200mL of isopropanol and sonicate for 30min to obtain a cerium oxide suspension;
[0060] S202. Mix 400g of cerium oxide suspension with 20g of compound solution at a mass ratio of 20:1, then add 0.02g of hydroxytyrosol, 0.01g of sorbic acid and 0.5g of N-phenyl-2-naphthylamine, stir until completely dissolved, and adjust the pH to 7 to obtain the nanocomposite.
[0061] The methods for preparing the compound solution include:
[0062] 2g of lithium stearate was dissolved in 20g of isopropanol at 50℃ to obtain a first solution. 5g of sophorolipid was dissolved in 25g of deionized water at 40℃ to obtain a second solution. The first and second solutions were then mixed to obtain a compound solution.
[0063] Example 5
[0064] The composite polymerization inhibitor provided in this embodiment includes 25g of modified chitosan, 25g of nanocomposite and 0.5g of N,N-di-n-butyldithiocarbamate copper.
[0065] The composite polymerization inhibitor is prepared by mixing 25g of modified chitosan, 25g of nanocomposite and 1.5g of N,N-di-n-butyldithiocarbamate, and then treating the mixture at 5000rpm for 30min using a high-shear emulsifier to obtain the composite polymerization inhibitor.
[0066] The method for preparing modified chitosan is as follows:
[0067] S101. Dissolve 60g of chitosan in 6L of 1wt% acetic acid solution, stir at 60℃ for 2h, add 10g of dimethylaminosulfonyl chloride, adjust the pH to 8, react for 4h, filter and freeze dry to obtain intermediate product.
[0068] S102. Mix 32g of intermediate product with 192g of modified solution and react under nitrogen atmosphere for 6h. Dialyze the resulting reaction solution for 48h and freeze-dry to obtain modified chitosan.
[0069] The modified solution consists of 6g maleic anhydride, 0.2g ammonium persulfate, and 200g deionized water.
[0070] The preparation method of the nanocomposite is as follows:
[0071] S201. Disperse 0.05g of cerium oxide in 200mL of isopropanol and sonicate for 30min to obtain a cerium oxide suspension;
[0072] S202. Mix 400g of cerium oxide suspension with 20g of compound solution at a mass ratio of 20:1, add 0.02g of hydroxytyrosol and 0.01g of sorbic acid, stir until completely dissolved, adjust pH to 7, and obtain nanocomposite.
[0073] The methods for preparing the compound solution include:
[0074] 2g of lithium stearate was dissolved in 20g of isopropanol at 50℃ to obtain a first solution. 5g of sophorolipid was dissolved in 25g of deionized water at 40℃ to obtain a second solution. The first and second solutions were then mixed to obtain a compound solution.
[0075] Comparative Example 1
[0076] The difference between this and Example 1 is that no modification solution is added in the preparation of modified chitosan; the product obtained directly from the intermediate product is used as modified chitosan.
[0077] Comparative Example 2
[0078] The difference between this and Example 1 is that dimethylaminosulfonyl chloride is not added in the preparation of the modified chitosan.
[0079] Comparative Example 3
[0080] The difference between this and Example 1 is that sophorolipids are not added to the compound solution in the preparation of the nanocomposite.
[0081] Comparative Example 4
[0082] The difference between this and Example 1 is that no cerium oxide is added in the preparation of the nanocomposite; only a compound solution is used as the nanocomposite.
[0083] Comparative Example 5
[0084] The difference between this and Example 1 is that no modification solution is added in the preparation of modified chitosan, and the product obtained from the intermediate product is directly used as modified chitosan. At the same time, no cerium oxide is added in the preparation of the nanocomposite, and only a compound solution is used as the nanocomposite.
[0085] The cerium oxide particle size used in the above embodiments and comparative examples is 80 nm.
[0086] The composite polymerization inhibitors prepared in Examples 1-5 and Comparative Examples 1-5 were tested.
[0087] 100g of acrylonitrile and 50mL of deionized water were mixed to obtain AN solution. The mixture was stirred and heated to 80℃. The composite polymerization inhibitors of each example and each comparative example were weighed at 0.1% of the monomer mass and added to the AN solution. The induction period (min) was then timed.
[0088] After the 2-hour reaction is completed, take the reaction solution, add excess methanol to precipitate polyacrylamide (i.e., self-polymer), filter, dry and weigh. Self-polymerization rate = (mass of self-polymer / initial mass of AN) × 100%.
[0089] The test results are shown in Table 1.
[0090] Table 1
[0091]
[0092]
[0093] As shown in Table 1, the composite polymerization inhibitor prepared in the examples has a better polymerization inhibition effect and a relatively higher free radical scavenging efficiency. A comparison of Examples 2 and 3 with Example 1 shows that a slightly higher proportion of nanocomposite components reduces the free radical scavenging ability due to insufficient density of chitosan groups. Combined with Example 5, it indicates that the dimethylaminosulfonyl chloride-modified chitosan, by introducing strongly polar sulfonic acid groups, improves water solubility and free radical scavenging ability. Simultaneously, the absence of N-phenyl-2-naphthylamine further reduces the free radical scavenging efficiency. A comparison of Example 4 with Example 1 shows that increasing the amount of copper salt (N,N-di-n-butyldithiocarbamate) to 1.5g leads to a shortened induction period. A comparison of Comparative Example 1 with Example 1 shows that Comparative Example 1, without the addition of a modified solution, lacks a conjugated structure and cannot effectively scavenge free radicals. In Comparative Example 3, the absence of sophorolipid in the compound solution leads to the aggregation of cerium oxide particles, reducing the effective surface area and lowering the polymerization inhibition efficiency. Comparative Example 4 shows that the lack of cerium oxide particles and the inability to provide antioxidant capacity led to an increase in the self-polymerization rate; Comparative Example 5 had the highest self-polymerization rate and the lowest yield.
[0094] This application also provides the application of the above-mentioned composite polymerization inhibitor in inhibiting monomer self-polymerization in acrylamide production, specifically including the following steps:
[0095] Step 1: Precision Temperature Control System: Acrylonitrile is added to the reactor, and an intelligent temperature control device (Eurotherm 2408 temperature controller) is used to precisely control the reaction temperature within 5-10℃. A high-precision temperature sensor is used to monitor the temperature of the reaction system in real time, and the preheater is automatically adjusted through a feedback control system to ensure that the temperature fluctuation is within ±0.5℃.
[0096] Step 2: Addition of composite polymerization inhibitor: The composite polymerization inhibitor is added to the reactor through a precision metering pump (gear-type micro metering pump, specifically JONSN MPG series precision micro gear pump), and the amount of composite polymerization inhibitor added is 0.08-0.12% of the monomer mass.
[0097] Step 3: Balanced distillation: The discharged material enters the balanced distillation device and is subjected to balanced distillation under vacuum. Unreacted acrylonitrile in the material is recovered to the process water tank for recycling. The material circulation tank is ventilated to keep the material in a boiling state. Furthermore, the controlled temperature is 55-60℃ and the vacuum degree is 0.06-0.065MPa. It should be noted that the controlled temperature and vacuum degree are range values, as there is room for fluctuation during the production process.
[0098] Step 4: Concentration Process: The material enters the concentration tower for further purification, evaporating excess water. The temperature is controlled at 65-70℃, the tower pressure is 16kPa, and the air volume is 25m³ / h. 3 / h;
[0099] Step 5: Refining process: After the material temperature is reduced to below 35℃, it is put into a storage tank and the pH value is adjusted to 7 to obtain acrylamide.
[0100] Furthermore, by installing a Coriolis mass flow meter on the discharge pipe, the mass flow rate can be directly obtained by measuring the Coriolis effect of the fluid in the vibrating tube, thus avoiding the impact of temperature and pressure fluctuations on the metering accuracy.
[0101] Example 6
[0102] Acrylamide production was carried out according to the operational steps of the composite polymerization inhibitor prepared in Example 1 above for inhibiting monomer self-polymerization in acrylamide production:
[0103] In a production process with a capacity of 3.5T (100% concentration) / h, without adding a composite polymerization inhibitor, and following the above process control steps, after 7 hours of production, 130kg of self-polymerized material was collected through a bag filter, with a self-polymerization rate of 0.525%.
[0104] Example 7
[0105] Acrylamide production was carried out according to the operational steps of the composite polymerization inhibitor prepared in Example 1 above for inhibiting monomer self-polymerization in acrylamide production:
[0106] In a production process with a capacity of 3.5T (100% concentration) / h, a total of 8.32kg of composite polymerization inhibitor was added using a precision metering pump. Following the process control steps described above, after 3 hours, the mass of micropolymers in the storage tank was measured through a bag filter, and the monomer self-polymerization rate was 0.0075%.
[0107] Example 8
[0108] Acrylamide production was carried out according to the operational steps of the composite polymerization inhibitor prepared in Example 1 above for inhibiting monomer self-polymerization in acrylamide production:
[0109] In a production process with a capacity of 3.5T (100% concentration) / h, a total of 10.5kg of composite polymerization inhibitor was added using a precision metering pump. Following the process control steps described above, after 3 hours, the mass of micropolymers in the storage tank was measured through a bag filter, and the result was 0.25kg. The monomer self-polymerization rate was 0.0024%.
[0110] As can be seen, the composite polymerization inhibitor prepared by the method of this application, combined with a preparation process that precisely controls temperature and environment, can reduce the self-polymerization rate of acrylamide monomers to below 0.01%, a reduction of 5-8 percentage points compared to traditional methods, effectively improving monomer utilization. Simultaneously, it reduces the formation of self-polymerization products, increasing the purity of acrylamide products to over 99.9%, resulting in more stable product performance and quality, meeting the needs of high-end applications. Furthermore, the composite polymerization inhibitor, combined with precise reaction condition control, reduces the number of backwashing cycles in the subsequent coarse filtration process, extending the equipment cleaning cycle from 7 days to 30 days, increasing production efficiency by 20-30%, while simultaneously reducing energy consumption and production costs.
[0111] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. 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 this application. Therefore, this application 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 claimed herein.
Claims
1. A composite polymerization inhibitor, characterized in that, It includes: The modified chitosan comprises 40-60 parts, the nanocomposite comprises 40-60 parts, and N,N-di-n-butyldithiocarbamate copper comprises 1-3 parts; the preparation method of the modified chitosan includes the following steps: S101, dissolving chitosan in 1wt% acetic acid solution, stirring at 60℃ for 2h, adding dimethylaminosulfonyl chloride, adjusting the pH to 8, reacting for 4h, filtering and lyophilizing to obtain an intermediate product, wherein the mass-volume ratio of chitosan to acetic acid solution is 1g:100mL. The mass ratio of dimethylaminosulfonyl chloride to chitosan is 1:(4-6); S102, the intermediate product is mixed with the modification solution and reacted under nitrogen for 6 hours. The resulting reaction solution is dialyzed for 48 hours and then freeze-dried to obtain modified chitosan. The mass ratio of the intermediate product to the modification solution is 1:(4-6); the modification solution includes maleic anhydride, ammonium persulfate, and deionized water in a mass ratio of (2-4):0.1:100; Preparation of the nanocomposite The method includes the following steps: S201, dispersing cerium oxide in isopropanol and sonicating for 30 min to obtain a cerium oxide suspension, wherein the mass-to-volume ratio of cerium oxide to isopropanol is 1 g: 4000 mL; S202, mixing the cerium oxide suspension with a compound solution at a mass ratio of 20:1, adding hydroxytyrosol and sorbic acid, stirring until completely dissolved, adjusting the pH to 7 to obtain a nanocomposite, wherein the mass ratio of hydroxytyrosol to sorbic acid is 2:1, and the mass of sorbic acid is 20% of the mass of cerium oxide; the preparation method of the compound solution includes: dissolving lithium stearate in isopropanol at 50 °C to obtain a first solution, dissolving sophorolipid in deionized water at 40 °C to obtain a second solution, and mixing the first solution and the second solution to obtain the compound solution; wherein the mass ratio of lithium stearate to isopropanol is 1:10, the mass ratio of sophorolipid to deionized water is 1:5, and the mass ratio of lithium stearate to sophorolipid is 2:
5.
2. The composite polymerization inhibitor as described in claim 1, characterized in that: S202 further includes, N-phenyl-2-naphthylamine is added, wherein the mass ratio of N-phenyl-2-naphthylamine to hydroxytyrosol is 25:
1.
3. A method for preparing a composite polymerization inhibitor as described in any one of claims 1-2, characterized in that, It includes the following steps: Mix 40-60 parts of modified chitosan, 40-60 parts of nanocomposite and 1-3 parts of N,N-di-n-butyldithiocarbamate, and then treat with a high-shear emulsifier at 5000-10000 rpm for 30 min to obtain a composite polymerization inhibitor.
4. The application of the composite polymerization inhibitor as described in any one of claims 1-2 in inhibiting monomer self-polymerization in the acrylamide production process.
5. The application as described in claim 4, characterized in that, It includes the following steps: Step 1: Precision Temperature Control System: Acrylonitrile is added to the reactor. Intelligent temperature control equipment is used to precisely control the reaction temperature within 5-10℃. A high-precision temperature sensor monitors the reaction system temperature in real time, and a feedback control system automatically adjusts the heating device to ensure temperature fluctuations are within ±0.5℃. Step 2: Addition of Composite Inhibitor: A composite inhibitor is added to the reactor via a precision metering pump. The amount of the composite inhibitor added is 0.08-0.12% of the monomer mass. Step 3: Equilibrium Distillation: The discharged material enters an equilibrium distillation device. Equilibrium distillation is performed under vacuum to recover unreacted acrylonitrile into a process water tank for recycling. The material circulation tank is ventilated to maintain the material in a boiling state. Step 4: Concentration Process: The material enters the concentration tower for further purification, evaporating excess water. The temperature is controlled at 65-70℃, the tower pressure is 16kPa, and the air volume is 20-30m³ / h. 3 / h; Step 5: Refining process: After the material temperature is reduced to below 35℃, it enters the storage tank and the pH value is adjusted to 7-9 to obtain acrylamide.
6. The application as described in claim 5, characterized in that, It includes the following steps: In the third step, the controlled temperature is 55-60℃ and the vacuum degree is 0.06-0.065MPa.
Citation Information
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