Method for testing water content of organic peroxides and use thereof

Abstract

The present application relates to a kind of organic peroxide water content testing method and its application, the testing method includes: organic peroxide sample and reducing agent are mixed to obtain reactant;Test the water content of the reactant and the water content of reducing agent, calculate the water content of the organic peroxide sample;The organic peroxide includes any one or the combination of two in benzoyl peroxide or cumene hydroperoxide;The reducing agent includes sulfide compound.The organic peroxide water content testing method provided by the present application introduces sulfide compound as reducing agent, which can effectively avoid the deviation caused by the reaction of organic peroxide with Karl Fischer reagent during water content test, realize the high-precision, high-accuracy water content determination, and the testing method is simple to operate, with high practical value.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of analytical detection technology, and in particular to a test method for water content of organic peroxide and application thereof. BACKGROUND

[0002] Karl Fischer titration is a widely used moisture determination technique in analytical chemistry, known for its high precision and reliability. The core principle of this method is based on the quantitative chemical reaction between iodine and water: in anhydrous solvent, sulfur dioxide, iodine, and water react quantitatively to produce hydrogen iodide and sulfuric acid. Karl Fischer reagent is usually composed of iodine, sulfur dioxide, and an organic base such as pyridine or imidazole, dissolved in a suitable solvent such as methanol. When the reagent comes into contact with the moisture in the sample, a quantitative reaction occurs, and the amount of iodine consumed is directly proportional to the moisture content. By measuring the consumption of iodine through potentiometric or coulometric titration, the moisture content in the sample can be accurately calculated. Due to its high precision, ease of operation, and good result stability, Karl Fischer method is widely used in quality control and research and development in pharmaceutical, food, chemical, and other industries.

[0003] However, the existing conventional Karl Fischer technique cannot directly determine the water content of organic peroxide, as organic peroxide will oxidize iodine ions in the Karl Fischer system to elemental iodine, interfering with the titration process. In the patent "Method for measuring trace water content in cumene hydroperoxide solution" (CN115356430A), the peroxide concentration is first determined, and then the peroxide in the system is removed by using triphenylphosphine for accurate quantitative reduction before water content determination. Although this method has good parallelism, the operation steps are relatively complicated. Moreover, because triphenylphosphine will rapidly react with elemental iodine to form iodine triphenylphosphine, a slight excess of triphenylphosphine will affect the accuracy of the results, making the experiment difficult. In the patent "Method for determining water content in oxides" (CN112505242B), a low-temperature Karl Fischer moisture meter is designed, which effectively suppresses the oxidation-reduction reaction between peroxide and iodine ions by reducing the temperature of the reaction system, improving the accuracy of the end point. The recovery rate of this method is between 95.0-102.4%, and the method is feasible, but low temperature only reduces the rate of peroxide and iodine ion reaction, and does not fundamentally eliminate the problem. Moreover, low temperature will also lead to a decrease in the rate of Karl Fischer reaction and the sensitivity of the electrode, and the cooling process will also prolong the pre-equilibrium time. Additionally, the additional cooling device will increase the cost of equipment and the difficulty of operation.

[0004] Therefore, it is necessary to develop a test method for the water content of organic peroxide to improve the precision and accuracy of the detection, and to better apply it to daily detection. SUMMARY

[0005] To solve the above technical problems, the application provides a test method for water content of organic peroxide and application thereof. The test method for water content of organic peroxide provided by the application introduces a sulfide compound as a reducing agent, which can effectively avoid the deviation caused by the reaction of the organic peroxide with Karl Fischer reagent during the water content test, realize the high-precision and high-accuracy water content test, and has high practical value due to simple operation.

[0006] To achieve the above purpose, the application adopts the following technical solutions:

[0007] In the first aspect, the application provides a test method for water content of organic peroxide, which comprises the following steps:

[0008] The organic peroxide sample and the reducing agent are mixed and reacted to obtain a reaction product; the water content c2 of the reaction product and the water content c1 of the reducing agent are tested to obtain the water content c of the organic peroxide sample, and the calculation formula is as follows:

[0009]

[0010] wherein m1 is the mass of the reducing agent, and m is the mass of the organic peroxide sample.

[0011] The organic peroxide comprises any one or a combination of benzoyl peroxide or cumene hydroperoxide.

[0012] The reducing agent comprises a sulfide compound.

[0013] The organic peroxide can react with iodine in the Karl Fischer system, so it cannot be directly tested for water content. The application introduces a sulfide compound as a reducing agent, which is fully reduced to the peroxide before the water content test. This method effectively avoids the influence of peroxide on the water content test, and the selected reducing agent itself and the generated substances will not react with Karl Fischer reagent, thereby ensuring the precision and accuracy of the test results. At the same time, the test method provided by the application is simple in operation, low in cost, and can meet the daily detection requirements, and has high practicability.

[0014] Preferably, the sulfide compound comprises any one or a combination of at least two of methylthioacetate, methyl phenyl sulfide, bis(4-hydroxy-3-methylphenyl) sulfide, 4-methoxy anise sulfide, 3,3'-thiodipropionic acid dimethyl ester, or 1-methylthio-2-propanone.

[0015] Preferably, the sulfide compound comprises any one or a combination of at least two of methyl phenyl sulfide, 4-methoxy anise sulfide, or 3,3'-thiodipropionic acid dimethyl ester.

[0016] In the present application, when methyl phenyl sulfide, 4-methoxy anise sulfide or 3,3'-thiodipropionic acid dimethyl ester is selected, not only the precision and accuracy of the test can be improved, but also the efficiency of the detection is significantly improved due to the shorter required reaction time, and the practicality is stronger.

[0017] Preferably, the organic peroxide sample is an organic peroxide or a solution of the organic peroxide dissolved in a solvent.

[0018] Preferably, the solvent comprises any one or a combination of at least two of butyl acetate, acetonitrile, ethanol or N,N-dimethylformamide.

[0019] Preferably, the molar ratio of the organic peroxide in the organic peroxide sample to the reducing agent is 1:(1.1-1.5) (for example, it can be 1:1.1, 1:1.2, 1:1.3, 1:1.4, 1:1.5, etc.).

[0020] In the present application, it is not necessary to strictly control the amount of the reducing agent, and the detection effect of the present application can be achieved when the reducing agent is excessive relative to the organic peroxide.

[0021] Preferably, the temperature of the reaction is 20-80℃ (for example, it can be 20℃, 30℃, 40℃, 50℃, 60℃, 70℃, 80℃, etc.), and the time of the reaction is 5-60min (for example, it can be 5min, 10min, 20min, 30min, 40min, 50min, 60min, etc.).

[0022] Preferably, the temperature of the reaction is 50-60℃, and the time of the reaction is 8-15min.

[0023] In the present application, when the reaction temperature is too low, the reaction speed is too slow, and in the preferred reaction temperature range of the present application, the reaction time can be significantly shortened, and the reaction efficiency is improved.

[0024] Preferably, the water content is tested by Karl Fischer volumetry.

[0025] Preferably, the test method comprises:

[0026] The organic peroxide sample and the reducing agent are mixed and reacted at 20-80℃ for 5-60min to obtain a reaction product; the water content c2 of the reaction product and the water content c1 of the reducing agent are tested to obtain the water content c of the organic peroxide sample, and the calculation formula is as follows:

[0027]

[0028] Wherein, m1 is the mass of the reducing agent, and m is the mass of the organic peroxide sample.

[0029] The organic peroxide includes any one or a combination of benzoyl peroxide or cumene hydroperoxide;

[0030] The reducing agent includes a sulfide compound;

[0031] The molar ratio of the organic peroxide and the reducing agent in the organic peroxide sample is 1:(1.1-1.5).

[0032] In a second aspect, the present application provides an application of the test method for the water content of the organic peroxide according to the first aspect in the development, production and detection of the organic peroxide.

[0033] Compared with the prior art, the present application has at least the following beneficial effects:

[0034] The test method for the water content of the organic peroxide provided by the present application introduces a sulfide compound as a reducing agent, which can effectively avoid the deviation caused by the reaction of the organic peroxide with Karl Fischer reagent during the water content test, realizes the high-precision and high-accuracy determination of the water content, and has high practical value. BRIEF DESCRIPTION OF DRAWINGS

[0035] Figure 1 LC-MS spectrum in Example 1. DETAILED DESCRIPTION

[0036] The technical solutions of the present application will be further described below by combining the drawings and through specific embodiments. However, the following examples are only simple examples of the present application, and do not represent or limit the protection scope of the present application, and the protection scope of the present application is subject to the claims.

[0037] Example 1

[0038] The present embodiment provides a test method for the water content of an organic peroxide, which comprises:

[0039] 30 g (all accurate to 0.0001 g below) of an organic peroxide (benzoyl peroxide) and 80 mL of butyl acetate are mixed and dissolved to obtain an organic peroxide sample; 1.5 g of the organic peroxide sample and 0.38 g of a reducing agent (3,3'-thiodipropionic acid dimethyl ester) are placed in a sealed tube (the molar ratio of the organic peroxide and the reducing agent is 1:1.1), mixed, reacted at 55℃ for 10 min, cooled to 25℃, and then the water content c2 of the reaction solution is tested by Karl Fischer volumetry, and the water content c1 of the reducing agent is also tested, to obtain the water content c of the organic peroxide sample, and the calculation formula is as follows:

[0040]

[0041] Wherein, m1 is the mass of the reducing agent, and m is the mass of the organic peroxide sample.

[0042] The LC-MS spectrum in Example 1 is shown in Figure 1, from top to bottom in turn are the organic peroxide sample, 3,3'-thiobispropionic acid dimethyl ester standard and the mixed solution after reaction, it can be seen that the organic peroxide has been fully reacted. Figure 1

[0043] Example 2

[0044] The present example provides a test method for the water content of an organic peroxide, which comprises:

[0045] An organic peroxide (benzoyl peroxide) 30 g (all accurate to 0.0001 g below) and acetonitrile 80 mL are mixed and dissolved to obtain an organic peroxide sample; 1.5 g of the organic peroxide sample and 0.31 g of a reducing agent (methyl phenyl sulfide) are placed in a sealed tube (the molar ratio of the organic peroxide to the reducing agent is 1:1.5, mixed, reacted at 50°C for 15 min, cooled to 25°C, and then Karl Fischer volumetric method is used to test the water content c2 of the reaction solution, and the water content c1 of the reducing agent is also tested, to obtain the water content c of the organic peroxide sample, and the calculation formula is as follows:

[0046]

[0047] Wherein, m1 is the mass of the reducing agent, and m is the mass of the organic peroxide sample.

[0048] Example 3

[0049] The present example provides a test method for the water content of an organic peroxide, which comprises:

[0050] An organic peroxide (cumene hydroperoxide) 30 g (all accurate to 0.0001 g below) and ethanol 80 mL are mixed and dissolved to obtain an organic peroxide sample; 1.5 g of the organic peroxide sample and 0.58 g of a reducing agent (4-methoxy anisyl sulfide) are placed in a sealed tube (the molar ratio of the organic peroxide to the reducing agent is 1:1.4, mixed, reacted at 60°C for 8 min, cooled to 25°C, and then Karl Fischer volumetric method is used to test the water content c2 of the reaction solution, and the water content c1 of the reducing agent is also tested, to obtain the water content c of the organic peroxide sample, and the calculation formula is as follows:

[0051]

[0052] Wherein, m1 is the mass of the reducing agent, and m is the mass of the organic peroxide sample.

[0053] Example 4

[0054] ​The embodiment provides a test method of water content of an organic peroxide, and the test method comprises the following steps:

[0055] An organic peroxide (benzoyl peroxide) 30 g (all accurate to 0.0001 g) and N,N-dimethylformamide 80 mL are mixed and dissolved to obtain an organic peroxide sample; 1.5 g of the organic peroxide sample and 0.42 g of a reducing agent (3,3'-thiodipropionic acid dimethyl ester) are placed in a sealed tube (the molar ratio of the organic peroxide to the reducing agent is 1:1.2), mixed, and reacted at 60 DEG C for 8 min; after being cooled to 25 DEG C, Karl Fischer volumetry is used to test the water content c2 of the reaction solution, and the water content c1 of the reducing agent is tested at the same time, so that the water content c of the organic peroxide sample is obtained, and the calculation formula is as follows:

[0056]

[0057] Wherein, m1 is the mass of the reducing agent, and m is the mass of the organic peroxide sample.

[0058] Example 5

[0059] The embodiment provides a test method of water content of an organic peroxide, and the test method comprises the following steps:

[0060] 1.0 g (all accurate to 0.0001 g) of an organic peroxide sample (cumene hydroperoxide) and 1.2 g of a reducing agent (methyl phenyl sulfide) are placed in a sealed tube (the molar ratio of the organic peroxide to the reducing agent is 1:1.5), mixed, and reacted at 45 DEG C for 25 min; after being cooled to 25 DEG C, Karl Fischer volumetry is used to test the water content c2 of the reaction solution, and the water content c1 of the reducing agent is tested at the same time, so that the water content c of the organic peroxide sample is obtained, and the calculation formula is as follows:

[0061]

[0062] Wherein, m1 is the mass of the reducing agent, and m is the mass of the organic peroxide sample.

[0063] Example 6

[0064] The embodiment provides a test method of water content of an organic peroxide, and the difference between the test method and the embodiment 1 is that the organic peroxide sample and the reducing agent are mixed and reacted at 40 DEG C for 10 min, and other operations refer to the embodiment 1.

[0065] Example 7

[0066] The embodiment provides a test method of water content of an organic peroxide, and the difference between the test method and the embodiment 1 is that the reducing agent is replaced by bis (4-hydroxy-3-methyl phenyl) sulfide, and the reaction is carried out at 60 DEG C for 10 min, and other operations refer to the embodiment 1.

[0067] Example 8

[0068] The present example provides a test method for water content of organic peroxide, which is only different from Example 1 in that the reducing agent is replaced by methylthioacetate methyl ester, and the reaction is carried out at 60°C for 10 min, and the other operations refer to Example 1.

[0069] Example 9

[0070] The present example provides a test method for water content of organic peroxide, which is only different from Example 1 in that the reducing agent is replaced by 1-methylthio-2-propanone, and the titrant is replaced by Karl Fischer aldehyde ketone reagent, and the other operations refer to Example 1.

[0071] Comparative Example 1

[0072] The present comparative example provides a test method for water content of organic peroxide, which is only different from Example 1 in that the reducing agent is replaced by stannous chloride dihydrate, and the other operations refer to Example 1.

[0073] Comparative Example 2

[0074] The present comparative example provides a test method for water content of organic peroxide, which is only different from Example 1 in that the reducing agent is replaced by triphenylphosphine, and the other operations refer to Example 1.

[0075] Comparative Example 3

[0076] The present comparative example provides a test method for water content of organic peroxide, which comprises:

[0077] The organic peroxide (benzoyl peroxide) 30 g (all accurate to 0.0001 g below) and butyl acetate 80 mL are mixed and dissolved to obtain an organic peroxide sample; 1.5 g of the organic peroxide sample is directly tested for water content by Karl Fischer volumetric method.

[0078] Comparative Example 4

[0079] The present example provides a test method for water content of organic peroxide, which is only different from Example 1 in that the reducing agent is replaced by 3,3'-dimethylthiopropionate, and the reaction is carried out at 60°C for 60 min, and the other operations refer to Example 1.

[0080] Test Example 1

[0081] Precision test

[0082] The water content of the organic peroxide sample is determined by the test method provided in the above examples and comparative examples, and the results are shown in Table 1.

[0083] Table 1

[0084] Group Number of determinations Average water content (%) RSD (%) Example 1 6 0.549 1.030 Example 2 6 0.587 1.124 Example 3 6 0.734 1.057 Example 4 6 0.659 1.349 Example 5 6 0.084 2.517 Example 6 6 0.059 7.124 Example 7 6 0.102 6.792 Example 8 6 0.541 1.218 Example 9 6 0.401 2.974 Comparative Example 1 6 - - Comparative Example 2 6 - - Comparative Example 3 6 - - Comparative Example 4 6 - -

[0085] Test Example 2

[0086] Accuracy test

[0087] The test method provided by the above examples and comparative examples was used to determine the recovery rate of a known water content of a benzoyl peroxide acetonitrile solution. The test method was as follows: 9 parts of a benzoyl peroxide acetonitrile solution with a water content of 0.547% were taken, different known amounts of water were added, and then the water content of the sample after the addition of water was tested, the recovery rate of the addition of standard was calculated, the average value was calculated, the RSD was calculated, and the results are shown in Table 2.

[0088] Table 2

[0089] Group Number of determinations Average recovery (%) RSD (%) Example 1 9 100.63 1.97 Example 2 9 102.34 2.34 Example 3 9 99.09 2.10 Example 4 9 102.05 2.49 Example 5 9 98.37 2.24 Example 6 9 - - Example 7 9 - - Example 8 9 101.81 2.28 Example 9 9 96.15 3.67 Comparative Example 1 9 - - Comparative Example 2 9 - - Comparative Example 3 9 - - Comparative Example 4 9 - -

[0090] From the test results of Table 1 and Table 2, it can be seen that:

[0091] (1) As can be seen from Examples 1 to 9, the thioether compound is used as a reducing agent for the organic peroxide in the present application. The reactants and products in the reaction process do not react with iodine in the Karl Fischer reagent, avoiding the deviation caused by the oxidation of iodine ions by the organic peroxide, and higher precision and accuracy can be achieved in the preferred scheme.

[0092] (2) As can be seen from the comparison of Example 1 and Example 6, when the reaction temperature is low and the reaction time is short, the organic peroxide does not react completely, and the titration phenomenon occurs, the precision decreases, and the accuracy test cannot be performed.

[0093] As can be seen from the comparison of Example 1 and Example 7, when bis(4-hydroxy-3-methylphenyl) sulfide is used as a reducing agent, the reaction speed of the organic peroxide is slower, and because bis(4-hydroxy-3-methylphenyl) sulfide is a solid, the system after the reaction is biphasic, the precision of the water content test decreases, and the accuracy test cannot be performed.

[0094] As can be seen from the comparison of Example 1 and Example 8, when methyl thioacetate is used as a reducing agent, the effect is similar to that of 3,3'-thiodipropionic acid dimethyl ester.

[0095] As can be seen from the comparison of Example 1 and Example 9, when 1-methylthio-2-propanone is used as a reducing agent, the carbonyl group present therein is easy to react with methanol in the Karl Fischer reagent, making it difficult to reach the titration endpoint for the water content test, and a special Karl Fischer titrant for aldehydes and ketones needs to be selected for the test, but the test precision and accuracy decrease compared with Examples 1-5.

[0096] (3) By comparing Example 1 with Comparative Example 1-3, it can be seen that when using stannous chloride dihydrate, triphenylphosphine as a reducing agent or directly determining the water content of the organic peroxide sample, the results are high and affect the end point determination because the above-mentioned substances will react with iodine in the Karl Fischer reagent, so the water content cannot be precisely and accurately tested.

[0097] By comparing Example 1 with Comparative Example 4, it can be seen that when using 3,3'-dimethyl 3,3'-dithiodipropionate as a reducing agent to determine the water content of the organic peroxide sample, the water content cannot be precisely and accurately tested because the substance almost does not react with the organic peroxide sample.

[0098] The applicant declares that the above is only a specific embodiment of the present application, but the protection scope of the present application is not limited thereto. It should be understood by those skilled in the art that any changes or replacements within the technical scope disclosed by the present application can be easily thought of by those skilled in the art, and all fall within the protection scope and disclosure scope of the present application.

Claims

1. A method for testing the water content of organic peroxides, characterized in that, The test method comprises the following steps: The organic peroxide sample and the reducing agent are mixed and reacted to obtain a reaction product; the water content c2 of the reaction product and the water content c1 of the reducing agent are tested to obtain the water content c of the organic peroxide sample, and the calculation formula is as follows: ； Wherein, m1 is the mass of the reducing agent, and m is the mass of the organic peroxide sample; The organic peroxide is any one or a combination of the two of benzoyl peroxide or cumene hydroperoxide; The reducing agent is any one or a combination of at least two of methylthioacetate, methyl phenyl sulfide, 4-methoxy anise sulfide, dimethyl 3,3'-thiodipropionate or 1-methylthio-2-propanone.

2. The test method of claim 1, wherein, The reducing agent is any one or a combination of at least two of methyl phenyl sulfide, 4-methoxy anise sulfide or dimethyl 3,3'-thiodipropionate.

3. The test method of claim 1, wherein, The organic peroxide sample is an organic peroxide or a solution obtained by dissolving an organic peroxide in a solvent.

4. The test method of claim 3, wherein, The solvent is any one or a combination of at least two of butyl acetate, acetonitrile, ethanol or N,N-dimethylformamide.

5. The test method of claim 1, wherein, The molar ratio of the organic peroxide in the organic peroxide sample to the reducing agent is 1: (1.1-1.5).

6. The test method of claim 1, wherein, The temperature of the reaction is 20-80℃, and the time of the reaction is 5-60 min.

7. The test method of claim 6, wherein, The temperature of the reaction is 50-60℃, and the time of the reaction is 8-15 min.

8. The test method of claim 1, wherein, The water contents c1 and c2 are both tested by Karl Fischer volumetry.

9. The test method of claim 1, wherein, The organic peroxide sample and the reducing agent are mixed and reacted at 20-80℃ for 5-60 min to obtain a reaction product; the molar ratio of the organic peroxide in the organic peroxide sample to the reducing agent is 1: (1.1-1.5).

10. The use of the test method for the water content of the organic peroxide according to any one of claims 1-9 in the research and development, production and detection of the organic peroxide.

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