Ammonia value testing method

Abstract

The invention provides an ammonia value testing method which comprises the following steps: drying a to-be-tested sample under a first preset condition to obtain the to-be-tested sample, and dissolving the to-be-tested sample in a preset solvent to form a to-be-tested solution; the sample to be detected comprises an amino-containing oiling agent; taking a preset standard solution as a titrating solution, putting the to-be-tested solution into a test instrument, and testing the ammonia value of the to-be-tested solution through the preset standard solution. The testing method is simple and convenient to operate, high in accuracy, high in automation degree and wide in application range, and can be used for testing the ammonia value in the amino-containing oiling agent with large molecular weight and high viscosity.

Description

Technical Field

[0001] The present invention relates to the technical field of chemical analysis, and in particular to a method for testing an ammonia value. Background Art

[0002] In the production process of carbon fiber, amino silicone oil plays an important role as an indispensable component of carbon fiber oil. Amino groups have strong polarity and are easy to react chemically with hydroxyl and carboxyl groups in carbon fiber, so that the main chain of polysiloxane is oriented and adsorbed on the surface of carbon fiber, reducing the friction coefficient between fibers, thus giving carbon fiber excellent softness, smoothness and washability. At the same time, the introduction of amino groups improves the hydrophilicity of polysiloxane, making it easy to emulsify. The ammonia value of carbon fiber oil should be within an appropriate range. If it is too low, it cannot achieve the effect of soft and smooth carbon fiber, and if it is too high, it will cause serious yellowing of carbon fiber. Therefore, the detection of the ammonia value of oil and silicone oil is also an important means to evaluate their characteristics.

[0003] The method for detecting the ammonia value in amino silicone oil in the related art is to use an ultraviolet spectrophotometer to test standard solutions with different ammonia value gradients, draw a standard curve, dilute the sample to be tested, test the absorbance, and then calculate the ammonia value. This method has cumbersome operation steps and a limited scope of application. It cannot detect amino silicone oil with an ammonia value of less than 0.1mmol / g or greater than 1.2mmol / g. Summary of the invention

[0004] In order to solve the problems existing in the related art, the present disclosure provides a method for testing ammonia value, the testing method comprising:

[0005] Drying the sample to be tested under a first preset condition to obtain a sample to be tested, and dissolving the sample to be tested in a preset solvent to form a solution to be tested; the sample to be tested includes an oil containing amino groups;

[0006] The preset standard solution is used as a titrant, the solution to be tested is placed in a testing instrument, and the ammonia value of the solution to be tested is tested by the preset standard solution.

[0007] In some embodiments of the present disclosure, the method of using a preset standard solution as a titrant, placing the solution to be tested in a testing instrument, and testing the ammonia value of the solution to be tested by using the preset standard solution includes:

[0008] The solution to be tested is placed in the testing instrument, and under the second preset condition, the solution to be tested is titrated with the preset standard solution by biamperometric titration. After the titration, the ammonia value of the solution to be tested is calculated by the following formula:

[0009]

[0010] Among them, A is the ammonia value of the solution to be tested, in mmol / g; C is the concentration of the preset standard solution, in mmol / L; V1 is the volume of the preset standard solution consumed during the titration process, in L; V0 is the volume of the preset standard solution consumed by the blank control group, in L; m is the mass of the sample to be tested, in g.

[0011] In some embodiments of the present disclosure, the testing instrument includes a never-stop titrator.

[0012] In some embodiments of the present disclosure, the preset standard solution includes ferric chloride-hydrochloric acid solution.

[0013] In some embodiments of the present disclosure, the second preset condition includes: the initial applied voltage is 10-200 mV.

[0014] In some embodiments of the present disclosure, the preset solvent includes a first solvent and a second solvent;

[0015] wherein the first solvent comprises at least one of toluene and xylene;

[0016] The second solvent includes at least one of isopropanol, petroleum ether and carbon tetrachloride.

[0017] In some embodiments of the present disclosure, in the preset solvent, the volume ratio of the first solvent to the second solvent is 2-8:1-3.

[0018] In some embodiments of the present disclosure, the average molecular weight of the sample to be tested is 2000-50000 g / mol; the viscosity of the sample to be tested is 1000-50000 mPa·s.

[0019] In some embodiments of the present disclosure, the first preset condition includes:

[0020] The preset temperature is 110-130℃; the preset time is 0.5-2 hours.

[0021] In some embodiments of the present disclosure, the ammonia value is 0.01-1.8 mmol / g.

[0022] The beneficial effects of the present disclosure include but are not limited to: the test method of ammonia value provided by the present disclosure, drying the sample to be tested under a first preset condition to obtain the sample to be tested, dissolving the sample to be tested in a preset solvent to form a solution to be tested, using a preset standard solution as a titrant, placing the solution to be tested in a testing instrument, and testing the ammonia value of the solution to be tested by the preset standard solution. This test method is simple to operate, has high accuracy, high degree of automation, and a wide range of adaptability, and can test the ammonia value in a large molecular weight, high viscosity amino-containing oil.

[0023] It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The accompanying drawings incorporated into the specification and constituting a part of the specification illustrate embodiments of the present disclosure and are used together with the description to explain the principles of the embodiments of the present disclosure. In these drawings, similar reference numerals are used to represent similar elements. The drawings described below are some embodiments of the present disclosure, rather than all embodiments. For those skilled in the art, other drawings can be obtained based on these drawings without paying creative work.

[0025] Figure 1 The figure is a flow chart of a method for testing ammonia value according to an exemplary embodiment of the present disclosure. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical solution and advantages of the present disclosure clearer, the technical solution of the present disclosure will be clearly and completely described in combination with the embodiments of the present disclosure. Obviously, the described embodiments are only part of the embodiments of the present disclosure, not all of the embodiments. Based on the embodiments in the present disclosure, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present disclosure. It should be noted that the embodiments in the present disclosure and the features in the embodiments can be arbitrarily combined with each other without conflict.

[0027] The method for detecting the ammonia value in amino silicone oil in the related art is to use an ultraviolet spectrophotometer to test standard solutions with different ammonia value gradients, draw a standard curve, dilute the sample to be tested, test the absorbance, and then calculate the ammonia value. This method has cumbersome operation steps and a limited scope of application. It cannot detect amino silicone oil with an ammonia value of less than 0.1mmol / g or greater than 1.2mmol / g.

[0028] Based on this, the exemplary embodiment of the present disclosure provides a method for testing ammonia value, such as Figure 1 As shown, the test method includes:

[0029] S100, drying the sample to be tested under a first preset condition to obtain the sample to be tested, dissolving the sample to be tested in a preset solvent to form a solution to be tested; the sample to be tested includes an oil containing amino groups.

[0030] The sample to be tested includes an amino-containing oil, and the amino-containing oil is dried under a first preset condition to remove the solvent in the amino-containing oil, and retain the amino-containing component to prepare a solid sample to be tested. The sample to be tested is dispersed and dissolved in a preset solvent to form a test solution to be used for the test of the ammonia value.

[0031] For example, the amino group-containing oil may be an amino silicone oil of a primary amine or secondary amine series.

[0032] S200, using a preset standard solution as a titrant, placing the solution to be tested in a testing instrument, and testing the ammonia value of the solution to be tested using the preset standard solution.

[0033] Use the preset standard solution as the titrant, place the solution to be tested in the testing instrument, and titrate the solution to be tested with the preset standard solution. The ammonia value of the solution to be tested can be obtained based on the titration amount of the preset standard solution, that is, the ammonia value of the sample to be tested can be obtained.

[0034] The method for testing the ammonia value provided by this exemplary embodiment is simple to operate, highly accurate, highly automated, and has a wide range of applications, and can test the ammonia value in oils containing amino groups with large molecular weight and high viscosity.

[0035] In the exemplary embodiment provided by the present disclosure, a preset standard solution is used as a titrant, a solution to be tested is placed in a testing instrument, and the ammonia value of the solution to be tested is tested by the preset standard solution, including: placing the solution to be tested in the testing instrument, titrating the solution to be tested with the preset standard solution by biamperometric titration under a second preset condition, and after the titration is completed, calculating the ammonia value of the solution to be tested by the following formula:

[0036]

[0037] Wherein, A is the ammonia value of the solution to be tested, in mmol / g; C is the concentration of the preset standard solution, in mmol / L; V1 is the volume of the preset standard solution consumed during the titration process, in L; V0 is the volume of the preset standard solution consumed by the blank control group, in L; m is the mass of the sample to be tested, in g.

[0038] It should be noted that before the solution to be tested is placed in the testing instrument for titration test, a control group with the same amount as the solution to be tested but only including the preset solvent in the solution to be tested and excluding the test sample is used as the blank control group. The blank control group is first placed in the testing instrument for titration test to obtain the volume of the preset standard solution consumed by the blank control group. When calculating the ammonia value of the solution to be tested, the volume of the preset standard solution consumed during the titration process is subtracted from the volume of the preset standard solution consumed by the blank control group. This is used as the actual volume consumption of the preset standard solution during the titration process. This can eliminate the operating errors of the instrument and the tester, thereby improving the accuracy of the test results of the ammonia value.

[0039] In this exemplary embodiment, a preset standard solution is used as a titrant, and the solution to be tested is placed in a testing instrument. Under the second preset condition, the preset standard solution is used to titrate the solution to be tested by biamperometric titration. The ammonia value of the solution to be tested can be obtained according to the titration amount of the preset standard solution, that is, the ammonia value of the sample to be tested can be obtained. This testing method is simple to operate, has high accuracy, high automation, and a wide range of adaptability, and can test the ammonia value of amino-containing oils with large molecular weight and high viscosity.

[0040] In an exemplary embodiment provided by the present disclosure, the testing instrument includes a never-stop titrator.

[0041] In this exemplary embodiment, the solution to be tested is placed in a permanent stop titrator, and under the second preset condition, the solution to be tested is titrated with a preset standard solution by biamperometric titration. When the titration endpoint is reached, the permanent stop titrator displays that the current drops to the minimum and stagnates, thereby accurately testing the titration amount of the preset standard solution, and then the ammonia value of the solution to be tested can be obtained, that is, the ammonia value of the sample to be tested can be obtained. This test method is simple to operate, highly accurate, highly automated, and has a wide range of applications, and can test the ammonia value in high molecular weight, high viscosity amino-containing oils.

[0042] In the exemplary embodiments provided in the present disclosure, the preset standard solution includes a ferric chloride-hydrochloric acid solution. For example, the preset standard solution can be a ferric chloride-hydrochloric acid solution with a concentration of 0.05-0.15 mol / L, for example, a ferric chloride-hydrochloric acid solution with a concentration of 0.05 mol / L, 0.1 mol / L or 0.15 mol / L. Before using the ferric chloride-hydrochloric acid solution for titration of a blank control group or titration of a solution to be tested, potassium thiocyanate can be used to calibrate the ferric chloride-hydrochloric acid solution.

[0043] In an exemplary embodiment provided by the present disclosure, the second preset condition includes: an initial applied voltage of 10-200 mV.

[0044] In this exemplary embodiment, the solution to be tested is placed in a permanent stop titrator, two identical platinum electrodes are used, the initial applied voltage is set to 10-200mV, and the solution to be tested is titrated with a ferric chloride-hydrochloric acid solution by biamperometric titration. When the titration endpoint is reached, the permanent stop titrator displays that the current drops to the minimum and stagnates, thereby accurately testing the titration amount of the ferric chloride-hydrochloric acid solution, and then the ammonia value of the solution to be tested can be obtained, that is, the ammonia value of the sample to be tested can be obtained. This test method is simple to operate, highly accurate, highly automated, and has a wide range of adaptability, and can test the ammonia value in high molecular weight, high viscosity amino-containing oils.

[0045] In the exemplary embodiment provided by the present disclosure, the preset solvent includes a first solvent and a second solvent, wherein the first solvent includes at least one of toluene and xylene; and the second solvent includes at least one of isopropanol, petroleum ether, and carbon tetrachloride.

[0046] In this exemplary embodiment, an organic mixed solvent of a first solvent and a second solvent is used as a preset solvent to disperse and dissolve solid test samples. This can dissolve solid test samples after removing the solvent from a large molecular weight, high viscosity amino-containing oil, and can also dissolve solid test samples after removing the solvent from a multi-component finished oil. It has a wide detection range and universal applicability.

[0047] In an exemplary embodiment provided by the present disclosure, in the preset solvent, the volume ratio of the first solvent to the second solvent is 2-8:1-3.

[0048] In this exemplary embodiment, the first solvent includes at least one of toluene and xylene, and the second solvent includes at least one of isopropanol, petroleum ether, and carbon tetrachloride. The first solvent and the second solvent are prepared as a preset solvent in a volume ratio of 2 to 8: 1 to 3, and are used to disperse and dissolve solid test samples. In this way, the solid test samples after the removal of solvent from the oil containing amino groups with large molecular weight and high viscosity can be dissolved, and the solid test samples after the removal of solvent from the finished oil of multiple components can also be dissolved. The detection range is wide and it has universal applicability.

[0049] In the exemplary embodiments provided in the present disclosure, the average molecular weight of the sample to be tested is 2000-50000 g / mol, and the viscosity of the sample to be tested is 1000-50000 mPa·s.

[0050] In this exemplary embodiment, the first solvent and the second solvent are prepared as a preset solvent in a volume ratio of 2 to 8:1 to 3, which is used to disperse and dissolve solid test samples. The test samples with an average molecular weight of 2000-50000 g / mol and a viscosity of 1000-50000 mPa·s can be dissolved, and the detection range is wide and it has universal applicability.

[0051] In the exemplary embodiment provided in the present disclosure, the first preset condition includes: a preset temperature of 110-130° C., and a preset time of 0.5-2 hours.

[0052] In this exemplary embodiment, the sample to be tested includes an oil agent containing amino groups. The sample to be tested is dried at a temperature of 110-130° C. for 0.5-2 hours to remove the solvent in the oil agent containing amino groups and retain the components containing amino groups to prepare a solid sample to be tested. The solid sample to be tested is then dissolved in a preset solvent to form a test solution to be used for testing the ammonia value, thereby determining the ammonia value of the sample to be tested.

[0053] In the exemplary embodiments provided in the present disclosure, the ammonia value is 0.01-1.8 mmol / g.

[0054] In this exemplary embodiment, the first solvent and the second solvent are prepared as a preset solvent in a volume ratio of 2 to 8: 1 to 3, which is used to disperse and dissolve the solid test sample. This can dissolve the solid test sample after removing the solvent from the oil containing amino groups with a large molecular weight and high viscosity, and can test the oil containing amino groups with an ammonia value of 0.01-1.8 mmol / g. It has a wide detection range and is generally applicable.

[0055] In order to more clearly explain the technical solution of the present disclosure, a specific example of a method for testing ammonia value provided by an exemplary embodiment of the present disclosure is given below.

[0056] Example 1

[0057] Dry the carbon fiber oil in an oven at 120°C for 1h, accurately weigh 1g (accurate to 0.0001) of the dried test sample into a conical flask, measure 30ml of toluene and 15ml of isopropanol, mix and add to the conical flask, dissolve the test sample under stirring to obtain the test solution. Prepare 0.1mol / L ferric chloride-hydrochloric acid solution, and use potassium thiocyanate to calibrate the ferric chloride-hydrochloric acid solution. Apply a voltage of 10mV to the permanent stop titrator, and use the calibrated ferric chloride-hydrochloric acid solution to titrate the test solution. Observe the current mutation between the two platinum electrodes during the titration process, determine the titration end point based on the current change, and repeat three sets of tests.

[0058] Example 2

[0059] Place the primary amine-modified amino silicone oil with a molecular weight of 2000g / mol and a viscosity of 50000mPa·s in a 120℃ oven and dry for 1h. Accurately weigh 1g (accurate to 0.0001) of the dried sample to be tested in a conical flask. Measure 30ml of toluene and 20ml of isopropanol and mix them in the conical flask. Dissolve the sample under stirring. Prepare a 0.1mol / L ferric chloride-hydrochloric acid solution and calibrate the ferric chloride-hydrochloric acid solution with potassium thiocyanate. Apply a voltage of 50mV to the permanent stop titrator, and use the calibrated ferric chloride-hydrochloric acid solution to titrate the test solution. Observe the sudden change in current between the two platinum electrodes during the titration process. Determine the titration endpoint based on the current change. Repeat three sets of tests.

[0060] Example 3

[0061] Place the primary amine-modified amino silicone oil with a molecular weight of 20000g / mol and a viscosity of 25000mPa·s in a 120℃ oven for drying for 1h, accurately weigh 1g (accurate to 0.0001) of the dried sample to be tested in a conical flask, measure 25ml of toluene and 10ml of isopropanol and mix them in the conical flask, and dissolve the sample to be tested under stirring. Prepare 0.1mol / L ferric chloride-hydrochloric acid solution, and use potassium thiocyanate to calibrate the ferric chloride-hydrochloric acid solution. The permanent stop titrator applies a voltage of 100mV, and the calibrated ferric chloride-hydrochloric acid solution is used to titrate the test solution. Observe the sudden change in current between the two platinum electrodes during the titration process, determine the titration end point based on the current change, and repeat three sets of tests.

[0062] Example 4

[0063] Place the secondary amine-modified amino silicone oil with a molecular weight of 2000g / mol and a viscosity of 50000mPa·s in a 120℃ oven for drying for 1h, accurately weigh 1g (accurate to 0.0001) of the dried test sample in a conical flask, measure 30ml of toluene and 20ml of isopropanol and mix them in the conical flask, and dissolve the test sample under stirring. Prepare 0.1mol / L ferric chloride-hydrochloric acid solution, and use potassium thiocyanate to calibrate the ferric chloride-hydrochloric acid solution. The permanent stop titrator applies a voltage of 150mV, and the calibrated ferric chloride-hydrochloric acid solution is used to titrate the test solution. Observe the sudden change in current between the two platinum electrodes during the titration process, determine the titration end point based on the current change, and repeat three sets of tests.

[0064] Example 5

[0065] Dry the carbon fiber oil agent A in an oven at 120℃ for 1h, accurately weigh 1g (accurate to 0.0001) of the dried test sample into a conical flask, measure 30ml of toluene and 15ml of carbon tetrachloride, mix and add to the conical flask, and dissolve the test sample under stirring. Prepare 0.1mol / L ferric chloride-hydrochloric acid solution, and use potassium thiocyanate to calibrate the ferric chloride-hydrochloric acid solution. Apply a voltage of 200mV to the permanent stop titrator, and use the calibrated ferric chloride-hydrochloric acid solution to titrate the test solution. Observe the sudden change in current between the two platinum electrodes during the titration process, determine the titration end point based on the current change, and repeat three sets of tests.

[0066] Comparative Examples 1-5

[0067] The samples to be tested in all the above-mentioned Examples 1-5 were titrated manually, 3-4 drops of bromophenol blue indicator (0.1% (W / V) aqueous solution) were dripped into a conical flask, and titrated with a hydrochloric acid standard solution. The end point was when the solution color changed from blue to light yellow (obvious jump), and the volume of the hydrochloric acid standard solution consumed in the titration was recorded to calculate the ammonia value of the sample. The ammonia value test results of the examples and comparative examples are shown in Table 1.

[0068] Table 1

[0069]

[0070] It can be seen from the data in Table 1 that the RSD values ​​(relative standard deviation) of the ammonia value results measured in Examples 1-5 of the present disclosure are significantly lower than those in Comparative Examples 1-5, indicating that the ammonia value testing method provided by the exemplary embodiments of the present disclosure has better accuracy.

[0071] The contents described above may be implemented individually or in combination in various ways, and these variations are all within the protection scope of the present disclosure.

[0072] Finally, it should be noted that in this article, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or apparatus that includes a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or apparatus.

[0073] The above embodiments are only used to illustrate the technical solutions of the present disclosure, rather than to limit them. Although the present disclosure is described in detail with reference to the above embodiments, a person skilled in the art should understand that the technical solutions described in the above embodiments can still be modified, or some of the technical features can be replaced by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present disclosure.

Claims

1. A method for testing ammonia value, characterized in that: The test method includes: Drying the sample to be tested under a first preset condition to obtain a sample to be tested, and dissolving the sample to be tested in a preset solvent to form a solution to be tested; the sample to be tested includes an oil containing amino groups; The preset standard solution is used as a titrant, the solution to be tested is placed in a testing instrument, and the ammonia value of the solution to be tested is tested by the preset standard solution.

2. The method for testing ammonia value according to claim 1, characterized in that: The method of using a preset standard solution as a titrant, placing the solution to be tested in a testing instrument, and testing the ammonia value of the solution to be tested by using the preset standard solution includes: The solution to be tested is placed in the testing instrument, and under the second preset condition, the solution to be tested is titrated with the preset standard solution by biamperometric titration. After the titration, the ammonia value of the solution to be tested is calculated by the following formula: Among them, A is the ammonia value of the solution to be tested, in mmol / g; C is the concentration of the preset standard solution, in mmol / L; V1 is the volume of the preset standard solution consumed during the titration process, in L; V0 is the volume of the preset standard solution consumed by the blank control group, in L; m is the mass of the sample to be tested, in g.

3. The method for testing ammonia value according to claim 1 or 2, characterized in that: The testing instrument comprises a never-stop titrator.

4. The method for testing ammonia value according to claim 1 or 2, characterized in that: The preset standard solution includes ferric chloride-hydrochloric acid solution.

5. The method for testing ammonia value according to claim 2, characterized in that: The second preset condition includes: the initial applied voltage is 10-200 mV.

6. The method for testing ammonia value according to claim 1, characterized in that: The preset solvent includes a first solvent and a second solvent; wherein the first solvent comprises at least one of toluene and xylene; The second solvent includes at least one of isopropanol, petroleum ether and carbon tetrachloride.

7. The method for testing ammonia value according to claim 6, characterized in that: In the preset solvent, the volume ratio of the first solvent to the second solvent is 2-8:1-3.

8. The method for testing ammonia value according to claim 1, characterized in that: The average molecular weight of the sample to be tested is 2000-50000 g / mol; the viscosity of the sample to be tested is 1000-50000 mpa·s.

9. The method for testing ammonia value according to claim 1, characterized in that: The first preset condition includes: The preset temperature is 110-130℃; the preset time is 0.5-2 hours.

10. The method for testing ammonia value according to claim 1, characterized in that: The ammonia value is 0.01-1.8 mmol / g.

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