Preparation method of oxalic acid guanidine hydrochloride

Abstract

The invention discloses a preparation method of guanidine oxalate hydrochloride, which comprises the following steps: step 1, uniformly stirring oxalic acid and guanidine hydrochloride, heating and melting; the heating temperature is controlled to be 120-135 DEG C; adding a catalyst and a molecular weight regulator, heating, and stirring at constant temperature until no cooling water is generated in a return pipe; 2, carrying out water separation treatment in the whole reaction process; keeping the temperature for half an hour when no water is generated in the reaction, carefully pouring the reaction liquid into a beaker while the beaker is hot, and putting the beaker into a ventilation cabinet for next-step neutralization reaction; according to the polyoxalic acid-based guanidine hydrochloride, the structure of a guanidine disinfectant is improved, an electron withdrawing group acyl is introduced, and due to the existence of ortho-position electron withdrawing guanidyl, an electron cloud of the guanidyl shifts to the acyl, so that the guanidyl originally shows positive charges, and the positive charges of the guanidyl are more changed and are increased due to charge transfer.

Description

Technical Field

[0001] The invention belongs to the technical field of preparation of guanidine-based polymers, and particularly relates to a method for preparing oxalylguanidine hydrochloride. Background Art

[0002] Although there are many types of sterilization products on the market, their sterilization mechanisms, sterilization ranges, and sterilization effects are also different. For example, although quaternary ammonium salts, iodine, peroxides, and metal ions have good sterilization effects, they have large toxic side effects or are highly irritating. Substituted benzene sterilizers have a small range; ethanol imidazole sterilization time is short and inconvenient to use; so a highly efficient, long-lasting, and non-toxic sterilizer is needed. Guanidine polymers contain guanidine groups in their structural formulas. Guanidine compounds are positively charged, so they are easily adsorbed by various bacteria and pathogens that are usually electronegative. This inhibits bacterial division and makes them lose their reproductive ability. In addition, the film formed by the polymer sterilizer blocks the respiratory tract of microorganisms, causing them to suffocate and die quickly, so it has high physical method characteristic sterilization. Summary of the invention

[0003] The technical problem to be solved by the present invention is to overcome the existing defects and provide a method for preparing oxalylguanidine hydrochloride to solve the problems raised in the above background technology.

[0004] To achieve the above object, the present invention provides the following technical solution: a method for preparing oxalylguanidine hydrochloride, comprising the following steps:

[0005] Step 1, stir oxalic acid and guanidine hydrochloride evenly, heat and melt; control the heating temperature at 120°C to 135°C; add a catalyst and a molecular weight regulator, heat and stir at a constant temperature until no cooling water is produced in the reflux pipe;

[0006] Step 2: The whole reaction process is carried out in water separation; if no water is produced during the reaction, keep the temperature for half an hour, carefully pour the reaction solution into a beaker while it is still hot, put it into a fume hood, and carry out the next step of neutralization reaction;

[0007] Step 3: Take an appropriate amount of the above white solid gel product, weigh an appropriate number of grams according to the amount of disinfectant, put it into a beaker, use hydrochloric acid to adjust the pH value, start to drip it slightly quickly, when the pH reaches close to 3, slowly add hydrochloric acid, and when the pH is close to 5, use a micro sampler to add hydrochloric acid;

[0008] Step 4: Stir evenly when pH reaches 5, let it stand for half an hour, and observe the pH change; if the pH changes, continue to adjust the pH to 5.5 with hydrochloric acid; when adjusting the pH, the disinfectant must be kept acidic; if it is alkaline, the positive charge on the guanidine group of the disinfectant's bactericidal group is neutralized by the base; then the guanidine disinfectant will have no disinfecting effect.

[0009] Preferably, the molar ratio of oxalic acid:guanidine hydrochloride catalyst and molecular weight regulator is: 1:1:0.01:0.02-0.06.

[0010] Preferably, the catalyst is methanesulfonic acid, concentrated sulfuric acid, or phosphoric acid.

[0011] Preferably, the molecular weight regulator is mercaptopropionic acid or isooctyl 3-mercaptopropionate.

[0012] Compared with the prior art, the present invention provides a method for preparing oxalylguanidine hydrochloride, which has the following beneficial effects:

[0013] 1. The polyoxalic acid-based guanidine hydrochloride of the present invention improves the structure of guanidine disinfectants and introduces an electron-withdrawing acyl group. Because of the presence of the adjacent electron-withdrawing guanidine group, the electron cloud of the guanidine group is shifted toward the acyl group. Therefore, the original positive charge of the guanidine group is positive. Because of the charge transfer, the positive charge of the guanidine group becomes more positive and the charge increases. Refer to CN105315459.A, a method for preparing polyoxalic acid-based guanidine hydrochloride, and CN201911059343.4, a method for preparing malonic acid-based guanidine hydrochloride. The present invention further improves the structure of the previous research. Under the premise of using malonic acid to replace adipic acid, the present invention will use acetic acid instead of propionic acid to carry forward the research results of the predecessors, so that the charge of the polymer guanidine group contained in the polymer is positive, and the bactericidal ability is better than that of the original patent. And all guanidine polymers with more positive charges have greatly improved the killing effect on bacteria and microorganisms.

[0014] 2. The polyoxaloguanidine hydrochloride of the present invention improves the structure of the polyguanidine disinfectant by introducing an electron-withdrawing acyl group into the polymer long chain; electron-withdrawing acyl groups are added on both sides of the guanidine group of the polymer long chain, because acyl groups have the ability to withdraw electrons chemically, and the guanidine group has electron-withdrawing acyl groups on both sides, so that the electron cloud of the guanidine group shifts to the acyl groups on both sides, and the electron cloud density of the guanidine group after the electron shift is reduced, resulting in more positive charges on the guanidine group; the polyguanidine disinfectant uses the principle that the guanidine group carries an electric charge to inhibit bacteria and viruses to death to achieve sterilization. effect; using oxalic acid and a preparation method of polymalonic acid guanidine hydrochloride (application number CN209191059343.4) the molecular weight of polyoxalic acid guanidine hydrochloride is smaller than that of polymalonic acid, and the guanidine group contained in oxalic acid guanidine hydrochloride of the same quality guanidine fungicide hydrochloride is relatively more than the guanidine group content of malonic acid guanidine hydrochloride, so the bactericidal effect is much better; this point has been fully confirmed by the Oxford cup experiment on Escherichia coli and Aspergillus flavus in the laboratory by the research group of this patent. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0016] Figure 1 Schematic diagram of the structure of polyoxaloguanidine hydrochloride;

[0017] Figure 2 Schematic diagram of the structure of polymalonate guanidine hydrochloride. DETAILED DESCRIPTION

[0018] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0019] See also Figure 1-2 The present invention provides a technical solution: a method for preparing oxalylguanidine hydrochloride, comprising the following steps:

[0020] Step 1, stir oxalic acid and guanidine hydrochloride evenly, heat and melt; control the heating temperature at 120°C to 135°C; add a catalyst and a molecular weight regulator, heat and stir at a constant temperature until no cooling water is produced in the reflux pipe;

[0021] Step 2: The whole reaction process is carried out in water separation; if no water is produced during the reaction, keep the temperature for half an hour, carefully pour the reaction solution into a beaker while it is still hot, put it into a fume hood, and carry out the next step of neutralization reaction;

[0022] Step 3: Take an appropriate amount of the above white solid gel product, weigh an appropriate number of grams according to the amount of disinfectant, put it into a beaker, use hydrochloric acid to adjust the pH value, start to drip it slightly quickly, when the pH reaches close to 3, slowly add hydrochloric acid, and when the pH is close to 5, use a micro sampler to add hydrochloric acid;

[0023] Step 4: Stir evenly when pH reaches 5, let it stand for half an hour, and observe the pH change; if the pH changes, continue to adjust the pH to 5.5 with hydrochloric acid; when adjusting the pH, the disinfectant must be kept acidic; if it is alkaline, the positive charge on the guanidine group of the disinfectant's bactericidal group is neutralized by the base; then the guanidine disinfectant will have no disinfecting effect.

[0024] In the present invention, preferably, the molar ratio of oxalic acid:guanidine hydrochloride catalyst and molecular weight regulator is: 1:1:0.01:0.02-0.06.

[0025] In the present invention, preferably, the catalyst is methanesulfonic acid, concentrated sulfuric acid, or phosphoric acid.

[0026] In the present invention, preferably, the molecular weight regulator is mercaptopropionic acid or isooctyl 3-mercaptopropionate.

[0027] Embodiment 1

[0028] A preparation method of oxalylguanidine hydrochloride comprises the following steps: adding 90.03 g of acetic acid and 95.53 g of guanidine hydrochloride to a three-necked bottle (500 mL) equipped with a thermometer, a water separator and a mechanical stirring device, heating to 78°C, starting to melt, stirring, and starting to add 1.06 g of mercaptopropionic acid as a molecular weight regulator and 0.96 g of methanesulfonic acid as a catalyst after melting; gradually heating to 120°C after loading the reaction raw materials, and water starts to appear in the water separator as the reaction proceeds; reacting for about three hours, after the water output of the water separator decreases, stopping heating, gradually cooling, preparing a 500 mL beaker, and when the temperature drops to 80°C, pouring the synthesized disinfectant into the beaker, putting it in a ventilated kitchen, and cooling it, the yield is 95%. Using edible hydrochloric acid to adjust the pH value, adding it appropriately quickly at the beginning of the adjustment, slowly adding hydrochloric acid when the pH is close to about 7, stirring for a period of time and leaving it for half an hour when the pH is about 5; slowly adding hydrochloric acid if the pH is stable and the pH is unchanged after detecting the pH. Stop until pH = 5. Calculate the concentration of the disinfectant to obtain a concentrated solution of oxaloguanidine hydrochloride. When using the disinfectant, adjust the concentration of the disinfectant as needed.

[0029] Embodiment 2

[0030] A method for preparing oxalic acid guanidine hydrochloride, wherein 90.3 grams of oxalic acid, 95.5 grams of guanidine hydrochloride, and 2.0 grams of ethyl mercaptopropionate are added to a four-necked bottle equipped with a thermometer, a water separator, a stirrer, and a condenser. The material begins to melt when heated to about 80°C, and the temperature is slowly raised to 120°C for constant temperature reaction for three hours. When the temperature starts to rise, water will appear in the water separator; as the reaction proceeds, the amount of water in the water separator gradually decreases after about two hours of reaction. When there is basically no water generated in the water separator, the temperature is slowly lowered to 80°C, a 1000 mL large beaker is prepared, and the polyoxalic acid guanidine synthesis product is sealed in the beaker. The yield is 98%. When disinfectant is needed, weigh a certain amount of polyoxaloguanidine, add it to a beaker, and use hydrochloric acid to adjust the pH. Start adding hydrochloric acid slowly. When the pH reaches about 7, be more careful to add hydrochloric acid, because pH has a great influence on polyguanidine disinfectant. When the pH value is close to 6, stop adding it temporarily, stir for half an hour, and check the pH value. If the pH value is equal to 5 and remains stable, it can be used. Guanidine group b must be in acidic conditions to have a positive charge of guanidine group. If it is in alkaline conditions, there will be no bactericidal effect.

[0031] Embodiment 3

[0032] A preparation method of oxalylguanidine hydrochloride, wherein 90.3 grams of oxalic acid, 95.5 grams of guanidine hydrochloride, 1.0 grams of ethyl mercaptopropionate and 0.5 grams of mercaptopropionic acid are added to a four-necked bottle equipped with a thermometer, a water separator, a stirrer and a condenser. The material begins to melt when heated to about 80°C, and the temperature is slowly raised to 120°C for constant temperature reaction for three hours. When the temperature starts to rise, water will appear in the water separator; as the reaction proceeds, the amount of water in the water separator gradually decreases after about two hours of reaction. When there is basically no water generated in the water separator, the temperature is slowly lowered to 80°C, and a 1000 mL large beaker is prepared to obtain a milky white waxy polyoxalylguanidine with a yield of 98%. The polyoxalylguanidine synthesis product is sealed in a beaker. When disinfectant is needed, weigh a certain amount of polyoxaloguanidine, add it to a beaker, and use hydrochloric acid to adjust the pH. Start adding hydrochloric acid slowly. When the pH reaches about 7, be more careful to add hydrochloric acid, because pH has a great influence on polyguanidine disinfectant. When the pH value is close to 6, stop adding it temporarily, stir for half an hour, and check the pH value. If the pH value is equal to 5 and remains stable, it can be used. According to chemical knowledge, guanidine must be in acidic conditions to have a positive charge of guanidine. If it is in alkaline conditions, there will be no bactericidal effect.

[0033] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing oxalylguanidine hydrochloride, characterized in that: The following steps are involved: Step 1, stir oxalic acid and guanidine hydrochloride evenly, heat and melt; control the heating temperature at 120°C to 135°C; add a catalyst and a molecular weight regulator, heat and stir at a constant temperature until no cooling water is produced in the reflux pipe; Step 2: The whole reaction process is carried out in water separation; if no water is produced during the reaction, keep the temperature for half an hour, carefully pour the reaction solution into a beaker while it is still hot, put it into a fume hood, and carry out the next step of neutralization reaction; Step 3: Take an appropriate amount of the above white solid gel product, weigh an appropriate number of grams according to the amount of disinfectant, put it into a beaker, use hydrochloric acid to adjust the pH value, start to drip it slightly quickly, when the pH reaches close to 3, slowly add hydrochloric acid, and when the pH is close to 5, use a micro sampler to add hydrochloric acid; Step 4: Stir evenly when pH reaches 5, let it stand for half an hour, and observe the pH change; if the pH changes, continue to adjust the pH to 5.5 with hydrochloric acid; when adjusting the pH, the disinfectant must be kept acidic; if it is alkaline, the positive charge on the guanidine group of the disinfectant's bactericidal group is neutralized by the base; then the guanidine disinfectant will have no disinfecting effect.

2. A method for preparing oxalylguanidine hydrochloride according to claim 1, characterized in that: The molar ratio of oxalic acid:guanidine hydrochloride catalyst and molecular weight regulator is: 1:1:0.01:0.02-0.

06.

3. A method for preparing oxalylguanidine hydrochloride according to claim 1, characterized in that: The catalysts are methanesulfonic acid, concentrated sulfuric acid, and phosphoric acid.

4. A method for preparing oxalylguanidine hydrochloride according to claim 1, characterized in that: The molecular weight regulator is mercaptopropionic acid or isooctyl 3-mercaptopropionate.

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