High-water-absorption cross-linked carboxymethyl cellulose as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of natural polymers and fine chemical engineering, and particularly relates to cross-linked carboxymethyl cellulose as well as a preparation method and application thereof. The preparation method of the super absorbent cross-linked carboxymethyl cellulose comprises the following steps: (1) dissolving an amide reaction catalyst in water to obtain a catalyst solution; (2) adding the catalyst solution into the sodium carboxymethyl cellulose solution, and stirring at 0-80 DEG C for 1-2 hours to obtain a suspension; (3) adding an amino compound solution into the suspension obtained in the step (2), and stirring and reacting at 0-80 DEG C for 4-48 hours to obtain a reaction mixture; and (4) filtering and drying the reaction mixture to obtain the super absorbent cross-linked carboxymethyl cellulose. According to the method disclosed by the invention, the cross-linked carboxymethyl cellulose with relatively low impurity content and relatively good quality can be prepared.

Description

Technical Field

[0001] The present invention belongs to the technical fields of natural polymers and fine chemicals, and particularly relates to a crosslinked carboxymethyl cellulose and a preparation method and application thereof. Background Art

[0002] Crosslinked carboxymethyl cellulose is a material obtained by connecting carboxymethyl cellulose through chemical bonds. Different from carboxymethyl cellulose, it is insoluble in water but can absorb a large amount of water and swell. It has important applications in the fields of medicine, food, agriculture, personal care, cleaning, etc. However, there are few reported preparation methods for crosslinked carboxymethyl cellulose, and the water absorption capacity of the crosslinked carboxymethyl cellulose obtained by the existing preparation methods is limited. Therefore, it is imperative to develop new preparation methods. Summary of the Invention

[0003] In order to improve the deficiencies of the prior art, the present invention provides a preparation method of a highly water-absorbent crosslinked carboxymethyl cellulose, which can prepare a crosslinked carboxymethyl cellulose with better water absorption.

[0004] In a first aspect, the present invention provides a preparation method of a highly water-absorbent crosslinked carboxymethyl cellulose, and the preparation method comprises the following steps:

[0005] (1) Dissolve an amide reaction catalyst in water to obtain a catalyst solution;

[0006] (2) Add the catalyst solution to a sodium carboxymethyl cellulose solution, and stir at 0 - 80°C for 1 - 2 h to obtain a suspension;

[0007] (3) Add an amino compound solution to the suspension obtained in step (2), and stir and react at 0 - 80°C for 4 - 48 h to obtain a reaction mixture;

[0008] (4) Filter and dry the reaction mixture to obtain a highly water-absorbent crosslinked carboxymethyl cellulose.

[0009] According to an embodiment of the present invention, step (1) comprises the following steps: dissolve an amide reaction catalyst in water, and add an acid until the pH of the solution is 4 - 5 to obtain a catalyst solution.

[0010] According to an embodiment of the present invention, the amide reaction catalyst is at least one of 4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholine hydrochloride (NMC), 2-morpholinoethyl chloride hydrochloride (CMH), azodicarbonylmorpholine (ADM), 1-cyclohexyl-2-(morpholinoethyl)carbodiimide methyl p-toluenesulfonate (CMT), 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide (EDC), N-hydroxysuccinimide (NHS), for example, a mixture of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide and N-hydroxysuccinimide.

[0011] According to an embodiment of the present invention, the concentration of the amide reaction catalyst in the catalyst solution is 5-170 mg / mL, preferably the concentration of the amide reaction catalyst in the catalyst solution is 10-120 mg / mL, and further preferably, the concentration of the amide reaction catalyst in the catalyst solution is 10-20 mg / mL.

[0012] According to an embodiment of the present invention, when the amide reaction catalyst is a mixture of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide and N-hydroxysuccinimide, the concentration of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide in the catalyst solution is 50-150 mg / mL, preferably the concentration of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide in the catalyst solution is 70-100 mg / mL.

[0013] According to an embodiment of the present invention, when the amide reaction catalyst is a mixture of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide and N-hydroxysuccinimide, the concentration of N-hydroxysuccinimide in the catalyst solution is 50-80 mg / mL, preferably the concentration of N-hydroxysuccinimide in the catalyst solution is 60-70 mg / mL.

[0014] According to an embodiment of the present invention, when the amide reaction catalyst is NMC, CMH, ADM or CMT, the concentration of the amide reaction catalyst in the catalyst solution is 5-20 mg / mL, preferably 10-15 mg / mL.

[0015] According to an embodiment of the present invention, the acid is selected from at least one of phosphoric acid, hydrochloric acid, sulfuric acid, malic acid, citric acid, tartaric acid, succinic acid, fumaric acid, maleic acid, edetic acid, adipic acid, oxalic acid, diethylenetriaminepentaacetic acid, polyphosphoric acid, diethylenetriaminepenta(methylphosphonic acid), nitric acid, sodium hydrogen phosphate, sodium dihydrogen phosphate, potassium hydrogen phosphate, potassium dihydrogen phosphate, lactic acid, acetic acid, formic acid, propionic acid, monochloroacetic acid, trichloroacetic acid, for example, hydrochloric acid, oxalic acid, formic acid or citric acid.

[0016] According to an embodiment of the present invention, the degree of substitution of the sodium carboxymethyl cellulose is 0.55 to 1.00, and preferably the degree of substitution of the sodium carboxymethyl cellulose is 0.70 to 0.85.

[0017] According to an embodiment of the present invention, in step (2), the solvent of the sodium carboxymethyl cellulose solution is an alcohol solvent, and the sodium carboxymethyl cellulose and the alcohol solvent form a sodium carboxymethyl cellulose / alcohol solution.

[0018] According to an embodiment of the present invention, the solvent is selected from at least one of methanol, ethanol, and isopropanol.

[0019] According to an embodiment of the present invention, the mass concentration of the sodium carboxymethyl cellulose in the sodium carboxymethyl cellulose solution is 20 to 50%, and preferably the mass concentration of the sodium carboxymethyl cellulose in the sodium carboxymethyl cellulose / alcohol is 25 to 45%.

[0020] According to an embodiment of the present invention, the mass ratio of the catalyst solution to the sodium carboxymethyl cellulose solution is 1:100 to 1:10, preferably the mass ratio of the catalyst solution to the sodium carboxymethyl cellulose solution is 1:80 to 1:20, and further preferably, the mass ratio of the catalyst solution to the sodium carboxymethyl cellulose solution is 1:60 to 1:40.

[0021] According to an embodiment of the present invention, in step (2), the stirring temperature is 10 to 60 °C, and preferably the stirring temperature is 20 to 40 °C.

[0022] According to an embodiment of the present invention, in step (3), the solvent of the amino compound solution is an alcohol to form an amino compound / alcohol solution, and the alcohol solvent has the definition as described above.

[0023] According to an embodiment of the present invention, the amino compound is selected from at least one of ethylenediamine, phenylenediamine, amiphenol, benzoguanamine, triethylenetetramine, tetraethylenepentamine, triethylenetetramine, pentaethylenehexamine, diethylenetriamine, dipropylenetriamine, N-(3-aminopropyl)-N-methyl-1,3-propanediamine, 2-methyl-1,2-propanediamine, 1,2-propanediamine, 1,3-propanediamine, 2-hydroxy-1,3-diaminopropane, 2,2-dimethyl-1,3-propanediamine, and polyethyleneimine.

[0024] According to an embodiment of the present invention, the mass concentration of the amino compound in the amino compound solution is 10 to 20%, and preferably the mass concentration of the amino compound in the amino compound / alcohol solution is 12 to 18%.

[0025] According to an embodiment of the present invention, the mass ratio of the amino compound to sodium carboxymethyl cellulose is 1:1000 to 1:50, and preferably the mass ratio of the amino compound to sodium carboxymethyl cellulose is 1:500 to 1:200.

[0026] According to an embodiment of the present invention, in step (3), the reaction temperature is 20 to 60 °C, and the stirring time is 10 to 40 h. Preferably, the reaction temperature is 30 to 50 °C, and the stirring time is 20 to 30 h.

[0027] According to an embodiment of the present invention, the drying in step (4) includes the following steps: drying for 1 to 4 h under the condition of a temperature of 40 to 100 °C.

[0028] In a second aspect, the present invention also provides a highly water-absorbent crosslinked carboxymethyl cellulose prepared by the above method, and the water absorption ratio of the highly water-absorbent crosslinked carboxymethyl cellulose is 1000% to 10000%.

[0029] According to an embodiment of the present invention, the highly water-absorbent cellulose powder is a fibrous solid material with a diameter of 10 μm to 100 μm.

[0030] According to an embodiment of the present invention, the highly water-absorbent crosslinked carboxymethyl cellulose is insoluble in water, has high water absorbency, and the water absorption ratio is 2000% to 8000%, and preferably the water absorption ratio is 4000% to 6000%.

[0031] In a third aspect, the present invention also provides an application of the above highly water-absorbent crosslinked carboxymethyl cellulose in medicine, food, agriculture, personal care, and cleaning, such as being used as a filler.

[0032] Beneficial effects

[0033] The present invention uses an amine substance with good biocompatibility as a crosslinking agent, and through an efficient amidation reaction, prepares sodium highly water-absorbent crosslinked carboxymethyl cellulose, providing a new method for the preparation of crosslinked carboxymethyl cellulose and having important practical value. Description of the drawings

[0034] Figure 1 It is the infrared spectrum of the highly water-absorbent crosslinked carboxymethyl cellulose powder in Example 1.

[0035] Figure 2 It is the scanning electron microscope photograph of the highly water-absorbent crosslinked carboxymethyl cellulose powder in Example 1.

[0036] Figure 3 It is the water absorption photograph of the highly water-absorbent crosslinked carboxymethyl cellulose powder in Example 1.

[0037] Figure 4It is the infrared spectrum of the highly water-absorbent crosslinked carboxymethyl cellulose powder in Example 2.

[0038] Figure 5 It is the optical microscope photograph of the highly water-absorbent crosslinked carboxymethyl cellulose powder in Example 3. Detailed implementation manners

[0039] The following will further elaborate on the highly water-absorbent crosslinked carboxymethyl cellulose of the present invention, its preparation method and applications in conjunction with specific examples. It should be understood that the following examples are only for illustrative explanation of the present invention and should not be construed as limiting the protection scope of the present invention. All technologies implemented based on the above content of the present invention are covered within the scope intended to be protected by the present invention.

[0040] Unless otherwise specified, the raw materials and reagents used in the following examples are all commercially available products or can be prepared by known methods.

[0041] Example 1

[0042] The preparation of the highly water-absorbent crosslinked carboxymethyl cellulose material includes the following steps:

[0043] (1) Dissolve 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide (EDC) and N-hydroxysuccinimide (NHS) in water (EDC concentration is 100 mg / mL, NHS concentration is 50 mg / mL), add hydrochloric acid, and adjust the pH of the solution to 4.5 to obtain an EDC / NHS aqueous solution.

[0044] (2) Add 1 g of the EDC / NHS aqueous solution to 50 g of sodium carboxymethyl cellulose / ethanol (the substitution degree of sodium carboxymethyl cellulose is 0.75, and the mass concentration of sodium carboxymethyl cellulose is 20%), and stir at 25 °C for 1 h to obtain a suspension.

[0045] (3) Add 1 g of ethylenediamine / ethanol solution (ethylenediamine mass concentration 20%) to the suspension obtained in (2), and stir and react at 25 °C for 48 h to obtain a reaction mixture.

[0046] (4) Filter the reaction mixture, wash with ethanol, and dry at 80 °C for 2 h to obtain the highly water-absorbent crosslinked carboxymethyl cellulose material, which is in a powdery structure.

[0047] See Figure 1 As shown, it is the infrared spectrum of the highly water-absorbent crosslinked carboxymethyl cellulose powder obtained in this example. It can be seen from the figure that the stretching vibration peak of hydroxyl O-H is 3261 cm -1 , the stretching vibration peak of COONa is 1585 cm -1 and the stretching vibration peak of O=C-NH- is 1722 cm -1, indicating that the crosslinking of sodium carboxymethylcellulose is achieved in this embodiment.

[0048] See Figure 2 As shown, it is the SEM image of the sodium carboxymethylcellulose powder obtained in this embodiment. It can be seen from the figure that the sodium carboxymethylcellulose prepared in this embodiment is a fibrous structure with a diameter of 20 μm.

[0049] As Figure 3 shown, 0.5 g of the sodium carboxymethylcellulose powder obtained in this embodiment is placed in 50 mL of water, and it can absorb water to 20 mL, indicating that the water absorption ratio of the highly water-absorbent crosslinked sodium carboxymethylcellulose powder prepared in this embodiment is 4000%, showing a significant water absorption effect.

[0050] Example 2

[0051] Preparation of highly water-absorbent crosslinked sodium carboxymethylcellulose material, including the following steps:

[0052] (1) Dissolve 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide (EDC) and N-hydroxysuccinimide (NHS) in water (EDC concentration is 80 mg / mL, NHS concentration is 80 mg / mL), add oxalic acid, and adjust the pH of the solution to 4.7 to obtain 1 g of EDC / NHS aqueous solution.

[0053] (2) Add 1 g of EDC / NHS aqueous solution to 50 g of sodium carboxymethylcellulose / ethanol (the substitution degree of sodium carboxymethylcellulose is 0.70, and the mass concentration of sodium carboxymethylcellulose is 40%), stir at 25 °C for 1 h to obtain a suspension.

[0054] (3) Add 1.5 g of amiphenol / ethanol solution (the mass concentration of amiphenol is 15%) to the suspension obtained in step (2), stir and react at 60 °C for 6 h to obtain a reaction mixture.

[0055] (4) Filter the reaction mixture, wash with ethanol, and dry at 80 °C for 2 h to obtain a highly water-absorbent crosslinked sodium carboxymethylcellulose material, which is a powdery structure.

[0056] See Figure 4 As shown, it is the infrared spectrum of the highly water-absorbent crosslinked sodium carboxymethylcellulose powder obtained in this embodiment. It can be seen from the figure that the stretching vibration peak of hydroxyl O-H is 3217 cm -1 , the stretching vibration peak of COONa is 1587 cm -1 and the stretching vibration peak of O=C-NH- is 1716 cm -1 , indicating that the crosslinking of sodium carboxymethylcellulose is achieved in this embodiment.

[0057] The superabsorbent crosslinked carboxymethyl cellulose powder obtained in this example is insoluble in water and has high water absorbency. When 1.0 g of the superabsorbent crosslinked carboxymethyl cellulose powder obtained in this example is placed in 50 mL of water, it can absorb water up to 27 mL, indicating that the water absorption ratio of the superabsorbent crosslinked carboxymethyl cellulose powder prepared in this example is 2700%, showing a significant water absorption effect.

[0058] Example 3

[0059] Preparation of the superabsorbent crosslinked carboxymethyl cellulose material includes the following steps:

[0060] (1) Dissolve 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide (EDC) and N-hydroxysuccinimide (NHS) in water (EDC concentration is 50 mg / mL, NHS concentration is 50 mg / mL), add formic acid, and adjust the pH of the solution to 4.7 to obtain an EDC / NHS aqueous solution.

[0061] (2) Add 1 g of the EDC / NHS aqueous solution to 50 g of sodium carboxymethyl cellulose / ethanol (the degree of substitution of sodium carboxymethyl cellulose is 0.70, and the mass concentration of sodium carboxymethyl cellulose is 30%), stir at 25 °C for 1 h to obtain a suspension;

[0062] (3) Add 1.5 g of 1,2-propanediamine / ethanol solution (mass concentration of 1,2-propanediamine is 20%) to the suspension obtained in step (2), stir at 60 °C for 6 h to obtain a reaction mixture.

[0063] (4) Filter the reaction mixture, wash with ethanol, and dry at 80 °C for 2 h to obtain the superabsorbent crosslinked carboxymethyl cellulose material, which is in a powdery structure.

[0064] See Figure 5 As shown, it is the SEM image of the superabsorbent crosslinked carboxymethyl cellulose obtained in this example. It can be seen from the figure that the superabsorbent crosslinked carboxymethyl cellulose has a fibrous microstructure with a diameter of 5 - 10 μm.

[0065] The superabsorbent crosslinked carboxymethyl cellulose powder obtained in this example is insoluble in water and has high water absorbency. When 1.0 g of the superabsorbent crosslinked carboxymethyl cellulose powder obtained in this example is placed in 50 mL of water, it can absorb water up to 23 mL, indicating that the water absorption ratio of the superabsorbent crosslinked carboxymethyl cellulose powder prepared in this example is 2300%, showing a significant water absorption effect.

[0066] Example 4

[0067] Preparation of the superabsorbent crosslinked carboxymethyl cellulose material includes the following steps:

[0068] (1) Dissolve 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide (EDC) and N-hydroxysuccinimide (NHS) in water (EDC concentration is 150 mg / mL, NHS concentration is 70 mg / mL); add citric acid and adjust the pH of the solution to 4.3 to obtain an EDC / NHS aqueous solution.

[0069] (2) Add 1 g of the EDC / NHS aqueous solution to 50 g of sodium carboxymethyl cellulose / ethanol (the degree of substitution of sodium carboxymethyl cellulose is 0.70, and the mass concentration of sodium carboxymethyl cellulose is 25%), and stir at 25 °C for 1 h to obtain a suspension.

[0070] (3) Add 2.0 g of 2-hydroxy-1,3-propanediamine / ethanol solution (the mass concentration of 2-hydroxy-1,3-propanediamine is 10%) to the suspension obtained in step (2), and stir at 60 °C for 6 h to obtain a reaction mixture.

[0071] (4) Filter the reaction mixture, wash it with ethanol, and dry it at 80 °C for 2 h to obtain highly water-absorbent cross-linked sodium carboxymethyl cellulose.

[0072] The highly water-absorbent cross-linked sodium carboxymethyl cellulose powder obtained in this example is insoluble in water and has high water absorbency. Place 1.0 g of the highly water-absorbent cross-linked sodium carboxymethyl cellulose powder obtained in this example in 50 mL of water, and it can absorb water up to 20 mL. It shows that the water absorption ratio of the highly water-absorbent cross-linked sodium carboxymethyl cellulose powder prepared in this example is 2000%, and it has a significant water absorption effect.

[0073] Example 5

[0074] Preparation of the highly water-absorbent cross-linked sodium carboxymethyl cellulose material, including the following steps:

[0075] (1) Dissolve 1-cyclohexyl-2-(morpholinoethyl)carbodiimide methyl p-toluenesulfonate (CMT) in water (CMT concentration is 10 mg / mL); add citric acid and adjust the pH of the solution to 4.3 to obtain a CMT aqueous solution.

[0076] (2) Add 0.5 g of the CMT aqueous solution to 50 g of sodium carboxymethyl cellulose / ethanol (the degree of substitution of sodium carboxymethyl cellulose is 0.70, and the mass concentration of sodium carboxymethyl cellulose is 25%), and stir at 25 °C for 1 h to obtain a suspension.

[0077] (3) Add 2.0 g of 2-hydroxy-1,3-propanediamine / ethanol solution (the mass concentration of 2-hydroxy-1,3-propanediamine is 10%) to the suspension obtained in step (2), and stir at 60 °C for 6 h to obtain a reaction mixture.

[0078] (4) Filter the reaction mixture, wash it with ethanol, and dry it at 80 °C for 2 h to obtain highly water-absorbent cross-linked sodium carboxymethyl cellulose.

[0079] The superabsorbent crosslinked carboxymethyl cellulose powder obtained in this example is insoluble in water and has high water absorbency. When 1.0 g of the superabsorbent crosslinked carboxymethyl cellulose powder obtained in this example is placed in 50 mL of water, it can absorb water up to 22 mL. This indicates that the water absorption ratio of the superabsorbent crosslinked carboxymethyl cellulose powder prepared in this example is 2200%, showing a significant water absorption effect.

[0080] Example 6

[0081] Preparation of the superabsorbent crosslinked carboxymethyl cellulose material, including the following steps:

[0082] (1) Dissolve azodicarbonylmorpholine (ADM) in water (CMT concentration is 15 mg / mL); add malic acid and adjust the pH of the solution to 5.0 to obtain an ADM aqueous solution.

[0083] (2) Add 0.5 g of the ADM aqueous solution to 50 g of sodium carboxymethyl cellulose / ethanol (the substitution degree of sodium carboxymethyl cellulose is 0.70, and the mass concentration of sodium carboxymethyl cellulose is 25%), and stir at 25 °C for 1 h to obtain a suspension.

[0084] (3) Add 2.0 g of 2-hydroxy-1,3-propanediamine / ethanol solution (the mass concentration of 2-hydroxy-1,3-propanediamine is 10%) to the suspension obtained in step (2), and stir at 60 °C for 6 h to obtain a reaction mixture.

[0085] (4) Filter the reaction mixture, wash with ethanol, and dry at 80 °C for 2 h to obtain the superabsorbent crosslinked carboxymethyl cellulose.

[0086] The superabsorbent crosslinked carboxymethyl cellulose powder obtained in this example is insoluble in water and has high water absorbency. When 1.0 g of the superabsorbent crosslinked carboxymethyl cellulose powder obtained in this example is placed in 50 mL of water, it can absorb water up to 25 mL. This indicates that the water absorption ratio of the superabsorbent crosslinked carboxymethyl cellulose powder prepared in this example is 2500%, showing a significant water absorption effect.

[0087] The specific embodiments of the present invention have been exemplarily described above through examples. However, the protection scope of the present invention is not limited to the above exemplary embodiments. Any modifications, equivalent substitutions, improvements, etc. made by those skilled in the art within the spirit and principle of the present invention shall be included within the protection scope of the claims of the present invention.

Claims

1. A preparation method of superabsorbent crosslinked carboxymethyl cellulose, characterized in that, The preparation method comprises the following steps: (1) Dissolve the amide reaction catalyst in water to obtain a catalyst solution; (2) Add the catalyst solution to the sodium carboxymethyl cellulose solution and stir at 0 - 80°C for 1 - 2 h to obtain a suspension; (3) Add the amino compound solution to the suspension obtained in step (2) and stir and react at 0 - 80°C for 4 - 48 h to obtain a reaction mixture; (4) Filter and dry the reaction mixture to obtain superabsorbent crosslinked sodium carboxymethyl cellulose.

2. The preparation method of the highly water-absorbent crosslinked carboxymethyl cellulose according to claim 1, characterized in that, Step (1) comprises the following steps: Dissolve the amide reaction catalyst in water, add an acid until the pH of the solution is 4 - 5 to obtain a catalyst solution; The amide reaction catalyst is at least one of 4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholine hydrochloride, 2-morpholinoethyl chloride hydrochloride, azodicarbonylmorpholine, 1-cyclohexyl-2-(morpholinoethyl)carbodiimide methyl p-toluenesulfonate, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide, and N-hydroxysuccinimide.

3. The preparation method of the highly water-absorbent crosslinked carboxymethyl cellulose according to claim 2, wherein, When the amide reaction catalyst is a mixture of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide and N-hydroxysuccinimide, the concentration of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide in the catalyst solution is 50 - 150 mg / mL, and the concentration of N-hydroxysuccinimide in the catalyst solution is 50 - 80 mg / mL. Preferably, when the amide reaction catalyst is NMC, CMH, ADM, or CMT, the concentration of the amide reaction catalyst in the catalyst solution is 5 - 20 mg / mL. Preferably, the acid is selected from at least one of phosphoric acid, hydrochloric acid, sulfuric acid, malic acid, citric acid, tartaric acid, succinic acid, fumaric acid, maleic acid, edetic acid, adipic acid, oxalic acid, diethylenetriaminepentaacetic acid, polyphosphoric acid, diethylenetriaminepenta(methylphosphonic acid), nitric acid, sodium hydrogen phosphate, sodium dihydrogen phosphate, potassium hydrogen phosphate, potassium dihydrogen phosphate, lactic acid, acetic acid, formic acid, propionic acid, monochloroacetic acid, and trichloroacetic acid, for example, hydrochloric acid, oxalic acid, formic acid, or citric acid.

4. The preparation method of the highly water-absorbent crosslinked carboxymethyl cellulose according to any one of claims 1-3, characterized in that, The degree of substitution of the sodium carboxymethyl cellulose is 0.55 - 1.

00. Preferably, in step (2), the solvent of the sodium carboxymethyl cellulose solution is an alcohol solvent, and the sodium carboxymethyl cellulose and the alcohol solvent form a sodium carboxymethyl cellulose / alcohol solution; the mass concentration of sodium carboxymethyl cellulose in the sodium carboxymethyl cellulose solution is 20 - 50%.

5. The preparation method of the highly water-absorbent crosslinked carboxymethyl cellulose according to any one of claims 1 to 3, characterized in that, The mass ratio of the catalyst solution to the sodium carboxymethyl cellulose solution is 1:100 - 1:

10. Preferably, the stirring temperature in step (2) is 10 - 60°C.

6. The preparation method of the superabsorbent crosslinked carboxymethyl cellulose according to any one of claims 1-3, characterized in that, In step (3), the solvent of the amino compound solution is an alcohol to form an amino compound / alcohol solution. Preferably, the amino compound is selected from at least one of ethylenediamine, phenylenediamine, amiphenol, benzoguanamine, triethylenetetramine, tetraethylenepentamine, triethylene tetramine, pentaethylenehexamine, diethylenetriamine, dipropylenetriamine, N-(3-aminopropyl)-N-methyl-1,3-propanediamine, 2-methyl-1,2-propanediamine, 1,2-propanediamine, 1,3-propanediamine, 2-hydroxy-1,3-diaminopropane, 2,2-dimethyl-1,3-propanediamine, and polyethyleneimine.

7. The preparation method of the highly water-absorbent crosslinked carboxymethyl cellulose according to claim 6, characterized in that, The mass concentration of the amino compound in the amino compound solution is 10-20%, and the mass ratio of the amino compound to sodium carboxymethylcellulose is 1:1000-1:

50.

8. The preparation method of the superabsorbent crosslinked carboxymethyl cellulose according to claim 6, characterized in that, In step (3), the reaction temperature is 20-60 °C, and the stirring time is 10-40 h. Preferably, the drying in step (4) includes the following steps: drying for 1-4 h under the condition of a temperature of 40-100 °C.

9. Superabsorbent crosslinked carboxymethyl cellulose prepared by the method according to any one of claims 1-8, characterized in that, The water absorption ratio of the highly water-absorbent crosslinked carboxymethylcellulose is 1000%-10000%, and the highly water-absorbent cellulose powder is a fibrous solid material with a diameter of 10 μm-100 μm.

10. Use of the highly water-absorbent crosslinked carboxymethylcellulose prepared by the method according to any one of claims 1-8 or the highly water-absorbent crosslinked carboxymethylcellulose according to claim 9 in medicine, food, agriculture, personal care, and cleaning, for example, as a filler.

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