A highly stable hypochlorous acid and its preparation method

Abstract

The present invention discloses a highly stable hypochlorous acid and a preparation method thereof. In the preparation of the highly stable hypochlorous acid of the present invention, the raw materials used at least include 1-100 parts of alkali metal chloride, 0.1-1 part of lactate, 0.1-10 parts of β-cyclodextrin / chitosan complex, and 1000-2000 parts of water; a pH regulator is further included in the raw materials of the highly stable hypochlorous acid. The present invention also provides a preparation method thereof. Compared with the prior art, the highly stable hypochlorous acid prepared by the present invention has strong stability and can still have a disinfection effect after two years.

Description

Technical Field

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

[0002] Hypochlorous acid is a widely used disinfectant, which has the advantages of good bactericidal effect, broad bactericidal spectrum, low price, etc. It is widely used in disinfection and sterilization in fields such as families, medical institutions, agriculture, industry, food industry, and pharmaceutical industry, demonstrating the importance of hypochlorous acid in the field of sterilization. However, the hypochlorous acid solution itself has poor stability. At present, the actual shelf life of the hypochlorous acid solution is only 3 months, and the short shelf life seriously affects the popularization and application of hypochlorous acid disinfectants.

[0003] CN115590034A discloses a preparation method of a highly stable hypochlorous acid solution, which improves the stability performance of the hypochlorous acid solution by adding nano boron nitride. There is no effective treatment method for metal ions in the hypochlorous acid solution prepared by this method, which affects the stability of hypochlorous acid.

[0004] CN115568476A discloses a hypochlorous acid disinfectant solution, which improves the stability performance of the hypochlorous acid disinfectant solution by adding one or more of hypohalite, disodium hydrogen phosphate, sodium dihydrogen phosphate, sulfate, carbonate, and bicarbonate. The additives used in the hypochlorous acid disinfectant solution prepared by this method mainly adjust the pH value of the solution, and the improvement of the stability effect is relatively low.

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

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

[0007] To achieve the above purpose, the present invention provides a highly stable hypochlorous acid and a preparation method thereof.

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

[0009] The present invention provides a highly stable hypochlorous acid, which is prepared from the following raw materials:

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

[0011] The alkali metal chloride 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, reducing the influence of metal ions on the decomposition of hypochlorous acid.

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

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

[0016] By mass, dissolve 3-8 parts of β-cyclodextrin in 10-30 parts of a 15-35 wt% NaOH aqueous solution, stir at 800-1200 rpm, and gelatinize at 20-40 °C for 20-40 min; slowly add 1-4 parts of epichlorohydrin dropwise over 20-40 min, add 1-4 parts of chitosan and react for 1-2 h; add 50-70 parts of N,N-dimethylformamide, stir at 1500-1800 rpm, react at 70-100 °C for 3-6 h; wash with 12-15 wt% hydrochloric acid and water 3-5 times each, take the filter cake, and dry at 50-80 °C for 4-6 h to obtain.

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

[0018] (1) Mix the alkali metal chloride and water evenly to obtain a mixed solution 1;

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

[0020] (3) Add the pH regulator to the mixed solution 2 and adjust the pH value to 6.5-10.5 to obtain a mixed solution 3;

[0021] (4) Electrolyze the mixed solution 3 by electrolyzing a chloride salt solution to obtain high-stability hypochlorous acid.

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

[0023] Advantages of the present invention:

[0024] 1. Compared with the prior art, the highly stable 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 highly stable hypochlorous acid of the present invention has good thermal stability, and the effective chlorine decline rate is 0.98% after being stored at 55°C for 14 days.

[0026] 3. It has higher stability than the prior art and a shelf life of more than two years.

[0027] 4. It has high safety. The oral toxicity test shows that it is non-toxic, has no skin irritation, eye irritation, or mucosal irritation, has no bioaccumulation, and has self-degradability. Detailed implementation mode

[0028] A highly stable hypochlorous acid comprises the following components:

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

[0030] The alkali metal chloride is at least one of sodium chloride, potassium chloride, and lithium chloride. In this embodiment, the alkali metal chloride is sodium chloride. Sodium chloride is an inorganic ionic compound. In the present invention, it is used for electrolytic preparation of hypochlorous acid solution. A chlorine evolution reaction occurs at the anode part of the electrolytic cell to generate hypochlorous acid solution; a hydrogen evolution reaction occurs at the cathode to generate sodium hydroxide solution.

[0031] The lactate is at least one of sodium lactate, potassium lactate, calcium lactate, and magnesium lactate. In this embodiment, the lactate is sodium lactate. Sodium lactate can stabilize the pH value of the solution and has a buffering effect to avoid the decomposition of hypochlorous acid caused by pH value fluctuations; sodium lactate may form complexes with metal ions in the solution through its carboxyl and hydroxyl groups, thereby reducing the catalytic decomposition effect of metal ions on hypochlorous acid; sodium lactate may have the ability to scavenge free radicals in the solution, reduce the attack of free radicals on hypochlorous acid, and extend its stability; sodium lactate may form a protective film and solution viscosity around hypochlorous acid molecules, slow down their contact with the external environment and the molecular movement of hypochlorous acid, and reduce the decomposition rate.

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

[0033] Dissolve 3 - 8 parts by mass of β - cyclodextrin in 10 - 30 parts of a 15 - 35 wt% NaOH aqueous solution, and gelatinize at 800 - 1200 rpm and 20 - 40 °C for 20 - 40 min; slowly add 1 - 4 parts of epichlorohydrin dropwise within 20 - 40 min, add 1 - 4 parts of chitosan and react for 1 - 2 h; add 50 - 70 parts of N,N - dimethylformamide, react at 1500 - 1800 rpm and 70 - 100 °C for 3 - 6 h; wash with 12 - 15 wt% hydrochloric acid and water 3 - 5 times each, take the filter cake, and dry at 50 - 80 °C for 4 - 6 h to obtain the product.

[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 micro - environment for hypochlorous acid, reducing its direct contact with the external environment and 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. Both β - cyclodextrin and chitosan are biocompatible and biodegradable materials. This complex as a stabilizer has the characteristics of environmental friendliness, which helps to reduce the environmental impact during the chemical treatment process.

[0035] The water mentioned is deionized water. There are almost no metal ions in deionized water, reducing the influence of metal ions on the decomposition of hypochlorous acid.

[0036] Example 1

[0037] A preparation method of highly stable hypochlorous acid, comprising the following steps:

[0038] (1) Mix 30 g of sodium chloride with 1 kg of water evenly to obtain mixed solution 1;

[0039] (2) Add 0.1 g of sodium lactate and 1 g of β - cyclodextrin / chitosan complex to mixed solution 1, and stir to obtain mixed solution 2;

[0040] (3) Add 30 wt% NaOH aqueous solution to mixed solution 2, and adjust the pH value to 8.0 to obtain mixed solution 3;

[0041] (4) Put mixed solution 3 into the electrolytic cell of a hypochlorous acid reactor, and generate highly stable hypochlorous acid by electrolyzing a chloride salt solution.

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

[0043] The β-cyclodextrin / chitosan complex is prepared by the following method: Dissolve 4 g of β-cyclodextrin in 30 g of 30 wt% aqueous NaOH solution, react at 25 °C for 30 min at 1200 rpm; slowly add 2 g of epichlorohydrin dropwise, finish adding in 30 min, add 2 g of chitosan and react for 2 h; add 60 g of N,N-dimethylformamide, react at 1800 rpm and 100 °C for 6 h; wash three times with 12 wt% hydrochloric acid and water respectively, take the filter cake, and dry at 60 °C for 4 h to obtain.

[0044] Example 2

[0045] A preparation method of highly stable hypochlorous acid, comprising the following steps:

[0046] (1) Mix 30 g of sodium chloride with 1 kg of water evenly to obtain mixed solution 1;

[0047] (2) Add 0.1 g of sodium lactate and 1 g of β-cyclodextrin to mixed solution 1, stir to obtain mixed solution 2;

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

[0049] (4) Put mixed solution 3 into the electrolytic cell of a hypochlorous acid reactor, and generate highly stable hypochlorous acid by electrolyzing a chlorinated salt solution.

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

[0051] Example 3

[0052] A preparation method of highly stable hypochlorous acid, comprising the following steps:

[0053] (1) Mix 30 g of sodium chloride with 1 kg of water evenly to obtain mixed solution 1;

[0054] (2) Add 0.1 g of sodium lactate and 1 g of chitosan to mixed solution 1, stir to obtain mixed solution 2;

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

[0056] (4) Put mixed solution 3 into the electrolytic cell of a hypochlorous acid reactor, and generate highly stable hypochlorous acid by electrolyzing a chlorinated salt solution.

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

[0058] Example 4

[0059] A method for preparing highly stable hypochlorous acid, comprising the following steps:

[0060] (1) Mix 30 g of sodium chloride with 1 kg of water evenly to obtain mixed solution 1;

[0061] (2) Add 0.1 g of sodium lactate, 0.5 g of β-cyclodextrin, and 0.5 g of chitosan to mixed solution 1, and stir to obtain mixed solution 2;

[0062] (3) Add 30 wt% NaOH aqueous solution to mixed solution 2, and adjust the pH value to 8.0 to obtain mixed solution 3;

[0063] (4) Put mixed solution 3 into the electrolytic cell of the hypochlorous acid reactor, and generate highly stable hypochlorous acid by electrolyzing the chlorinated salt solution.

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

[0065] Example 5

[0066] A method for preparing highly stable hypochlorous acid, comprising the following steps:

[0067] (1) Mix 30 g of sodium chloride with 1 kg of water evenly to obtain mixed solution 1;

[0068] (2) Add 0.1 g of sodium lactate to mixed solution 1, and stir to obtain mixed solution 2;

[0069] (3) Add 30 wt% NaOH aqueous solution to mixed solution 2, and adjust the pH value to 8.0 to obtain mixed solution 3;

[0070] (4) Put mixed solution 3 into the electrolytic cell of the hypochlorous acid reactor, and generate highly stable hypochlorous acid by electrolyzing the chlorinated salt solution.

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

[0072] Example 6

[0073] A method for preparing highly stable hypochlorous acid, comprising the following steps:

[0074] (1) Mix 30 g of sodium chloride with 1 kg of water evenly to obtain mixed solution 1;

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

[0076] (3) Add 30 wt% NaOH aqueous solution to the mixed solution 2, and adjust the pH value to 8.0 to obtain the mixed solution 3;

[0077] (4) Put the mixed solution 3 into the electrolytic cell of the hypochlorous acid reactor, and generate highly stable hypochlorous acid by electrolyzing the chloride salt solution.

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

[0079] The β-cyclodextrin / Span80 complex is prepared by the following method: dissolve 4 g of β-cyclodextrin in 30 g of 30 wt% NaOH aqueous solution, react at 1200 rpm and 25 °C for 30 min; slowly dropwise add 2 g of epichlorohydrin, finish dropping in 30 min, add 2 g of Span80 and react for 2 h; a mixture of 60 g of kerosene and 10 g of isooctane, react at 1800 rpm and 60 °C for 4 h; centrifuge at 2000 rpm to obtain the precipitate, wash with ethanol 3 times, and take the filter cake to dry at 60 °C for 4 h to obtain.

[0080] Example 7

[0081] A preparation method of highly stable hypochlorous acid, comprising the following steps:

[0082] (1) Mix 30 g of sodium chloride with 1 kg of water evenly to obtain the mixed solution 1;

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

[0084] (3) Add 30 wt% NaOH aqueous solution to the mixed solution 2, and adjust the pH value to 8.0 to obtain the mixed solution 3;

[0085] (4) Put the mixed solution 3 into the electrolytic cell of the hypochlorous acid reactor, and generate highly stable hypochlorous acid by electrolyzing the chloride salt solution.

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

[0087] The β-cyclodextrin / pentaerythritol complex is prepared by the following method: Dissolve 4 g of β-cyclodextrin in 30 g of 30 wt% aqueous NaOH solution, react at 1200 rpm and 25 °C for 30 min; slowly dropwise add 2 g of epichlorohydrin, finish dropping in 30 min, add 2 g of pentaerythritol and react for 2 h; add 60 g of N,N-dimethylformamide, react at 1800 rpm and 100 °C for 6 h; wash with 12 wt% hydrochloric acid and water three times each, take the filter cake, dry at 60 °C for 4 h to obtain.

[0088] Test Example 1

[0089] Evaluation of disinfectant stability: The highly stable hypochlorous acid prepared in Examples 1-7 was stored at 37 °C for 90 days according to the technical requirements of GB / T 38499-2020 "Method for Evaluating the Stability of Disinfectants", and the experimental results are shown in Table 1. The experimental results of storing at 55 °C for 14 days are shown in Table 2.

[0090] Precisely weigh 0.0500 g of the β-cyclodextrin complex sample, perform thermogravimetric analysis using TGA Q5000 (TA Instruments, USA), with a heating rate of 10 °C / min and a temperature range of 20-800 °C; record the temperatures at 10% and 50% weight loss as T 10 / °C and T 50 / °C, and the test results are shown in Table 3.

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

[0092]

[0093]

[0094] Through the comparison of Examples 1-7, it can be found that the decline rate of Example 1 is the lowest. The decline rates of Examples 1-7 being below 10% indicates that the storage time of the highly stable hypochlorous acid prepared by the electrolysis method can reach two years.

[0095] In Examples 2-7, the degradation rates of Examples 2-4 are relatively close, and the degradation rate of Example 5 is higher. The possible reason is that in Example 2, the stabilizer β-cyclodextrin was added. β-cyclodextrin can form an inclusion complex with hypochlorous acid, reducing its contact with light, heat, and oxygen in the external environment and lowering the decomposition rate of hypochlorous acid. In Example 3, the stabilizer chitosan was added. Chitosan molecules can adsorb on the surface of hypochlorous acid to form a protective film, reducing the decomposition rate of hypochlorous acid. The degradation rates of Examples 6 and 7 are relatively close to that of Example 1 because in Example 6, a β-cyclodextrin / Span80 complex was added. The β-cyclodextrin / Span80 complex retains the cavity structure of β-cyclodextrin, and Span80, as a surfactant, has a certain effect on improving the stability of hypochlorous acid. Span80 embedded in β-cyclodextrin further broadens the cavity of β-cyclodextrin. In Example 7, a β-cyclodextrin / pentaerythritol complex was added. The β-cyclodextrin / pentaerythritol complex is in a four-legged shape, and its special cavity structure reduces the decomposition rate of hypochlorous acid.

[0096] The degradation rate of Example 1 is the lowest. The possible reason is that a β-cyclodextrin / chitosan complex was 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 interactions, which may provide a stable microenvironment for hypochlorous acid, reducing direct contact with the external environment and thus lowering its decomposition rate. 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.

[0097] Table 2: Experimental results of storage at 55 °C for 14 days

[0098]

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

[0100]

[0101] By comparing Examples 1-7, it can be found that the degradation rate of Example 1 is 0.98%. The possible reason is that a β-cyclodextrin / chitosan complex was 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 interactions, which may provide a stable microenvironment for hypochlorous acid, reducing direct contact with the external environment and thus lowering its decomposition rate. From Table 3, it can be seen that the decomposition temperature of the β-cyclodextrin / chitosan complex at T 10 / °C is 297.2 °C, and the decomposition temperature at T 50 / °C is 589.1 °C. It has good thermal stability. Hypochlorous acid protected in the β-cyclodextrin / chitosan complex can be largely isolated from the influence of temperature, 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 / T 38502-2020 "Test Methods for Laboratory Bactericidal Effects of Disinfectants", the killing tests of the highly stable hypochlorous acid prepared in Examples 1-7 on Bacillus subtilis var. niger spores (ATCC 9372), Escherichia coli (8099), and Candida albicans (ATCC 10231) were carried out after storage at 37°C for 90 days. The experimental results are shown in Table 4, where KL is the logarithm of killing, and the larger the value, the better the effect. The samples were those of Examples 1-7 after storage at 37°C for 90 days.

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

[0105]

[0106] The experimental results showed that for the highly stable hypochlorous acid added with β-cyclodextrin / chitosan complex, β-cyclodextrin / Span80 complex, and β-cyclodextrin / pentaerythritol complex in Examples 1, 6, and 7 respectively, after storage at 37°C for 90 days, the logarithm of killing of the samples on Bacillus subtilis var. niger spores (ATCC 9372), Escherichia coli (8099), and Candida albicans (ATCC 10231) was greater than 5.0, indicating that the samples of Examples 1, 6, and 7 still had good bactericidal effects after stable storage for 2 years; for Examples 2-4 added with β-cyclodextrin, chitosan, β-cyclodextrin, and chitosan as stabilizers, after storage at 37°C for 90 days, the logarithm of killing of the samples on Bacillus subtilis var. niger spores (ATCC 9372), Escherichia coli (8099), and Candida albicans (ATCC 10231) was less than 5.0 and greater than 4.0, indicating that the bactericidal effects of the samples of Examples 4-5 decreased significantly after stable storage for 2 years; for Example 5 without adding β-cyclodextrin, chitosan, β-cyclodextrin, chitosan, and β-cyclodextrin / chitosan complex as stabilizers, after storage at 37°C for 90 days, the logarithm of killing of the samples on Bacillus subtilis var. niger spores (ATCC 9372), Escherichia coli (8099), and Candida albicans (ATCC 10231) was less than 4, indicating that the bactericidal effect of the sample of Example 5 was significantly poor after storage for 2 years.

Claims

1. A method for preparing high-stability hypochlorous acid, characterized in that: The following steps are involved: (1) uniformly mixing 1-100 parts of alkali metal chloride with 1000-2000 parts of water to obtain a mixed solution 1; (2) adding 0.1-1 parts of lactate and 0.1-10 parts of β-cyclodextrin / chitosan complex to the mixed solution 1, 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) electrolyzing the mixed solution 3 by a method of electrolyzing a chloride salt solution to obtain highly stable hypochlorous acid; 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 for 20-40min, and 1-4 parts of chitosan are added for reaction 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.

2. 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.

3. 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.

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

5. The method for preparing high-stability hypochlorous acid according to claim 1, characterized in that: The pH adjuster is any one of a NaOH aqueous solution and a KOH aqueous solution.

6. 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.

7. A high stability hypochlorous acid, characterized in that: The method is prepared by any one of claims 1 to 6.

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