Modified cellulose fluid loss additive and method of making same
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SHANDONG DESHUNYUAN PETROLEUM SCI&TECH CO LTD
- Filing Date
- 2026-06-23
- Publication Date
- 2026-07-21
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Figure SMS_1
Abstract
Description
Technical Field
[0001] This invention relates to the field of oilfield chemical technology, specifically to a modified cellulose filtration reducer and its preparation method. Background Technology
[0002] In oil and gas drilling engineering, water-based drilling fluids are a key system for ensuring drilling safety, protecting oil and gas reservoirs, and maintaining wellbore stability. Filtration loss reducers, as core treatment agents, reduce formation damage by decreasing filtration loss and optimizing filter cake quality. With increasing drilling depth, the high-temperature, high-salt, and high-calcium environment downhole places higher demands on the comprehensive performance of filtration loss reducers.
[0003] Cellulose-based filtration reducers are widely used in drilling fluids due to their advantages such as readily available raw materials, biodegradability, and low cost. However, traditional cellulose derivatives have significant drawbacks: their molecular chains are easily hydrolyzed and broken under high temperatures, their molecular structure lacks salt- and calcium-resistant functional groups, their adsorption capacity with clay particles is limited, and the resulting filter cake is loose and porous, making it difficult to effectively seal and reduce filtration loss. Currently, most existing modified cellulose technologies use single-functional group modification, which improves filtration loss reduction performance to some extent, but generally suffers from insufficient high-temperature resistance, weak salt and calcium resistance, and poor structural stability. Furthermore, some modification processes have harsh reaction conditions and cumbersome steps, limiting their industrial application and promotion.
[0004] For example, patent application CN119431610A discloses an amino-modified polyanionic cellulose filtration loss reducer and its preparation method. This invention provides an amino-modified polyanionic cellulose filtration loss reducer with good temperature resistance and significant filtration loss reduction effect, but its salt and calcium resistance needs to be improved. Therefore, developing a novel modified cellulose filtration loss reducer that combines high temperature resistance, salt and calcium resistance, high efficiency in filtration loss reduction, and environmental friendliness, and providing a simple, mild preparation method suitable for large-scale production, is of great significance for improving the performance of drilling fluids in deep and complex wells and promoting green and efficient drilling in oilfields. Summary of the Invention
[0005] In order to overcome the shortcomings of the prior art, the present invention aims to provide a modified cellulose filtration loss reducer and its preparation method. The modified cellulose filtration loss reducer prepared by the present invention has good high temperature resistance, salt and calcium resistance and filtration loss reduction performance.
[0006] To achieve the above objectives, the present invention provides the following technical solution: a method for preparing a modified cellulose filtration loss reducer, comprising the following steps: (1) Add hydroxyethyl cellulose to isopropanol, stir at 400-500 r / min for 25-30 min, then add 5% sodium hydroxide solution dropwise, purge with nitrogen for 15-20 min, and swell and activate at room temperature for 24-26 h to obtain cellulose suspension; In the above steps, isopropanol, as a suspension medium, can fully disperse cellulose, and together with the subsequent alkaline solution, achieve uniform swelling and activation.
[0007] (2) Add deionized water to the cellulose suspension, mix well, add modified m-aminotrifluorotoluene and modified itaconic acid monolaurate, stir at 500-600 r / min for 15-20 min, then heat to 60-70℃, add ammonium persulfate dropwise to the system under nitrogen protection, continue the reaction for 4-6 h, after the reaction is completed, cool, wash and dry, pulverize to obtain modified cellulose filtration loss reducer; In step (1), the ratio of isopropanol, hydroxyethyl cellulose, and 5% sodium hydroxide solution is 40-50 mL: 2-2.2 g: 6-7 mL. In step (2), the ratio of deionized water, modified m-aminotrifluorotoluene, modified itaconic acid monolaurate, and ammonium persulfate is 10-15 mL: 1.8-2 g: 2-3 g: 0.12-0.15 g.
[0008] Furthermore, the preparation method of the modified m-aminotrifluorotoluene in step (2) is as follows: Step 1: Add ammonium thiocyanate to acetonitrile solvent, mix well, and add 4-vinylbenzoyl chloride dropwise while stirring at room temperature. After the addition is complete, stir the reaction for 4-6 hours. After the reaction is complete, filter and concentrate under reduced pressure to obtain 4-vinylbenzoyl isothiocyanate. In the above steps, the thiocyanate ion acts as a nucleophile, attacking the partially positively charged carbonyl carbon atom in 4-vinylbenzoyl chloride, resulting in a nucleophilic addition-elimination reaction. Subsequently, the chloride ion is removed as a leaving group to obtain 4-vinylbenzoyl isothiocyanate with an isothiocyanate group.
[0009] Step 2: Under nitrogen protection, add 4-vinylbenzoyl isothiocyanate and m-aminotrifluorotoluene to N,N-dimethylformamide solvent, stir and mix, then add triethylamine, and react at 60-70℃ for 10-12 h. After the reaction is completed, cool the reaction solution to room temperature, pour in deionized water while stirring, filter, wash, recrystallize, and dry to obtain modified m-aminotrifluorotoluene.
[0010] In the above steps, the primary amino group on m-aminotrifluorotoluene is nucleophilic. The lone pair of electrons on its nitrogen atom attacks the electron-deficient central carbon atom in the isothiocyanate group, resulting in nucleophilic addition to generate a zwitterionic intermediate. Subsequently, proton transfer occurs, and rearrangement forms a stable acylthiourea structure, yielding modified m-aminotrifluorotoluene.
[0011] Furthermore, in step one, the ratio of acetonitrile, ammonium thiocyanate, and 4-vinylbenzoyl chloride is 30-40 mL: 2-2.1 g: 3.3-3.4 g.
[0012] Furthermore, in step two, the ratio of N,N-dimethylformamide, 4-vinylbenzoyl isothiocyanate, m-aminotrifluorotoluene, triethylamine, and deionized water is 30-40 mL: 2.5-2.6 g: 2.1-2.2 g: 1-1.1 g: 200-220 mL.
[0013] Furthermore, the preparation method of the modified itaconic acid monolaurate in step (2) is as follows: S1: Add lauryl alcohol, itaconic anhydride, and anhydrous sodium acetate to the reactor and stir at 60-70℃ for 3-4 hours. After the reaction is complete, add n-hexane and continue stirring at 60-70℃ for 10-15 minutes. Then cool to room temperature, filter, recrystallize 3-4 times in anhydrous ethanol, and dry to obtain itaconic acid lauryl ester. In the above steps, the hydroxyl oxygen atom of lauryl alcohol acts as a nucleophile, attacking the carbonyl carbon on the acid anhydride. Under the action of anhydrous sodium acetate catalyst, the acid anhydride ring is opened to generate itaconic acid lauryl ester.
[0014] S2: Add itaconic acid lauryl ester and N,N-dimethylethanolamine to N,N-dimethylformamide solvent, mix well, then add p-toluenesulfonic acid, react at 70-80℃ for 6-8h, after the reaction is completed, recrystallize 2-3 times in anhydrous ethanol, filter, dry, and obtain intermediate 1. In the above steps, under the catalysis of p-toluenesulfonic acid, the free carboxyl group in itaconic acid lauryl ester undergoes an esterification reaction with the primary hydroxyl group of N,N-dimethylethanolamine to generate intermediate 1 containing a tertiary amine group.
[0015] S3: Add deionized water and ethanol to the reactor and mix to prepare a solvent. Then add intermediate 1,3-chloro-2-hydroxypropanesulfonate sodium salt and react at 70-80℃ for 8-12 hours. After the reaction is completed, remove the solvent by rotary evaporation, wash, filter and dry to obtain modified itaconic acid monolaurate.
[0016] In the above steps, the tertiary amine nitrogen atom on intermediate 1 actively attacks the carbon atom bonded to the chlorine atom in sodium 3-chloro-2-hydroxypropanesulfonate. The chloride ion, as a good leaving group, is released, and the tertiary amine is converted into a quaternary ammonium salt to obtain modified itaconic acid monolaurate.
[0017] Furthermore, the ratio of lauryl alcohol, itaconic anhydride, anhydrous sodium acetate, and n-hexane in S1 is 4.7-4.8g:3-3.1g:0.07-0.08g:6-7mL.
[0018] Further, the ratio of N,N-dimethylformamide, itaconic acid lauryl ester, N,N-dimethylethanolamine, and p-toluenesulfonic acid in S2 is 30-40mL:5-5.1g:1.5-1.6g:0.3-0.4g.
[0019] Furthermore, the ratio of deionized water, ethanol, and intermediate 1,3-chloro-2-hydroxypropanesulfonate sodium in S3 is 20-30mL:40-50mL:4.5-4.6g:3-3.1g.
[0020] The present invention also protects a modified cellulose filtration loss reducer, which is prepared by any of the preparation methods described above.
[0021] Compared with the prior art, the present invention has the following beneficial technical effects: This invention forms a stable three-dimensional network structure by covalently grafting modified m-aminotrifluorotoluene and modified itaconic acid monolaurate onto the hydroxyethyl cellulose backbone. The trifluoromethyl group on the modified m-aminotrifluorotoluene structure has a strong electron-withdrawing effect and hydrophobic properties, which can significantly improve the thermal stability of the polymer backbone and inhibit the thermal oxidative degradation of the molecular chain at high temperatures. The acylthiourea and benzene ring structure can enhance the rigidity of the molecular chain, inhibit the main chain breakage at high temperatures, and improve the high-temperature resistance of the modified cellulose filtration loss reducer. The sulfonic acid group in the modified itaconic acid monolauryl ester is not sensitive to high-valence metal ions and can still maintain the extended state of the molecular chain in high-salt and high-calcium environments. The quaternary ammonium cation can be strongly adsorbed on the negatively charged clay surface through electrostatic interaction to form a dense hydration film, so that the modified cellulose filtration loss reducer of this invention can still maintain excellent filtration loss reduction performance under complex working conditions of high salt and high calcium. Moreover, the long-chain alkyl group can enhance the adsorption and coating effect of the product on the surface of clay particles, improve the compatibility with the drilling fluid system, and can synergistically block the pores of the mud cake to form a thin, tough, and dense high-quality filter cake, which can significantly reduce the filtration loss at high temperature and high pressure. Detailed Implementation
[0022] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are described clearly and completely. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0023] Example 1
[0024] (1) Add 2g of ammonium thiocyanate to 30mL of acetonitrile solvent, mix well, and add 3.3g of 4-vinylbenzoyl chloride dropwise while stirring at room temperature. After the addition is complete, stir the reaction for 4h. After the reaction is complete, filter and concentrate under reduced pressure to obtain 4-vinylbenzoyl isothiocyanate. (2) Under nitrogen protection, 2.5 g of 4-vinylbenzoyl isothiocyanate and 2.1 g of m-aminotrifluorotoluene were added to 30 mL of N,N-dimethylformamide solvent and stirred. Then, 1 g of triethylamine was added and the mixture was reacted at 60 °C for 10 h. After the reaction was completed, the reaction solution was cooled to room temperature and 200 mL of deionized water was poured in while stirring. The mixture was filtered, washed, recrystallized, and dried to obtain modified m-aminotrifluorotoluene. (3) Add 4.7g of lauryl alcohol, 3g of itaconic anhydride and 0.07g of anhydrous sodium acetate to the reactor, stir at 60°C for 3h, after the reaction is completed, add 6mL of n-hexane, continue stirring at 60°C for 10min, then cool to room temperature, filter, recrystallize 3 times in anhydrous ethanol, dry, and obtain itaconic acid lauryl ester; (4) Add 5g of itaconic acid lauryl ester and 1.5g of N,N-dimethylethanolamine to 30mL of N,N-dimethylformamide solvent, mix well, then add 0.3g of p-toluenesulfonic acid, react at 70℃ for 6h, after the reaction is completed, recrystallize twice in anhydrous ethanol, filter, dry to obtain intermediate 1; (5) Add 20 mL of deionized water and 40 mL of ethanol to the reactor and mix to prepare a solvent. Then add 4.5 g of intermediate 1 and 3 g of sodium 3-chloro-2-hydroxypropanesulfonate. React at 70 °C for 8 h. After the reaction is complete, remove the solvent by rotary evaporation, wash, filter and dry to obtain modified itaconic acid monolaurate. (6) Add 2g of hydroxyethyl cellulose to 40mL of isopropanol, stir at 400r / min for 25min, then add 6mL of 5% sodium hydroxide solution, purge with nitrogen for 15min, and swell and activate at room temperature for 24h to obtain cellulose suspension. (7) Add 10 mL of deionized water to the cellulose suspension, mix well, add 1.8 g of modified m-aminotrifluorotoluene and 2 g of modified itaconic acid monolaurate, stir at 500 r / min for 15 min, then heat to 60 °C, under nitrogen protection, add 0.12 g of ammonium persulfate dropwise to the system, continue the reaction for 4 h, after the reaction is completed, cool, wash and dry, pulverize to obtain modified cellulose filtration loss reducer.
[0025] Example 2
[0026] (1) Add 2.1g of ammonium thiocyanate to 40mL of acetonitrile solvent, mix well, and add 3.4g of 4-vinylbenzoyl chloride dropwise while stirring at room temperature. After the addition is complete, stir the reaction for 6h. After the reaction is complete, filter and concentrate under reduced pressure to obtain 4-vinylbenzoyl isothiocyanate. (2) Under nitrogen protection, 2.6 g of 4-vinylbenzoyl isothiocyanate and 2.2 g of m-aminotrifluorotoluene were added to 40 mL of N,N-dimethylformamide solvent and stirred. Then, 1.1 g of triethylamine was added and the mixture was reacted at 70 °C for 12 h. After the reaction was completed, the reaction solution was cooled to room temperature and 220 mL of deionized water was poured in while stirring. The mixture was filtered, washed, recrystallized, and dried to obtain modified m-aminotrifluorotoluene. (3) Add 4.8g of lauryl alcohol, 3.1g of itaconic anhydride and 0.08g of anhydrous sodium acetate to the reactor, stir at 70°C for 4h, after the reaction is completed, add 7mL of n-hexane, continue stirring at 70°C for 15min, then cool to room temperature, filter, recrystallize 4 times in anhydrous ethanol, dry, and obtain itaconic acid lauryl ester; (4) Add 5.1 g of itaconic acid lauryl ester and 1.6 g of N,N-dimethylethanolamine to 40 mL of N,N-dimethylformamide solvent, mix well, then add 0.4 g of p-toluenesulfonic acid, react at 80 °C for 8 h, after the reaction is completed, recrystallize 3 times in anhydrous ethanol, filter, dry to obtain intermediate 1; (5) Add 30 mL of deionized water and 50 mL of ethanol to the reactor and mix to prepare a solvent. Then add 4.6 g of intermediate 1 and 3.1 g of sodium 3-chloro-2-hydroxypropanesulfonate to it and react at 80 °C for 12 h. After the reaction is completed, remove the solvent by rotary evaporation, wash, filter and dry to obtain modified itaconic acid monolaurate. (6) Add 2.2g of hydroxyethyl cellulose to 50mL of isopropanol, stir at 500r / min for 30min, then add 7mL of 5% sodium hydroxide solution, purge with nitrogen for 20min, and swell and activate at room temperature for 26h to obtain cellulose suspension. (7) Add 15 mL of deionized water to the cellulose suspension, mix well, add 2 g of modified m-aminotrifluorotoluene and 3 g of modified itaconic acid monolaurate, stir at 600 r / min for 20 min, then heat to 70 °C, under nitrogen protection, add 0.15 g of ammonium persulfate dropwise to the system, continue the reaction for 6 h, after the reaction is completed, cool, wash and dry, pulverize to obtain modified cellulose filtration loss reducer.
[0027] Example 3
[0028] (1) Add 2.05 g of ammonium thiocyanate to 35 mL of acetonitrile solvent, mix well, and add 3.35 g of 4-vinylbenzoyl chloride dropwise while stirring at room temperature. After the addition is complete, stir the reaction for 5 h. After the reaction is complete, filter and concentrate under reduced pressure to obtain 4-vinylbenzoyl isothiocyanate. (2) Under nitrogen protection, 2.55 g of 4-vinylbenzoyl isothiocyanate and 2.15 g of m-aminotrifluorotoluene were added to 35 mL of N,N-dimethylformamide solvent and stirred. Then, 1.05 g of triethylamine was added and the mixture was reacted at 65 °C for 11 h. After the reaction was completed, the reaction solution was cooled to room temperature and 210 mL of deionized water was poured in while stirring. The mixture was filtered, washed, recrystallized, and dried to obtain modified m-aminotrifluorotoluene. (3) Add 4.75 g of lauryl alcohol, 3.05 g of itaconic anhydride and 0.07 g of anhydrous sodium acetate to the reactor, stir at 65 °C for 3 h, after the reaction is completed, add 6.5 mL of n-hexane, continue stirring at 65 °C for 12 min, then cool to room temperature, filter, recrystallize 3 times in anhydrous ethanol, dry, and obtain itaconic acid lauryl ester; (4) Add 5.05 g of itaconic acid lauryl ester and 1.55 g of N,N-dimethylethanolamine to 35 mL of N,N-dimethylformamide solvent, mix well, then add 0.35 g of p-toluenesulfonic acid, react at 75 °C for 7 h, after the reaction is completed, recrystallize twice in anhydrous ethanol, filter, dry to obtain intermediate 1; (5) Add 25 mL of deionized water and 45 mL of ethanol to the reactor and mix to prepare a solvent. Then add 4.55 g of intermediate 1 and 3.05 g of sodium 3-chloro-2-hydroxypropanesulfonate to it and react at 75 °C for 10 h. After the reaction is completed, remove the solvent by rotary evaporation, wash, filter and dry to obtain modified itaconic acid monolaurate. (6) Add 2.1 g of hydroxyethyl cellulose to 45 mL of isopropanol, stir at 400 r / min for 28 min, then add 6.5 mL of 5% sodium hydroxide solution, purge with nitrogen for 18 min, and swell and activate at room temperature for 25 h to obtain a cellulose suspension. (7) Add 12 mL of deionized water to the cellulose suspension, mix well, add 1.9 g of modified m-aminotrifluorotoluene and 2.5 g of modified itaconic acid monolaurate, stir at 500 r / min for 18 min, then heat to 65 °C, add 0.13 g of ammonium persulfate dropwise to the system under nitrogen protection, continue the reaction for 5 h, after the reaction is completed, cool, wash and dry, pulverize to obtain modified cellulose filtration loss reducer.
[0029] Comparative Example 1 The main difference between this comparative example and Example 3 is that 4-vinylbenzoyl isothiocyanate is used instead of modified m-aminotrifluorotoluene.
[0030] Comparative Example 2 The main difference between this comparative example and Example 3 is that itaconic acid lauryl ester is used instead of modified itaconic acid monolauryl ester.
[0031] Comparative Example 3 The main difference between this comparative example and Example 3 is that ammonium persulfate is not added in step (7), graft polymerization is not carried out, and only physical mixing is performed.
[0032] Comparative Example 4 The main difference between this comparative example and Example 3 is that the grafting reaction temperature in step (7) is changed to 50°C.
[0033] Performance testing The modified cellulose filtration reducers prepared in Examples 1-3 and Comparative Examples 1-4 were subjected to performance tests.
[0034] Test Method: 0.9 g of sodium carbonate, 45 g of sodium bentonite, and 1000 mL of water were mixed and stirred for 20 min. The mixture was then sealed and cured at room temperature for 24 h to obtain a freshwater-based slurry. 1.5% (w / v) of the modified cellulose filtration reducer samples prepared in Examples 1-3 and Comparative Examples 1-4 were added, and the mixture was stirred thoroughly to obtain the test slurry. The prepared test slurry was then placed in a high-temperature aging tank and placed in a roller furnace for rolling heat aging at 110℃ and 160℃ for 16 h, respectively. After aging, the mixture was cooled to room temperature. Following GB / T16783.1-2025 standard, a high-temperature, high-pressure filtration analyzer was used to measure the filtration loss for 30 min at the corresponding aging temperature and a pressure difference of 3.45 MPa. The high-temperature and high-pressure filtration loss was measured. Separately, a freshwater-based slurry was prepared by adding 25% sodium chloride and 1.5% calcium chloride by mass, stirring for 20 minutes to form a brine calcium-contaminated slurry. Then, 1.5% (w / v) of the modified cellulose filtration loss reducer prepared in Examples 1-3 and Comparative Examples 1-4 was added and mixed to obtain a brine test slurry. The prepared brine test slurry was then placed in a high-temperature aging tank and placed in a roller furnace for rolling heat aging at 160°C for 16 hours. After aging, the slurry was cooled to room temperature. Referring to GB / T16783.1-2025 standard, the high-temperature and high-pressure filtration loss was measured for 30 minutes using a high-temperature and high-pressure filtration loss meter at the corresponding aging temperature and a pressure difference of 3.45 MPa. The test results are shown in Table 1.
[0035] Table 1: Performance Tests
[0036] As can be seen from Table 1, the modified cellulose filtration reducers prepared in Examples 1-3 have good high temperature resistance, salt and calcium resistance, and filtration reduction properties.
[0037] The comparison shows that Comparative Example 1, which uses 4-vinylbenzoyl isothiocyanate instead of modified m-aminotrifluorotoluene, fails to introduce a fluorinated rigid side group conjugated with the benzene ring, resulting in a significant decrease in the thermal stability of the polymer backbone. At high temperatures, the molecular chain is prone to thermal oxidative degradation. Furthermore, the lack of hydrophobicity and heat resistance from fluorinated groups prevents the formation of a stable adsorption hydration film, leading to a decline in performance. Comparative Example 2, which uses itaconic acid lauryl ester instead of modified itaconic acid monolauryl ester, fails to introduce a strongly hydrating sulfonic acid group, resulting in significantly insufficient salt and calcium resistance. In high-salt, high-calcium environments, the polymer molecular chain is prone to salt-sensitive shrinkage and flocculation, failing to effectively adsorb viscous substances. Soil particles form a dense filter cake, resulting in a decrease in performance. In Comparative Example 3, ammonium persulfate was not added in step (7), and graft polymerization was not carried out. Only physical mixing was performed. The modified monomer could not be grafted onto the hydroxyethyl cellulose backbone through chemical bonding, and a stable chemical bond network structure could not be formed. It was easy to decompose and lose at high temperature, and could not play the role of reducing filtration loss, protecting the wall and blocking. Therefore, the performance was the worst. In Comparative Example 4, the grafting reaction temperature was changed to 50°C in step (7), which was lower than the optimal initiation temperature of ammonium persulfate. This resulted in a low monomer grafting rate, insufficient copolymerization reaction, incomplete cellulose modification, and incomplete molecular structure. The performance decreased under high temperature and high salt environment.
[0038] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.
[0039] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.
[0040] Those skilled in the art should understand that the above descriptions are merely several specific embodiments of the present invention, and not all embodiments.
Claims
1. A method for preparing a modified cellulose filtration loss reducer, characterized in that, Includes the following steps: (1) Add hydroxyethyl cellulose to isopropanol, stir at 400-500 r / min for 25-30 min, then add 5% sodium hydroxide solution dropwise, purge with nitrogen for 15-20 min, and swell and activate at room temperature for 24-26 h to obtain cellulose suspension; (2) Add deionized water to the cellulose suspension, mix well, add modified m-aminotrifluorotoluene and modified itaconic acid monolaurate, stir at 500-600 r / min for 15-20 min, then heat to 60-70℃, add ammonium persulfate dropwise to the system under nitrogen protection, continue the reaction for 4-6 h, after the reaction is completed, cool, wash and dry, pulverize to obtain modified cellulose filtration loss reducer; In step (1), the ratio of isopropanol, hydroxyethyl cellulose, and 5% sodium hydroxide solution is 40-50 mL: 2-2.2 g: 6-7 mL. In step (2), the ratio of deionized water, modified m-aminotrifluorotoluene, modified itaconic acid monolaurate, and ammonium persulfate is 10-15 mL: 1.8-2 g: 2-3 g: 0.12-0.15 g.
2. The method for preparing the modified cellulose filtration loss reducer according to claim 1, characterized in that, The preparation method of the modified m-aminotrifluorotoluene in step (2) is as follows: Step 1: Add ammonium thiocyanate to acetonitrile solvent, mix well, and add 4-vinylbenzoyl chloride dropwise while stirring at room temperature. After the addition is complete, stir the reaction for 4-6 hours. After the reaction is complete, filter and concentrate under reduced pressure to obtain 4-vinylbenzoyl isothiocyanate. Step 2: Under nitrogen protection, add 4-vinylbenzoyl isothiocyanate and m-aminotrifluorotoluene to N,N-dimethylformamide solvent, stir and mix, then add triethylamine, and react at 60-70℃ for 10-12 h. After the reaction is completed, cool the reaction solution to room temperature, pour in deionized water while stirring, filter, wash, recrystallize, and dry to obtain modified m-aminotrifluorotoluene.
3. The method for preparing the modified cellulose filtration loss reducer according to claim 2, characterized in that, In step one, the ratio of acetonitrile, ammonium thiocyanate, and 4-vinylbenzoyl chloride is 30-40 mL: 2-2.1 g: 3.3-3.4 g.
4. The method for preparing the modified cellulose filtration loss reducer according to claim 2, characterized in that, In step two, the ratio of N,N-dimethylformamide, 4-vinylbenzoyl isothiocyanate, m-aminotrifluorotoluene, triethylamine, and deionized water is 30-40 mL: 2.5-2.6 g: 2.1-2.2 g: 1-1.1 g: 200-220 mL.
5. The method for preparing the modified cellulose filtration loss reducer according to claim 1, characterized in that, The preparation method of the modified itaconic acid monolaurate in step (2) is as follows: S1: Add lauryl alcohol, itaconic anhydride, and anhydrous sodium acetate to the reactor and stir at 60-70℃ for 3-4 hours. After the reaction is complete, add n-hexane and continue stirring at 60-70℃ for 10-15 minutes. Then cool to room temperature, filter, recrystallize 3-4 times in anhydrous ethanol, and dry to obtain itaconic acid lauryl ester. S2: Add itaconic acid lauryl ester and N,N-dimethylethanolamine to N,N-dimethylformamide solvent, mix well, then add p-toluenesulfonic acid, react at 70-80℃ for 6-8h, after the reaction is completed, recrystallize 2-3 times in anhydrous ethanol, filter, dry, and obtain intermediate 1. S3: Add deionized water and ethanol to the reactor and mix to prepare a solvent. Then add intermediate 1,3-chloro-2-hydroxypropanesulfonate sodium salt and react at 70-80℃ for 8-12 hours. After the reaction is completed, remove the solvent by rotary evaporation, wash, filter and dry to obtain modified itaconic acid monolaurate.
6. The method for preparing the modified cellulose filtration loss reducer according to claim 5, characterized in that, The ratio of lauryl alcohol, itaconic anhydride, anhydrous sodium acetate, and n-hexane in S1 is 4.7-4.8g:3-3.1g:0.07-0.08g:6-7mL.
7. The method for preparing the modified cellulose filtration loss reducer according to claim 5, characterized in that, The ratio of N,N-dimethylformamide, itaconic acid lauryl ester, N,N-dimethylethanolamine, and p-toluenesulfonic acid in S2 is 30-40 mL: 5-5.1 g: 1.5-1.6 g: 0.3-0.4 g.
8. The method for preparing the modified cellulose filtration loss reducer according to claim 5, characterized in that, The ratio of deionized water, ethanol, and intermediate 1,3-chloro-2-hydroxypropanesulfonate sodium in S3 is 20-30 mL: 40-50 mL: 4.5-4.6 g: 3-3.1 g.
9. A modified cellulose filtration loss reducer, characterized in that, It is prepared by the preparation method described in any one of claims 1-8.