Water-soluble amino cellulose, its preparation method and use as an antibacterial material

Abstract

The application relates to a water-soluble amino cellulose, a preparation method thereof and application thereof as antibacterial material, and belongs to the field of bio-based new material manufacturing. The preparation method of the water-soluble amino cellulose is as follows: cellulose, acetic acid, fatty acid anhydride and concentrated sulfuric acid are mixed, reaction is carried out at room temperature to 80 DEG C for 0.5-12 hours, the obtained solution after reaction is placed in excessive water, and the precipitate is collected by filtration; the obtained precipitate is mixed with an amino compound and a solvent, and then reaction is carried out at 50-120 DEG C for 0.5-8 hours; the obtained solution after reaction is poured into excessive saturated monohydric alcohol, the precipitate is collected by filtration and dried, and then the amino cellulose is obtained. The preparation method of the water-soluble amino cellulose antibacterial material provided by the application uses cellulose fatty acid ester as a reaction intermediate, replaces traditional reaction intermediates such as nitro compounds and azide compounds, and the reaction process is green and environment-friendly.

Description

Technical Field

[0001] This invention relates to a water-soluble aminocellulose, its preparation method, and its application as an antibacterial material, belonging to the field of bio-based new material manufacturing. Background Technology

[0002] With the increasing depletion of fossil fuels, the use of renewable resources to prepare functional chemicals, polymer materials, and adsorbents has attracted significant attention. Cellulose, the most abundant renewable resource, boasts advantages such as environmental friendliness, biodegradability, and low cost, and has been widely used in various fields of industrial production, showing promise as a substitute for corresponding petroleum-based products. However, due to its highly crystalline structure and strong intramolecular and intermolecular hydrogen bonding, cellulose is insoluble in conventional solvents, greatly limiting its applications. Chemical modification is an effective means to improve the performance of cellulose. Through chemical modification, cellulose esters, cellulose ethers, oxidized cellulose, and aminocellulose can be obtained. Among them, aminocellulose, as a nitrogen-containing cellulose derivative, has wide applications in agriculture, food industry, textile industry, and daily chemical industry. In the field of environmental protection, aminocellulose can effectively adsorb or capture heavy metal ions in solution through coordination, achieving the removal of toxic heavy metal ions such as lead, mercury, and chromium from water bodies; in the field of enzyme immobilization, aminocellulose can bind to enzyme proteins to achieve enzyme immobilization; and in the field of catalysis, due to the presence of amino groups, aminocellulose can be directly used as a catalyst.

[0003] Based on its reactive intermediates, there are currently four methods for synthesizing aminocellulose: nitro reduction, halogenated cellulose, cellulose p-toluenesulfonate, and cellulose azide. However, these synthetic methods require the use of toxic and harmful chemicals such as nitro compounds, halogens, and azide compounds. Summary of the Invention

[0004] To avoid the use of the aforementioned toxic and hazardous chemicals, this invention proposes a method for synthesizing aminocellulose using cellulose fatty acid esters as intermediates. This method first converts cellulose into cellulose fatty acid ester derivatives, which are then directly mixed and reacted with amino compounds to prepare the corresponding aminocellulose derivatives. Compared with existing methods, the aminocellulose preparation method provided by this invention does not require the use of nitro compounds, halogens, azide chemicals, or other chemicals, providing a mild and environmentally friendly method for preparing aminocellulose.

[0005] A method for preparing water-soluble aminocellulose is as follows: cellulose, acetic acid, fatty acid anhydride, and concentrated sulfuric acid are mixed and reacted at room temperature to 80°C for 0.5–12 hours. The resulting solution is placed in excess water, filtered, and the precipitate is collected. The precipitate is mixed with an amino compound and a solvent, and reacted at 50–120°C for 0.5–8 hours. The resulting solution is poured into excess saturated monohydric alcohol, filtered, the precipitate is collected, and dried to obtain aminocellulose.

[0006] The preferred weight ratio of cellulose, acetic acid, fatty acid anhydride and concentrated sulfuric acid is 1:10-20:1-5:0.1-0.5; the weight ratio of cellulose, amino compound and solvent is 1:10-30:0-20.

[0007] The most preferred ratio of cellulose, acetic acid, fatty acid anhydride and concentrated sulfuric acid by weight is 1:15:3:0.3; and the ratio of cellulose, amino compound and solvent by weight is 1:25:10.

[0008] Preferably, the cellulose is selected from at least one of nanocellulose and microcrystalline cellulose.

[0009] Preferably, the fatty acid anhydride is selected from at least one of acetic anhydride, propionic anhydride, butyric anhydride and valeric anhydride.

[0010] Preferably, the amino compound is selected from at least one of ethylenediamine, propylenediamine, butanediamine, pentanediamine, hexanediamine, phenylenediamine, phenylenediamine, diethylenetriamine, tris(2-aminoethyl)amine, melamine, and triethylenetetramine.

[0011] Preferably, the solvent is selected from at least one of dimethyl sulfoxide, dimethylacetamide, dimethylformamide, N-methylpyrrolidone, and N-methylpiperidine.

[0012] Preferably, the saturated monohydric alcohol is selected from at least one of methanol, ethanol, propanol, and isopropanol.

[0013] Another object of the present invention is to provide a water-soluble aminocellulose prepared by the above method.

[0014] Furthermore, the degree of substitution of the aminocellulose is 0.1 to 2.3.

[0015] Furthermore, the solubility of the aminocellulose in water is 12.8–49.9 g / L.

[0016] Another object of the present invention is to provide the application of the above-mentioned water-soluble aminocellulose as an antibacterial material.

[0017] Furthermore, the antimicrobial material can inhibit the growth of both Gram-negative and Gram-positive bacteria.

[0018] The beneficial effects of this invention are as follows: Compared with the prior art, the preparation method of the water-soluble aminocellulose antibacterial material provided by this invention utilizes cellulose fatty acid esters as reaction intermediates, replacing traditional reaction intermediates such as nitro compounds and azide compounds, making the reaction process green and environmentally friendly. The aminocellulose derivative provided by this invention can inhibit the growth of both Gram-negative and Gram-positive bacteria. The aminocellulose derivative provided by this invention has good water solubility, with a maximum solubility of 49.9 g / L in water. Attached Figure Description

[0019] Figure 1 Synthesis route diagram for water-soluble aminocellulose antibacterial materials;

[0020] Figure 2 Image of a water-soluble aminocellulose antibacterial material;

[0021] Figure 3 Diagram of an aqueous solution of water-soluble aminocellulose antibacterial material;

[0022] Figure 4 This is a diagram of the inhibition zone of a water-soluble aminocellulose antibacterial material. Detailed Implementation

[0023] The following non-limiting embodiments are intended to enable those skilled in the art to more fully understand the invention, but do not limit the invention in any way.

[0024] Unless otherwise specified, the experimental methods described in the following examples are conventional methods; the reagents and materials described are commercially available unless otherwise specified.

[0025] One of the specific implementation methods:

[0026] A method for preparing aminocellulose, comprising the following steps:

[0027] (1) Mix 1 part cellulose, 5-20 parts acetic acid, 0.2-5 parts fatty acid anhydride and 0.01-0.5 parts concentrated sulfuric acid, and react for 0.5-12 hours at room temperature to 80°C.

[0028] (2) Pour the solution from step (1) into excess water, filter and collect the precipitate;

[0029] (3) Based on 1 part of cellulose, add the precipitate from step (2) to 5-30 parts of amino compound and 0-20 parts of solvent, and react at 50-120°C for 0.5-8 hours;

[0030] (4) Pour the solution from step (3) into an excess of saturated monohydric alcohol, filter, collect the precipitate, and dry to obtain aminocellulose.

[0031] Preferably, the cellulose is selected from at least one of nanocellulose and microcrystalline cellulose.

[0032] Preferably, the fatty acid anhydride is selected from at least one of acetic anhydride, propionic anhydride, butyric anhydride, and valeric anhydride.

[0033] Preferably, the amino compound is selected from at least one of ethylenediamine, propylenediamine, butanediamine, pentanediamine, hexanediamine, phenylenediamine, phenylenediamine, diethylenetriamine, tris(2-aminoethyl)amine, melamine, and triethylenetetramine.

[0034] Preferably, the solvent is selected from at least one of dimethyl sulfoxide, dimethylacetamide, dimethylformamide, N-methylpyrrolidone, and N-methylpiperidine.

[0035] Preferably, the saturated monohydric alcohol is selected from at least one of methanol, ethanol, propanol and isopropanol.

[0036] Example 1

[0037] (1) Mix 1.0g microcrystalline cellulose, 5.0mL acetic acid, 0.2mL acetic anhydride and 0.01mL concentrated sulfuric acid and react at 20℃ for 0.5 hours;

[0038] (2) Pour the solution from step (1) into excess water, filter and collect the precipitate;

[0039] (3) Add the precipitate from step (2) to 5.0 mL of ethylenediamine and react at 50 °C for 0.5 hours;

[0040] (4) Pour the solution from step (3) into an excess of isopropanol, filter, collect the precipitate, and dry to obtain aminocellulose.

[0041] The water-soluble aminocellulose antibacterial material in this embodiment (see...) Figure 2 Compared to cellulose, it has better water solubility. According to ASTM E1148 – Standard Test Method for Measurement of Water Solubility, cellulose is insoluble in aqueous solution at pH 7. The obtained water-soluble aminocellulose antibacterial material has a solubility of 12.8 g / L in aqueous solution at pH 7, demonstrating good water solubility (see...). Figure 3 ); Elemental analysis revealed that the degree of amino substitution in the water-soluble aminocellulose antibacterial material reached 2.3, and the inhibition zone of aminocellulose against Escherichia coli reached 13.2 mm (see...). Figure 4 a) The inhibition zone against Staphylococcus aureus reached 13.5 mm (see...). Figure 4 e).

[0042] Example 2

[0043] (1) Mix 1.0g microcrystalline cellulose, 10.0mL acetic acid, 1.0mL propionic anhydride and 0.05mL concentrated sulfuric acid and react at 40℃ for 4 hours;

[0044] (2) Pour the solution from step (1) into excess water, filter and collect the precipitate;

[0045] (3) Add the precipitate from step (2) to 10.0 mL of hexanediamine, mix with 5 mL of dimethyl sulfoxide, and react at 80 °C for 3 hours;

[0046] (4) Pour the solution from step (3) into excess methanol, filter, collect the precipitate, and dry to obtain aminocellulose.

[0047] The water-soluble aminocellulose antibacterial material of this embodiment exhibits better water solubility than cellulose. According to ASTM E1148 – Standard Test Method for Measurement of Water Solubility, cellulose is insoluble in aqueous solution at pH 7. The obtained water-soluble aminocellulose antibacterial material has a solubility of 49.9 g / L in aqueous solution at pH 7, demonstrating good water solubility. Elemental analysis shows that the degree of amino substitution in the water-soluble aminocellulose antibacterial material reaches 1.1, and the inhibition zone of aminocellulose against *Escherichia coli* reaches 16.0 mm (see...). Figure 4 b) The inhibition zone against Staphylococcus aureus reached 14.8 mm (see... Figure 4 f).

[0048] Example 3

[0049] (1) Mix 1.0g nanocellulose, 15.0mL acetic acid, 2.0mL butyric anhydride and 0.2mL concentrated sulfuric acid, and react at 60℃ for 8 hours;

[0050] (2) Pour the solution from step (1) into excess water, filter and collect the precipitate;

[0051] (3) Add the precipitate from step (2) to 20.0 mL of phenylenediamine, mix with 10 mL of dimethylformamide, and react at 100 °C for 6 hours;

[0052] (4) Pour the solution from step (3) into excess ethanol, filter, collect the precipitate, and dry to obtain aminocellulose.

[0053] The water-soluble aminocellulose antibacterial material of this embodiment exhibits better water solubility than cellulose. According to ASTM E1148 – Standard Test Method for Measurement of Water Solubility, cellulose is insoluble in aqueous solution at pH 7. The obtained water-soluble aminocellulose antibacterial material has a solubility of 33.9 g / L in aqueous solution at pH 7, demonstrating good water solubility. Elemental analysis shows that the degree of amino substitution in the water-soluble aminocellulose antibacterial material reaches 1.8, and the inhibition zone of aminocellulose against *Escherichia coli* reaches 14.2 mm (see...). Figure 4 c) The inhibition zone against Staphylococcus aureus reached 14.0 mm (see c). Figure 4 g).

[0054] Example 4

[0055] (1) Mix 1.0g nanocellulose, 20.0mL acetic acid, 5.0mL valeric anhydride and 0.5mL concentrated sulfuric acid, and react at 80℃ for 12 hours;

[0056] (2) Pour the solution from step (1) into excess water, filter and collect the precipitate;

[0057] (3) Add the precipitate from step (2) to 30.0 mL of melamine, mix with 20 mL of N-methylpiperidine, and react at 120 °C for 8 hours;

[0058] (4) Pour the solution from step (3) into excess ethanol, filter, collect the precipitate, and dry to obtain aminocellulose.

[0059] The water-soluble aminocellulose antibacterial material of this embodiment exhibits better water solubility than cellulose. According to ASTM E1148 – Standard Test Method for Measurement of Water Solubility, cellulose is insoluble in aqueous solution at pH 7. The obtained water-soluble aminocellulose antibacterial material has a solubility of 33.7 g / L in aqueous solution at pH 7, demonstrating good water solubility. Elemental analysis shows that the degree of amino substitution in the water-soluble aminocellulose antibacterial material reaches 1.5, and the inhibition zone of aminocellulose against *Escherichia coli* reaches 12.0 mm (see...). Figure 4 d) The inhibition zone against Staphylococcus aureus reached 13.8 mm (see... Figure 4 h).

Claims

1. A method for preparing water-soluble aminocellulose, comprising: mixing cellulose, acetic acid, fatty acid anhydride and concentrated sulfuric acid, reacting at room temperature to 80°C for 0.5-12 hours; placing the resulting solution in excess water, filtering and collecting the precipitate; mixing the precipitate with an amino compound and a solvent, reacting at 50-120°C for 0.5-8 hours; pouring the resulting solution into excess saturated monohydric alcohol, filtering, collecting the precipitate, and drying to obtain aminocellulose; in, The weight ratio of cellulose, acetic acid, fatty acid anhydride and concentrated sulfuric acid is 1:5~20:0.2~5:0.01~0.5; the weight ratio of cellulose, amino compound and solvent is 1:5~30:0~20. The cellulose is selected from at least one of nanocellulose and microcrystalline cellulose; the fatty acid anhydride is selected from at least one of acetic anhydride, propionic anhydride, butyric anhydride and valeric anhydride; the amino compound is selected from at least one of ethylenediamine, propylenediamine, butylenediamine, pentanediamine, hexamethylenediamine, phenylenediamine, phenylenediamine, diethylenetriamine, tris(2-aminoethyl)amine, melamine and triethylenetetramine.

2. The method according to claim 1, characterized in that, The weight ratio of cellulose, acetic acid, fatty acid anhydride and concentrated sulfuric acid is 1:10~20:1~5:0.1~0.5; the weight ratio of cellulose, amino compound and solvent is 1:10~30:0~20.

3. The method according to claim 1, characterized in that, The weight ratio of cellulose, acetic acid, fatty acid anhydride and concentrated sulfuric acid is 1:15:3:0.3; the weight ratio of cellulose, amino compound and solvent is 1:25:

10.

4. The method according to claim 1, characterized in that, The solvent is selected from at least one of dimethyl sulfoxide, dimethylacetamide, dimethylformamide, N-methylpyrrolidone, and N-methylpiperidine; the saturated monohydric alcohol is selected from at least one of methanol, ethanol, propanol, and isopropanol.

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