Acid and alkali resistant antibacterial agent as well as preparation method and application thereof

Abstract

The invention relates to an acid and alkali resistant antibacterial agent as well as a preparation method and application thereof, in an inert atmosphere, an amido-containing monomer and an ester-containing monomer are uniformly mixed and react under the action of an initiator, and a polyquaternium cation acid and alkali resistant antibacterial agent is obtained. Compared with the prior art, the antibacterial agent prepared by the method has excellent antibacterial property, the antibacterial rate of staphylococcus aureus and escherichia coli reaches 100%, and the antibacterial agent can be kept stable under acidic and alkaline conditions.

Description

Technical Field

[0001] This invention relates to the field of antibacterial technology, and in particular to an acid and alkali resistant antibacterial agent, its preparation method, and its application. Background Technology

[0002] Bacteria, viruses, and other microorganisms that thrive in water not only degrade water quality but also spread diseases, endangering human health. Therefore, developing efficient, safe, and environmentally friendly antibacterial agents for water treatment is of great significance.

[0003] Currently, commonly used antibacterial agents can be mainly divided into three categories according to their structure: inorganic antibacterial agents, organic antibacterial agents, and natural biological antibacterial agents. Traditional chlorine-based disinfectants are more effective under acidic conditions, but tend to lose their effectiveness under alkaline conditions. Nano-silver antibacterial agents are most effective under near-neutral conditions, but they are prone to aggregation under strong acid or strong alkaline conditions, leading to a decrease in antibacterial performance. Therefore, there is an urgent need to develop an antibacterial agent that maintains stability under both acidic and alkaline conditions. Summary of the Invention

[0004] The purpose of this invention is to overcome the defects of the prior art and provide an acid and alkali resistant antibacterial agent, its preparation method and application.

[0005] The objective of this invention can be achieved through the following technical solutions:

[0006] One of the technical solutions of the present invention is to provide an acid and alkali resistant antibacterial agent, the chemical structural formula of which is shown below:

[0007]

[0008] Where n1, n2, and n3 are 3 to 10, and X is a water-soluble functional group.

[0009] In some specific embodiments, X is selected from one or more hydrophilic groups containing -CONH2, -CONH-, -CONH-CH2CH2OH or –OH.

[0010] In the above reaction formula, structure I and structure II are monomers containing amide groups and monomers containing ester groups, respectively; the water-soluble functional group X in structure III can change the physical properties of the polymer, such as water solubility and molecular weight.

[0011] The second technical solution of the present invention is to provide a method for preparing an acid and alkali resistant antibacterial agent as described in one of the above technical solutions. Under an inert atmosphere, an amide-containing monomer, an ester-containing monomer and a water-soluble monomer are mixed and reacted under the action of an initiator to obtain a polyquaternary ammonium salt cationic acid and alkali resistant antibacterial agent.

[0012] In some specific embodiments, the molar ratio of the amide-containing monomer to the ester-containing monomer is 1:0.5 to 1:2.33, and the molar amount of the water-soluble monomer is equal to the sum of the molar amounts of the amide-containing monomer and the ester-containing monomer.

[0013] In some specific embodiments, the total concentration of the amide-containing monomer and the ester-containing monomer is 10%-70%.

[0014] In some specific embodiments, the amide-containing monomer is a compound with the structural formula shown in QACs1, the ester-containing monomer is a compound with the structural formula shown in QACs2, the initiator is selected from any one of ammonium persulfate and potassium persulfate, and the water-soluble monomer is a compound with the structural formula shown below: C=CX, where X is selected from one or more hydrophilic groups containing -CONH2, -CONH-, -CONH-CH2CH2OH or –OH;

[0015]

[0016] In some specific embodiments, the amount of the initiator added is 0.5-2% of the total mass of the reactants.

[0017] In some specific embodiments, the reaction temperature is (60-70)℃ and the reaction time is (3-5)h.

[0018] In some specific embodiments, the inert atmosphere is selected from either nitrogen or argon.

[0019] The reaction formula for synthesizing acid and alkali resistant antibacterial agents is as follows:

[0020]

[0021] The third technical solution of the present invention is to provide an application of an acid and alkali resistant antibacterial agent as described in one of the above technical solutions in water treatment.

[0022] In some specific implementations, the pH of the solution used for water treatment is 1 to 13.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] (1) The antibacterial agent prepared by the present invention using QACs1 monomer (containing amide group) and QACs2 monomer (containing ester group) can maintain excellent antibacterial performance in a wide pH range (e.g., pH 1-13) and is suitable for various water quality conditions.

[0025] (2) The water treatment antibacterial agent prepared by the present invention using QACs1 monomer (containing amide group) and QACs2 monomer (containing ester group) has broad-spectrum antibacterial properties and can effectively kill bacteria, viruses and other microorganisms in water. The antibacterial rate against Staphylococcus aureus and Escherichia coli reaches 100%.

[0026] (3) The antibacterial agent prepared by the present invention is safe and non-toxic and will not cause secondary pollution.

[0027] (4) The preparation method of the antibacterial agent of the present invention is simple, low in cost, and easy to industrialize. Attached Figure Description

[0028] Figure 1 The infrared spectrum of the product of Example 1 is shown. Detailed Implementation

[0029] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. These embodiments are based on the technical solution of the present invention and provide detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0030] Unless otherwise specified, the raw materials or processing techniques used in the following embodiments and comparative examples are all conventional commercially available raw materials or conventional processing techniques in the art.

[0031] Example 1

[0032] First, 0.35 g of amide-containing monomer QACs1, 0.65 g of ester-containing monomer QACs2 (molar ratio of QACs1 to QACs2 is 1:2), and 0.19 g of water-soluble monomer acrylamide (X is an amide group, -CONH2, molar ratio of its molar to the sum of the moles of QACs1 and QACs2 monomers is 1:1) were added to 8 mL of distilled water (total concentration of QACs1 and QACs2 monomers is 12.5%). Nitrogen gas was then introduced and the mixture was stirred for 30 minutes. Next, 1% ammonium persulfate (APS) was added to the solution, and the mixture was stirred for another 10 minutes. The mixture was reacted at 70°C for 4 hours, and the reaction was terminated at room temperature. The product was precipitated with acetone and washed three times. Afterward, it was dried in a vacuum oven at 45°C to obtain a white crystalline powder, which is the acid and alkali resistant antibacterial agent.

[0033] The reaction formula is as follows:

[0034]

[0035] The infrared spectrum of this acid and alkali resistant antibacterial agent product is as follows: Figure 1 As shown, it retains the characteristic peaks of QACs1 and QACs2, with a peak size of 1720 cm⁻¹. -1 The absorption peak for the ester group C=O is 1163 cm⁻¹.-1 The asymmetric stretching vibration of COC with an ester group may overlap with the CN stretching vibration peak of the quaternary ammonium salt, 1558 cm⁻¹. -1 and 1665cm -1 The absorption peak for the amide group is 3302 cm⁻¹. -1 The peak value for the stretching vibration of NH is 2924 cm⁻¹. -1 and 2854cm -1 The peak represents the stretching vibration of long-chain alkyl antisymmetric and symmetric CH, at 721 cm⁻¹. -1 The weaker peak is due to the ordered arrangement of long-chain alkyl groups, 1465 cm⁻¹. -1 The shear bending vibration of CH2 may be related to CN in the quaternary ammonium salt. + The stretching vibrations overlap, 1351cm -1 The symmetric bending vibration of CH3 proves that the obtained product matches the target product.

[0036] Example 2

[0037] First, 0.51 g of amide-containing monomer QACs1, 0.49 g of ester-containing monomer QACs2 (molar ratio of QACs1 to QACs2 is 1:1), and 0.18 g of water-soluble monomer acrylamide (X is an amide group, -CONH2, molar ratio of its molar to the sum of the molars of QACs1 and QACs2 monomers is 1:1) were added to 8 mL of distilled water (total concentration of QACs1 and QACs2 monomers is 12.5%). Nitrogen gas was then introduced and the mixture was stirred for 30 minutes. Next, 1% ammonium persulfate (APS) was added to the solution, and the mixture was stirred for another 10 minutes. The mixture was reacted at 70°C for 4 hours, and the reaction was terminated at room temperature. The product was precipitated with acetone and washed three times. Afterward, it was dried in a vacuum oven at 45°C to obtain a white crystalline powder, which is the acid and alkali resistant antibacterial agent.

[0038] The reaction formula is as follows:

[0039]

[0040] Example 3

[0041] First, 0.69 g of amide-containing monomer QACs1, 0.43 g of ester-containing monomer QACs2 (molar ratio of QACs1 to QACs2 is 3:2), and 0.21 g of water-soluble monomer acrylamide (X is an amide group, -CONH2, molar ratio of its molar to the sum of the molars of QACs1 and QACs2 monomers is 1:1) were added to 9 mL of distilled water (total concentration of QACs1 and QACs2 monomers is 12.5%). Nitrogen gas was then introduced and the mixture was stirred for 30 minutes. Next, 1% ammonium persulfate (APS) was added to the solution, and the mixture was stirred for another 10 minutes. The mixture was reacted at 70°C for 4 hours, and the reaction was terminated at room temperature. The product was precipitated with acetone and washed three times. Afterward, it was dried in a vacuum oven at 45°C to obtain a white crystalline powder, which is the acid- and alkali-resistant antibacterial agent.

[0042] The reaction formula is as follows:

[0043]

[0044] Example 4

[0045] First, 0.75 g of amide-containing monomer QACs1, 0.35 g of ester-containing monomer QACs2 (molar ratio of QACs1 to QACs2 is 2:1), and 0.2 g of water-soluble monomer acrylamide (X is an amide group, -CONH2, molar ratio of its molar to the sum of the molars of QACs1 and QACs2 monomers is 1:1) were added to 8.8 mL of distilled water (total concentration of QACs1 and QACs2 monomers is 12.5%). Nitrogen gas was then introduced and the mixture was stirred for 30 minutes. Next, 1% ammonium persulfate (APS) was added to the solution, and the mixture was stirred for another 10 minutes. The mixture was reacted at 70°C for 4 hours, and the reaction was terminated at room temperature. The product was precipitated with acetone and washed three times. Afterward, it was dried in a vacuum oven at 45°C to obtain a white crystalline powder, which is the acid and alkali resistant antibacterial agent.

[0046] The reaction formula is as follows:

[0047]

[0048] The antibacterial properties of the acid and alkali resistant antibacterial agents prepared in Examples 1-4 were tested, and the results are shown in Table 1:

[0049] Table 1. Hydrolysis rate and antibacterial performance of different monomer ratios for Escherichia coli.

[0050]

[0051] Table 2. Hydrolysis rate and antibacterial performance against Staphylococcus aureus with different monomer ratios.

[0052]

[0053] As shown in Tables 1 and 2, with the increase of the monomer ratio (QACs1:QAC2), the amide group content also increases. At pH 1, the hydrolysis rate gradually increases and the antibacterial rate gradually decreases, but the antibacterial rate against Staphylococcus aureus and Escherichia coli remains above 96%. At pH 13, the hydrolysis rate gradually decreases, and the antibacterial rate against Staphylococcus aureus and Escherichia coli gradually increases to 99%. At pH 7.5, the hydrolysis rate fluctuates around 1%, with the lowest hydrolysis rate at a ratio of 1:1. At a ratio of 3:2, the antibacterial rate reaches 100%. With the increase of the ratio, the inhibition rate against Staphylococcus aureus and Escherichia coli increases, reaching over 99%. This indicates that the antibacterial agent remains relatively stable under both acidic and alkaline conditions, and has excellent antibacterial effects.

[0054] Example 5

[0055] First, 0.69 g of amide-containing monomer QACs1, 0.43 g of ester-containing monomer QACs2 (molar ratio of QACs1 to QACs2 is 3:2), and 0.21 g of water-soluble monomer acrylamide (X is an amide group, -CONH2, molar ratio of its molar to the sum of the molars of QACs1 and QACs2 monomers is 1:1) were added to 18.7 mL of distilled water (total concentration of QACs1 and QACs2 monomers is 6%). Nitrogen gas was then introduced and the mixture was stirred for 30 minutes. Next, 1% ammonium persulfate (APS) was added to the solution, and the mixture was stirred for another 10 minutes. The mixture was reacted at 70°C for 4 hours, and the reaction was terminated at room temperature. The product was precipitated with acetone and washed three times. Afterward, it was dried in a vacuum oven at 45°C to obtain a white crystalline powder, which is the acid and alkali resistant antibacterial agent.

[0056] The reaction formula is as follows:

[0057]

[0058] Example 6

[0059] First, 0.69 g of amide-containing monomer QACs1, 0.43 g of ester-containing monomer QACs2 (molar ratio of QACs1 to QACs2 is 3:2), and 0.21 g of water-soluble monomer acrylamide (X is an amide group, -CONH2, molar ratio of its molar to the sum of the molars of QACs1 and QACs2 monomers is 1:1) were added to 6.2 mL of distilled water (total concentration of QACs1 and QACs2 monomers is 18%). Nitrogen gas was then introduced and the mixture was stirred for 30 minutes. Next, 1% ammonium persulfate (APS) was added to the solution, and the mixture was stirred for another 10 minutes. The mixture was reacted at 70°C for 4 hours, and the reaction was terminated at room temperature. The product was precipitated with acetone and washed three times. Afterward, it was dried in a vacuum oven at 45°C to obtain a white crystalline powder, which is the acid and alkali resistant antibacterial agent.

[0060] The reaction formula is as follows:

[0061]

[0062] Example 7

[0063] First, 0.69 g of amide-containing monomer QACs1, 0.43 g of ester-containing monomer QACs2 (molar ratio of QACs1 to QACs2 is 3:2), and 0.21 g of water-soluble monomer acrylamide (X is an amide group, -CONH2, molar ratio of its molar to the sum of the molars of QACs1 and QACs2 monomers is 1:1) were added to 4.5 mL of distilled water (total concentration of QACs1 and QACs2 monomers is 25%). Nitrogen gas was then introduced and the mixture was stirred for 30 minutes. Next, 1% ammonium persulfate (APS) was added to the solution, and the mixture was stirred for another 10 minutes. The mixture was reacted at 70 °C for 4 hours, and the reaction was terminated at room temperature. The product was precipitated with acetone and washed three times. Afterward, it was dried in a vacuum oven at 45 °C to obtain a white crystalline powder, which is the acid and alkali resistant antibacterial agent.

[0064] The reaction formula is as follows:

[0065]

[0066] The antibacterial properties of the acid and alkali resistant antibacterial agents prepared in Examples 3, 5, 6, and 7 were tested, and the results are shown in Table 2.

[0067] Table 3. Antibacterial performance test at different monomer concentrations at pH 7.5

[0068]

[0069] As the monomer concentration increases, the molecular weight of the polymer also increases. As can be seen from Table 3, as the cationic content gradually increases, the inhibition rate against Staphylococcus aureus and Escherichia coli improves and reaches over 99%. When the monomer concentration is 12.5%, the antibacterial rate reaches 100%, which indicates that the antibacterial agent has excellent antibacterial effect.

[0070] Comparative Example 1

[0071] First, 1 g of amide-containing monomer QACs1 and 0.18 g of water-soluble monomer acrylamide (X is amide group -CONH2, with a molar ratio of 1:1 to the sum of the moles of QACs1 and QACs2 monomers) were added to 8 mL of distilled water (QACs1 monomer concentration was 12.5%). Nitrogen gas was then introduced and the mixture was stirred for 30 minutes. Next, 1% ammonium persulfate (APS) was added to the solution, and the mixture was stirred for another 10 minutes. The mixture was reacted at 70°C for 4 hours, and the reaction was terminated at room temperature. The product was precipitated with acetone and washed three times. Afterward, it was dried in a vacuum oven at 45°C to obtain a white crystalline powder, which was the amide homopolymer.

[0072] The structural formula of the amide homopolymer is shown below:

[0073]

[0074] Comparative Example 2

[0075] First, 1 g of ester-containing monomer QACs2 and 0.18 g of water-soluble monomer acrylamide (X is amide group -CONH2, with a molar ratio of 1:1 to the sum of the moles of QACs1 and QACs2 monomers) were added to 8 mL of distilled water (QACs2 monomer concentration was 12.5%). Nitrogen gas was then introduced and the mixture was stirred for 30 minutes. Next, 1% ammonium persulfate (APS) was added to the solution, and the mixture was stirred for another 10 minutes. The mixture was reacted at 70 °C for 4 hours, and the reaction was terminated at room temperature. The product was precipitated with acetone and washed three times. Afterward, it was dried in a vacuum oven at 45 °C to obtain a white crystalline powder, which was an ester-based homopolymer.

[0076] The structural formula of the ester homopolymer is shown below:

[0077]

[0078] The products prepared in Example 1 and Comparative Examples 1-2 were tested for hydrolysis rate and antibacterial activity against Escherichia coli and Staphylococcus aureus at different pH values. The results are shown in Tables 4 and 5.

[0079] Table 4. Polymer hydrolysis rate and antibacterial rate of Escherichia coli at different pH values ​​after 30 hours.

[0080]

[0081] Table 5. Polymer hydrolysis rate and antibacterial rate against Staphylococcus aureus at different pH values ​​after 30 hours.

[0082]

[0083] As shown in Tables 4 and 5, all three polymers are relatively stable under neutral conditions (pH = 7.5), with antibacterial effects exceeding 99%. The amide homopolymer prepared in Comparative Example 1 is alkali-resistant but acid-resistant, and is easily hydrolyzed under acidic conditions, reducing the antibacterial rate against *E. coli* to 79% and against *Staphylococcus aureus* to 80.5%. Under alkaline conditions, it shows almost no hydrolysis and maintains a good antibacterial effect of 99.99% against both *E. coli* and *Staphylococcus aureus*. The ester homopolymer prepared in Comparative Example 2 is acid-resistant but alkali-resistant, showing significant hydrolysis under alkaline conditions, resulting in reduced antibacterial efficacy against *E. coli*. The antibacterial effect against Escherichia coli decreased to 67%, and the antibacterial rate against Staphylococcus aureus decreased to 65.4%. Under acidic conditions, the hydrolysis rate was relatively low, and the antibacterial effect against Escherichia coli decreased to 98%, while the antibacterial rate against Staphylococcus aureus decreased to 97.5%. However, the copolymer prepared in Example 1 has both amide and ester groups. Under acidic and alkaline conditions, its hydrolysis rate is significantly reduced compared to polymers with single ester or single amide groups. The antibacterial effect against Escherichia coli and Staphylococcus aureus is above 96% under both acidic and alkaline conditions, indicating that the antibacterial agent can remain stable under both acidic and alkaline conditions.

[0084] Comparative Example 3

[0085] First, 0.51 g of amide-containing monomer QACs1', 0.32 g of ester-containing monomer QACs2' (molar ratio of QACs1' and QACs2' is 3:2), and 0.15 g of water-soluble monomer acrylamide (X is amide group -CONH2, molar ratio of X to the sum of the molar amounts of QACs1' and QACs2' monomers is 1:1) were added to 6.6 mL of distilled water (total concentration of QACs1' and QACs2' monomers is 12.5%). Nitrogen gas was then introduced and the mixture was stirred for 30 minutes. Next, 1% ammonium persulfate (APS) was added to the solution, and the mixture was stirred for another 10 minutes. The mixture was reacted at 70°C for 4 hours, and the reaction was terminated at room temperature. The product was precipitated with acetone and washed three times. Afterward, it was dried in a vacuum oven at 45°C to obtain a white crystalline powder, which is the acid and alkali resistant antibacterial agent.

[0086] The reaction formula is as follows:

[0087]

[0088] Comparative Example 4

[0089] First, 0.52 g of amide-containing monomer QACs1”, 0.33 g of ester-containing monomer QACs2” (molar ratio of QACs1” to QACs2” is added to 6.8 mL of distilled water (total concentration of QACs1” and QACs2” monomers is 12.5%). Nitrogen gas is then introduced and the mixture is stirred for 30 minutes. Next, 1% ammonium persulfate (APS) is added to the solution, and the mixture is stirred for another 10 minutes. The mixture is then reacted at 70°C for 4 hours, and the reaction is terminated at room temperature. The product is precipitated with acetone and washed three times. Afterward, it is dried in a vacuum oven at 45°C to obtain a white crystalline powder, which is the acid and alkali resistant antibacterial agent.

[0090] The reaction formula is as follows:

[0091]

[0092] The products prepared in Examples 3 and 3-4 were tested for hydrolysis rate and antibacterial activity against Escherichia coli and Staphylococcus aureus at different pH values. The results are shown in Tables 6 and 7.

[0093] Table 6. Polymer hydrolysis rate and antibacterial rate of Escherichia coli at different pH values ​​after 30 hours.

[0094]

[0095] Table 7. Polymer hydrolysis rate and antibacterial rate against Staphylococcus aureus at different pH values ​​after 30 hours.

[0096]

[0097] As can be seen from Tables 6 and 7, by changing different ester-containing and amide-containing monomers, it was found that the hydrolysis rates of the three polymers did not change much under neutral and acidic / alkaline conditions and were all below 10%. This indicates that the structure containing both ester and amide groups can remain stable under both acidic and alkaline conditions. However, Comparative Example 3 is an amphoteric polymer and Comparative Example 4 is a benzyl polymer. Antibacterial tests showed that although these two structures were not easily hydrolyzed, they did not have good antibacterial effects against Escherichia coli and Staphylococcus aureus, with antibacterial rates below 75%. In contrast, the long-chain alkyl polymer in Example 3 showed antibacterial rates of over 96% against Escherichia coli and Staphylococcus aureus, indicating that the antibacterial agent prepared by this invention has excellent antibacterial properties.

[0098] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.

Claims

1. An acid- and alkali-resistant antibacterial agent, characterized in that, Its chemical structural formula is shown below: Where n1, n2, and n3 are 3 to 10, and X is a water-soluble functional group.

2. The acid and alkali resistant antibacterial agent according to claim 1, characterized in that, X is selected from one or more hydrophilic groups containing -CONH2, -CONH-, -CONH-CH2CH2OH or –OH.

3. A method for preparing an acid and alkali resistant antibacterial agent as described in claim 1 or 2, characterized in that, In an inert atmosphere, amide-containing monomers, ester-containing monomers, and water-soluble monomers are mixed and reacted under the action of an initiator to obtain a polyquaternary ammonium salt cationic acid and alkali resistant antibacterial agent.

4. The preparation method according to claim 3, characterized in that, The molar ratio of the amide-containing monomer to the ester-containing monomer is 1:0.5 to 1:2.33; the total concentration of the amide-containing monomer and the ester-containing monomer is 10%-70%; and the molar amount of the water-soluble monomer is equal to the sum of the molar amounts of the amide-containing monomer and the ester-containing monomer.

5. The preparation method according to claim 3, characterized in that, The amide-containing monomer is a compound with the structural formula shown in QACs1, the ester-containing monomer is a compound with the structural formula shown in QACs2, the initiator is selected from any one of ammonium persulfate and potassium persulfate, and the water-soluble monomer is a compound with the structural formula shown below: C=CX, where X is selected from one or more hydrophilic groups containing -CONH2, -CONH-, -CONH-CH2CH2OH or –OH.

6. The preparation method according to claim 3, characterized in that, The amount of initiator added is 0.5-2% of the total mass of the reactants.

7. The preparation method according to claim 3, characterized in that, The reaction temperature is (60~70)℃ and the reaction time is (3~5)h.

8. The preparation method according to claim 3, characterized in that, The inert atmosphere is selected from either nitrogen or argon.

9. The application of an acid and alkali resistant antibacterial agent as described in claim 1 or 2 in water treatment.

10. The application according to claim 9, characterized in that, The pH of the solution used in water treatment is 1 to 13.

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