Method for synthesizing epoxysuccinic acid under catalysis of titanate
By using titanate catalysts and specific process steps, the problems of difficult catalyst recovery and heavy metal residue in the synthesis of epoxy succinic acid have been solved, achieving efficient and low-cost catalytic effects suitable for industrial production.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SHANDONG TAIHE WATER TREATMENT TECH CO LTD
- Filing Date
- 2026-03-26
- Publication Date
- 2026-05-15
AI Technical Summary
The existing process for synthesizing epoxy succinic acid involves cumbersome catalyst recovery steps, low catalytic efficiency, and high costs. It also results in serious heavy metal residues in the product, affecting product quality and safety.
Using titanate as a catalyst, epoxy succinic acid is synthesized through specific process steps and conditions, including stirring and heating, adding hydrogen peroxide solution and alkali solution dropwise, controlling the pH value, reacting under negative pressure, and the catalyst can be easily separated and recovered after the reaction.
It achieves efficient separation and recovery of catalysts, maintains good catalytic activity, reduces production costs, avoids heavy metal residues, simplifies the process, and is suitable for industrial production.
Abstract
Description
Technical Field
[0001] This invention belongs to the field of organic chemical synthesis technology, specifically relating to a method for the catalytic synthesis of epoxy succinic acid using titanate. Background Technology
[0002] Epoxysuccinic acid (ESA), as an important fine chemical intermediate, is widely used in environmental water treatment agents, surfactants, plasticizers, and other fields. Its downstream polymer, polyepoxysuccinic acid, is an ideal substitute for traditional organophosphonic acid scale inhibitors due to its phosphorus- and nitrogen-free nature and easy biodegradability, resulting in continuously growing market demand. Currently, the mainstream industrial synthesis process of epoxysuccinic acid uses maleic anhydride (or maleic acid) as a raw material, which is cyclized by hydrogen peroxide under the action of a catalyst. Tungstate, molybdate, and their heteropolyacid salts are the most widely used catalytic systems.
[0003] Patent CN 1228301C discloses a method for preparing sodium epoxysuccinate using sodium tungstate as a catalyst. Maleic anhydride is dissolved in water, the pH is adjusted with sodium hydroxide, sodium tungstate is added, and then hydrogen peroxide solution is added dropwise to obtain sodium epoxysuccinate. Patent CN116102727A uses a mixture of sodium tungstate and sodium molybdate as a catalyst, accelerating the epoxidation rate while reducing catalyst costs. Patent CN 119505216A prepares epoxysuccinic acid by adding tungsten or vanadium catalysts in batches to ensure the effective concentration of the catalyst. A common problem with the above-disclosed patents is that tungstate or molybdate in the product mixes with byproducts tartaric acid and epoxysuccinic acid, making separation difficult and resulting in decreased product purity. Patent CN 112521348B discloses a method for synthesizing epoxysuccinic acid using molecular sieves as a catalyst. In this method, the catalyst can be recovered by filtration, and the problem of heavy metal ion residue is solved from the source. However, the catalytic effect of the reused catalyst is significantly reduced. Patent 112517032B developed a composite supported heteropolyacid catalyst, which loads molybdate or tungstate onto titanium silicate molecular sieves to reduce the content of heavy metal ions in the product. However, with the increase of reuse, tungsten or molybdenum ions are easily desorbed into the product. Patent CN 119613356A proposed that after the first catalysis is completed, molybdenum / tungstate is adsorbed and desorbed by a specific resin. The adsorbed resin is then rinsed with deionized water and used for the next catalysis. The operation is simple and avoids the generation of waste brine. However, it also faces the problem of residual heavy metals in the reaction solution.
[0004] In summary, the difficulty in catalyst recovery not only wastes precious metal resources such as tungsten and molybdenum, increasing the production cost of epoxy succinic acid, but also leads to residual heavy metal ions in the product, affecting product quality and application safety. Therefore, developing a technical solution that achieves efficient catalysis and convenient recovery, addressing the technical shortcomings of low catalyst recovery efficiency, complex processes, and high costs in the synthesis of epoxy succinic acid, is of great significance for promoting the sustainable development of the epoxy succinic acid industry. Summary of the Invention
[0005] To address the aforementioned problems, this invention provides a method for the catalytic synthesis of epoxy succinic acid using titanate catalysts, solving the issues of cumbersome catalyst recovery steps, low cyclic catalytic efficiency, high cost, and high heavy metal residue in existing epoxy succinic acid synthesis products.
[0006] This invention is achieved through the following technical solution: The present invention provides a method for the catalytic synthesis of epoxysuccinic acid using titanate, comprising the following steps: (1) Mix maleic anhydride, 32% liquid alkali and water, add catalyst (titanium salt), stir and heat. (2) Add 27.5% hydrogen peroxide solution dropwise, and at the same time add 32% liquid alkali to maintain the pH value of the system, turn on the negative pressure, and collect water from outside; (3) After the hydrogen peroxide solution in step (2) is added, titanate catalyst is added every 30 minutes for 4 times, while hydrogen peroxide solution is added for 2 hours. After the addition is finished, the negative pressure is turned off. (2) Keep the reaction at a constant temperature for 1 to 4 hours, then cool down and filter to separate the titanate catalyst. The filtrate is an epoxy succinic acid solution.
[0007] According to the method for synthesizing epoxy succinic acid by titanate catalysis, the catalyst is a metal titanate, specifically one or more of sodium titanate, potassium titanate, barium titanate, calcium titanate, strontium titanate, lead titanate, magnesium titanate, and bismuth titanate.
[0008] According to the method for synthesizing epoxy succinic acid by titanate catalysis, the catalyst is a composite system of one, two, or three of sodium titanate, potassium titanate, and magnesium titanate.
[0009] According to the method for synthesizing epoxy succinic acid by titanate catalysis, in step (1), the mass ratio of maleic anhydride, liquid alkali and water is 1.5-2.5:2.0-3.5:1; the molar ratio of maleic anhydride and total hydrogen peroxide solution is 1:1.25-2.0; in step (2), the amount of hydrogen peroxide solution used accounts for 60-67% of the total amount; and in step (3), the amount of hydrogen peroxide solution used accounts for 33-40% of the total amount.
[0010] According to the method for catalytic synthesis of epoxy succinic acid using titanate, the amount of catalyst used is 4-6% of the mass of maleic anhydride, wherein the amount of catalyst used in step (1) accounts for 65-75% of the total amount, and the amount of catalyst used in step (3) accounts for 25-35% of the total amount, and is added in equal batches.
[0011] According to the method for synthesizing epoxy succinic acid by titanate catalysis, the dropping temperature and the holding temperature in steps (2) and (3) are 70-75℃.
[0012] According to the method for synthesizing epoxy succinic acid by titanate catalysis, the pH of the system in step (2) is maintained at 5.5 to 7.0.
[0013] According to the method for synthesizing epoxy succinic acid by titanate catalysis, the negative pressure conditions in steps (2) and (3) are -0.015 to -0.045 MPa.
[0014] According to the method for catalytic synthesis of epoxy succinic acid using titanate, the catalyst separated by filtration is washed with pure water and dried under negative pressure before being used for cyclic catalytic use.
[0015] Beneficial effects of this invention: This invention uses titanate as a catalyst. Sodium titanate has a good effect on promoting the conversion of maleic anhydride and inhibiting the formation of tartaric acid, with excellent catalytic effect, yield of over 98%, and selectivity ≥99.0%. The catalyst is insoluble in water, easy to separate in the reaction system, has a high recovery rate, and maintains high catalytic activity after multiple catalytic cycles, which can reduce production costs. The titanate is stable under the system conditions, and there are no heavy metal residues in the product, making the process environmentally friendly. The reaction can be carried out efficiently under isothermal conditions, avoiding gradient heating, simplifying the process, and making it suitable for industrial production. Detailed Implementation
[0016] The specific details of this invention will be further explained below: The present invention provides a method for the catalytic synthesis of epoxysuccinic acid using titanate, comprising the following steps: 1) Mix maleic anhydride, 32% liquid alkali, and water in a mass ratio of 1.5–2.5:2.0–3.5:1; add a catalyst, which is a metal titanate, such as sodium titanate, potassium titanate, barium titanate, calcium titanate, strontium titanate, lead titanate, magnesium titanate, or bismuth titanate. The total amount of catalyst is 4–6% of the mass of maleic anhydride, and the amount of catalyst used in this step accounts for 65–75% of the total amount. 2) Stirring and heating; Take hydrogen peroxide solution, and the molar ratio of maleic anhydride to hydrogen peroxide solution is 1:1.25-2.0. Add 27.5% hydrogen peroxide solution dropwise, with the amount of hydrogen peroxide solution added accounting for 60-67% of the total amount. At the same time, add 32% liquid alkali to maintain the pH value of the system. The dropping temperature and the heat preservation temperature are 70-75℃. Turn on the negative pressure and collect water from outside. 3) After the hydrogen peroxide solution is added in the above steps, continue to add hydrogen peroxide solution for 2 hours. During this process, the amount of hydrogen peroxide solution used accounts for 33-40% of the total amount. At the same time, titanate catalyst is added every 30 minutes, and this is done 4 times. During this process, the amount of catalyst used accounts for 25-35% of the total amount. The dropping temperature and the heat preservation temperature are 70-75℃. After the dropping is finished, the negative pressure is turned off. 4) Keep the reaction at a constant temperature for 1-4 hours, then cool down and filter to separate the titanate catalyst. The filtrate is an epoxy succinic acid solution.
[0017] The present invention will be further described below with reference to specific embodiments: Example
[0018] Add 122.5 kg of maleic anhydride, 170.0 kg of liquid alkali and 50.0 kg of pure water to the reactor. Weigh 4.4 kg of sodium titanate into the reactor, start stirring, mix well and heat to 73℃. Add 150.1 kg of hydrogen peroxide solution to the reactor at a dropping rate of 50 kg / h, while adding liquid alkali at the same time, maintaining the pH of the system between 5.5 and 6. After adding for 10 minutes, start the negative pressure external water intake and set the negative pressure to -0.03 MPa. After the hydrogen peroxide solution was added dropwise, 0.4 kg of sodium titanate was added every 30 minutes, for a total of four additions. Then, 90 kg of hydrogen peroxide solution was added dropwise into the reactor at a rate of 45 kg / h. Once the addition was complete, the addition of liquid alkali was stopped. A total of 108.0 kg of liquid alkali was consumed. The negative pressure was turned off, and 98.4 kg of water was collected externally. The reactor was kept at this temperature for another 4 hours, then cooled. The sodium titanate was separated by filtration to obtain an epoxy succinic acid solution. Liquid chromatography analysis showed an ESA content of 27.48%, a maleic anhydride content of 0.20%, and a tartaric acid content of 0.16%. The conversion rate was 99.04%, the selectivity was 99.51%, and the product yield was 98.54% (based on maleic anhydride). The catalyst was recovered and recycled. Example
[0019] In this embodiment, the sodium titanate catalyst in Example 1 is replaced with potassium titanate in equal amounts, and other process conditions and operating steps are the same as in Example 1.
[0020] 122.5 kg of maleic anhydride, 170.0 kg of liquid alkali, and 50.0 kg of pure water were added to the reactor. 4.4 kg of barium titanate was weighed and added to the reactor. Stirring was started, and after mixing, the temperature was raised to 73°C. 150.1 kg of hydrogen peroxide solution was added dropwise to the reactor at a rate of 50 kg / h, while liquid alkali was added dropwise simultaneously, maintaining the pH of the system between 5.5 and 6. After 10 minutes of dropwise addition, negative pressure was turned on to collect water from the external source, with the negative pressure set at -0.03 MPa. After the hydrogen peroxide solution was completely added, 0.4 kg of barium titanate was added every 30 minutes, for a total of four additions. Then, 90 kg of hydrogen peroxide solution was added dropwise to the reactor at a rate of 45 kg / h. After the addition was completed, the addition of liquid alkali was stopped. A total of 107.9 kg of liquid alkali was consumed. The negative pressure was turned off, and a total of 99.2 kg of water was collected from the external source. The reactor was kept at the same temperature for 4 hours, then cooled down. The barium titanate was separated by filtration to obtain an epoxy succinic acid solution. Liquid chromatography analysis revealed an ESA content of 19.62%, a maleic anhydride content of 4.83%, a tartaric acid content of 2.11%, a conversion rate of 76.83%, a selectivity of 91.42%, and a product yield of 70.19% (based on maleic anhydride). The catalyst was recovered and recycled. Example
[0021] 122.5 kg of maleic anhydride, 170.0 kg of liquid alkali, and 50.0 kg of pure water were added to the reactor. 6.0 kg of sodium titanate was weighed and added to the reactor. Stirring was started, and after mixing, the temperature was raised to 73°C. 240.1 kg of hydrogen peroxide solution was added dropwise to the reactor at a rate of 50 kg / h, while liquid alkali was added dropwise simultaneously, maintaining the pH of the system between 5.5 and 6. After 10 minutes of dropwise addition, negative pressure was turned on to collect water from the external source, with the negative pressure set at -0.03 MPa. After the hydrogen peroxide solution was completely added, the dropwise addition of liquid alkali was stopped. A total of 108.4 kg of liquid alkali was consumed. The negative pressure was turned off, and a total of 100.7 kg of water was collected from the external source. The reactor was kept at the same temperature for 4 hours, then cooled down. Sodium titanate was separated by filtration to obtain an epoxy succinic acid solution. Liquid chromatography analysis revealed an ESA content of 13.66%, maleic anhydride content of 9.47%, tartaric acid content of 1.78%, a conversion rate of 54.44%, a selectivity of 89.71%, and a product yield of 49.12% (based on maleic anhydride). The catalyst was recovered and recycled.
[0022] Example 4
[0023] The sodium titanate catalyst obtained by filtration and separation in Example 1 was washed and dried to obtain 5.99 kg, with a recovery rate of 99.8%. The cyclic catalytic epoxidation reaction of maleic anhydride was carried out under the reaction conditions of Example 1, and the catalytic activity of the catalyst was evaluated by the product yield. The catalyst was subjected to 1, 4, 7, and 10 cycles, respectively. The results are shown in Table 1: Product yield of catalyst at different cycle numbers. Loop count 0 1 4 7 10 Product yield / % 98.54 98.46 98.21 97.91 97.54 Table 1 The results showed that sodium titanate maintained good catalytic activity after multiple catalytic cycles.
[0024] Comparative Example 1: In Example 1, sodium titanate was replaced with sodium tungstate, and everything else remained the same as in Example 1. Liquid chromatography analysis showed an ESA content of 20.64%, maleic anhydride content of 3.82%, tartaric acid content of 2.42%, a conversion rate of 81.60%, a selectivity of 90.65%, and a product yield of 73.97% (based on maleic anhydride).
[0025] Comparative Example 2: In Example 1, sodium titanate was replaced with sodium molybdate, while other aspects remained the same as in Example 1. Liquid chromatography analysis revealed an ESA content of 17.16%, maleic anhydride content of 5.92%, tartaric acid content of 3.13%, a conversion rate of 71.22%, a selectivity of 86.17%, and a product yield of 61.35% (based on maleic anhydride).
[0026] Table 2 summarizes the results of the examples and comparative examples. ESA / % maleic anhydride / % tartaric acid / % Conversion rate / % Selectivity / % Yield / % Example 1 27.48 0.20 0.16 99.04 99.51 98.54 Example 2 19.62 4.83 2.11 76.83 91.42 70.19 Example 3 13.66 9.47 1.78 54.44 89.71 49.12 Comparative Example 1 20.64 3.82 2.42 81.60 90.65 73.97 Comparative Example 2 17.16 5.92 3.13 71.22 86.17 61.35 Table 2 Comparing the data in Table 2 of Examples 1, 2, 1, and 2, it was found that sodium titanate had a better catalytic effect, effectively promoting the conversion of maleic anhydride and inhibiting the formation of tartaric acid, with a conversion rate and selectivity of up to 99%. Data from Example 4 showed that sodium titanate could still maintain a yield of over 97% after multiple catalytic cycles. Comparing Examples 1 and 3, it was found that adding the catalyst in batches was more effective, suggesting that adding the catalyst in one batch led to the enrichment of epoxysuccinic acid, which then underwent ring-opening to form tartaric acid.
[0027] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.
Claims
1. A method for the catalytic synthesis of epoxysuccinic acid using titanate, characterized in that, Includes the following steps: (1) Mix maleic anhydride, 32% liquid alkali and water, add catalyst (titanium salt), stir and heat. (2) Add 27.5% hydrogen peroxide solution dropwise, and at the same time add 32% liquid alkali to maintain the pH value of the system, turn on the negative pressure, and collect water from outside; (3) After the hydrogen peroxide solution in step (2) is added, titanate catalyst is added every 30 minutes for 4 times, while hydrogen peroxide solution is added for 2 hours. After the addition is finished, the negative pressure is turned off. (4) Keep the reaction at a constant temperature for 1 to 4 hours, then cool down and filter to separate the titanate catalyst. The filtrate is an epoxy succinic acid solution.
2. The method for catalytic synthesis of epoxysuccinic acid using titanate according to claim 1, characterized in that, The catalyst is a metal titanate, specifically one or more of sodium titanate, potassium titanate, barium titanate, calcium titanate, strontium titanate, lead titanate, magnesium titanate, and bismuth titanate.
3. The method for catalytic synthesis of epoxysuccinic acid using titanate according to claim 1, characterized in that, The catalyst is a composite system of one, two, or three of sodium titanate, potassium titanate, and magnesium titanate.
4. The method for catalytic synthesis of epoxysuccinic acid using titanate according to claim 1, characterized in that, In step (1), the mass ratio of maleic anhydride, liquid alkali and water is 1.5-2.5:2.0-3.5:1; the molar ratio of maleic anhydride and hydrogen peroxide solution is 1:1.25-2.0; in step (2), the amount of hydrogen peroxide solution used accounts for 60-67% of the total amount; and in step (3), the amount of hydrogen peroxide solution used accounts for 33-40% of the total amount.
5. The method for catalytic synthesis of epoxysuccinic acid using titanate according to claim 1, characterized in that, The amount of catalyst used is 4-6% of the mass of maleic anhydride, of which the amount of catalyst used in step (1) accounts for 65-75% of the total amount, and the amount of catalyst used in step (3) accounts for 25-35% of the total amount, and is added in equal batches.
6. The method for catalytic synthesis of epoxysuccinic acid using titanate according to claim 1, characterized in that, The dripping temperature and the heat preservation temperature in steps (2) and (3) are 70-75℃.
7. The method for catalytic synthesis of epoxysuccinic acid using titanate according to claim 1, characterized in that, In step (2), the pH of the system is maintained at 5.5 to 7.
0.
8. The method for catalytic synthesis of epoxysuccinic acid using titanate according to claim 1, characterized in that, The negative pressure conditions in steps (2) and (3) are -0.015 to -0.045 MPa.
9. The method for catalytic synthesis of epoxysuccinic acid using titanate according to claim 1, characterized in that, The filtered catalyst is washed with pure water and dried under negative pressure before being used for cyclic catalysis.