Method for measuring purity of trifluoromethylsulfonyl fluoride gas

Abstract

The invention discloses a method for determining the purity of trifluoromethylsulfonyl fluoride gas. The method comprises the following steps: detecting the trifluoromethylsulfonyl fluoride gas to be detected by using a gas chromatograph-mass spectrometer to determine the molecular structure of impurities in a gas sample; preparing standard gas; detecting the standard gas by using a gas chromatograph equipped with TCD and FID to obtain a single-point correction curve; the method comprises the following steps: detecting trifluoromethylsulfonyl fluoride gas to be detected by using a gas chromatograph equipped with TCD and FID to obtain chromatographic peak areas of impurities, and quantitatively calculating volume fractions of the impurities through a single-point correction curve of standard gas; and calculating the purity of the trifluoromethylsulfonyl fluoride by adopting a subtraction method. The method is accurate and reliable in detection and simple to operate.

Description

Technical Field

[0001] The invention relates to the technical field of product detection and analysis, and in particular to a method for measuring the purity of trifluoromethylsulfonyl fluoride gas. Background Art

[0002] Trifluoromethylsulfonyl fluoride can be used in the synthesis of fluorine-containing materials and intermediates, and has potential application value in many fields. 3 SO 2 F as an Alternative Gas to SF 6 》The research results show that the insulation strength of trifluoromethylsulfonyl fluoride is better than that of sulfur hexafluoride, and it may become a substitute for sulfur hexafluoride in the power insulation industry.

[0003] GB / T 12022 "Industrial sulfur hexafluoride" stipulates that the purity of sulfur hexafluoride for power insulation should not be less than 99.9%, and the content of air and carbon tetrafluoride should not be higher than 0.04%. T / CSEE 0308-2022 "Perfluoroisobutyronitrile gas for electrical equipment" stipulates that the purity of perfluoroisobutyronitrile should not be less than 99.5%, and the total content of nitrogen and sample should not be higher than 0.1%. There is no public information on the analysis and detection methods and technical indicators of trifluoromethylsulfonyl fluoride as a new insulating gas, and the existing insulating gases have strict requirements for purity and other indicators. Therefore, it is urgent to establish a purity analysis and detection method for trifluoromethylsulfonyl fluoride.

[0004] The Chinese patent application document with publication number CN117405811A discloses a method for determining trifluoromethylsulfonyl fluoride and its decomposition product based on gas chromatography-mass spectrometry, mainly comprising a discharge generating device, an experimental gas tank, a gas chromatography-mass spectrometer, a barometer, an electrode, and a gas circuit. Before the experiment, trifluoromethylsulfonyl fluoride gas is filled into the experimental gas tank to the experimental air pressure, and then the power frequency AC high voltage is applied to the electrode by the discharge generating device to generate a local discharge to obtain the decomposed gas. Before and after the experiment, the gas in the experimental gas tank is respectively passed through the gas circuit to the gas chromatography-mass spectrometer to separate the mixed gas and perform the detection of the full scan mode, by comparing the retention time of the standard gas and the standard mass spectrum database, the impurities of trifluoromethylsulfonyl fluoride and the components of the decomposition product are determined, and the purpose of separating and detecting the trifluoromethylsulfonyl fluoride mixed gas is achieved, but the chromatographic column it adopts is a GasPro column, and the various organic components in trifluoromethylsulfonyl fluoride cannot be completely separated, and it is difficult to accurately identify its molecular structure when each impurity overlaps together, and it is also difficult to accurately quantify, which limits its application. Summary of the invention

[0005] The technical problem to be solved by the present invention is how to detect the purity of trifluoromethylsulfonyl fluoride gas and the types and contents of impurity components contained therein.

[0006] The present invention solves the above technical problems through the following technical means:

[0007] A method for determining the purity of trifluoromethylsulfonyl fluoride gas comprises the following steps:

[0008] S1. Using a gas chromatography-mass spectrometer to detect the trifluoromethylsulfonyl fluoride gas to be tested, and determining the molecular structure of the impurities in the gas sample based on the mass-charge ratio data of the ion fragments of each component obtained;

[0009] S2. Prepare standard gas;

[0010] S3, using a gas chromatograph equipped with a thermal conductivity cell detector and a hydrogen flame ionization detector to detect the standard gas to obtain a single-point calibration curve;

[0011] S4. Detect the trifluoromethylsulfonyl fluoride gas to be detected using a gas chromatograph equipped with a thermal conductivity cell detector and a hydrogen flame ionization detector to obtain the chromatographic peak area of ​​the impurity, and then quantitatively calculate the volume fraction of each impurity using a single-point calibration curve of the standard gas;

[0012] S5. Calculate the purity of trifluoromethylsulfonyl fluoride by subtraction method;

[0013] Among them, in S1, the chromatographic column used in the gas chromatography-mass spectrometry is a capillary chromatographic column, including one of DB-VRX, DB-1, and SE-30 chromatographic columns; in S3 and S4, in the gas chromatograph, the chromatographic column connected to the thermal conductivity cell detector is a filling column, including one of Porapak Q, 5A molecular sieve, and Haysep Q, and the chromatographic column connected to the hydrogen flame ionization detector is a capillary chromatographic column, including one of DB-VRX, DB-1, and SE-30 chromatographic columns.

[0014] Preferably, in S1, determining the molecular structure of impurities in the gas sample based on the mass-to-charge ratio data of the ion fragments of each component includes comparing and searching the mass-to-charge ratio data of the ion fragments of each component with the NIST database to determine the molecular structure of the impurities in the trifluoromethylsulfonyl fluoride gas.

[0015] Preferably, in S2, the standard gas is prepared according to the technical indicators of the gas product purity index and the molecular structure of the impurities; the gas product purity index includes that the volume content of air in trifluoromethylsulfonyl fluoride is not higher than 0.5% and the purity is not lower than 99%.

[0016] Preferably, for impurities without standard substances, known substances are used as references, and the volume fraction of the impurities is semi-quantitatively calculated using a reference calibration method.

[0017] Preferably, in S2, the standard gas is a mixed gas including air, sulfur dioxide and chlorotrifluoromethane, and the volume content of air is not higher than 0.5%, the volume content of sulfur dioxide is not higher than 0.6%, and the volume content of chlorotrifluoromethane is not higher than 0.5%.

[0018] Preferably, in S2, the standard gas is a mixture of air, sulfur dioxide, chlorotrifluoromethane and argon, the volume fractions of air, sulfur dioxide and chlorotrifluoromethane are 0.488%, 0.523% and 0.485% respectively, and the balance is argon.

[0019] Preferably, in S3, the working range of the obtained single-point calibration curve should be greater than the content of impurities in the sample.

[0020] Preferably, the impurity content is calculated according to the following formula:

[0021]

[0022] Among them, A i is the peak area of ​​the corresponding substance in the standard gas, is the concentration of the corresponding substance in the standard gas, A 杂质 is the peak area of ​​the impurity in the sample to be tested, is the concentration of impurities in the sample to be tested.

[0023] Preferably, the impurities include inorganic impurities and organic impurities and exclude moisture and acidity.

[0024] Preferably, the chromatographic conditions of the capillary chromatographic column include: chromatographic column: DB-VRX; chromatographic column specifications: column length × inner diameter × film thickness: 30m × 0.32mm × 1.5μm; vaporization chamber temperature: 150-250°C; detector temperature: 250°C; column box temperature: 30-50°C for 5min, heated to 150°C at 10°C / min, and maintained for 5min; carrier gas flow rate: 2-3mL·min -1 ; Split ratio: 25-100:1; Injection volume: 0.25 mL; Packing column chromatography conditions include: Chromatographic column: Porapak Q; Chromatographic column specifications: 3m×3mm; Vaporization chamber temperature: 150℃; Detector temperature: 250℃; Column box temperature: 150℃ constant temperature for 15min; Carrier gas flow rate: 30mL·min -1 ; Injection volume: 0.25mL.

[0025] Preferably, the chromatographic conditions of the capillary chromatographic column include: chromatographic column: DB-VRX; chromatographic column specifications: column length × inner diameter × film thickness: 30m × 0.32mm × 1.5μm; vaporization chamber temperature: 150°C; detector temperature: 250°C; column box temperature: 30°C for 5min, heated to 150°C at 10°C / min, and maintained for 5min; carrier gas flow rate: 2mL·min -1 ; Split ratio: 40; Injection volume: 0.25 mL; Packing column chromatography conditions include: Chromatographic column: Porapak Q; Chromatographic column specifications: 3m×3mm; Vaporization chamber temperature: 150℃; Detector temperature: 250℃; Column box temperature: 150℃ constant temperature for 15min; Carrier gas flow rate: 30mL·min -1 ; Injection volume: 0.25mL.

[0026] The invention has the advantages that: the invention specifically adopts a gas chromatography-mass spectrometer and a gas chromatograph to carry out detection and analysis, and specifically controls the chromatographic conditions used for the analysis, adopts a single-point external standard method to carry out quantitative and semi-quantitative analysis of inorganic and organic impurities in trifluoromethylsulfonyl fluoride (TCD is a universal detector, which responds to both inorganic and organic substances, but its reproducibility in analyzing organic substances in the invention is poor, and the invention only uses TCD to analyze inorganic substances, and uses FID to analyze organic substances), and uses a subtraction method to obtain the purity of trifluoromethylsulfonyl fluoride, the analysis method is accurate and reliable, the instrument configuration is simple, and the operation is easy, and the invention is suitable for the analysis and testing of trifluoromethylsulfonyl fluoride. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 is a flow chart of a method for determining the purity of trifluoromethylsulfonyl fluoride gas in an embodiment of the present invention;

[0028] Figure 2 The analytical spectra of crude trifluoromethylsulfonyl fluoride using different chromatographic columns in the embodiments of the present invention;

[0029] Figure 3 The trifluoromethylsulfonyl fluoride sample analysis spectra using different chromatographic conditions in the embodiments of the present invention;

[0030] Figure 4 This is the GCMS spectrum of the crude trifluoromethylsulfonyl fluoride in Example 1 of the present invention;

[0031] Figure 5 The standard gas chromatogram in Example 1 of the present invention;

[0032] Figure 6 This is the chromatogram of the trifluoromethylsulfonyl fluoride gas sample in Example 1 of the present invention. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described in combination with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0034] Unless otherwise specified, the test materials and reagents used in the following examples can be obtained from commercial sources.

[0035] If no specific techniques or conditions are specified in the examples, they can be carried out according to the techniques or conditions described in the literature in the art or according to the product instructions.

[0036] In the embodiment of the present invention, the trifluoromethylsulfonyl fluoride gas impurities are divided into two categories: inorganic impurities and organic impurities. Figure 1 As shown, the determination method includes using a gas chromatography-mass spectrometer to perform qualitative analysis on each component in the sample, preparing a standard gas according to the impurity composition and technical index requirements, analyzing the standard gas using a thermal conductivity cell detector and a hydrogen flame ionization detector to obtain a single-point calibration curve, analyzing the sample using a thermal conductivity cell detector and a hydrogen flame ionization detector, quantitatively analyzing the volume fraction of each impurity, and obtaining the sample purity by subtraction; first, using a gas chromatography-mass spectrometer to detect the crude trifluoromethylsulfonyl fluoride, and according to the mass-to-charge ratio data of each impurity ion fragment and combined with a standard database, the molecular structure of each impurity in the sample gas is obtained to achieve qualitative analysis of various impurities; according to the requirements of the gas product purity index of standard T / CSEE 0308-2022 "Perfluoroisobutyronitrile Gas for Electrical Equipment", that is, the volume purity is not less than 99%, and the air volume content is not higher than 0.5%, prepare a standard gas including three components of air, sulfur dioxide, and trifluorochloromethane. Since there is no standard substance for bis(trifluoromethyl) disulfide, chlorotrifluoromethane is used as a reference substance to perform semi-quantitative analysis on bis(trifluoromethyl) disulfide. The balance gas can be an inert gas such as helium or argon; the single-point external standard method is used to test the inorganic and organic components in the standard gas using the thermal conductivity cell detector and the hydrogen flame ionization detector in the gas chromatograph, and a standard curve of concentration and peak area is established; the trifluoromethylsulfonyl fluoride sample is then tested using a gas chromatograph to obtain the chromatographic peak area of ​​each component, which is then brought into the above standard curve for calculation to obtain the concentration value of each component; the purity of trifluoromethylsulfonyl fluoride is calculated using the subtraction method. It is worth noting that the analytical instrument and conditions of the sample to be tested must be consistent with those of the standard gas (see Table 1 for instrument conditions and Table 2 for standard gas).

[0037] Table 1 Chromatographic operating conditions of packed columns and capillary columns

[0038]

[0039]

[0040] Table 2 Concentration of each component in standard gas

[0041]

[0042] The influence of suitable chromatographic column on the accuracy of sample analysis is obvious. By using gas chromatography-mass spectrometry, according to the conditions in Table 1, only the capillary column used is replaced, and the spectra of trifluoromethylsulfonyl fluoride samples analyzed by different capillary columns are compared (see Figure 2 ) It can be seen that the Gaspro and HP-5 columns cannot completely separate all organic impurities in the sample, which is not conducive to accurate qualitative and quantitative analysis of each impurity, while the DB-VRX column can better separate various impurities in the sample. Therefore, the DB-VRX capillary column is selected as the recommended chromatographic column; keeping other test conditions unchanged, after further optimizing the chromatographic conditions, each impurity has a good separation degree (optimized chromatographic conditions and test results are shown in Figure 3 ,in, Figure 3 The sample tested was a sample with a higher purity of the target substance, and except for trifluoromethylsulfonyl fluoride, the content of other impurities was very low).

[0043] Example 1

[0044] A method for determining the purity of trifluoromethylsulfonyl fluoride gas comprises the following steps:

[0045] S1. Using a gas chromatography-mass spectrometer and the analytical conditions of the capillary column in Table 1, the crude trifluoromethylsulfonyl fluoride to be tested was detected to obtain Figure 4 The mass spectrum shown in the figure; according to the mass-to-charge ratio data of each impurity ion fragment and combined with the NIST standard database, the molecular structure of each impurity in the sample gas is obtained to achieve qualitative analysis of various impurities;

[0046] from Figure 4 It can be seen that the sample mainly contains carbon tetrafluoride, trifluorochloromethane, trifluoromethylsulfonyl fluoride, bis(trifluoromethyl)disulfide, sulfur dioxide, and trifluoromethylsulfonyl chloride. The mass-to-charge ratio and molecular formula of each substance are shown in Table 3.

[0047] Table 3 Summary of impurities in crude trifluoromethylsulfonyl fluoride

[0048]

[0049] S2. According to the molecular structure of the impurities in Table 3, prepare standard gas containing air, chlorotrifluoromethane and sulfur dioxide, as shown in Table 2 (Among the three substances, air and sulfur dioxide are inorganic substances, and chlorotrifluoromethane is an organic substance. The air content is the content required to be measured in the product technical indicators; sulfur dioxide is an intermediate product in the production process, and the measurement of this indicator is mainly used for production process control; chlorotrifluoromethane is an organic impurity in the product, so chlorotrifluoromethane is used as a reference substance for semi-quantitative analysis of carbon tetrafluoride, bis(trifluoromethyl) disulfide and trifluoromethylsulfonyl chloride.

[0050] S3, the prepared standard gas is analyzed by a gas chromatograph equipped with a thermal conductivity cell detector and a hydrogen flame ionization detector according to the conditions in Table 1 to obtain a chromatogram as shown in Figure 5 As shown, the chromatographic peak area of ​​each component is shown in Table 4, and a single-point calibration curve is obtained;

[0051] Air: y = 1.73 × 10 7 x

[0052] Sulfur dioxide: y = 5.55 × 10 6 x

[0053] Chlorotrifluoromethane: y = 1.2 × 10 6 x

[0054] Where: y is the gas content (volume fraction), %; x is the chromatographic peak area

[0055] Table 4 Summary of peak areas of components in standard gas

[0056]

[0057]

[0058] S4. Analyze the trifluoromethylsulfonyl fluoride gas sample using a gas chromatograph equipped with a thermal conductivity cell detector and a hydrogen flame ionization detector according to the conditions in Table 1 to obtain a chromatogram as shown in Figure 6 The chromatographic peak area and single-point quantitative analysis results of each component are shown in Table 5.

[0059] Table 5 Summary of peak areas of various components in trifluoromethylsulfonyl fluoride gas samples

[0060]

[0061] Among them, ND in the table means not detected, / means that the substance was not detected, so it was not calculated; other organic substances mainly include carbon tetrafluoride and bis(trifluoromethyl disulfide), which is the sum of the quantitative analysis results of these two substances. According to the semi-quantitative calculation results, the air content in the trifluoromethylsulfonyl fluoride gas sample is 0.351%, the organic impurity content is 0.151%, and the overall purity is 99.498%.

[0062] Table 3 shows the crude product during the reaction, which aims to include all impurities, facilitate the screening of chromatographic columns, and provide a basis for qualitative analysis.

[0063] Table 5 shows the pure trifluoromethylsulfonyl fluoride obtained after purification, which is convenient for verifying the precision of the quantitative analysis method and also proves that the product meets the technical index requirements.

[0064] Example 2

[0065] The trifluoromethylsulfonyl fluoride sample containing air, sulfur dioxide, carbon tetrafluoride, trifluorochloromethane, and trifluoromethylsulfonyl chloride was tested according to the steps of Example 1S3. The results are shown in Tables 6 and 7.

[0066] Table 6 Repeatability test results of air and sulfur dioxide

[0067]

[0068] Table 7 Repeatability test results of carbon tetrafluoride / chlorotrifluoromethane and trifluoromethylsulfonyl chloride

[0069]

[0070] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for measuring the purity of trifluoromethylsulfonyl fluoride gas, characterized in that: The following steps are involved: S1. Using a gas chromatography-mass spectrometer to detect the trifluoromethylsulfonyl fluoride gas to be tested, and determining the molecular structure of the impurities in the gas sample based on the mass-charge ratio data of the ion fragments of each component obtained; S2. Prepare standard gas; S3, using a gas chromatograph equipped with a thermal conductivity cell detector and a hydrogen flame ionization detector to detect the standard gas to obtain a single-point calibration curve; S4. Detect the trifluoromethylsulfonyl fluoride gas to be detected using a gas chromatograph equipped with a thermal conductivity cell detector and a hydrogen flame ionization detector to obtain the chromatographic peak area of ​​the impurity, and then quantitatively calculate the volume fraction of each impurity using a single-point calibration curve of the standard gas; S5. Calculate the purity of trifluoromethylsulfonyl fluoride by subtraction method; Among them, in S1, the chromatographic column used in the gas chromatography-mass spectrometry is a capillary chromatographic column, including one of DB-VRX, DB-1, and SE-30 chromatographic columns; in S3 and S4, in the gas chromatograph, the chromatographic column connected to the thermal conductivity cell detector is a filling column, including one of Porapak Q, 5A molecular sieve, and Haysep Q, and the chromatographic column connected to the hydrogen flame ionization detector is a capillary chromatographic column, including one of DB-VRX, DB-1, and SE-30 chromatographic columns.

2. The method for measuring the purity of trifluoromethylsulfonyl fluoride gas according to claim 1, characterized in that: In S1, determining the molecular structure of impurities in the gas sample based on the mass-to-charge ratio data of the ion fragments of each component includes comparing and searching the mass-to-charge ratio data of the ion fragments of each component with the NIST database to determine the molecular structure of the impurities in the trifluoromethylsulfonyl fluoride gas.

3. The method for measuring the purity of trifluoromethylsulfonyl fluoride gas according to claim 1, characterized in that: In S2, standard gas is prepared according to the technical indicators of gas product purity index and molecular structure of impurities; the gas product purity index includes that the volume content of air in trifluoromethylsulfonyl fluoride is not higher than 0.5% and the purity is not lower than 99%.

4. The method for determining the purity of trifluoromethylsulfonyl fluoride gas according to claim 1, characterized in that: For impurities without standard substances, known substances were used as references, and the reference calibration method was used to semi-quantitatively calculate the volume fraction of the impurities.

5. The method for determining the purity of trifluoromethylsulfonyl fluoride gas according to claim 1, characterized in that: In S2, the standard gas is a mixed gas including air, sulfur dioxide and chlorotrifluoromethane, and the volume content of air is not higher than 0.5%, the volume content of sulfur dioxide is not higher than 0.6%, and the volume content of chlorotrifluoromethane is not higher than 0.5%.

6. The method for determining the purity of trifluoromethylsulfonyl fluoride gas according to claim 1, characterized in that: In S2, the standard gas is a mixture of air, sulfur dioxide, chlorotrifluoromethane and argon, the volume fractions of air, sulfur dioxide and chlorotrifluoromethane are 0.488%, 0.523% and 0.485% respectively, and the balance is argon.

7. The method for determining the purity of trifluoromethylsulfonyl fluoride gas according to claim 1, characterized in that: In S3, the working range of the obtained single-point calibration curve should be larger than the content of impurities in the sample.

8. The method for determining the purity of trifluoromethylsulfonyl fluoride gas according to claim 1, characterized in that: The impurity content is calculated according to the following formula: Among them, A i is the peak area of ​​the corresponding substance in the standard gas, is the concentration of the corresponding substance in the standard gas, A 杂质 is the peak area of ​​the impurity in the sample to be tested, is the concentration of impurities in the sample to be tested.

9. The method for determining the purity of trifluoromethylsulfonyl fluoride gas according to claim 1, characterized in that: The impurities include inorganic impurities and organic impurities and exclude moisture and acidity.

10. The method for determining the purity of trifluoromethylsulfonyl fluoride gas according to any one of claims 1 to 9, characterized in that: The chromatographic conditions of the capillary column include: chromatographic column: DB-VRX; chromatographic column specifications: column length × inner diameter × film thickness: 30m × 0.32mm × 1.5μm; vaporization chamber temperature: 150-250℃; detector temperature: 250℃; column box temperature: 30-50℃ for 5min, heating to 150℃ at 10℃ / min, and maintaining for 5min; carrier gas flow rate: 2-3mL·min -1 ; Split ratio: 25-100:1; Injection volume: 0.25 mL; Packing column chromatography conditions include: Chromatographic column: Porapak Q; Chromatographic column specifications: 3m×3mm; Vaporization chamber temperature: 150℃; Detector temperature: 250℃; Column box temperature: 150℃ constant temperature for 15min; Carrier gas flow rate: 30mL·min -1 ; Injection volume: 0.25mL.

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