CN113607657A - Electronic grade pyromellitic anhydride chromaticity detection method - Google Patents
Electronic grade pyromellitic anhydride chromaticity detection method Download PDFInfo
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- CN113607657A CN113607657A CN202110896895.1A CN202110896895A CN113607657A CN 113607657 A CN113607657 A CN 113607657A CN 202110896895 A CN202110896895 A CN 202110896895A CN 113607657 A CN113607657 A CN 113607657A
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Abstract
The invention relates to the technical field of product chromaticity detection, in particular to an electronic-grade pyromellitic dianhydride chromaticity detection method, which comprises the following steps: s1, adding 2.5000 +/-0.0002 g of pyromellitic dianhydride into an organic solvent, continuously stirring and heating to 55 ℃ under the protection of nitrogen, then cooling to room temperature, filtering to remove insoluble impurities, evaporating filtrate, recovering the organic solvent, and separating out pure pyromellitic dianhydride; s2, adding 50mL of analytically pure methanol into pure pyromellitic dianhydride until the volume is constant, stirring the mixture by using a magnetic rod in a closed environment, and stirring the mixture until the mixture is dissolved to form a transparent solution; s3, place the solution in a cuvette, designated "sample solution", and place methanol in another cuvette, designated "reference solution". The invention not only can improve the accuracy of sample detection, but also can enable the detection scheme to be more data, and can more intuitively express the difference degree of PMDA chromaticity.
Description
Technical Field
The invention relates to the technical field of product chromaticity detection, in particular to an electronic-grade pyromellitic dianhydride chromaticity detection method.
Background
Color is commonly represented by lightness and chroma, while chroma is the property of a color that excludes lightness, which reflects the hue and saturation of a color.
Taking pyromellitic dianhydride (PMDA) as an example, when colorimetric analysis is performed on the PMDA, the PMDA can be distinguished through the difference in color, but the quality of the PMDA cannot be judged through the detection capability, so an electronic grade pyromellitic dianhydride colorimetric detection method is proposed to solve the problems.
Disclosure of Invention
The invention aims to solve the defects in the prior art and provides an electronic grade pyromellitic dianhydride chroma detection method.
An electronic grade pyromellitic anhydride chroma detection method comprises the following steps:
s1, adding 2.5000 +/-0.0002 g of pyromellitic dianhydride into an organic solvent, continuously stirring and heating to 55 +/-5 ℃ under the protection of nitrogen, then cooling to room temperature, filtering to remove insoluble impurities, evaporating filtrate, recovering the organic solvent, and separating out pure pyromellitic dianhydride;
s2, adding 50mL of analytically pure methanol into pure pyromellitic dianhydride until the volume is constant, stirring the mixture by using a magnetic rod in a closed environment, and stirring the mixture until the mixture is dissolved to form a transparent solution;
s3, placing the solution into a cuvette and marking the solution as a sample solution, and placing methanol into another cuvette and marking the solution as a reference solution;
s4, adjusting the wavelength of the visible spectrophotometer at 430 +/-1 nm, placing a light shielding body, and adjusting the transmittance to zero;
s5, placing the sample solution into a reference solution, adjusting the absorbance to be full, and then placing the sample solution into the reference solution to test the absorbance within the wavelength range of 430 +/-1 nm;
s6, the read data is multiplied by 100 to obtain the colorimetric value of the pyromellitic anhydride sample;
and S7, cleaning the cuvette with methanol, then with distilled water, lightly wiping the cuvette with lens paper, and naturally drying the cuvette for later use.
Preferably, the S2 medium volumetric flask is a 50mL brown volumetric flask.
Preferably, the organic solvent in S1 is acetic acid, and the amount added is the minimum amount capable of dissolving the pyromellitic anhydride.
Preferably, the standard for analyzing pure methanol in S2 is to use a 1cm absorbance cell, and to use distilled water as a reference, when the absorbance is measured in the wavelength range of 430 ± 1nm, the absorbance does not exceed 0.02, otherwise, purification is required.
Preferably, the purification method comprises the following steps: methanol was dehydrated for 8 hours at 300 ℃ using a 3A molecular sieve.
Preferably, the cuvette is a quartz cuvette with an optical path length of 5 cm.
Preferably, the visible spectrophotometer in S4 has a bandwidth of less than or equal to 2nm within the wavelength range of 430 +/-1 nm and a wavelength repetition of less than or equal to 1 nm.
Preferably, the method for zeroing the transmittance in S4 is as follows: putting in a light-shading body, closing the sample chamber cover, enabling the sample chamber cover to enter the light path, pressing a key of adjusting 0% T to adjust T to zero, displaying 00.0 or-00.0 by the instrument at the moment, and taking out the light-shading body after the T to zero is completed.
Preferably, the method for adjusting the absorbance to full in S5 includes: distilled water is used as a reference sample and placed in a sample rack with a 5cm optical path, a sample rack pull rod is pushed and pulled to enter the optical path, then a key for adjusting 100% T is pressed, and at the moment, a screen displays 'BL' and displays '100.0' (in a T mode) or '000' (in an A mode) after time delay of a plurality of seconds, and then 100% T/0A can be automatically adjusted.
The invention has the beneficial effects that:
according to the method, the pyromellitic dianhydride sample is purified by acetic acid, insoluble impurities are removed, and then the pyromellitic dianhydride sample is dissolved by analytically pure methanol, so that the product chromaticity is not influenced by the pretreatment, the subsequent absorbance test is more accurate, and the visible absorbance of the solution is measured within the wavelength range of 430 +/-1 nm, so that the quality of the pyromellitic dianhydride sample is judged, the accuracy of the sample in detection can be improved, the detection scheme can be more data, and the difference degree of the PMDA chromaticity can be more intuitively expressed.
Detailed Description
The present invention will be further illustrated with reference to the following specific examples.
An electronic grade pyromellitic anhydride chroma detection method comprises the following steps:
s1, adding 2.5000 +/-0.0002 g of pyromellitic dianhydride into an organic solvent, continuously stirring and heating to 55 +/-5 ℃ under the protection of nitrogen, then cooling to room temperature, filtering to remove insoluble impurities, evaporating filtrate, recovering the organic solvent, and separating out pure pyromellitic dianhydride; the organic solvent is acetic acid, and the addition amount of the organic solvent is the minimum amount capable of dissolving the pyromellitic anhydride;
s2, adding 50mL of analytically pure methanol into pure pyromellitic dianhydride until the volume is constant, stirring the mixture by using a magnetic rod in a closed environment, and stirring the mixture until the mixture is dissolved to form a transparent solution;
s3, placing the solution into a quartz cuvette with an optical path length of 5cm to mark as a sample solution, and placing methanol into another quartz cuvette with an optical path length of 5cm to mark as a reference solution;
s4, adjusting the wavelength of the visible spectrophotometer at 430 +/-1 nm, placing a light shielding body, and adjusting the transmittance to zero;
s5, placing the sample solution into a reference solution, adjusting the absorbance to be full, and then placing the sample solution into the reference solution to test the absorbance within the wavelength range of 430 +/-5 nm;
s6, the read data is multiplied by 100 to obtain the colorimetric value of the pyromellitic anhydride sample;
s7, cleaning the quartz cuvette with methanol and then with distilled water, wiping the cuvette with lens paper and naturally drying the cuvette for later use.
The following examples were conducted to examine the color values of visible light of pyromellitic dianhydride at prescribed wavelengths:
the first embodiment is as follows:
s1, adding 2.5002g of pyromellitic dianhydride into an organic solvent, continuously stirring and heating to 55 ℃ under the protection of nitrogen, then cooling to room temperature, filtering to remove insoluble impurities, evaporating filtrate, recovering the organic solvent, and separating out pure pyromellitic dianhydride, wherein the organic solvent is acetic acid, and the addition amount is the minimum amount capable of dissolving the pyromellitic dianhydride;
s2, adding 50mL of analytically pure methanol into pure pyromellitic dianhydride until the volume is constant, stirring the mixture by using a magnetic rod in a closed environment, and stirring the mixture until the mixture is dissolved to form a transparent solution;
s3, placing the solution into a quartz cuvette with an optical path length of 5cm to mark as a sample solution, and placing methanol into another quartz cuvette with an optical path length of 5cm to mark as a reference solution;
s4, adjusting the wavelength of the visible spectrophotometer at 429nm, placing a light shielding body, and zeroing the transmittance;
s5, placing the sample solution into a reference solution, adjusting the absorbance to be full, and then placing the sample solution into the reference solution to test the absorbance within the wavelength range of 429 nm;
s6, the read data is multiplied by 100 to obtain the colorimetric value of the pyromellitic anhydride sample;
s7, cleaning the quartz cuvette with methanol and then with distilled water, wiping the cuvette with lens paper and naturally drying the cuvette for later use.
Example two:
s1, adding 2.5002g of pyromellitic dianhydride into an organic solvent, continuously stirring and heating to 55 ℃ under the protection of nitrogen, then cooling to room temperature, filtering to remove insoluble impurities, evaporating filtrate, recovering the organic solvent, and separating out pure pyromellitic dianhydride, wherein the organic solvent is acetic acid, and the addition amount is the minimum amount capable of dissolving the pyromellitic dianhydride;
s2, adding 50mL of analytically pure methanol into pure pyromellitic dianhydride until the volume is constant, stirring the mixture by using a magnetic rod in a closed environment, and stirring the mixture until the mixture is dissolved to form a transparent solution;
s3, placing the solution into a quartz cuvette with an optical path length of 5cm to mark as a sample solution, and placing methanol into another quartz cuvette with an optical path length of 5cm to mark as a reference solution;
s4, adjusting the wavelength of the visible spectrophotometer at 430nm, placing a light shielding body, and adjusting the transmittance to zero;
s5, placing the sample solution into a reference solution, adjusting the absorbance to be full, and then placing the sample solution into the reference solution to test the absorbance within the wavelength range of 430 nm;
s6, the read data is multiplied by 100 to obtain the colorimetric value of the pyromellitic anhydride sample;
s7, cleaning the quartz cuvette with methanol and then with distilled water, wiping the cuvette with lens paper and naturally drying the cuvette for later use.
Example three:
s1, adding 2.5002g of pyromellitic dianhydride into an organic solvent, continuously stirring and heating to 55 ℃ under the protection of nitrogen, then cooling to room temperature, filtering to remove insoluble impurities, evaporating filtrate, recovering the organic solvent, and separating out pure pyromellitic dianhydride, wherein the organic solvent is acetic acid, and the addition amount is the minimum amount capable of dissolving the pyromellitic dianhydride;
s2, adding 50mL of analytically pure methanol into pure pyromellitic dianhydride until the volume is constant, stirring the mixture by using a magnetic rod in a closed environment, and stirring the mixture until the mixture is dissolved to form a transparent solution;
s3, placing the solution into a quartz cuvette with an optical path length of 5cm to mark as a sample solution, and placing methanol into another quartz cuvette with an optical path length of 5cm to mark as a reference solution;
s4, adjusting the wavelength of the visible spectrophotometer at 431nm, placing a light shielding body, and zeroing the transmittance;
s5, placing the sample solution into a reference solution, adjusting the absorbance to be full, and then placing the sample solution into the reference solution to test the absorbance within the wavelength range of 431 nm;
s6, the read data is multiplied by 100 to obtain the colorimetric value of the pyromellitic anhydride sample;
s7, cleaning the quartz cuvette with methanol and then with distilled water, wiping the cuvette with lens paper and naturally drying the cuvette for later use.
Example four
And selecting the same visual color of the pyromellitic dianhydride as the three phases of the example to carry out the detection of the absorbance according to the scheme of the third example.
In the first to fourth embodiments, the standard for analyzing pure methanol in S2 is to use a 1cm cuvette, and to measure the absorbance within the wavelength range of 430 ± 1nm using distilled water as a reference, the absorbance does not exceed 0.02, otherwise, the purification is required, and the method comprises: methanol was dehydrated for 8 hours at 300 ℃ using a 3A molecular sieve.
In S4, the width of the visible spectrophotometer in the wavelength range of 430 +/-1 nm is less than or equal to 2nm, the repetition of the wavelength is less than or equal to 1nm, and the method for zeroing the transmittance comprises the following steps: putting in a light-shading body, closing the sample chamber cover, enabling the sample chamber cover to enter the light path, pressing a key of adjusting 0% T to adjust T to zero, displaying 00.0 or-00.0 by the instrument at the moment, and taking out the light-shading body after the T to zero is completed.
The method for adjusting the absorbance to full in S5 comprises the following steps: distilled water is used as a reference sample and placed in a sample rack with a 5cm optical path, a sample rack pull rod is pushed and pulled to enter the optical path, then a key for adjusting 100% T is pressed, and at the moment, a screen displays 'BL' and displays '100.0' (in a T mode) or '000' (in an A mode) after time delay of a plurality of seconds, and then 100% T/0A can be automatically adjusted.
And the absorbance and chroma values measured in the above examples are shown in the following table:
as can be seen from the data in the table, in the first to third examples, the absorbance of the pyromellitic dianhydride with different visual colors is tested by the method of the invention and then converted into the chromaticity, the obtained chromaticity value can be matched with the visual color, and the larger the value is, the darker the color is;
in addition, it can be found that, for the third embodiment and the fourth embodiment, the colors in the embodiments are all white by visual inspection from the appearance, but the quality of the PMDA in each embodiment can be further judged according to the magnitude of the absorbance and the chroma value, the data is more significant, the visual defect can be made up, and the requirements of customers can be met.
The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art should be considered to be within the technical scope of the present invention, and the technical solutions and the inventive concepts thereof according to the present invention should be equivalent or changed within the scope of the present invention.
Claims (9)
1. An electronic grade pyromellitic anhydride chroma detection method is characterized by comprising the following steps:
s1, adding 2.5000 +/-0.0002 g of pyromellitic dianhydride into an organic solvent, continuously stirring and heating to 55 +/-5 ℃ under the protection of nitrogen, then cooling to room temperature, filtering to remove insoluble impurities, evaporating filtrate, recovering the organic solvent, and separating out pure pyromellitic dianhydride;
s2, adding 50mL of analytically pure methanol into pure pyromellitic dianhydride until the volume is constant, stirring the mixture by using a magnetic rod in a closed environment, and stirring the mixture until the mixture is dissolved to form a transparent solution;
s3, placing the solution into a cuvette and marking the solution as a sample solution, and placing methanol into another cuvette and marking the solution as a reference solution;
s4, adjusting the wavelength of the visible spectrophotometer at 430 +/-1 nm, placing a light shielding body, and adjusting the transmittance to zero;
s5, placing the sample solution into a reference solution, adjusting the absorbance to be full, and then placing the sample solution into the reference solution to test the absorbance within the wavelength range of 430 +/-1 nm;
s6, the read data is multiplied by 100 to obtain the colorimetric value of the pyromellitic anhydride sample;
and S7, cleaning the cuvette with methanol, then with distilled water, lightly wiping the cuvette with lens paper, and naturally drying the cuvette for later use.
2. The method for detecting the color of the electronic grade pyromellitic dianhydride according to claim 1, wherein a 50mL brown volumetric flask is selected as the volumetric flask in the S2.
3. The method for detecting the chroma of the electronic-grade pyromellitic anhydride according to claim 1, wherein the organic solvent in the S1 is acetic acid, and the addition amount of the acetic acid is the minimum amount capable of dissolving the pyromellitic anhydride.
4. The method of claim 1, wherein the analytical grade methanol at S2 is analyzed by using a 1cm cuvette and distilled water as a reference, and the absorbance is measured at a wavelength of 430 ± 1nm, wherein the absorbance does not exceed 0.02, otherwise, the absorbance needs to be purified.
5. The method for detecting the chroma of the electronic-grade pyromellitic anhydride according to claim 3, wherein the purification method comprises the following steps: methanol was dehydrated for 8 hours at 300 ℃ using a 3A molecular sieve.
6. The method for detecting the chroma of the electronic-grade pyromellitic anhydride according to claim 1, wherein the cuvette is a quartz cuvette with an optical path length of 5 cm.
7. The method for detecting the chroma of the electronic-grade pyromellitic anhydride according to claim 1, wherein the spectral bandwidth of the visible spectrophotometer at S4 is less than or equal to 2nm within the wavelength range of 430 +/-1 nm, and the wavelength repetition is less than or equal to 1 nm.
8. The method for detecting the chroma of the electronic grade pyromellitic anhydride according to claim 1, wherein the method for zeroing the transmittance in S4 is as follows: putting in a light-shading body, closing the sample chamber cover, enabling the sample chamber cover to enter the light path, pressing a key of adjusting 0% T to adjust T to zero, displaying 00.0 or-00.0 by the instrument at the moment, and taking out the light-shading body after the T to zero is completed.
9. The method for detecting the chroma of the electronic-grade pyromellitic anhydride according to claim 1, wherein the method for adjusting the full absorbance in S5 is as follows: distilled water is used as a reference sample and placed in a sample rack with a 5cm optical path, a sample rack pull rod is pushed and pulled to enter the optical path, then a key for adjusting 100% T is pressed, and at the moment, a screen displays 'BL' and displays '100.0' (in a T mode) or '000' (in an A mode) after time delay of a plurality of seconds, and then 100% T/0A can be automatically adjusted.
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Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1970560A (en) * | 2005-07-21 | 2007-05-30 | 三菱瓦斯化学株式会社 | Method for producing high-purity pyromellitic dianhydride |
| CN102336762A (en) * | 2010-12-17 | 2012-02-01 | 常熟市联邦化工有限公司 | Solvent refining method for pyromellitic dianhydride |
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- 2021-08-05 CN CN202110896895.1A patent/CN113607657A/en active Pending
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1970560A (en) * | 2005-07-21 | 2007-05-30 | 三菱瓦斯化学株式会社 | Method for producing high-purity pyromellitic dianhydride |
| CN102336762A (en) * | 2010-12-17 | 2012-02-01 | 常熟市联邦化工有限公司 | Solvent refining method for pyromellitic dianhydride |
Non-Patent Citations (1)
| Title |
|---|
| 济南军区后勤部卫生部: "医院制剂操作技术", 山东科学技术出版社, pages: 473 - 475 * |
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