Potassium hydroxide ethanol standard solution and preparation method thereof

Abstract

The potassium hydroxide ethanol standard solution comprises the following raw materials in parts by weight: 200-300 parts of a potassium hydroxide solution, 600-800 parts of ethanol and 3-5 parts of a protective solvent. According to the potassium hydroxide ethanol standard solution and the preparation method thereof, the stability of the standard solution can be improved, and the preservation time of the standard solution can be prolonged, so that the requirement of high-precision analysis can be met.

Description

Technical Field

[0001] The invention relates to the technical field of standard substance preparation, and in particular to a potassium hydroxide ethanol standard solution and a preparation method thereof. Background Art

[0002] Potassium hydroxide-ethanol titration solution is widely used in testing, but because ethanol will oxidize to aldehyde under alkaline conditions, the solution will turn yellow, which not only affects the accuracy of the test, but also produces invalid data, and limits the wide use of potassium hydroxide-ethanol titration solution. The usual solution is to prepare it for immediate use, but this method only treats the symptoms and not the root cause, and it cannot be implemented in many occasions, and it cannot be made into a standard substance product for sale. Summary of the invention

[0003] In view of this, the object of the present invention is to provide a potassium hydroxide ethanol standard solution and a preparation method thereof, which can improve the stability of the standard solution and extend the storage time of the standard solution to meet the requirements of high-precision analysis.

[0004] In order to achieve the above object, the present invention provides the following technical solutions:

[0005] A potassium hydroxide ethanol standard solution is characterized by comprising the following raw materials in parts by weight: 200-300 parts of potassium hydroxide solution, 600-800 parts of ethanol and 3-5 parts of protective solvent.

[0006] Preferably, the mass fraction of the potassium hydroxide solution is 54-57%, and the mass fraction of the ethanol solution is 95%.

[0007] A method for preparing a potassium hydroxide ethanol standard solution comprises the following steps:

[0008] S1: preparing protective solvent;

[0009] S2: Mix the potassium hydroxide solution and the ethanol solution with a mass fraction of 95% to obtain a potassium hydroxide ethanol mixed solution; prepare a potassium hydroxide ethanol standard titration solution according to GB / T601-2016 "Preparation of Standard Titration Solutions for Chemical Reagents";

[0010] S3: adding the protective solvent to the potassium hydroxide ethanol standard titration solution described in step S2, stirring evenly, filling into a glass ampoule, filling with nitrogen, and standing to obtain a potassium hydroxide ethanol standard solution.

[0011] Preferably, the preparation method of the protective solvent is:

[0012] S11: preparing chitosan cross-linking solution;

[0013] S12: Mix 25% potassium tripolyphosphate, ionic solution, α-tocopherol and anhydrous ethanol, add to the chitosan cross-linking solution obtained in step S11, stir for 50-60 minutes, ultrasonically treat for 5-8 minutes, and distill under reduced pressure to obtain a protective solvent.

[0014] Preferably, the weight ratio of the potassium tripolyphosphate, the ionic solution, α-tocopherol, anhydrous ethanol and the chitosan cross-linking solution is 1:1:1:2:2.

[0015] Preferably, the preparation method of the chitosan cross-linking solution is specifically as follows: chitosan, sorbitan monooleate, polyvinyl alcohol, acetic acid and 50% by mass of potassium citrate are mixed, and stirred at 35-40° C. for 1 hour to obtain the chitosan cross-linking solution.

[0016] Preferably, the weight ratio of chitosan, sorbitan monooleate, polyvinyl alcohol, acetic acid and sodium citrate is 1:1:1:1:2.

[0017] Preferably, the preparation method of the ionic solution is: 1-butyl-3-methylimidazole dihydrogen phosphate, 50% by mass sodium hydroxymethyl cellulose solution and 1,4-di-tert-butyl peroxyisopropylbenzene are mixed, and the mixture is stirred and reacted for 1-2 hours at a temperature of 25-30° C. under a nitrogen environment to obtain an ionic solution.

[0018] Preferably, the weight ratio of the 1-butyl-3-methylimidazole dihydrogen phosphate, the sodium hydroxymethyl cellulose solution and the 1,4-di-tert-butylperoxyisopropylbenzene is 2:4:3.

[0019] Preferably, in step S3, the stirring rate is 100-300 rpm, and the stirring time is 50-60 min.

[0020] The ionic cross-linked solution formed by chitosan can reduce the steric hindrance of the mixed solution with alpha-tocopherol, form a long chain of the mixture, increase the reactive sites and the activity of the active sites, thereby better adsorbing the alpha-tocopherol, and cooperate with the effect of strong hydrogen bonds to more stably embed the alpha-tocopherol active substance while maintaining the activity of the alpha-tocopherol, thereby achieving a long-acting sustained release effect, and after a protective liquid layer is formed on the surface of the solution through static treatment, the upper protective liquid layer can be removed with a dropper when in use, thereby increasing the stability of the standard solution. DETAILED DESCRIPTION

[0021] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present invention. In addition, it is specifically stated that the raw materials and equipment of the present invention can be obtained from commercial sources, and no longer listed one by one. Among them, the raw materials of the present invention can be obtained from commercial sources and are well known to those skilled in the art.

[0022] Embodiment 1:

[0023] A potassium hydroxide ethanol standard solution comprises the following raw materials in parts by weight: 200 parts of potassium hydroxide solution with a mass fraction of 54%, 600 parts of ethanol with a mass fraction of 95% and 3 parts of a protective solvent.

[0024] A method for preparing a potassium hydroxide ethanol standard solution comprises the following steps:

[0025] S1: Preparation of protective solvent:

[0026] S11: preparing a chitosan cross-linking solution: mixing chitosan, sorbitan monooleate, polyvinyl alcohol, acetic acid and 50% potassium citrate in a weight ratio of 1:1:1:1:2, and stirring at 35° C. for 1 h to obtain a chitosan cross-linking solution;

[0027] Preparation of ionic solution: 1-butyl-3-methylimidazole dihydrogen phosphate, 50% sodium hydroxymethyl cellulose solution and 1,4-di-tert-butyl peroxyisopropylbenzene are mixed in a weight ratio of 2:4:3, and stirred for reaction for 1-2 hours at a temperature of 25-30° C. under a nitrogen environment to obtain an ionic solution.

[0028] S12: Mix 25% by mass of potassium tripolyphosphate, ionic solution, α-tocopherol and anhydrous ethanol, and add the mixture to the chitosan cross-linking solution obtained in step S11, wherein the weight ratio of potassium tripolyphosphate, ionic solution, α-tocopherol, anhydrous ethanol and chitosan cross-linking solution is 1:1:1:2:2, stir for 50 minutes, perform ultrasonic treatment for 5 minutes, and perform vacuum distillation to obtain a protective solvent;

[0029] S2: Mix a potassium hydroxide solution and an ethanol solution with a mass fraction of 95% to obtain a potassium hydroxide-ethanol mixed solution; prepare a potassium hydroxide-ethanol standard titration solution according to GB / T 601-2016 "Preparation of Standard Titration Solutions for Chemical Reagents" (wherein, GB / T 601-2016 includes the preparation of a blank solution to facilitate accurate measurement and calibration during the preparation process, that is, take 50 ml of carbon dioxide-free water, add 2 drops of phenolphthalein indicator solution (10 g / L), and titrate with the prepared potassium hydroxide-ethanol solution until the solution turns pink to prepare a blank solution);

[0030] S3: adding the protective solvent to the potassium hydroxide ethanol standard titration solution described in step S2, stirring evenly, the stirring rate is 100 rpm, the stirring time is 50 min, filling into a glass ampoule, filling with nitrogen, and letting it stand.

[0031] Embodiment 2:

[0032] A potassium hydroxide ethanol standard solution comprises the following raw materials in parts by weight: 300 parts of a potassium hydroxide solution with a mass fraction of 57%, 800 parts of ethanol with a mass fraction of 95% and 5 parts of a protective solvent.

[0033] A method for preparing a potassium hydroxide ethanol standard solution comprises the following steps:

[0034] S1: Preparation of protective solvent:

[0035] S11: preparing a chitosan cross-linking solution: mixing chitosan, sorbitan monooleate, polyvinyl alcohol, acetic acid and 50% potassium citrate in a weight ratio of 1:1:1:1:2, and stirring at 40° C. for 1 h to obtain a chitosan cross-linking solution;

[0036] Preparation of ionic solution: 1-butyl-3-methylimidazole dihydrogen phosphate, 50% sodium hydroxymethyl cellulose solution and 1,4-di-tert-butyl peroxyisopropylbenzene are mixed in a weight ratio of 2:4:3, and stirred for reaction for 1-2 hours at a temperature of 25-30° C. under a nitrogen environment to obtain an ionic solution.

[0037] S12: Mix 25% by mass of potassium tripolyphosphate, ionic solution, α-tocopherol and anhydrous ethanol, and add the mixture to the chitosan cross-linking solution obtained in step S11, wherein the weight ratio of potassium tripolyphosphate, ionic solution, α-tocopherol, anhydrous ethanol and chitosan cross-linking solution is 1:1:1:2:2, stir for 60 minutes, perform ultrasonic treatment for 8 minutes, and perform vacuum distillation to obtain a protective solvent;

[0038] S2: Mix a potassium hydroxide solution and an ethanol solution with a mass fraction of 95% to obtain a potassium hydroxide mixed solution; prepare a potassium hydroxide ethanol standard titration solution according to GB / T 601-2016 "Preparation of Standard Titration Solutions for Chemical Reagents" (wherein, GB / T 601-2016 includes the preparation of a blank solution to facilitate accurate measurement and calibration during the preparation process, that is, take 50 ml of carbon dioxide-free water, add 2 drops of phenolphthalein indicator solution (10 g / L), and titrate with the prepared potassium hydroxide-ethanol solution until the solution turns pink to prepare a blank solution);

[0039] S3: adding the protective solvent to the potassium hydroxide ethanol standard titration solution described in step S2, stirring evenly, the stirring rate is 300 rpm, the stirring time is 60 min, filling into a glass ampoule, filling with nitrogen, and letting it stand.

[0040] Embodiment three:

[0041] A potassium hydroxide ethanol standard solution comprises the following raw materials in parts by weight: 250 parts of a potassium hydroxide solution with a mass fraction of 56%, 700 parts of ethanol with a mass fraction of 95% and 4 parts of a protective solvent.

[0042] A method for preparing a potassium hydroxide ethanol standard solution comprises the following steps:

[0043] S1: Preparation of protective solvent:

[0044] S11: preparing a chitosan cross-linking solution: mixing chitosan, sorbitan monooleate, polyvinyl alcohol, acetic acid and 50% potassium citrate in a weight ratio of 1:1:1:1:2, and stirring at 38° C. for 1 h to obtain a chitosan cross-linking solution;

[0045] Preparation of ionic solution: 1-butyl-3-methylimidazole dihydrogen phosphate, 50% sodium hydroxymethyl cellulose solution and 1,4-di-tert-butyl peroxyisopropylbenzene are mixed in a weight ratio of 2:4:3, and stirred for reaction for 1-2 hours at a temperature of 25-30° C. under a nitrogen environment to obtain an ionic solution.

[0046] S12: Mix 25% by mass of potassium tripolyphosphate, ionic solution, α-tocopherol and anhydrous ethanol, and add the mixture to the chitosan cross-linking solution obtained in step S11, wherein the weight ratio of potassium tripolyphosphate, ionic solution, α-tocopherol, anhydrous ethanol and chitosan cross-linking solution is 1:1:1:2:2, stir for 55 minutes, perform ultrasonic treatment for 6 minutes, and perform vacuum distillation to obtain a protective solvent;

[0047] S2: Mix a potassium hydroxide solution and an ethanol solution with a mass fraction of 95% to obtain a potassium hydroxide mixed solution; prepare a potassium hydroxide ethanol standard titration solution according to GB / T 601-2016 "Preparation of Standard Titration Solutions for Chemical Reagents" (wherein, GB / T 601-2016 includes the preparation of a blank solution to facilitate accurate measurement and calibration during the preparation process, that is, take 50 ml of carbon dioxide-free water, add 2 drops of phenolphthalein indicator solution (10 g / L), and titrate with the prepared potassium hydroxide-ethanol solution until the solution turns pink to prepare a blank solution);

[0048] S3: adding the protective solvent to the potassium hydroxide mixed solution described in step S2, stirring evenly, the stirring rate is 200 rpm, the stirring time is 55 min, filling into a glass ampoule, filling with nitrogen, and letting it stand.

[0049] Comparative Example 1:

[0050] The preparation process of Comparative Example 1 is basically the same as that of Example 1, except that no protective solvent is used, specifically:

[0051] A potassium hydroxide ethanol standard solution comprises the following raw materials in parts by weight: 200 parts of potassium hydroxide solution with a mass fraction of 54%, 600 parts of ethanol with a mass fraction of 95%, and 3 parts of a protective solvent.

[0052] A method for preparing a potassium hydroxide ethanol standard solution comprises the following steps: mixing a potassium hydroxide solution and an ethanol solution with a mass fraction of 95%, preparing a potassium hydroxide ethanol standard titration solution according to GB / T 601-2016 "Preparation of Chemical Reagent Standard Titration Solution" (GB / T 601-2016 includes the preparation of a blank solution, so as to facilitate accurate measurement and calibration during the preparation process, that is, taking 50 ml of carbon dioxide-free water, adding 2 drops of phenolphthalein indicator solution (10 g / L), and titrating with the prepared potassium hydroxide-ethanol solution until the solution is pink, so as to prepare a blank solution); stirring evenly, with a stirring rate of 100 revolutions / min and a stirring time of 50 minutes, filling in a glass ampoule bottle, filling with nitrogen, and standing.

[0053] The potassium hydroxide ethanol standard solutions (1 mol / L) obtained in Examples 1-3 and Comparative Example 1 were respectively subjected to stability monitoring for one year, with sampling and titration once a month.

[0054] The test results are shown in the following table.

[0055] Test data of Example 1

[0056]

[0057] Test data of Example 2

[0058]

[0059] Test data of Example 3

[0060]

[0061] Test data of comparative example 1:

[0062]

[0063]

[0064] It can be seen from the above table that the relative standard deviation of the concentration change of the standard solution obtained in Examples 1-3 is much smaller than that of the standard solution obtained in the comparative example, and the solution stability is also better.

[0065] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A potassium hydroxide ethanol standard solution, characterized in that The method comprises the following raw materials in parts by weight: 200-300 parts of potassium hydroxide solution, 600-800 parts of ethanol and 3-5 parts of protective solvent.

2. Potassium hydroxide ethanol standard solution as claimed in claim 1, characterized in that, The mass fraction of the potassium hydroxide solution is 54-57%, and the mass fraction of the ethanol solution is 95%.

3. A method for preparing a potassium hydroxide ethanol standard solution as claimed in claim 1, characterized in that: The following steps are involved: S1: preparing protective solvent; S2: Mix the potassium hydroxide solution and the ethanol solution with a mass fraction of 95% to obtain a potassium hydroxide ethanol mixed solution; prepare the potassium hydroxide ethanol standard titration solution according to GB / T 601-2016 "Preparation of Standard Titration Solutions for Chemical Reagents"; S3: adding the protective solvent to the potassium hydroxide ethanol standard titration solution described in step S2, stirring evenly, filling into a glass ampoule, filling with nitrogen, and standing to obtain a potassium hydroxide ethanol standard solution.

4. The preparation method of potassium hydroxide ethanol standard solution as claimed in claim 3, characterized in that, The preparation method of the protective solvent is: S11: preparing chitosan cross-linking solution; S12: Mix 25% potassium tripolyphosphate, ionic solution, α-tocopherol and anhydrous ethanol, add to the chitosan cross-linking solution obtained in step S11, stir for 50-60 minutes, ultrasonically treat for 5-8 minutes, and distill under reduced pressure to obtain a protective solvent.

5. The preparation method of potassium hydroxide ethanol standard solution as claimed in claim 4, characterized in that, The weight ratio of the potassium tripolyphosphate, the ion solution, alpha-tocopherol, anhydrous ethanol and the chitosan cross-linking solution is 1:1:1:2:

2.

6. The preparation method of potassium hydroxide ethanol standard solution as claimed in claim 5, characterized in that, The preparation method of the chitosan cross-linking solution is specifically as follows: chitosan, sorbitol monooleate, polyvinyl alcohol, acetic acid and 50% potassium citrate are mixed, and stirred at 35-40° C. for 1 hour to obtain the chitosan cross-linking solution.

7. The preparation method of potassium hydroxide ethanol standard solution as claimed in claim 6, characterized in that, The weight ratio of the chitosan, sorbitan monooleate, polyvinyl alcohol, acetic acid and sodium citrate is 1:1:1:1:

2.

8. The preparation method of potassium hydroxide ethanol standard solution as claimed in claim 4, characterized in that, The preparation method of the ionic solution is as follows: 1-butyl-3-methylimidazole dihydrogen phosphate, 50% sodium hydroxymethyl cellulose solution by mass and 1,4-di-tert-butyl peroxyisopropylbenzene are mixed, and the mixture is stirred and reacted for 1-2 hours at a temperature of 25-30° C. in a nitrogen environment to obtain the ionic solution.

9. The preparation method of potassium hydroxide ethanol standard solution as claimed in claim 8, characterized in that: The weight ratio of the 1-butyl-3-methylimidazole dihydrogen phosphate, the sodium hydroxymethyl cellulose solution and the 1,4-di-tert-butyl peroxyisopropylbenzene is 2:4:

3.

10. The method for preparing a potassium hydroxide ethanol standard solution as claimed in claim 3, wherein: In step S3, the stirring rate is 100-300 rpm, and the stirring time is 50-60 min.

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