A modified polymethyl methacrylate type pour point depressant and a preparation method thereof

Abstract

The application is suitable for the technical field of materials, and provides a modified polymethyl methacrylate type pour point depressant and a preparation method thereof, which comprises the following steps: dissolving polymethyl methacrylate in an organic solvent, adding a long-chain alkyl modifier, and fully reacting under stirring to obtain a modified liquid; adding an initiator to the modified liquid, and reacting at a temperature of 65-75 DEG C for 3-4 h, and then performing cooling, water precipitation, separation and drying treatment to obtain the product. The long-chain alkyl structure in the application can form a loose network by acting on crude oil hydrocarbon molecules, can reduce intermolecular forces to improve low-temperature fluidity, and can improve the oiliness to improve the physical properties of crude oil and reduce the freezing point. The synthesis process is mild and low in consumption, the molecular weight and distribution of the product can be accurately controlled, the use of harmful solvents is reduced, the green chemistry principle is met, the application is not only suitable for crude oil pour point depression, but also can be used for modification of other petroleum products, and the solid form is convenient for storage and transportation, has low leakage risk, is convenient to add, and can quickly respond to the pour point depression demand of oil fields.

Description

Technical Field

[0001] This application belongs to the field of materials technology, and in particular relates to a modified polymethyl methacrylate type pour point depressant and its preparation method. Background Technology

[0002] In the transportation of waxy crude oil, the use of pour point depressants is widely recognized as an effective solution. Pour point depressants, by adding specific chemicals to crude oil, can alter the formation characteristics of wax crystals, inhibiting their aggregation into complex three-dimensional networks under low-temperature conditions, thereby significantly improving the fluidity of the crude oil and lowering its pour point. Compared to traditional methods, adding pour point depressants is relatively simple, requires lower equipment investment, and typically does not require subsequent processing. This makes the application of pour point depressants more flexible and facilitates automated management, making them particularly suitable for use in offshore oil and gas exploration and transportation. Therefore, as an effective means of reducing crude oil viscosity and pour point, the application of chemical pour point depressants has become a key approach to ensuring the smooth transportation of crude oil under both ambient and cryogenic conditions.

[0003] Recently, solid pour point depressants have gradually become a research hotspot and a major focus of research due to their advantages in pour point depressing effect, ease of storage and transportation, and adaptability. Solid pour point depressants not only possess higher stability but also maintain excellent performance under various complex environmental conditions, thus attracting widespread attention from research institutions and industries worldwide. Current research mainly focuses on the following aspects: First, developing novel polymeric solid pour point depressants to improve their pour point depressing performance through chemical modification and structural optimization; second, exploring the application of nanotechnology in pour point depressants, utilizing the high specific surface area and excellent properties of nanomaterials to enhance the pour point depressing effect. In addition, researchers are also exploring the compounding of multiple types of pour point depressants to leverage synergistic effects and improve overall pour point depressing performance. Therefore, through in-depth research on solid pour point depressants, scholars hope to break through the limitations of traditional pour point depressants and develop more efficient and environmentally friendly new pour point depressing materials.

[0004] Currently, a variety of solid pour point depressants have appeared on the market. Although traditional solid pour point depressants such as ethylene-vinyl acetate copolymer and polymethyl methacrylate have been industrialized, they are difficult to meet the complex oil and gas production environment and increasingly stringent technical standards, and still face the need for performance improvement. Summary of the Invention

[0005] The purpose of this application is to provide a method for preparing a modified polymethyl methacrylate (PMMA) pour point depressant, which aims to solve the problem that existing solid pour point depressants are difficult to meet the requirements of complex oil and gas production environments and increasingly stringent technical standards.

[0006] The embodiments of this application are implemented as follows: a method for preparing a modified polymethyl methacrylate type pour point depressant includes: Polymethyl methacrylate was dissolved in an organic solvent, a long-chain alkyl modifier was added, and the mixture was stirred until fully reacted to obtain a modified solution. An initiator is added to the modified liquid, and the mixture is reacted at a temperature of 65-75℃ for 3-4 hours. After cooling, water precipitation, separation, and drying, a modified polymethyl methacrylate type pour point depressant is obtained.

[0007] Another objective of this application is to provide a modified polymethyl methacrylate (PMMA) pour point depressant, which is prepared by the above-described method for preparing a modified PMMA pour point depressant.

[0008] The long-chain alkyl-modified polymethyl methacrylate (PMMA) solid crude oil pour point depressant provided in this application, through its special long-chain alkyl structure, interacts with crude oil hydrocarbon molecules to form a loose molecular network, reducing intermolecular forces and significantly improving the low-temperature fluidity and lowering the pour point of crude oil. Its synthesis process is mild, efficient, and energy-saving, allowing for precise control of the product's molecular weight and distribution, ensuring product stability. The synthesis process uses environmentally friendly and non-toxic raw materials, reducing the use of harmful solvents and conforming to green chemistry principles. It is not only suitable for crude oil pour point depressing but can also be widely applied to the modification of other petroleum products. Its solid form facilitates storage and transportation, simplifies refueling operations, reduces leakage risk, and allows for rapid response to different pour point depressing needs in oil fields, providing an effective and environmentally friendly solution for improving crude oil fluidity. Attached Figure Description

[0009] Figure 1 DSC curve of blank crude oil provided for embodiments of this application; Figure 2 The DSC curve of crude oil after adding the pour point depressant product of Example 1 of this application; Figure 3 The DSC curve of crude oil after adding the pour point depressant product of Example 2 of this application; Figure 4 The DSC curve of crude oil after adding the pour point depressant product of Example 3 of this application; Figure 5 The DSC curve of crude oil after adding the pour point depressant product of Example 4 of this application; Figure 6 The DSC curve of crude oil after adding the pour point depressant product of Example 5 of this application; Figure 7 The DSC curve of crude oil after adding the pour point depressant product of Example 6 of this application; Figure 8 Infrared spectrum of polymethyl methacrylate raw material provided in the embodiments of this application; Figure 9The infrared spectrum of the modified polymethyl methacrylate type pour point depressant product provided in Example 1 of this application. Detailed Implementation

[0010] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0011] This application provides a method for preparing a modified polymethyl methacrylate (PMMA) type pour point depressant, comprising: Polymethyl methacrylate was dissolved in an organic solvent, a long-chain alkyl modifier was added, and the mixture was stirred until fully reacted to obtain a modified solution. An initiator was added to the modified liquid, and the mixture was reacted at 65-75°C for 3-4 hours. After cooling, water precipitation, separation, and drying, a modified polymethyl methacrylate (PMMA) type pour point depressant was obtained.

[0012] Preferably, the long-chain alkyl modifier is at least one selected from dodecyl methacrylate, tetradecyl methacrylate, hexadecyl methacrylate, and octadecyl methacrylate.

[0013] Preferably, the mass ratio of polymethyl methacrylate to long-chain alkyl modifier is 5:1.

[0014] Optionally, the organic solvent is at least one of toluene, butyl acetate, and ethyl carbamate.

[0015] Preferably, the mass-to-volume ratio of the polymethyl methacrylate to the organic solvent is 1:4.

[0016] Preferably, the initiator is at least one of azobisisobutyronitrile, benzoyl peroxide, and dicumyl peroxide.

[0017] Preferably, the mass ratio of polymethyl methacrylate to initiator is 100:1.

[0018] Preferably, the drying process is carried out at a temperature of 60-70°C for 3.5-4.5 hours.

[0019] Optionally, the preparation method of the modified polymethyl methacrylate type pour point depressant includes: Dissolve 50g of polymethyl methacrylate in 200mL of organic solvent, add 10g of long-chain alkyl modifier, and react fully under stirring at 65-75℃ to obtain the modified solution; Add 0.5g of initiator to the modified liquid and react at 65-75℃ for 3-4h. Cool the reaction system and place it in 500mL of water for precipitation treatment to obtain a solid pour point depressant. Dry the separated solid pour point depressant to obtain a modified polymethyl methacrylate type pour point depressant.

[0020] The modified polymethyl methacrylate (PMMA) pour point depressant and its preparation method described in detail below are specific embodiments. Unless otherwise specified, the experimental methods used in the following embodiments are conventional methods; the materials and reagents used are commercially available unless otherwise specified.

[0021] DSC curve determination method: SY / T0545-2012 "Determination of thermal characteristic parameters of crude oil wax precipitation - differential scanning calorimetry".

[0022] Crude oil samples were heated to above the wax precipitation point temperature using a differential scanning calorimeter (DSC), and then cooled at a certain rate. The differential heat flow of the sample and reference material at each temperature point was recorded. A differential scanning calorimeter curve (DSC curve) of crude oil wax precipitation was plotted with differential heat flow as the ordinate and temperature as the abscissa. When the temperature dropped through the wax precipitation zone of the sample, the differential heat flow changed due to the latent heat released by the wax precipitation, which was reflected on the DSC curve as an exothermic peak deviating from the baseline. As the temperature continued to decrease, the heat released by the wax precipitation gradually decreased, and the differential heat flow also decreased accordingly. Eventually, the curve returned to the baseline, at which point the wax precipitation process ended. The temperature at which the DSC curve began to deviate from the baseline is considered the wax precipitation point of the crude oil, and the peak temperature of the curve is considered the peak temperature of crude oil wax precipitation.

[0023] Example 1: Preparation of modified polymethyl methacrylate type pour point depressant (1) Dissolve 50g of polymethyl methacrylate in 200mL of toluene to form a homogeneous solution; (2) Gradually add 10g of dodecyl methacrylate to the solution, and heat the mixture to 70°C while stirring. Keep stirring to ensure that the modifier reacts fully with polymethyl methacrylate. (3) Add 0.5 g of azobisisobutyronitrile initiator to the reaction system and continue heating for 3 hours; (4) After the reaction is complete, cool the reaction system and pour it into about 500 mL of water for precipitation to obtain solid pour point depressant; (5) The separated solid pour point depressant is dried at 60°C for 4 hours to remove residual solvent and obtain the finished product.

[0024] DSC curves were performed on blank crude oil and crude oil after adding the pour point depressant synthesized in Example 1 (7.5 mg of pour point depressant was added to 1 L of crude oil). The DSC curves are shown below. Figure 1-2 As shown in the figure, the wax precipitation point of the blank crude oil was 35.1℃. After adding 7.5 ppm of the pour point depressant product synthesized in Example 1, the wax precipitation point of the crude oil was 22.3℃, a decrease of 12.8℃.

[0025] Furthermore, Fourier transform infrared spectroscopy (FTIR) was employed. Figure 9 The modified polymethyl methacrylate (PMMA) type pour point depressant obtained in Example 1 of this application was structurally characterized. The results showed that, compared with unmodified PMMA (PMMA... Figure 8 Compared to the modified product, the modified product was at 1730 cm⁻¹ -1 All peaks exhibited distinct absorption peaks due to the C=O stretching vibration of the ester group; simultaneously, at 2850-2920 cm⁻¹... -1 A strong -CH2- antisymmetric and symmetric stretching vibration absorption peak was observed within the range, which is attributed to the long-chain alkyl structure. These results indicate that long-chain alkyl groups were successfully introduced into the polymethyl methacrylate (PMMA) molecule to form a modified polymer.

[0026] Example 2: Preparation of modified polymethyl methacrylate type pour point depressant (1) Dissolve 50g of polymethyl methacrylate in 200mL of butyl acetate to form a homogeneous solution; (2) Gradually add 10g of tetradecyl methacrylate to the solution, while heating the mixture to 75°C under stirring, and maintaining stirring to ensure that the modifier reacts fully; (3) Add 0.5 g of benzoyl peroxide initiator to the reaction system and continue heating the reaction for 3.5 hours; (4) After the reaction is complete, cool the reaction system and pour it into about 500 mL of water for precipitation to obtain solid pour point depressant; (5) The separated solid pour point depressant is dried at 65°C for 3.5 hours to remove residual solvent and obtain the finished product.

[0027] The DSC curve of crude oil after adding the pour point depressant synthesized in Example 2 was determined. The DSC curve is shown below. Figure 3 As shown. Adding 5 ppm of the pour point depressant product synthesized in Example 2 reduced the wax precipitation point of crude oil to 24.4℃, a decrease of 10.7℃.

[0028] Example 3: Preparation of modified polymethyl methacrylate type pour point depressant (1) Dissolve 50g of polymethyl methacrylate in 200mL of urethane to form a homogeneous solution; (2) Gradually add 10g of hexadecyl methacrylate to the solution, and heat the mixture to 68°C under stirring to ensure that the modifier reacts fully with polymethyl methacrylate; (3) Add 0.5 g of dicumyl peroxide initiator to the reaction system and continue heating the reaction for 4 hours; (4) After the reaction is complete, cool the reaction system and pour it into about 500 mL of water for precipitation to obtain solid pour point depressant; (5) The separated solid pour point depressant is dried at 70°C for 4.5 hours to remove residual solvent and obtain the finished product.

[0029] DSC curves were measured on the crude oil after adding the pour point depressant synthesized in Example 3. The DSC curves are as follows: Figure 4 As shown. When 10 ppm of the pour point depressant product synthesized in Example 3 was added, the wax precipitation point of the crude oil was 19.4℃, which decreased by 9.2℃.

[0030] Example 4: Preparation of modified polymethyl methacrylate type pour point depressant (1) Dissolve 50g of polymethyl methacrylate in 200mL of toluene to form a homogeneous solution; (2) Gradually add 10g of octadecyl methacrylate to the solution, and heat the mixture to 72°C while stirring. Keep stirring to ensure that the modifier reacts fully with polymethyl methacrylate. (3) Add 0.5 g of azobisisobutyronitrile initiator to the reaction system and continue heating the reaction for 3.5 hours; (4) After the reaction is complete, cool the reaction system and pour it into about 500 mL of water for precipitation to obtain solid pour point depressant; (5) The separated solid pour point depressant is dried at 60°C for 3.5 hours to remove residual solvent and obtain the finished product.

[0031] DSC curves were measured on the crude oil after adding the pour point depressant synthesized in Example 4. The DSC curves are as follows: Figure 5 As shown. When 15 ppm of the pour point depressant product synthesized in Example 4 was added, the wax precipitation point of the crude oil was 11.3℃, which decreased by 23.8℃.

[0032] Example 5: Preparation of modified polymethyl methacrylate type pour point depressant (1) Dissolve 50g of polymethyl methacrylate in 200mL of butyl acetate to form a homogeneous solution; (2) Gradually add 10g of dodecyl methacrylate to the solution, and heat the mixture to 65°C under stirring to ensure that the modifier reacts fully with polymethyl methacrylate. (3) Add 0.5 g of benzoyl peroxide initiator to the reaction system and continue heating the reaction for 4 hours; (4) After the reaction is complete, cool the reaction system and pour it into about 500 mL of water for precipitation to obtain solid pour point depressant; (5) The separated solid pour point depressant is dried at 60°C for 4 hours to remove residual solvent and obtain the finished product.

[0033] The DSC curve of crude oil after adding the pour point depressant synthesized in Example 5 was determined, and the DSC curve is shown below. Figure 6 As shown. When 12 ppm of the pour point depressant product synthesized in Example 5 was added, the wax precipitation point of the crude oil was 14.2℃, which decreased by 20.9℃.

[0034] Example 6: Preparation of modified polymethyl methacrylate type pour point depressant (1) Dissolve 50g of polymethyl methacrylate in 200mL of urethane to form a homogeneous solution; (2) Gradually add 10g of tetradecyl methacrylate to the solution, while heating the mixture to 70°C under stirring, and maintaining stirring to ensure that the modifier reacts fully; (3) Add 0.5 g of dicumyl peroxide initiator to the reaction system and continue heating the reaction for 3 hours; (4) After the reaction is complete, cool the reaction system and pour it into about 500 mL of water for precipitation to obtain solid pour point depressant; (5) The separated solid pour point depressant is dried at 65°C for 3.5 hours to remove residual solvent and obtain the finished product.

[0035] DSC curves were measured on the crude oil after adding the pour point depressant synthesized in Example 6. The DSC curves are as follows: Figure 7 As shown. When 11 ppm of the pour point depressant product synthesized in Example 6 was added, the wax precipitation point of the crude oil was 14.36℃, which decreased by 20.74℃.

[0036] Furthermore, during the early research and development process of this application, comparative experiments were conducted on the reaction temperature, reaction time, and dosage of long-chain alkyl modifier in the preparation process of the modified polymethyl methacrylate type pour point depressant. The preparation process conditions are the same as in Example 1, as shown below: 1. Comparison Experiment of Reaction Temperature Different temperature conditions were set for the experiment (the reaction temperatures in step (2) were 60℃, 65℃, 70℃, and 75℃, respectively), while other conditions remained unchanged (reaction time: 3 hours, modifier: 1 molar amount, initiator: 0.1%). The molecular weight, molecular weight distribution, and pour point depressant of the obtained modified polymethyl methacrylate type were tested, and the test results are shown in Table 1 below.

[0037] Table 1

[0038] 2. Reaction Time Comparison Experiment Different reaction times were set in the experiment (the reaction times in step (3) were 3 hours, 3.5 hours, and 4 hours, respectively), while other conditions remained unchanged (reaction temperature: 70℃, modifier: 1 molar amount, initiator: 0.1%). The molecular weight, molecular weight distribution, and pour point depressant of the obtained modified polymethyl methacrylate type were tested, and the test results are shown in Table 2 below.

[0039] Table 2

[0040] 3. Comparison Experiment of Long-Chain Alkyl Modifier Dosage

[0041] Different amounts of long-chain alkyl modifier were used in the experiment (0.5 times, 1.0 times, and 1.5 times molar amount), while other conditions remained constant (reaction temperature: 70℃, reaction time: 3.5 hours, initiator: 0.1%). The molecular weight, molecular weight distribution, and pour point depressant of the obtained modified polymethyl methacrylate type were tested, and the test results are shown in Table 3 below.

[0042] Table 3

[0043] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

[0044] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A method for preparing a modified polymethyl methacrylate (PMMA) type pour point depressant, characterized in that, include: Polymethyl methacrylate was dissolved in an organic solvent, a long-chain alkyl modifier was added, and the mixture was stirred until fully reacted to obtain a modified solution. An initiator is added to the modified liquid, and the mixture is reacted at a temperature of 65-75℃ for 3-4 hours. After cooling, water precipitation, separation, and drying, a modified polymethyl methacrylate type pour point depressant is obtained.

2. The preparation method of the modified polymethyl methacrylate type pour point depressant according to claim 1, characterized in that, The long-chain alkyl modifier is at least one of dodecyl methacrylate, tetradecyl methacrylate, hexadecyl methacrylate, and octadecyl methacrylate.

3. The preparation method of the modified polymethyl methacrylate type pour point depressant according to claim 1, characterized in that, The mass ratio of polymethyl methacrylate to long-chain alkyl modifier is 5:

1.

4. The preparation method of the modified polymethyl methacrylate type pour point depressant according to claim 1, characterized in that, The organic solvent is at least one of toluene, butyl acetate, and ethyl carbamate.

5. The method for preparing the modified polymethyl methacrylate type pour point depressant according to claim 1, characterized in that, The mass-to-volume ratio of polymethyl methacrylate to organic solvent is 1:

4.

6. The method for preparing the modified polymethyl methacrylate type pour point depressant according to claim 1, characterized in that, The initiator is at least one of azobisisobutyronitrile, benzoyl peroxide, and dicumyl peroxide.

7. The method for preparing the modified polymethyl methacrylate type pour point depressant according to claim 1, characterized in that, The mass ratio of polymethyl methacrylate to initiator is 100:

1.

8. The method for preparing the modified polymethyl methacrylate type pour point depressant according to claim 1, characterized in that, The drying process is carried out at a temperature of 60-70℃ for 3.5-4.5 hours.

9. The method for preparing the modified polymethyl methacrylate type pour point depressant according to claim 1, characterized in that, include: Dissolve 50g of polymethyl methacrylate in 200mL of organic solvent, add 10g of long-chain alkyl modifier, and react fully under stirring at 65-75℃ to obtain the modified solution; Add 0.5g of initiator to the modified liquid and react at 65-75℃ for 3-4h. Cool the reaction system and place it in 500mL of water for precipitation treatment to obtain a solid pour point depressant. Dry the separated solid pour point depressant to obtain a modified polymethyl methacrylate type pour point depressant.

10. A modified polymethyl methacrylate type pour point depressant, characterized in that, The modified polymethyl methacrylate (PMMA) pour point depressant is prepared by the preparation method of the modified PMMA pour point depressant according to any one of claims 1-9.

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