阅读说明：本技术 一种硫酸乙烯酯制备过程中的气相色谱监测方法 (Gas chromatography monitoring method in vinyl sulfate preparation process ) 是由 谢芳 刘磊 魏志凯 苗力孝 于 2020-10-27 设计创作，主要内容包括：本发明公开了一种硫酸乙烯酯制备过程中的气相色谱监测方法,属于检测分析技术领域。所述气相色谱监测方法为：对硫酸乙烯酯和亚硫酸乙烯酯均进行气相色谱对标,建立色谱面积-质量浓度的标准曲线。本发明使用外标法同时建立原料(亚硫酸乙烯酯)和产品(硫酸乙烯酯)的质量浓度-色谱面积的标准曲线。该方法可以同时检测原料亚硫酸乙烯酯和产品硫酸乙烯酯的纯度,进而监测反应进度和反应异常变化。同时可快速读取亚硫酸乙烯酯的转化率以及硫酸乙烯酯的粗品收率。(The invention discloses a gas chromatography monitoring method in a vinyl sulfate preparation process, and belongs to the technical field of detection and analysis. The gas chromatography monitoring method comprises the following steps: and (3) performing gas chromatography calibration on the vinyl sulfate and the vinyl sulfite, and establishing a standard curve of chromatographic area-mass concentration. The invention uses an external standard method to establish a standard curve of mass concentration-chromatographic area of a raw material (ethylene sulfite) and a product (ethylene sulfate). The method can simultaneously detect the purity of the raw material of the ethylene sulfite and the product of the ethylene sulfate, and further monitor the reaction progress and the abnormal change of the reaction. Meanwhile, the conversion rate of the ethylene sulfite and the crude yield of the ethylene sulfate can be rapidly read.)

1. A gas chromatography monitoring method in the preparation process of vinyl sulfate is characterized in that the vinyl sulfate and the vinyl sulfite are subjected to gas chromatography calibration, and a standard curve of chromatographic area-mass concentration is established.

2. The method for monitoring the gas chromatography in the vinyl sulfate preparation process according to claim 1, wherein an autosampler is used for sample injection, and dry ice is used for cooling the autosampler before sample injection, so that the temperature of the inner wall of the autosampler is maintained at 0-5 ℃ during sample injection.

3. The method for monitoring gas chromatography in the preparation process of vinyl sulfate according to claim 2, wherein the flow rate of the dry ice is 0.45-0.55 kg/h.

4. The method for monitoring gas chromatography in the process of preparing vinyl sulfate according to claim 1, wherein the detection conditions of the gas chromatography are as follows: the chromatographic column is a (50% -phenyl) -methyl polysiloxane chromatographic column, the length of the column is 30m, the inner diameter of the column is 0.53mm, the thickness of the membrane is 0.50 mu m, the content of carrier gas is more than or equal to 99.999%, the sample injection amount is 0.6 mu L, the column flow is 3.0mL/min, the tail blowing flow is 25mL/min, the spacer blowing flow is 3mL/min, the reference flow is 15mL/min, the hydrogen flow is 30mL/min, and the air flow is 400 mL/min.

5. The method according to claim 1, wherein the temperature of the detector during the analysis by chromatography is 270 ℃, the temperature of the sample injector is 260 ℃, the initial temperature is 37 ℃ and the temperature is maintained for 2min, and the temperature is increased to 250 ℃ and the temperature is maintained for 5min at 15 ℃/min.

6. The method for monitoring gas chromatography in the preparation process of vinyl sulfate according to claim 1, wherein the mass concentration of the vinyl sulfate standard sample solution is 1-10%.

7. The method for monitoring gas chromatography in the production process of vinyl sulfate according to claim 1, wherein the mass concentration of the vinyl sulfite standard sample solution is 1% to 20%.

8. The method for monitoring gas chromatography in the production process of vinyl sulfate according to claim 6 or 7, wherein the solution of the standard samples of vinyl sulfate ester and vinyl sulfite is prepared using methylene chloride as a solvent.

9. The method according to claim 6 or 7, wherein the purity of the vinyl sulfate and the vinyl sulfite used for establishing the standard curve is not less than 99.5% by weight.

Technical Field

The invention belongs to the technical field of detection and analysis, and particularly relates to a gas chromatography monitoring method in a vinyl sulfate preparation process.

Background

The vinyl sulfate serving as an electrolyte additive of the lithium ion battery can improve the initial capacity of the battery and improve the capacity attenuation of the battery so as to prolong the cycle life of the battery; in addition, the electrolyte has obvious effects of improving the high-temperature performance of the battery and inhibiting high-temperature gas generation. The preparation method of vinyl sulfate which is reported in the prior publication is a redox method, namely under the protection of an organic solvent (generally dichloromethane or trichloromethane), vinyl sulfite is oxidized by an oxidant under the action of a catalyst to generate the vinyl sulfate. The reaction is a two-phase reaction in which a water phase and an organic phase coexist, raw material ethylene sulfite and product ethylene sulfate are dissolved in the organic phase, and a catalyst, an oxidant or a PH buffer solution involved in the reaction are dissolved in the water phase. The commonly used reaction process monitoring method is gas chromatography detection, and the progress of the oxidation reaction is judged by detecting the purity of DTD in an organic phase.

Both the ethylene sulfite and the ethylene sulfate are dissolved in the organic phase, theoretically, the higher the purity of the ethylene sulfate represents the more thorough the reaction, and the higher the conversion rate of the ethylene sulfite; otherwise, the conversion rate is low. However, vinyl sulfate has poor thermal stability, and its decomposition is caused if the temperature of the reaction system is increased, resulting in low chromatographic purity. Therefore, the purity of the vinyl sulfate alone cannot correctly reflect the change of the whole reaction process. In addition, the ethylene sulfite which is not completely reacted is mixed into the ethylene sulfate in the reaction process, thereby increasing the difficulty of product purification and influencing the product purity. Meanwhile, the method for calculating the yield in the prior art comprises the following steps: and (3) after the organic phase is subjected to the procedures of liquid separation, washing, dehydration, recrystallization and the like, weighing and calculating the obtained crystals. However, the method can only calculate the final product yield, cannot reflect the progress and abnormal change points of the reaction process in time, is not beneficial to real-time monitoring of the production process, and easily causes material waste, labor, electric power and other production line resource waste in the actual production process.

Disclosure of Invention

The invention aims to provide a gas chromatography monitoring method in the preparation process of vinyl sulfate, which can monitor the reaction process, has high detection accuracy and can rapidly read the conversion rate of the vinyl sulfite and the yield of the vinyl sulfate.

In order to achieve the purpose, the invention provides the following technical scheme:

the invention provides a gas chromatography monitoring method in a vinyl sulfate preparation process, which is used for performing gas chromatography calibration on both vinyl sulfate and vinyl sulfite and establishing a standard curve of chromatographic area-mass concentration.

Preferably, an automatic sample injector is adopted for sample injection, and dry ice is adopted to cool the automatic sample injector before sample injection, so that the temperature of the inner wall of the sample injector is maintained at 0-5 ℃ in the sample injection process.

Preferably, the flow rate of the dry ice is 0.45-0.55 Kg/h.

Preferably, the detection conditions of the gas chromatograph are as follows: the chromatographic column is a (50% -phenyl) -methyl polysiloxane chromatographic column, the length of the column is 30m, the inner diameter of the column is 0.53mm, the thickness of the membrane is 0.50 mu m, the content of carrier gas is more than or equal to 99.999%, the sample injection amount is 0.6 mu L, the column flow is 3.0mL/min, the tail blowing flow is 25mL/min, the spacer blowing flow is 3mL/min, the reference flow is 15mL/min, the hydrogen flow is 30mL/min, and the air flow is 400 mL/min.

Preferably, the detector temperature for chromatographic analysis is 270 ℃, the injector temperature is 260 ℃, the initial temperature is 37 ℃, the temperature is maintained for 2min, and the temperature is raised to 250 ℃ at 15 ℃/min, and the temperature is maintained for 5 min.

Preferably, the mass concentration of the vinyl sulfate standard sample solution is 1-10%.

Preferably, the mass concentration of the ethylene sulfite standard sample solution is 1-20%.

Preferably, methylene chloride is used as a solvent to prepare a standard sample solution of the vinyl sulfate ester and the vinyl sulfite.

Preferably, the purity of the vinyl sulfate and the vinyl sulfite used for establishing the standard curve is more than or equal to 99.5 percent in percentage by weight.

Compared with the prior art, the invention has the beneficial effects that:

the invention provides a gas chromatography monitoring method in a vinyl sulfate preparation process, which comprises the steps of carrying out gas chromatography calibration on both vinyl sulfate and vinyl sulfite, establishing a standard curve of chromatographic area-mass concentration, and simultaneously establishing a standard curve of mass concentration-chromatographic area of a raw material (vinyl sulfite) and a product (vinyl sulfate) by using an external standard method. The method can simultaneously detect the purity of the raw material of the ethylene sulfite and the product of the ethylene sulfate, and further monitor the reaction progress and the abnormal change of the reaction. Meanwhile, based on a mass concentration-chromatographic area curve, the conversion rate of the ethylene sulfite and the crude yield of the ethylene sulfate can be rapidly read. And the method can monitor the product purity and quality concentration change of each section (reaction, water washing, dehydration, recrystallization and the like) for preparing the vinyl sulfate.

Furthermore, the dry ice is adopted to cool the automatic sample injector before sample injection, so that the temperature of the inner wall of the sample injector is maintained at 0-5 ℃ in the sample injection process, the stability of the sample to be detected is ensured, and the accuracy of the detection result is improved.

Drawings

FIG. 1 shows the results of chromatographic measurements in a certain synthesis of vinyl sulfate in example 3.

Detailed Description

The invention provides a gas chromatography monitoring method in a vinyl sulfate preparation process, which is used for performing gas chromatography calibration on both vinyl sulfate and vinyl sulfite and establishing a standard curve of chromatographic area-mass concentration.

In the invention, an automatic sample injector is preferably adopted for sample injection, and dry ice is adopted for cooling the automatic sample injector before sample injection, so that the temperature of the inner wall of the sample injector is maintained at 0-5 ℃ in the sample injection process. In the invention, the flow rate of the dry ice is 0.45-0.55 Kg/h, and more preferably 0.5 Kg/h. The vinyl sulfate is easy to absorb water and hydrolyze and has poor thermal stability, and in the invention, the dry ice is adopted to cool the sample injector to prevent the decomposition of the vinyl sulfate and ensure the stability of the sample, thereby improving the accuracy of detection.

In the invention, the automatic sample injector is used for sample injection, the sample injection amount of the standard sample and the sample to be detected is strictly controlled, the error caused by inconsistent sample injection amount is eliminated, the operation process is simple and quick, and the accuracy is extremely high; in addition, by adopting a direct sample introduction mode, pretreatment is not needed, and errors caused by dilution of low-content or trace impurities are eliminated. The apparatus for gas chromatography of the present invention is not particularly limited, and may be any apparatus conventionally used in the art. In the embodiment of the present invention, Thermo Trace 1300E is used.

In the present invention, the detection conditions of the gas chromatography are preferably: the chromatographic column is a (50% -phenyl) -methyl polysiloxane chromatographic column, the length of the column is 30m, the inner diameter of the column is 0.53mm, the thickness of the membrane is 0.50 mu m, the content of carrier gas is more than or equal to 99.999%, the sample injection amount is 0.6 mu L, the column flow is 3.0mL/min, the tail blowing flow is 25mL/min, the spacer blowing flow is 3mL/min, the reference flow is 15mL/min, the hydrogen flow is 30mL/min, and the air flow is 400 mL/min.

In the present invention, the detector temperature for the chromatographic analysis is preferably 270 ℃, the injector temperature is preferably 260 ℃, the initial temperature is 37 ℃, the temperature is maintained for 2min, and the temperature is raised to 250 ℃ at 15 ℃/min, and the temperature is maintained for 5 min.

In the present invention, the mass concentration of the vinyl sulfate standard sample solution is preferably 1% to 10%. In the present invention, this concentration range should cover the theoretical concentration calculated from the reaction charge. In the present invention, the mass concentration of the ethylene sulfite standard sample solution is preferably 1% to 20%. In the present invention, this concentration range should cover the theoretical concentration of the input material. In the present invention, it is preferable to prepare a standard sample solution of vinyl sulfate ester and vinyl sulfite ester using methylene chloride as a solvent. In the present invention, the purity of both the vinyl sulfate and vinyl sulfite used to establish the standard curve is preferably 99.5% or more in terms of weight percentage. In the present invention, monitoring is performed by establishing an external standard curve, rather than an internal standard curve or standard addition method, by which it is not necessary to add a standard sample to the solution to be measured each time. After the standard curve is established, the chromatograph can directly analyze and read mass concentration data, and is simple and efficient.

In order to further illustrate the present invention, the following embodiments are described in detail, but they should not be construed as limiting the scope of the present invention.

Example 1

Establishing a gas chromatography standard curve of the vinyl sulfate:

preparing a vinyl sulfate solution with the mass concentration of 1-10%. Accurately weighing 0.1g, 0.25g, 0.5g, 0.75g and 1.0g of vinyl sulfate respectively in a clean and dry glass bottle, and adding a dichloromethane solution which is cooled in an ice water bath in advance to 10g (the weighing process needs to be rapid, and errors caused by volatilization of a dichloromethane solvent are prevented). Shaking the solution evenly, respectively taking 1.5mL of the solution, injecting the solution into a special sample bottle for gas chromatography, covering a cover, placing the sample bottle on the table top of an automatic sample injector (opening a dry ice switch in advance, adjusting the flow rate, and controlling the temperature of the inner wall of the sample table to be 0-5 ℃), editing the test conditions, setting the test procedures (sample name, test type (standard sample/unknown sample), sample injector position, sample injection amount, instrument method, processing method and the like), and automatically absorbing 0.6 mu L of sample by the sample injector to inject into the gas chromatography for analysis. After the test is finished, setting the peak area calculated according to the automatic integration of the instrument as a vertical coordinate, and inputting the actual mass concentration of the corresponding sample in one column of each level. The instrument can automatically simulate the standard curve of the chromatographic area-mass concentration of the vinyl sulfate through editing of correction software.

And (3) establishing a gas chromatography standard curve of the ethylene sulfite:

preparing a vinyl sulfate solution with the mass concentration of 1-20%. Accurately weighing 0.1g, 0.5g, 1.0g, 1.5g and 2.0g of ethylene sulfite into clean and dry glass bottles respectively, and adding a dichloromethane solution which is cooled in an ice water bath in advance to 10g (the weighing process needs to be rapid, and errors caused by volatilization of a dichloromethane solvent are prevented). Shaking the solution evenly, respectively taking 1.5mL of the solution, injecting the solution into a special sample bottle for the gas chromatography, covering a cover, placing the sample bottle on the table board of an automatic sample injector (opening a dry ice switch in advance, adjusting the flow rate, controlling the temperature of the inner wall of the sample table to be 0-5 ℃), editing the test conditions, setting a test program, and automatically absorbing a certain amount of sample by the sample injector to inject the sample into the gas chromatography for analysis. After the test is finished, setting the peak area calculated according to the automatic integration of the instrument as a vertical coordinate, and inputting the actual mass concentration of the corresponding sample in one column of each level. The instrument can automatically simulate the standard curve of the chromatographic area-mass concentration of the vinyl sulfate through editing of correction software.

Table 1 example 1 chromatographic areas corresponding to different mass concentrations of vinyl sulfate and vinyl sulfite

By automatic fitting with instrument software, the following curves can be obtained:

(1) vinyl sulfate:

peak area y₁And mass concentration x₁The standard curve of (a) is: y is₁＝11.397*x₁-0.6925，R²＝0.9973

(2) Ethylene sulfite:

peak area y₂And mass concentration x₂The standard curve of (a) is: y is₂＝11.903*x₂+4.9839，R²＝0.9991

Comparative example 1

According to the method for preparing the solution provided by the embodiment 1, 6 bottles of 5 mass percent vinyl sulfate solution are prepared, the glass bottle cap is covered, and the solution is stored in a refrigerator at 5 ℃ for standby. Of these, 3 vials (designated group a) were tested according to the injection test method provided in example 1, and the other 3 groups (designated group B) were tested according to the injection test method provided in example 1, but without dry ice gas. The purity of the vinyl sulfate was read by chromatographic area normalization. The specific results are shown in table 2:

TABLE 2 purity of vinyl sulfate measured separately with and without sample injector cooling

As can be seen from Table 2, the purity of the vinyl sulfate obtained by the sample injector without adopting the cooling treatment is lower than that of the vinyl sulfate obtained by adopting the cooling treatment, and the deviation of the three groups of contrasts is greater than that of the vinyl sulfate obtained by adopting the cooling treatment, which indicates that when the cooling treatment is not adopted, the sample injection process in part of the vinyl sulfate solution can be decomposed to influence the detection accuracy, and the cooling treatment of the sample injector is favorable for the stability of the vinyl sulfate.

Example 2

According to the method for preparing the solution provided in the embodiment 1, a solution of vinyl sulfate and vinyl sulfite with a certain mass concentration is prepared and recorded as a solution to be tested, the solution is tested according to the sample injection test method provided in the embodiment 1, the concentration is calibrated by using the established curve, and the specific results are shown in table 3:

TABLE 3 example II A series of solutions to be tested were prepared and tested for mass concentration by chromatograph

As can be seen from Table 3, the error between the results of this method and the actual concentration is < 1%. Errors may result from the evaporation of methylene chloride from the solution formulation, or from solvent residue from the injector wash solvent.

Example 3

Monitoring a certain sampling point in the synthesis process of the vinyl sulfate by using the method: the mass concentrations of the vinyl sulfate and the vinyl sulfite can be directly given, and the purity of the vinyl sulfate can be calculated by a normalization method. As shown in FIG. 1, at this sampling point, the mass concentrations of the vinyl sulfite and vinyl sulfate were 0.7603% and 9.7388%, respectively; the purity of the solvent-subtracted vinyl sulfate can be calculated as follows: 88.082 percent.

The crude product yield calculation method comprises the following steps: total weight of organic phase mass concentration of vinyl sulfate per theoretical concentration of reaction completion.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.