An inhibitor and scale inhibitor 2-phosphoryl pentane-1,2,4-tricarboxylic acid and its synthesis method and application

Abstract

The application relates to the technical field of industrial water treatment agents, in particular to an anti-corrosion and scale-inhibiting 2-phosphoryl pentane-1,2,4-tricarboxylic acid as well as a synthesis method and application thereof. The anti-corrosion and scale-inhibiting 2-phosphoryl pentane-1,2,4-tricarboxylic acid has a molecular formula of C8H 13 O9P. The synthesis method comprises the following steps: adding a methanol solution of a certain amount of dimethyl phosphite and sodium methoxide into a reaction kettle, starting stirring, controlling the temperature to be 10-30 DEG C, and dropwise adding a certain amount of dimethyl maleate; keeping stirring and temperature unchanged, continuously dropwise adding a certain amount of methyl methacrylate, adding a certain amount of hydrochloric acid into the reaction kettle, keeping stirring, and hydrolyzing under the condition of being heated to a reflux state, filtering, and evaporating hydrogen chloride and methanol from the filtrate to obtain 2-phosphoryl pentane-1,2,4-tricarboxylic acid.

Description

Technical Field

[0001] This invention relates to the field of industrial water treatment agent technology, specifically to a corrosion and scale inhibitor 2-phosphorylpentane-1,2,4-tricarboxylic acid, its synthesis method, and its application. Background Technology

[0002] 2-Phosphonobutane-1,2,4-tricarboxylic acid (PBTCA) is a widely used water treatment agent in industrial applications. It combines the structural characteristics of phosphonic acid and carboxylic acid, enabling it to chelate with various divalent metal ions, such as Fe2+, Mg2+, and Ca2+, preventing them from combining with OH- ions to form precipitates and scale. Simultaneously, PBTCA forms a double-layer structure on the pipe surface, hindering the aggregation of scale-forming ions and H+ ions on the metal surface. This further prevents scaling while reducing the contact and discharge of H+ ions with the pipe material, thus inhibiting corrosion. While exhibiting strong corrosion and scale inhibition performance, PBTCA has a significantly lower phosphorus content than other commonly used organophosphorus water treatment agents (such as HEDP and ATMP), making it more environmentally friendly and a superior, highly efficient, low-phosphorus corrosion and scale inhibitor.

[0003] Water treatment agents typically operate at temperatures not exceeding 100℃ and are mostly used in industrial circulating cooling water systems. However, in certain extreme environments, such as high-temperature oil drilling environments, the operating temperature of water treatment agents can reach 150~175℃. In these cases, in addition to requiring slow-release scale inhibition performance, high-temperature oxidation stability is also crucial. PBTCA is one of the few corrosion and scale inhibitors on the market that can relatively well meet these conditions, but it still has limitations under certain temperature conditions and can decompose, leading to a decrease in the slow-release scale inhibition performance of the operating system. Summary of the Invention

[0004] To address the aforementioned problems, this invention provides a corrosion and scale inhibitor, 2-phosphorylpentane-1,2,4-tricarboxylic acid, its synthesis method, and its application. It exhibits excellent slow-release scale inhibition performance in high-temperature environments and can be effectively used in high-temperature operating environments of oil drilling.

[0005] This invention is achieved using the following technical solution: This invention relates to a corrosion and scale inhibitor, 2-phosphorylpentane-1,2,4-tricarboxylic acid, with the molecular formula C8H10. 13 O9P, the structural formula is: .

[0006] The present invention discloses a method for synthesizing the corrosion and scale inhibitor 2-phosphorylpentane-1,2,4-tricarboxylic acid, comprising the following steps: 1) Add a quantitative amount of dimethyl phosphite and sodium methoxide in methanol to the reaction vessel, start stirring, control the temperature at 10~30℃, add a quantitative amount of dimethyl maleate dropwise, complete the dropwise addition in 30~60min, and keep warm for 2~3h; 2) Keep stirring and temperature constant, continue to add a fixed amount of methyl methacrylate dropwise, complete the addition in 30-60 minutes, and keep warm for 6-8 hours; 3) Add a measured amount of hydrochloric acid to the reaction vessel, keep stirring, heat to reflux and hydrolyze for 2-3 hours, filter, and distill off hydrogen chloride and methanol from the filtrate to obtain 2-phosphorylpentane-1,2,4-tricarboxylic acid.

[0007] According to the method for synthesizing the corrosion and scale inhibitor 2-phosphorylpentane-1,2,4-tricarboxylic acid, in step 1), the molar ratio of dimethyl phosphite and dimethyl maleate is 1:1, the mass fraction of the methanol solution of sodium methoxide is 25-30%, and the amount of sodium methoxide used is 0.1-1% of the total mass of dimethyl phosphite and dimethyl maleate.

[0008] According to the method for synthesizing the corrosion and scale inhibitor 2-phosphorylpentane-1,2,4-tricarboxylic acid, in step 1), the amount of sodium methoxide used is 0.3~0.5% of the total mass of dimethyl phosphite and dimethyl maleate.

[0009] According to the method for synthesizing the corrosion and scale inhibitor 2-phosphorylpentane-1,2,4-tricarboxylic acid, the amount of methyl methacrylate used in step 2) is 1 to 1.5 times the molar amount of dimethyl phosphite.

[0010] According to the synthesis method of the corrosion and scale inhibitor 2-phosphorylpentane-1,2,4-tricarboxylic acid, the hydrochloric acid content in step 3) is 20-30%, and the total amount of water as solvent is 5 times the molar amount of dimethyl phosphite.

[0011] The present invention relates to the application of the corrosion and scale inhibitor 2-phosphorylpentane-1,2,4-tricarboxylic acid, wherein the stable operating temperature of the corrosion and scale inhibitor 2-phosphorylpentane-1,2,4-tricarboxylic acid is 0~170℃, and it is used as a corrosion and scale inhibitor in oil and gas extraction operations.

[0012] According to the application described, it is characterized by its use as a corrosion and scale inhibitor in oil and gas extraction operations at high temperatures of 140~170°C.

[0013] The beneficial effects of this invention are: The 2-phosphorylpentane-1,2,4-tricarboxylic acid provided by this invention not only possesses corrosion and scale inhibition properties and antioxidant properties comparable to the traditional organophosphorus water treatment agent PBTCA, but also breaks through the high temperature resistance threshold of PBTCA, and can work stably at high temperatures of 140~170℃, enabling it to exhibit good corrosion and scale inhibition effects in extreme environments such as oil and gas extraction operations, thus expanding its application range. Attached Figure Description

[0014] Figure 1Thermogravimetric analysis diagram of the product obtained in Example 1; Figure 2 Thermogravimetric analysis diagram of PBTCA; Figure 3 This is a gas phase detection image of the product obtained in Example 1. Detailed Implementation

[0015] The present invention will be further described below with reference to embodiments. This invention relates to a corrosion and scale inhibitor, 2-phosphorylpentane-1,2,4-tricarboxylic acid, with the molecular formula C8H10. 13 O9P, the structural formula is: .

[0016] The synthesis method includes the following steps: 1) Add a quantitative amount of dimethyl phosphite and sodium methoxide in methanol to a reaction vessel. The mass fraction of the sodium methoxide in methanol is 25-30%. Start stirring and control the temperature at 10-30°C. Add a quantitative amount of dimethyl maleate dropwise. The molar ratio of dimethyl phosphite to dimethyl maleate is 1:1. The addition is completed in 30-60 minutes. Keep the temperature for 2-3 hours. The amount of sodium methoxide used is 0.1-1% of the total mass of dimethyl phosphite and dimethyl maleate, preferably 0.3-0.5%. 2) Keep stirring and temperature constant, and continue to add a fixed amount of methyl methacrylate. The amount of methyl methacrylate is 1 to 1.5 times the molar amount of dimethyl phosphite. The addition should be completed in 30 to 60 minutes, and the temperature should be maintained for 6 to 8 hours. 3) Add a measured amount of hydrochloric acid (20-30%) to the reaction vessel, and the total amount of water solvent is 5 times the molar amount of dimethyl phosphite. Keep stirring and heat to reflux for 2-3 hours for hydrolysis. Filter the solution and distill off hydrogen chloride and methanol from the filtrate to obtain 2-phosphorylpentane-1,2,4-tricarboxylic acid.

[0017] Relevant reaction formula: , The application of the 2-phosphorylpentane-1,2,4-tricarboxylic acid of the present invention as a corrosion and scale inhibitor in oil and gas extraction operations at 140~170℃.

[0018] The main raw materials and equipment specifications used in the 2-phosphorylpentane-1,2,4-tricarboxylic acid of this invention are as follows: Dimethyl phosphite, dimethyl maleate, methyl methacrylate, and sodium methoxide are all commercially available. The sodium methoxide is a 30% methanol liquid. The hydrochloric acid is produced by the company and has a 25% hydrochloric acid content.

[0019] The present invention will now be described with reference to specific parameters and embodiments: Example

[0020] Step 1): Add 110g of dimethyl phosphite and 2.54g of sodium methoxide in methanol to the reaction vessel, start stirring, control the temperature at 12±2℃, add 144g of dimethyl maleate dropwise to the reaction vessel at a flow rate of 4.8g / min, and finish the addition after 30min. Continue to keep the temperature and react for 2h. Step 2): Keep stirring and temperature constant, continue to add 100g of methyl methacrylate dropwise at a flow rate of 3.3g / min. The addition is completed after 31min, and the reaction is continued at the temperature for 6h. Step 3): While stirring, add 120g of 25% hydrochloric acid to the reactor. While stirring, heat to reflux and hydrolyze for 2 hours. After filtration, distill off hydrogen chloride and 143.8g of methanol from the filtrate to obtain 256.3g of 2-phosphorylpentane-1,2,4-tricarboxylic acid. Dilute with water to obtain 482.7g of a 50.01% aqueous solution of 2-phosphorylpentane-1,2,4-tricarboxylic acid, denoted as A1.

[0021] Gas chromatography analysis revealed that the purity of the prepared 2-phosphorylpentane-1,2,4-tricarboxylic acid was 87.32% (excluding methanol); the water content of externally distilled methanol was 0.08%. Example

[0022] Step 1): Add 110g of dimethyl phosphite and 4.23g of sodium methoxide in methanol to the reaction vessel, start stirring, control the temperature at 28±2℃, add 144g of dimethyl maleate dropwise to the reaction vessel at a flow rate of 2.4g / min, and finish the addition after 1h. Continue to keep the temperature and react for 3h. Step 2): Keep stirring and temperature constant, continue to add 150g of methyl methacrylate dropwise at a flow rate of 2.5g / min. The addition is completed after 1 hour, and the reaction is continued at the temperature for another 8 hours. Step 3): While stirring, add 120g of 25% hydrochloric acid to the reactor. While stirring, heat to reflux and hydrolyze for 3 hours. After filtration, distill off hydrogen chloride and 144.2g of methanol from the filtrate to obtain 259.2g of 2-phosphorylpentane-1,2,4-tricarboxylic acid. Dilute with water to obtain 488.3g of a 50.02% aqueous solution of 2-phosphorylpentane-1,2,4-tricarboxylic acid, denoted as A2.

[0023] Gas chromatography analysis revealed that the purity of the prepared 2-phosphorylpentane-1,2,4-tricarboxylic acid was 87.65% (excluding methanol); the externally distilled methanol-water content was 0.09%.

[0024] The performance of 2-phosphatylpentane-1,2,4-tricarboxylic acid and 2-phosphonobutane-1,2,4-tricarboxylic acid (PBTCA) prepared by this invention was compared and tested. PBTCA was a 50% aqueous solution and was produced by the company itself.

[0025] Scale inhibition performance testing: According to the method provided in the national standard GB / T16632-2019, "Determination of Scale Inhibition Performance of Water Treatment Agents - Calcium Carbonate Deposition Method", products A1 of Example 1, A2 of Example 2, and PBTCA were tested respectively.

[0026] Test conditions: dosage 5 ppm (on a dry basis), EDTA concentration 0.01 mol / L, standard calcium ion concentration 0.240 mg / ml, P1 is the calcium ion concentration after the test of the test solution with added water treatment agent; P2 is the calcium ion concentration after the test of the blank test solution without added water treatment agent.

[0027] The results are shown in Table 1 below.

[0028] , As can be seen from Table 1, the scale inhibition performance of 2-phosphorylpentane-1,2,4-tricarboxylic acid obtained in the embodiments of the present invention is comparable to that of PBTCA, and the scale inhibition rate is above 70% when 5 ppm of calcium ions are added.

[0029] Corrosion inhibition performance testing: According to the national standard GB / T25147-2010, the acid pickling corrosion inhibition performance of Product A1, Product A2, and PBTCA from Example 1 was tested. Test conditions: The test pieces were immersed in a 15% hydrochloric acid aqueous solution at 60℃ for 4 hours. The results are shown in the table below: , As can be seen from Table 2, both 2-phosphorylpentane-1,2,4-tricarboxylic acid and PBTCA obtained in the embodiments of the present invention have good corrosion inhibition properties, and their corrosion inhibition properties are comparable.

[0030] Thermogravimetric analysis: Thermogravimetric analysis (TGA) was performed on products A1 (Example 1), A2 (Example 2), and PBTCA according to the national standard GB / T 27761-2011, which describes the test method for weight loss and residue in thermogravimetric analysis. Test conditions: The samples were heated from 30°C to 500°C at a heating rate of 10°C / min, and the heating curves were recorded. The nitrogen purging rate was 80 ml / min. Results are shown below. Figure 1 and Figure 2 .

[0031] from Figure 1 and Figure 2The thermogravimetric curves show that PBTCA remains relatively stable in the ambient temperature range of 120-140℃. Above 140℃, PBTCA begins to decompose slowly, and the decomposition rate accelerates significantly at 150℃. In contrast, the 2-phosphorylpentane-1,2,4-tricarboxylic acid of this invention remains stable in the temperature range of 140-160℃, only beginning to decompose above 160℃, and the decomposition rate accelerates significantly only at 170℃. Compared to PBTCA, 2-phosphorylpentane-1,2,4-tricarboxylic acid has a thermal stability temperature that is about 20℃ higher. It can be predicted that 2-phosphorylpentane-1,2,4-tricarboxylic acid has stronger stability in extreme high-temperature working environments and can better exert its sustained slow-release scale inhibition performance.

[0032] The embodiments described above merely illustrate the implementation of this invention patent, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of this invention patent. It should be noted that for those skilled in the art, various modifications or variations that can be made without departing from the concept of this invention patent, without any inventive effort, are still within the protection scope of this invention.

Claims

1. A corrosion and scale inhibitor, 2-phosphorylpentane-1,2,4-tricarboxylic acid, characterized in that, Its molecular formula is: C8H 13 O9P, the structural formula is: .

2. A method for synthesizing the corrosion and scale inhibitor 2-phosphorylpentane-1,2,4-tricarboxylic acid as described in claim 1, characterized in that, Includes the following steps: 1) Add a quantitative amount of dimethyl phosphite and sodium methoxide in methanol to the reaction vessel, start stirring, control the temperature at 10~30℃, add a quantitative amount of dimethyl maleate dropwise, complete the dropwise addition in 30~60min, and keep warm for 2~3h; 2) Keep stirring and temperature constant, continue to add a fixed amount of methyl methacrylate dropwise, complete the addition in 30-60 minutes, and keep warm for 6-8 hours; 3) Add a measured amount of hydrochloric acid to the reaction vessel, keep stirring, heat to reflux and hydrolyze for 2-3 hours, filter, and distill off hydrogen chloride and methanol from the filtrate to obtain 2-phosphorylpentane-1,2,4-tricarboxylic acid.

3. The method for synthesizing the corrosion and scale inhibitor 2-phosphorylpentane-1,2,4-tricarboxylic acid according to claim 2, characterized in that, In step 1), the molar ratio of dimethyl phosphite and dimethyl maleate is 1:1, the mass fraction of the methanol solution of sodium methoxide is 25-30%, and the amount of sodium methoxide used is 0.1-1% of the total mass of dimethyl phosphite and dimethyl maleate.

4. The method for synthesizing the corrosion and scale inhibitor 2-phosphorylpentane-1,2,4-tricarboxylic acid according to claim 3, characterized in that, Step 1) The amount of sodium methoxide used is 0.3~0.5% of the total mass of dimethyl phosphite and dimethyl maleate.

5. The method for synthesizing the corrosion and scale inhibitor 2-phosphorylpentane-1,2,4-tricarboxylic acid according to claim 2, characterized in that, In step 2), the amount of methyl methacrylate used is 1 to 1.5 times the molar amount of dimethyl phosphite.

6. The method for synthesizing the corrosion and scale inhibitor 2-phosphorylpentane-1,2,4-tricarboxylic acid according to claim 2, characterized in that, The hydrochloric acid content in step 3) is 20-30%, and the total amount of water in the solvent is 5 times the molar amount of dimethyl phosphite.

7. The application of the corrosion and scale inhibitor 2-phosphorylpentane-1,2,4-tricarboxylic acid as described in claim 1, characterized in that, The corrosion and scale inhibitor 2-phosphorylpentane-1,2,4-tricarboxylic acid has a stable operating temperature of 0~170℃ and is used as a corrosion and scale inhibitor in oil and gas extraction operations.

8. The application according to claim 7, characterized in that, It is used as a corrosion and scale inhibitor in oil and gas extraction operations at high temperatures of 140~170℃.

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