A method for preparing high molecular weight anionic polyacrylamide
By mixing acrylamide and anionic monomers in a micro reactor, controlling the reaction conditions, and preparing high-molecular-weight anionic polyacrylamide, the problems of cumbersome operation and poor batch stability in the prior art are solved, and efficient and stable preparation of high-molecular-weight polymers are achieved.
Patent Information
- Application Number
- CN202411748667.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-02
- Publication Date
- 2025-04-08
AI Technical Summary
The prior art is cumbersome in the preparation of high molecular weight anionic polyacrylamide, and the batch stability is poor.
High molecular weight anionic polyacrylamide was prepared by using a micro reactor, and polymerization was carried out by mixing acrylamide and anionic monomer in a microchannel reactor, controlling the pH value, reaction time and temperature, and then purifying and drying.
The efficient preparation of high-molecular-weight anionic polyacrylamide has been achieved, with the monomer conversion rate reaching more than 91.5%, and the molecular weight can reach 8-10 million, which significantly improves the batch stability.
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Figure CN119775487A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to a chemical process and a technology in the field of high molecular weight anionic polyacrylamide, and specifically relates to a method for preparing high molecular weight anionic polyacrylamide. Background Art
[0002] Anionic polyacrylamide (APAM) is favored for its excellent flocculation ability, good dispersibility, strong water solubility and wide adaptability. High molecular weight anionic polyacrylamide shows excellent performance in flocculation, thickening and dispersion.
[0003] In the field of oil field exploitation, the introduction of high molecular weight and high viscosity polyacrylamide can change the hexagon of water, improve water drive efficiency, reduce oil permeability, and enable the water to flow forward more evenly, thereby increasing oil recovery. In the field of water treatment, anionic polyacrylamide (APAM) is often used as a water treatment agent, especially in the fields of sewage treatment, sedimentation separation, flotation, soil stabilization, etc.
[0004] With the rapid economic development of my country, the amount of sewage discharged by various industries is increasing. In order to cope with the pollution situation brought about by the current social development, it is very necessary to develop a flocculant with a wide range of applications, small dosage, stability and high efficiency. The aqueous solution polymerization method has the characteristics of simple operation, low pollution and low cost, and its industrialization system is relatively mature.
[0005] Microreactor is a new type of reaction technology, which has been widely used in chemical process due to its unique size advantage and efficient mass transfer and heat transfer performance. The main advantages of microreactor are its small size, fast reaction speed, high mass transfer and heat transfer efficiency, which can significantly improve the production efficiency and product quality in chemical process. Summary of the invention
[0006] Aiming at the defects of the prior art such as complicated operation mode and poor batch stability, the present invention proposes a method for preparing high molecular weight anionic polyacrylamide by using a microreactor, wherein the molecular weight can reach 8-10 million.
[0007] A method for preparing high molecular weight anionic polyacrylamide comprises the following steps: dissolving acrylamide and anionic monomers in water and passing nitrogen for half an hour to obtain a monomer solution; mixing the monomer solution and an initiator aqueous solution from two inlets of a microreactor respectively, adjusting the pH value to carry out polymerization reaction, purifying, and drying for 24 hours to obtain the high molecular weight anionic polyacrylamide.
[0008] Preferably, the monomer ratio in the monomer solution is 10% to 30%.
[0009] Preferably, the molar ratio of acrylamide to anionic monomer is 3:1.
[0010] Preferably, the anionic monomer is sodium acrylate.
[0011] Preferably, the initiator concentration in the initiator aqueous solution is 0.01% to 0.05%.
[0012] Preferably, the initiator is one or both of ammonium persulfate and sodium sulfite.
[0013] Preferably, the microchannel reactor is a capillary tube with an inner diameter of 0.25 to 3 mm and a length of 5 to 40 m. The liquid flow rate in the reaction channel is 1 to 3 ml / min, the residence time is 10 to 30 min, and the reaction temperature is 15 to 45°C.
[0014] Preferably, the purification is performed using an acetone solution.
[0015] Preferably, the molecular weight of the high molecular weight anionic polyacrylamide is 8-10 million.
[0016] Excellent effects of the present invention The present invention adds anionic monomers by adopting the capillary design in the microreactor and accurately controlling the monomer ratio, initiator concentration and feed stability, while optimizing the reaction conditions, so that the monomer conversion rate is above 91.5%. BRIEF DESCRIPTION OF THE DRAWINGS
[0017] Figure 1 Schematic diagram of the structure of the micro-reactor.
[0018] 1-monomer solution tank; 2-initiator aqueous solution tank; 3-precision horizontal flow pump A; 4-precision horizontal flow pump B; 5-micro mixer; 6-microchannel reactor; 7-product storage tank; 8-constant temperature oil bath tank. DETAILED DESCRIPTION
[0019] Example 1 A method for preparing high molecular weight anionic polyacrylamide, specifically comprising: dissolving 3 mol acrylamide and 1 mol anionic monomer in water, passing nitrogen for half an hour to obtain a monomer solution; storing the monomer solution and the initiator aqueous solution in a monomer solution tank 1 and an initiator aqueous solution tank 2, respectively, and transporting them to a micro mixer 5 through a precision advection pump A 3 and a precision advection pump B 4, respectively; controlling the temperature of a microchannel reactor 6 to 15-45° C., a flow rate of 1-3 ml / min, and a residence time of 10-30 min through a constant temperature oil bath tank 8, and performing a polymerization reaction; the obtained solution is stored in a product storage tank 7, purified with an acetone solution, and dried for 24 hours to obtain a high molecular weight anionic polyacrylamide; specifically, Figure 1 ; The anionic monomer is sodium acrylate.
[0020] Example 2 The monomer ratio in the monomer solution is 30%, the initiator is ammonium persulfate, the concentration is 0.03%, the inner diameter of the microreactor is 0.5 mm, the length is 20 mm, the reaction time is 15 min, the reaction temperature is 20 ° C, the flow rate is 1.0 ml / min, and the other conditions are the same as Example 1. The product molecular weight is 8.96 million, and the monomer conversion rate is 92.1%.
[0021] Example 3 The monomer ratio in the monomer solution is 20%, the initiator is ammonium persulfate, the concentration is 0.02%, the inner diameter of the microreactor is 3 mm, the length is 5 mm, the reaction time is 10 min, the reaction temperature is 15 ° C, the flow rate is 1.0 ml / min, and the other conditions are the same as Example 1. The product molecular weight is 9.21 million and the monomer conversion rate is 93.1%.
[0022] Example 4 The monomer ratio in the monomer solution is 30%, the initiator is ammonium persulfate, the concentration is 0.05%, the inner diameter of the microreactor is 0.25 mm, the length is 40 mm, the reaction time is 30 min, the reaction temperature is 30 ° C, the flow rate is 1.0 ml / min, and the rest is the same as Example 1. The product molecular weight is 9.86 million and the monomer conversion rate is 95.9%.
[0023] Example 5 The initiators are ammonium persulfate and sodium sulfite, the concentration is 0.01%, the reaction temperature is 45°C, and the other conditions are the same as in Example 1. The product molecular weight is 8.76 million and the conversion rate is 91.5%.
[0024] Example 6 The liquid flow rate in the reaction tube was 3 ml / min, and the other conditions were the same as in Example 1. The molecular weight of the product was 8.86 million, and the conversion rate was 91.7%.
[0025] Example 7 The monomer ratio in the monomer solution is 10%, the inner diameter of the microreactor is 0.5 mm, the length is 20 mm, the initiator is sodium sulfite, the concentration is 0.05%, the reaction time is 15 min, the reaction temperature is 20 ° C, the flow rate is 1.0 ml / min, and the other conditions are the same as Example 1. The product molecular weight is 9.05 million and the monomer conversion rate is 92.7%.
[0026] Example 8 The monomer ratio in the monomer solution is 30%, the initiator is ammonium persulfate, the concentration is 0.05%, the inner diameter of the microreactor is 0.25 mm, the length is 40 mm, the reaction time is 30 min, the reaction temperature is 45 ° C, the flow rate is 2.0 ml / min, and the other conditions are the same as Example 1. The product molecular weight is 10 million and the monomer conversion rate is 99%.
Claims
1. A method for preparing high molecular weight anionic polyacrylamide, characterized in that: The method comprises the following steps: dissolving acrylamide and anionic monomers in water and passing nitrogen for half an hour to obtain a monomer solution; mixing the monomer solution and the initiator aqueous solution from two inlets of a microreactor respectively, adjusting the pH value to carry out polymerization reaction, purifying, and drying for 24 hours to obtain a high molecular weight anionic polyacrylamide.
2. The method for preparing high molecular weight anionic polyacrylamide according to claim 1, characterized in that: The monomer ratio in the monomer solution is 10% to 30%.
3. The method for preparing high molecular weight anionic polyacrylamide according to claim 1, characterized in that: The molar ratio of the acrylamide and the anionic monomer is 3:
1.
4. The method for preparing high molecular weight anionic polyacrylamide according to claim 1, characterized in that: The anionic monomer is sodium acrylate.
5. The method for preparing high molecular weight anionic polyacrylamide according to claim 1, characterized in that: The initiator concentration in the initiator aqueous solution is 0.01% to 0.05%.
6. The method for preparing high molecular weight anionic polyacrylamide according to claim 4, characterized in that: The initiator is one or both of ammonium persulfate and sodium sulfite.
7. The method for preparing high molecular weight anionic polyacrylamide according to claim 1, characterized in that: The microchannel reactor is a capillary tube with an inner diameter of 0.25 to 3 mm and a length of 5 to 40 m. The liquid flow rate in the reaction channel is 1 to 3 ml / min, the residence time is 10 to 30 min, and the reaction temperature is 15 to 45°C.
8. The method for preparing high molecular weight anionic polyacrylamide according to claim 1, characterized in that: The purification is performed by using an acetone solution.
9. The method for preparing high molecular weight anionic polyacrylamide according to claim 1, characterized in that: The molecular weight of the high molecular weight anionic polyacrylamide is 8-10 million.