High-stability hypochlorous acid and preparation method thereof

Abstract

The invention discloses high-stability hypochlorous acid and a preparation method thereof. The high-stability hypochlorous acid disclosed by the invention is prepared from the following raw materials at least: 1 to 100 parts of alkali metal chlorine salt, 0.1 to 1 part of lactate, 0.1 to 10 parts of beta-cyclodextrin / chitosan compound and 1000 to 2000 parts of water. The high-stability hypochlorous acid raw material also comprises a pH regulator. The invention also provides a preparation method of the composition. Compared with the prior art, the high-stability hypochlorous acid prepared by the invention is high in stability and still has a disinfection effect after being kept for two years.

Description

Technical Field

[0001] The invention relates to the technical field of disinfectants, and in particular to high-stability hypochlorous acid and a preparation method thereof. Background Art

[0002] Hypochlorous acid is a widely used disinfectant with the advantages of good bactericidal effect, broad bactericidal spectrum and low price. It is widely used for disinfection and sterilization in households, medical institutions, agriculture, industry, food industry, pharmaceutical industry and other fields, demonstrating the importance of hypochlorous acid in the field of sterilization. However, the hypochlorous acid solution itself has poor stability. At present, the actual effective period of hypochlorous acid solution is only 3 months, which is short and seriously affects the promotion and application of hypochlorous acid poison.

[0003] CN115590034A discloses a method for preparing a high-stability hypochlorous acid solution, which improves the stability of the hypochlorous acid solution by adding nano boron nitride. The metal ions in the hypochlorous acid solution prepared by the method do not provide an effective treatment method, which affects the stability of the hypochlorous acid.

[0004] CN115568476A discloses a hypochlorous acid disinfectant, which improves the stability of the hypochlorous acid disinfectant by adding one or more of halogenates, dihydrogen phosphates, dihydrogen phosphates, sulfates, carbonates and bicarbonates. The additives used in the hypochlorous acid disinfectant prepared by the method are mainly used to adjust the pH value of the solution, and have a low effect on improving stability.

[0005] CN112544630A discloses a hypochlorous acid solution stabilizer and its application, wherein the hypochlorous acid solution stabilizer is any one or more of chitosan, cyclodextrin, polyol, surfactant, and aminosulfonate. The stabilizer of the invention is added after the hypochlorous acid solution is prepared, and has a low effect on improving stability. Summary of the invention

[0006] In view of the above-mentioned defects of the prior art, the object of the present invention is to provide a high-stability hypochlorous acid with good disinfection effect and high stability.

[0007] To achieve the above object, the present invention provides a high-stability hypochlorous acid and a preparation method thereof.

[0008] The detailed technical scheme of the present invention is as follows:

[0009] The present invention provides a high-stability hypochlorous acid prepared from the following raw materials:

[0010] In parts by mass, the raw materials at least include 1-100 parts of alkali metal chloride, 0.1-1 parts of lactate, 0.1-10 parts of β-cyclodextrin / chitosan complex, and 1000-2000 parts of water; the high-stability hypochlorous acid raw material also includes a pH regulator. The specific introduction of each raw material in the present invention is as follows:

[0011] The alkali metal chloride salt is at least one of sodium chloride, potassium chloride and lithium chloride.

[0012] The lactate is at least one of sodium lactate, potassium lactate, calcium lactate and magnesium lactate.

[0013] The water is deionized water, which contains almost no metal ions, thereby reducing the influence of metal ions on the decomposition of hypochlorous acid.

[0014] The pH adjuster is an alkali metal hydroxide. Specifically, the pH adjuster is any one of a NaOH aqueous solution and a KOH aqueous solution.

[0015] The β-cyclodextrin / chitosan complex is prepared by the following method:

[0016] By weight, 3-8 parts of β-cyclodextrin are dissolved in 10-30 parts of 15-35wt% NaOH aqueous solution, and gelatinized at 800-1200rpm and 20-40℃ for 20-40min; 1-4 parts of epichlorohydrin are slowly added dropwise for 20-40min, and 1-4 parts of chitosan are added for reaction for 1-2h; 50-70 parts of N,N-dimethylformamide are reacted at 1500-1800rpm and 70-100℃ for 3-6h; the mixture is washed with 12-15wt% hydrochloric acid and water for 3-5 times respectively, and the filter cake is taken and dried at 50-80℃ for 4-6h.

[0017] The present invention provides a method for preparing high-stability hypochlorous acid, and the preparation steps are as follows:

[0018] (1) mixing an alkali metal chloride salt and water uniformly to obtain a mixed solution 1;

[0019] (2) adding lactate and β-cyclodextrin / chitosan to the mixed solution 1 and stirring to obtain a mixed solution 2;

[0020] (3) adding a pH adjuster to the mixed solution 2 to adjust the pH to 6.5 to 10.5, thereby obtaining a mixed solution 3;

[0021] (4) The mixed solution 3 is electrolyzed by a method of electrolyzing a chloride salt solution to obtain highly stable hypochlorous acid.

[0022] The current density of the electrolysis in step (4) is 0.5-3.0A / dm 2 , the water temperature is 20-30℃.

[0023] Beneficial effects of the present invention:

[0024] 1. Compared with the prior art, the high-stability hypochlorous acid of the present invention still maintains a high bactericidal effect after being stored at 37°C for 90 days.

[0025] 2. Compared with the prior art, the high-stability hypochlorous acid of the present invention has good thermal stability, and the effective chlorine decrease rate is 0.98% after being stored at 55°C for 14 days.

[0026] 3. Compared with the existing technology, it has higher stability and a shelf life of more than two years.

[0027] 4. High safety. Oral toxicity test shows that it is non-toxic, has no skin irritation, eye irritation, mucous membrane irritation, is non-bioaccumulative, and is self-degradable. DETAILED DESCRIPTION

[0028] A high-stability hypochlorous acid, comprising the following components:

[0029] The raw materials for preparing the high-stability hypochlorous acid include at least 1-100 parts of alkali metal chloride, 0.1-1 parts of lactate, 0.1-10 parts of β-cyclodextrin / chitosan complex, and 1000-2000 parts of water, calculated by mass. The high-stability hypochlorous acid raw materials also include a pH regulator.

[0030] The alkali metal chloride salt is at least one of sodium chloride, potassium chloride and lithium chloride. The alkali metal chloride salt in this embodiment is sodium chloride, which is an inorganic ion compound. The present invention is used for preparing hypochlorous acid solution by electrolysis, and a chlorine evolution reaction occurs at the anode part of the electrolytic cell to generate a hypochlorous acid solution; a hydrogen evolution reaction occurs at the cathode to generate a sodium hydroxide solution.

[0031] The lactate is at least one of sodium lactate, potassium lactate, calcium lactate, and magnesium lactate. The lactate in this embodiment is sodium lactate, which can stabilize the pH value of the solution and has a buffering effect, thereby preventing the fluctuation of the pH value from causing the decomposition of hypochlorous acid; sodium lactate may form a complex with metal ions in the solution through its carboxyl and hydroxyl groups, thereby reducing the catalytic decomposition of hypochlorous acid by metal ions; sodium lactate may have the ability to remove free radicals in the solution, reduce the attack of free radicals on hypochlorous acid, and prolong its stability; sodium lactate may form a protective film and solution viscosity around the hypochlorous acid molecules, slowing down its contact with the external environment and the molecular movement of hypochlorous acid, thereby reducing the decomposition rate.

[0032] The β-cyclodextrin / chitosan complex is prepared by the following method:

[0033] By weight, 3-8 parts of β-cyclodextrin are dissolved in 10-30 parts of 15-35wt% NaOH aqueous solution, and gelatinized at 800-1200rpm and 20-40℃ for 20-40min; 1-4 parts of epichlorohydrin are slowly added dropwise for 20-40min, and 1-4 parts of chitosan are added for reaction for 1-2h; 50-70 parts of N,N-dimethylformamide are reacted at 1500-1800rpm and 70-100℃ for 3-6h; the mixture is washed with 12-15wt% hydrochloric acid and water for 3-5 times respectively, and the filter cake is taken and dried at 50-80℃ for 4-6h.

[0034] The obtained β-cyclodextrin / chitosan complex retains the cavity structure of β-cyclodextrin. β-cyclodextrin and chitosan can form a supramolecular assembly through non-covalent interactions, which may provide a stable microenvironment for hypochlorous acid, reduce direct contact with the external environment, and reduce its decomposition; chitosan can form a coordination bond with the chlorine in hypochlorous acid to further reduce the decomposition rate of hypochlorous acid and has better thermal stability. β-cyclodextrin and chitosan are both biocompatible and degradable materials. This complex has environmentally friendly properties as a stabilizer, which helps to reduce the environmental impact during chemical treatment.

[0035] The water is deionized water, which contains almost no metal ions, thus reducing the influence of metal ions on the decomposition of hypochlorous acid.

[0036] Example 1

[0037] A method for preparing high-stability hypochlorous acid comprises the following steps:

[0038] (1) 30 g of sodium chloride and 1 kg of water were mixed uniformly to obtain a mixed solution 1;

[0039] (2) adding 0.1 g of sodium lactate and 1 g of β-cyclodextrin / chitosan complex to the mixed solution 1 and stirring to obtain a mixed solution 2;

[0040] (3) adding 30 wt % NaOH aqueous solution to mixed solution 2, adjusting the pH to pH 8.0, to obtain mixed solution 3;

[0041] (4) The mixed solution 3 is placed in the electrolytic cell of the hypochlorous acid reactor to generate high-stability hypochlorous acid by electrolyzing the chloride salt solution.

[0042] The current density of the electrolysis in step (4) is 2.0 A / dm 2 , the water temperature is 25℃.

[0043] The β-cyclodextrin / chitosan complex is prepared by the following method: dissolving 4g of β-cyclodextrin in 30g of a 30wt% NaOH aqueous solution, reacting at 1200rpm and 25°C for 30min; slowly dripping 2g of epichlorohydrin for 30min, adding 2g of chitosan for 2h; adding 60g of N,N-dimethylformamide, reacting at 1800rpm and 100°C for 6h; washing with 12wt% hydrochloric acid and water for 3 times respectively, taking the filter cake, drying at 60°C for 4h to obtain the obtained product.

[0044] Example 2

[0045] A method for preparing high-stability hypochlorous acid comprises the following steps:

[0046] (1) 30 g of sodium chloride and 1 kg of water were mixed uniformly to obtain a mixed solution 1;

[0047] (2) adding 0.1 g of sodium lactate and 1 g of β-cyclodextrin to the mixed solution 1 and stirring to obtain a mixed solution 2;

[0048] (3) adding 30 wt % NaOH aqueous solution to mixed solution 2, adjusting the pH to pH 8.0, to obtain mixed solution 3;

[0049] (4) The mixed solution 3 is placed in the electrolytic cell of the hypochlorous acid reactor to generate high-stability hypochlorous acid by electrolyzing the chloride salt solution.

[0050] The current density of the electrolysis in step (4) is 2.0 A / dm 2 , the water temperature is 25℃.

[0051] Example 3

[0052] A method for preparing high-stability hypochlorous acid comprises the following steps:

[0053] (1) 30 g of sodium chloride and 1 kg of water were mixed uniformly to obtain a mixed solution 1;

[0054] (2) adding 0.1 g of sodium lactate and 1 g of chitosan to the mixed solution 1 and stirring to obtain a mixed solution 2;

[0055] (3) adding 30 wt % NaOH aqueous solution to mixed solution 2, adjusting the pH to pH 8.0, to obtain mixed solution 3;

[0056] (4) The mixed solution 3 is placed in the electrolytic cell of the hypochlorous acid reactor to generate high-stability hypochlorous acid by electrolyzing the chloride salt solution.

[0057] The current density of the electrolysis in step (4) is 2.0 A / dm 2 , the water temperature is 25℃.

[0058] Example 4

[0059] A method for preparing high-stability hypochlorous acid comprises the following steps:

[0060] (1) 30 g of sodium chloride and 1 kg of water were mixed uniformly to obtain a mixed solution 1;

[0061] (2) adding 0.1 g sodium lactate, 0.5 g β-cyclodextrin, and 0.5 g chitosan to the mixed solution 1 and stirring to obtain a mixed solution 2;

[0062] (3) adding 30 wt % NaOH aqueous solution to mixed solution 2, adjusting the pH to pH 8.0, to obtain mixed solution 3;

[0063] (4) The mixed solution 3 is placed in the electrolytic cell of the hypochlorous acid reactor to generate high-stability hypochlorous acid by electrolyzing the chloride salt solution.

[0064] The current density of the electrolysis in step (4) is 2.0 A / dm 2 , the water temperature is 25℃.

[0065] Example 5

[0066] A method for preparing high-stability hypochlorous acid comprises the following steps:

[0067] (1) 30 g of sodium chloride and 1 kg of water were mixed uniformly to obtain a mixed solution 1;

[0068] (2) adding 0.1 g of sodium lactate to the mixed solution 1 and stirring to obtain a mixed solution 2;

[0069] (3) adding 30 wt % NaOH aqueous solution to mixed solution 2, adjusting the pH to pH 8.0, to obtain mixed solution 3;

[0070] (4) The mixed solution 3 is placed in the electrolytic cell of the hypochlorous acid reactor to generate high-stability hypochlorous acid by electrolyzing the chloride salt solution.

[0071] The current density of the electrolysis in step (4) is 2.0 A / dm 2 , the water temperature is 25℃.

[0072] Example 6

[0073] A method for preparing high-stability hypochlorous acid comprises the following steps:

[0074] (1) 30 g of sodium chloride and 1 kg of water were mixed uniformly to obtain a mixed solution 1;

[0075] (2) adding 0.1 g of sodium lactate and 1 g of β-cyclodextrin / Span80 complex to the mixed solution 1 and stirring to obtain a mixed solution 2;

[0076] (3) adding 30 wt % NaOH aqueous solution to mixed solution 2, adjusting the pH to pH 8.0, to obtain mixed solution 3;

[0077] (4) The mixed solution 3 is placed in the electrolytic cell of the hypochlorous acid reactor to generate high-stability hypochlorous acid by electrolyzing the chloride salt solution.

[0078] The current density of the electrolysis in step (4) is 2.0 A / dm 2 , the water temperature is 25℃.

[0079] The β-cyclodextrin / Span80 complex is prepared by the following method: dissolving 4g of β-cyclodextrin in 30g of a 30wt% NaOH aqueous solution, reacting at 1200rpm and 25°C for 30min; slowly adding 2g of epichlorohydrin dropwise for 30min, adding 2g of Span80 and reacting for 2h; reacting a mixture of 60g of kerosene and 10g of isooctane at 1800rpm and 60°C for 4h; centrifuging at 2000rpm to obtain a precipitate, washing with ethanol three times, taking a filter cake and drying at 60°C for 4h.

[0080] Example 7

[0081] A method for preparing high-stability hypochlorous acid comprises the following steps:

[0082] (1) 30 g of sodium chloride and 1 kg of water were mixed uniformly to obtain a mixed solution 1;

[0083] (2) adding 0.1 g of sodium lactate and 1 g of β-cyclodextrin / pentaerythritol complex to the mixed solution 1 and stirring to obtain a mixed solution 2;

[0084] (3) adding 30 wt % NaOH aqueous solution to mixed solution 2, adjusting the pH to pH 8.0, to obtain mixed solution 3;

[0085] (4) The mixed solution 3 is placed in the electrolytic cell of the hypochlorous acid reactor to generate high-stability hypochlorous acid by electrolyzing the chloride salt solution.

[0086] The current density of the electrolysis in step (4) is 2.0 A / dm 2 , the water temperature is 25℃.

[0087] The β-cyclodextrin / pentaerythritol complex is prepared by the following method: dissolving 4g of β-cyclodextrin in 30g of a 30wt% NaOH aqueous solution, reacting at 1200rpm and 25°C for 30min; slowly dripping 2g of epichlorohydrin for 30min, adding 2g of pentaerythritol for 2h; adding 60g of N,N-dimethylformamide, reacting at 1800rpm and 100°C for 6h; washing with 12wt% hydrochloric acid and water for 3 times respectively, taking the filter cake, drying at 60°C for 4h to obtain the obtained product.

[0088] Test Example 1

[0089] Evaluation of disinfectant stability: The high-stability hypochlorous acid prepared in Examples 1-7 was stored in accordance with the technical requirements of GB / T38499-2020 "Method for Evaluation of Stability of Disinfectants". The experimental results of storage at 37°C for 90 days are shown in Table 1, and the experimental results of storage at 55°C for 14 days are shown in Table 2.

[0090] The weight of the β-cyclodextrin complex sample was accurately weighed to 0.0500 g, and thermogravimetric analysis was performed using TGA Q5000 (TA Company, USA) at a heating rate of 10°C / min and a temperature range of 20-800°C. The temperature at which the weight loss was 10% and 50% was recorded as T 10 / ℃ and T 50 / ℃, test results are shown in Table 3.

[0091] Table 1: Storage at 37°C for 90 days

[0092]

[0093]

[0094] By comparing Examples 1-7, it can be found that Example 1 has the lowest decrease rate. The decrease rates of Examples 1-7 are below 10%, which indicates that the storage time of high-stability hypochlorous acid prepared by electrolysis can reach two years.

[0095] The decline rate of Example 2-4 in Example 2-7 is closer to that of Example 5. The possible reason for the high decline rate is that Example 2 adds stabilizer β-cyclodextrin, which can form inclusion complexes with hypochlorous acid, reduce its contact with external light, heat, and oxygen, and reduce the decomposition rate of hypochlorous acid; Example 3 adds stabilizer chitosan, and chitosan molecules can be adsorbed on the surface of hypochlorous acid to form a protective film to reduce the decomposition rate of hypochlorous acid. The reason why the decline rates of Examples 6 and 7 are closer to Example 1 is that Example 6 adds β-cyclodextrin / Span80 complex, which retains the cavity structure of β-cyclodextrin, and Span80 is a surfactant that has a certain effect on improving the stability of hypochlorous acid. Span80 is embedded in β-cyclodextrin to further widen the cavity of β-cyclodextrin; Example 7 adds β-cyclodextrin / pentaerythritol complex, which is tetrapod-shaped, and the special cavity structure reduces the decomposition rate of hypochlorous acid.

[0096] The decrease rate in Example 1 is the lowest, which may be due to the addition of β-cyclodextrin / chitosan complex. The β-cyclodextrin / chitosan complex retains the cavity structure of β-cyclodextrin. β-cyclodextrin and chitosan can form a supramolecular assembly through non-covalent interactions, which may provide a stable microenvironment for hypochlorous acid, reduce direct contact with the external environment, and thus reduce its decomposition rate; chitosan can form a coordination bond with chlorine in hypochlorous acid to further reduce the decomposition rate of hypochlorous acid and has better thermal stability.

[0097] Table 2: Experimental results of 14-day storage at 55°C

[0098]

[0099] Table 3: Thermal performance parameters of β-cyclodextrin complex

[0100]

[0101] By comparing Examples 1-7, it can be found that the decrease rate of Example 1 is 0.98%. The possible reason is that the β-cyclodextrin / chitosan complex is added. The β-cyclodextrin / chitosan complex retains the cavity structure of β-cyclodextrin. β-cyclodextrin and chitosan can form a supramolecular assembly through non-covalent interaction, which may provide a stable microenvironment for hypochlorous acid, reduce direct contact with the external environment, and thus reduce its decomposition rate. Comprehensive Table 3 shows that the β-cyclodextrin / chitosan complex T 10 / ℃, the decomposition temperature is 297.2℃, T 50 The decomposition temperature is 589.1℃ at 400℃ and the thermal stability is good. The hypochlorous acid is protected in the β-cyclodextrin / chitosan complex, which can isolate the temperature influence to a large extent, so the decomposition rate is low.

[0102] Test Example 2

[0103] Evaluation of the bactericidal effect of disinfectants: According to the technical requirements of GB / T38502-2020 "Test Method for Laboratory Bactericidal Effect of Disinfectants", the high-stability hypochlorous acid prepared in Examples 1-7 was stored at 37°C for 90 days to kill Bacillus subtilis var. niger spores (ATCC 9372), Escherichia coli (8099), and Candida albicans (ATCC 10231). The experimental results are shown in Table 4, where KL is the killing logarithm, and the larger the value, the better the effect. The sample is Example 1-7 after being stored at 37°C for 90 days.

[0104] Table 4: Test data on the killing effect of bacteria after samples were stored at 37°C for 90 days

[0105]

[0106] The experimental results show that in Example 1, Example 6 and Example 7, high-stability hypochlorous acid of β-cyclodextrin / chitosan complex, β-cyclodextrin / Span80 complex and β-cyclodextrin / pentaerythritol complex was added respectively. After being stored at 37°C for 90 days, the killing logarithm of the samples against Bacillus subtilis black variant spores (ATCC 9372), Escherichia coli (8099) and Candida albicans (ATCC10231) was greater than 5.0, indicating that the samples of Example 1, Example 6 and Example 7 still have good bactericidal effects after being stably stored for 2 years; in Example 2-4, β-cyclodextrin, chitosan, β-cyclodextrin and chitosan were added as stabilizers. After being stored at 37°C for 90 days, the samples had good bactericidal effects against Bacillus subtilis black variant spores (ATCC 9372), Escherichia coli (8099) and Candida albicans (ATCC 10231) has a killing logarithm value less than 5.0 and greater than 4.0, indicating that the bactericidal effect of the samples of Example 4-5 has been significantly reduced after being stably stored for 2 years; Example 5 did not add β-cyclodextrin, chitosan, β-cyclodextrin and chitosan, and β-cyclodextrin / chitosan complex as stabilizers. After being stored at 37°C for 90 days, the killing logarithm values ​​of Bacillus subtilis var. niger spores (ATCC9372), Escherichia coli (8099), and Candida albicans (ATCC10231) were all less than 4, indicating that the bactericidal effect of the sample of Example 5 was significantly poor after being stored for 2 years.

Claims

1. A method for preparing high-stability hypochlorous acid, characterized in that: The following steps are involved: (1) mixing an alkali metal chloride salt and water uniformly to obtain a mixed solution 1; (2) adding lactate and β-cyclodextrin / chitosan complex to the mixed solution 1 and stirring evenly to obtain a mixed solution 2; (3) adding a pH adjuster to the mixed solution 2 to adjust the pH to 6.5-10.5, thereby obtaining a mixed solution 3; (4) The mixed solution 3 is electrolyzed by a method of electrolyzing a chloride salt solution to obtain highly stable hypochlorous acid.

2. The method for preparing high-stability hypochlorous acid according to claim 1, characterized in that: The dosage of each raw material is as follows: 1-100 parts of alkali metal chloride, 0.1-1 parts of lactate, 0.1-10 parts of β-cyclodextrin / chitosan complex, and 1000-2000 parts of water.

3. The method for preparing high-stability hypochlorous acid according to claim 1, characterized in that: The alkali metal chloride salt is at least one of sodium chloride, potassium chloride and lithium chloride.

4. The method for preparing high-stability hypochlorous acid according to claim 1, characterized in that: The lactate is at least one of sodium lactate, potassium lactate, calcium lactate and magnesium lactate.

5. The method for preparing high-stability hypochlorous acid according to claim 1, characterized in that: The pH regulator is an alkali metal hydroxide.

6. The method for preparing high-stability hypochlorous acid according to claim 6, characterized in that: The pH adjuster is any one of a NaOH aqueous solution and a KOH aqueous solution.

7. The method for preparing high-stability hypochlorous acid according to claim 1, characterized in that: The β-cyclodextrin / chitosan complex is prepared by the following method: by weight, 3-8 parts of β-cyclodextrin are dissolved in 10-30 parts of 15-35wt% NaOH aqueous solution, and gelatinized at 800-1200rpm and 20-40℃ for 20-40min; 1-4 parts of epichlorohydrin are slowly added dropwise, and the dripping is completed within 20-40min, and 1-4 parts of chitosan are added to react for 1-2h; 50-70 parts of N,N-dimethylformamide are added, and the reaction is carried out at 1500-1800rpm and 70-100℃ for 3-6h; 12-15wt% hydrochloric acid and water are used for washing 3-5 times respectively, and the filter cake is taken and dried at 50-80℃ for 4-6h to obtain the obtained product.

8. The method for preparing high-stability hypochlorous acid according to claim 1, characterized in that: The effective chlorine content in high-stability hypochlorous acid is 20-500 mg / L, the pH is 2.0-6.5, and the current density is 0.5-3.0 A / dm 2 , water temperature 15-30℃, residual chloride ion content less than 500mg / L.

9. A high stability hypochlorous acid, characterized in that: The method is prepared by any one of claims 1 to 8.

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