Efficient catalyst for synthesizing polymaleic anhydride as well as preparation method and application of efficient catalyst
By loading the catalyst with metal element M on the porous support, the problems of high catalyst cost and complex production process in the existing polymaleic anhydride synthesis method are solved, and efficient and economical polymaleic anhydride synthesis is achieved, with excellent product performance and catalyst recyclable.
Patent Information
- Application Number
- CN202411780871.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-05
- Publication Date
- 2025-02-28
AI Technical Summary
The existing polymaleic anhydride synthesis methods have problems such as high catalyst cost, large initiator usage, and complex production processes, making it difficult to achieve efficient and economical synthesis.
The catalyst is prepared by a specific preparative method for the synthesis of polymaleic anhydride in aqueous solution by using metal elements M (such as Fe3+, Cu2+, Co2+, Ni2+) supported on a porous support as a high-efficiency catalyst.
It realizes the efficient synthesis of polymaleic anhydride, the product has stable molecular weight and better performance than purchased products. The catalyst can be recycled and utilized multiple times, reducing production costs.
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Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of catalyst synthesis, and particularly relates to a high-efficiency catalyst for synthesizing polymaleic anhydride, a preparation method and application thereof. Background Art
[0002] Polymaleic anhydride (PMA) is acidic, non-toxic, ionizable, and easily soluble in water. Its relative molecular mass is 400-800. PMA molecules contain polar groups carboxyl (-COOH) and hydroxyl (-OH), which can form chelates with calcium, magnesium and other ions in water, and promote lattice distortion, thereby achieving the purpose of scale inhibition. The corrosion inhibition effect is better when combined with zinc salts. PMA is suitable for alkaline environments, has high chemical and thermal stability, and a high decomposition temperature. It is widely used in flash evaporation devices for seawater desalination, low-pressure boilers, and industrial circulating cooling water. It is one of the important green and environmentally friendly water treatment agents.
[0003] Synthesis method of PMA: Due to the low electron cloud density and large steric hindrance of maleic anhydride carbon-carbon double bond, it is difficult to homopolymerize without catalyst conditions, which is the bottleneck of the synthesis reaction. At present, there are three main methods for synthesizing polymaleic anhydride: 1. Radiation polymerization method, which requires a radiation source device, high conditions, and is mostly used for scientific research, and has almost no industrial application. 2. Solvent polymerization method, this method uses azobisisobutyronitrile, benzoyl peroxide, etc. as initiators, benzene, benzene homologues, etc. as organic solvents, first polymerize, then hydrolyze, wash and separate to obtain polymaleic anhydride. The disadvantage of this method is that it uses flammable and explosive organic solvents, the recovery energy consumption is large and the process is complicated. The initiator is expensive and the amount used is large, resulting in high production costs. 3. Aqueous solution polymerization method, this method uses water instead of organic solvents, eliminates the potential danger of benzene organic solvents, uses H2O2 as initiator, transition metal ions as catalysts, reacts in water phase, the process is safe, the process is simple and easy to operate, but the disadvantage is that the catalyst is expensive and the amount of initiator is large. Therefore, exploring a suitable catalyst is of great significance to this study. Summary of the invention
[0004] The purpose of the present invention is to provide a highly efficient catalyst for synthesizing polymaleic anhydride, a preparation method thereof and an application thereof. A metal element M is loaded on a porous carrier as a highly efficient catalyst, the polymaleic anhydride product prepared by the catalyst has a stable molecular weight and better performance than purchased products, and the catalyst can be recycled for multiple times, while reducing production costs.
[0005] To achieve the above object, the technical solution adopted by the present invention is:
[0006] A method for preparing a high-efficiency catalyst for synthesizing polymaleic anhydride comprises the following steps:
[0007] (1) dissolving nitrate composed of metal ions and nitrate, glucose, and ammonium chloride in water to obtain a mixed solution;
[0008] (2) reacting the mixed solution at 150-200°C for 12 h, allowing the mixture to stand at room temperature after the reaction, and centrifuging to obtain a solid;
[0009] (3) After drying the solid at 60°C for 24 h, the solid was placed in a vacuum tube furnace and then calcined at 500-900°C for 2 h at a heating rate of 5°C / min to obtain the catalyst.
[0010] Furthermore, in step (1), the metal ion is Fe 3+ , Cu 2+ 、Co 2+ 、Ni 2+ One of them.
[0011] Furthermore, in step (1), the dosage ratio of nitrate, glucose and ammonium chloride is 0.3 mmol-1.0 mmol: 1.0-2.5 mmol: 0.5 g-1.1 g.
[0012] Furthermore, the reaction temperature of the mixed solution in step (2) is preferably 160-185°C.
[0013] Furthermore, the calcination temperature in step (3) is preferably 700-850°C.
[0014] Furthermore, the catalyst prepared by the preparation method is used to synthesize polymaleic anhydride.
[0015] Furthermore, the specific process of using the catalyst to synthesize polymaleic anhydride is as follows: dissolving maleic anhydride and deionized water at 80°C, adding the catalyst prepared by the above preparation method, adding 27.5wt% hydrogen peroxide droplets into the reaction solution, reacting at 105°C-110°C for 1h, and cooling to room temperature after the reaction to obtain a dark brown transparent viscous liquid polymaleic anhydride solution.
[0016] Furthermore, the mass ratio of maleic anhydride, hydrogen peroxide and catalyst is 1:0.5-1.0:0.02.
[0017] Furthermore, the average molecular weight of the prepared polymaleic anhydride is 600-680.
[0018] The technical route of the present invention is:
[0019]
[0020] Compared with the prior art, the present invention has the following beneficial effects:
[0021] 1. The present invention selects a class of cheap and readily available high-efficiency catalysts through research, reduces the amount of initiator used, and makes the homopolymerization process of maleic anhydride controllable, with high monomer conversion rate and thorough polymerization reaction, to obtain polymaleic anhydride with uniform molecular weight, high scale inhibition rate and stable performance.
[0022] 2. The aqueous solution polymerization method has been verified by laboratory pilot tests and can synthesize products that meet national standards. DETAILED DESCRIPTION
[0023] The technical solutions and effects of the present invention are further described below in conjunction with specific embodiments, but the protection scope of the present invention is not limited thereto.
[0024] Example 1
[0025] In 50 mL of deionized water, 0.4 mmol Fe(NO3)3, 1.2 mmol glucose and 0.5 g ammonium chloride were added. After complete dissolution, the mixture was reacted at 165°C for 12 h, cooled to room temperature, and centrifuged. The obtained solid was dried at 60°C for 24 h, transferred to a quartz boat, and baked at 800°C for 2 h in a vacuum tube furnace at a heating rate of 5°C / min to obtain the catalyst.
[0026] The catalyst was applied to the synthesis reaction of polymaleic anhydride, the mass ratio of maleic anhydride to catalyst was 1:0.02, the amount of hydrogen peroxide used was 0.8 times the amount of maleic anhydride used, and the product obtained had a molecular weight of 640 and a relative scale inhibition rate of calcium carbonate of 60% after GPC detection.
[0027] Example 2
[0028] In 50 mL of deionized water, 0.7 mmol Cu(NO3)2, 1.5 mmol glucose and 0.8 g ammonium chloride were added. After complete dissolution, the mixture was reacted at 165°C for 12 h, cooled to room temperature, and centrifuged. The obtained solid was dried at 60°C for 24 h, transferred to a quartz boat, and baked at 750°C for 2 h in a vacuum tube furnace at a heating rate of 5°C / min to obtain the catalyst.
[0029] The catalyst was applied to the synthesis reaction of polymaleic anhydride, the mass ratio of maleic anhydride to catalyst was 1:0.02, the amount of hydrogen peroxide used was 1.0 times the amount of maleic anhydride used, and the product obtained had a molecular weight of 630 and a relative scale inhibition rate of calcium carbonate of 62% after GPC detection.
[0030] Example 3
[0031] In 50 mL of deionized water, 0.8 mmol Co(NO3)2·6H2O, 1.3 mmol glucose and 0.7 g ammonium chloride were added. After complete dissolution, the mixture was reacted at 165°C for 12 h, cooled to room temperature, and centrifuged. The obtained solid was dried at 60°C for 24 h, transferred to a quartz boat, and baked at 780°C for 2 h in a vacuum tube furnace at a heating rate of 5°C / min to obtain the catalyst.
[0032] The catalyst was applied to the synthesis reaction of polymaleic anhydride, the mass ratio of maleic anhydride to catalyst was 1:0.02, the amount of hydrogen peroxide used was 1.0 times the amount of maleic anhydride used, and the product obtained had a molecular weight of 648 and a relative scale inhibition rate of calcium carbonate of 59% after GPC detection.
[0033] Example 4
[0034] In 50 mL of deionized water, 1.0 mmol Ni(NO3)2, 1.8 mmol glucose and 1.1 g ammonium chloride were added. After complete dissolution, the mixture was reacted at 165°C for 12 h, cooled to room temperature, and centrifuged. The obtained solid was dried at 60°C for 24 h, transferred to a quartz boat, and baked at 850°C for 2 h in a vacuum tube furnace at a heating rate of 5°C / min to obtain the catalyst.
[0035] The catalyst was applied to the synthesis reaction of polymaleic anhydride, the mass ratio of maleic anhydride to catalyst was 1:0.02, the amount of hydrogen peroxide used was 0.7 times the amount of maleic anhydride used, and the product obtained had a molecular weight of 678 and a relative scale inhibition rate of calcium carbonate of 63% after GPC detection.
[0036] Example 5
[0037] In 50 mL of deionized water, 0.4 mmol Fe(NO3)3, 1.6 mmol glucose and 0.8 g ammonium chloride were added. After complete dissolution, the mixture was reacted at 165°C for 12 h, cooled to room temperature, and centrifuged. The obtained solid was dried at 60°C for 24 h, transferred to a quartz boat, and baked at 750°C for 2 h in a vacuum tube furnace at a heating rate of 5°C / min to obtain the catalyst.
[0038] The catalyst was applied to the synthesis reaction of polymaleic anhydride, the mass ratio of maleic anhydride to catalyst was 1:0.02, the amount of hydrogen peroxide used was 0.8 times the amount of maleic anhydride used, and the product obtained had a molecular weight of 668 and a relative scale inhibition rate of calcium carbonate of 62% after GPC detection.
[0039] The molecular weight of the purchased polymaleic anhydride (XF-321W) was 548 after GPC testing, and the relative scale inhibition rate of calcium carbonate was 53%.
[0040] The performance of the polymer obtained in the present invention is tested with reference to "Determination of scale inhibition performance of water treatment agents - Bubble method HG / T 2024-1991".
[0041] The catalyst obtained in Example 1 was used in the synthesis of polymaleic anhydride, filtered, washed and dried, and then reused multiple times. The performance test results are shown in Table 1.
[0042] Table 1 The results of the catalyst reuse performance obtained in Example 1
[0043]
[0044] It can be seen from Table 1 that after the catalyst prepared in Example 1 of the present invention is used multiple times, the calcium carbonate relative scale inhibition rate of the prepared polymaleic anhydride hardly decreases.
[0045] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.
Claims
1. A method for preparing a high-efficiency catalyst for synthesizing polymaleic anhydride, characterized in that: The preparation method comprises the following steps: (1) dissolving nitrate composed of metal ions and nitrate, glucose, and ammonium chloride in water to obtain a mixed solution; (2) reacting the mixed solution at 150-200°C for 12 h, allowing the mixture to stand at room temperature after the reaction, and centrifuging to obtain a solid; (3) After drying the solid at 60°C for 24 h, the solid was placed in a vacuum tube furnace and then calcined at 500-900°C for 2 h at a heating rate of 5°C / min to obtain the catalyst.
2. The method for preparing a highly efficient catalyst for synthesizing polymaleic anhydride according to claim 1, characterized in that: The metal ion in step (1) is Fe 3+ , Cu 2+ 、Co 2+ 、Ni 2+ One of them.
3. The method for preparing a highly efficient catalyst for synthesizing polymaleic anhydride according to claim 1, characterized in that: In the step (1), the dosage ratio of nitrate, glucose and ammonium chloride is 0.3 mmol-1.0 mmol: 1.0-2.5 mmol: 0.5 g-1.1 g.
4. The method for preparing a highly efficient catalyst for synthesizing polymaleic anhydride according to claim 1, characterized in that: The reaction temperature of the mixed solution in step (2) is preferably 160-185°C.
5. The method for preparing a highly efficient catalyst for synthesizing polymaleic anhydride according to claim 1, characterized in that: The calcination temperature in step (3) is preferably 700-850°C.
6. A highly efficient catalyst for synthesizing polymaleic anhydride, characterized in that: The compound is prepared by the preparation method described in any one of claims 1 to 5.
7. The high-efficiency catalyst for synthesizing polymaleic anhydride according to claim 6, characterized in that: The catalyst is used for synthesizing polymaleic anhydride.
8. The high-efficiency catalyst for synthesizing polymaleic anhydride according to claim 7, characterized in that: The specific process of using the catalyst to synthesize polymaleic anhydride is as follows: dissolving maleic anhydride and deionized water at 80° C., adding the catalyst prepared by the above preparation method, dropping 27.5wt% hydrogen peroxide into the reaction solution, reacting at 105° C.-110° C. for 1 hour, and cooling to room temperature after the reaction to obtain a dark brown transparent viscous liquid polymaleic anhydride solution.
9. The high-efficiency catalyst for synthesizing polymaleic anhydride according to claim 8, characterized in that: The mass ratio of maleic anhydride, hydrogen peroxide and catalyst is 1:0.5-1.0:0.
02.
10. The high-efficiency catalyst for synthesizing polymaleic anhydride according to claim 8, characterized in that: The average molecular weight of the prepared polymaleic anhydride is 600-680.