A method for detecting samples of a vinyl ethylene sulfite reaction process

Abstract

The application provides a vinyl ethylene sulfite reaction process sample detection method and relates to the technical field of electrolyte additive production. The vinyl ethylene sulfite reaction process sample detection method comprises the following steps: S1, nitrogen deacidification; S2, deacidification by a deacidification agent; S3, filtration desalination; S4, chromatographic detection; and S5, tail gas treatment. The vinyl ethylene sulfite reaction process sample detection method provided by the application adopts organic alkali neutralization, does not damage the original state of the sample, ensures the accuracy of the test sample, can conveniently monitor the reaction process, reduces the loss caused by insufficient reaction or excessive addition of raw materials, improves the conversion rate of the raw materials, can accurately determine the reaction endpoint and the purity of the material, and can cancel the subsequent water washing and alkali washing and other purification operations under the guidance of the detection method, thereby reducing the generation of salt-containing wastewater and the processing cost of the device.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electrolyte additive production, in particular to a vinyl sulfite reaction process sample detection method. BACKGROUND

[0002] Vinyl sulfite is an important lithium battery functional material, which can be added as an additive to electrolyte to improve the storage stability and low temperature performance of the electrolyte; it is also a raw material for synthesizing vinyl sulfite, an electrolyte additive; in addition, vinyl sulfite can also be used as a pharmaceutical intermediate in the pharmaceutical field.

[0003] The common vinyl sulfite production process mainly uses ethylene glycol and thionyl chloride as reaction raw materials, and after reaction, vinyl sulfite is obtained after water washing or alkali washing to remove impurities. Due to the extremely strong acidity of the reaction system, conventional detection needs to be neutralized first, but neutralization will destroy the original sample state, resulting in a large deviation between the detection result and the actual situation. Therefore, in order to ensure the quality of vinyl sulfite products, industrial production generally uses excessive thionyl chloride to ensure the conversion rate of raw material ethylene glycol as much as possible, and water-based or alkali washing is used to remove residual thionyl chloride in vinyl sulfite; neutralizing excessive thionyl chloride will produce a large amount of high-salt and high-chemical oxygen demand wastewater, making it difficult to treat brine or byproduct hydrochloric acid, and also causing partial loss of vinyl sulfite during the neutralization process, resulting in a decrease in product yield. The present application provides a vinyl sulfite reaction process sample detection method to solve the above problems in the prior art. SUMMARY

[0004] (I) Technical problems solved

[0005] In view of the deficiencies in the prior art, the present application provides a vinyl sulfite reaction process sample detection method, which solves the problem that the traditional detection method needs to destroy the original sample state, resulting in a large deviation between the detection result and the actual situation.

[0006] (II) Technical solutions

[0007] To achieve the above purpose, the present application is implemented by the following technical solutions: a vinyl sulfite reaction process sample detection method, comprising the following steps:

[0008] S1, nitrogen deacidification:

[0009] Put the sample to be tested in the test bottle, then tighten the test bottle plug and place it on the detection table, set the detection table temperature to the temperature in the reaction kettle at the time of sampling; connect the nitrogen pipeline to the test bottle nitrogen interface, and at the same time connect the tail gas interface to the tail gas treatment device, then open the nitrogen pressure reducing valve to start nitrogen bubbling, control the ventilation rate of nitrogen to be 1-200 L / min, and use a wet pH test paper to detect the pH of the gas outlet every 1-2 min, until the test paper does not change color, and the nitrogen deacidification is completed;

[0010] S2, deacidification agent deacidification:

[0011] After the nitrogen deacidification in step S1 is completed, add the deacidification agent to the test bottle, and when no white crystals are generated in the solution, test the pH of the organic phase using a pH test paper, if the pH test paper does not change color, the deacidification is completed; if the pH test paper shows acidity, continue to add the deacidification agent until the pH of the organic phase is neutral;

[0012] S3, filtration desalination:

[0013] The salt-containing mixture after deacidification in step S2 is filtered and desalted by constant pressure filtration or negative pressure filtration, and the organic phase is taken for chromatographic testing;

[0014] S4, chromatographic detection:

[0015] Turn on the gas chromatograph in advance, complete the preparation work before chromatographic detection according to the control program, take an appropriate amount of neutralized organic phase in the chromatographic bottle after the gas chromatograph is ready, select automatic sampling for testing, and calculate the raw material conversion rate and reaction yield according to the relative peak areas of ethylene glycol and ethylene sulfite after the test is completed;

[0016] S5, tail gas treatment:

[0017] The tail gas treatment uses secondary alkali absorption, and a tail gas absorption bottle is used to neutralize the hydrogen chloride gas carried by nitrogen, and 5-32% sodium hydroxide solution is placed in the tail gas absorption bottle.

[0018] Preferably, in step S1, the detection table has a temperature control function, and the top of the test bottle has two gas interfaces, one for nitrogen and one for tail gas treatment.

[0019] Preferably, in step S2, the amount of deacidification agent added is 0.1‰-5% of the mass of the organic phase.

[0020] Preferably, in step S2, the deacidification agent is an organic base, including but not limited to one or more of triethylamine, pyridine, and sodium methoxide.

[0021] (III) Beneficial effects

[0022] The application provides a vinyl ethylene sulfite reaction process sample detection method.

[0023] 1、The vinyl ethylene sulfite reaction process sample detection method provided by the application adopts organic alkali neutralization, does not damage the original state of the sample, ensures the accuracy of the test sample, can very conveniently monitor the reaction process, reduces the loss caused by insufficient reaction or excessive addition of raw materials, and improves the conversion rate of the raw materials.

[0024] 2、The vinyl ethylene sulfite reaction process sample detection method provided by the application can very accurately judge the reaction endpoint and the purity of the material, and under the guidance of the detection method, the optimal raw material ratio of the production device can be confirmed, the subsequent water washing and alkali washing and other purification operations can be cancelled, the generation of salt-containing wastewater is reduced, and the processing cost of the device is reduced. DETAILED DESCRIPTION

[0025] The technical solutions in the embodiments of the application will be clearly and completely described below with reference to the embodiments of the application. Obviously, the described embodiments are only part of the embodiments of the application, rather than all the embodiments of the application. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the application.

[0026] Embodiment one:

[0027] The application provides a vinyl ethylene sulfite reaction process sample detection method, which comprises the following steps:

[0028] S1, nitrogen deacidification:

[0029] The sample to be tested is placed in a test bottle, and then the test bottle stopcock is tightened and placed on a detection table, the detection table temperature is set to the temperature in the reaction kettle at the time of sampling; the nitrogen gas pipeline is connected to the nitrogen gas interface of the test bottle, and the tail gas interface is connected to the tail gas treatment device, then the nitrogen pressure reducing valve is opened to start nitrogen bubbling, the ventilation rate of nitrogen is controlled to be 25L / min, and the pH of the gas outlet is detected every 2min using a wet pH test paper until the test paper does not change color, and the nitrogen deacidification is completed;

[0030] S2, deacidification of deacidification agent:

[0031] After the nitrogen deacidification in step S1 is completed, 5% of the organic phase mass of triethylamine is added to the test bottle, when no white crystals are generated in the solution, the pH of the organic phase is tested using a pH test paper, if the pH test paper does not change color, the deacidification is completed; if the pH test paper shows acidity, continue to add triethylamine until the pH of the organic phase is neutral;

[0032] S3, filtration desalination:

[0033] The salt-containing mixture after deacidification in S2 is filtered by constant pressure filtration to remove salt, and the organic phase is subjected to chromatographic test;

[0034] S4, chromatographic test:

[0035] The gas chromatograph is started in advance, and the preparation work before the chromatographic test is completed according to the control program. After the gas chromatograph is ready, an appropriate amount of neutralized organic phase is taken in a chromatographic flask, and automatic sampling is selected for testing. After the test is completed, the raw material conversion rate and reaction yield are calculated according to the relative peak areas of ethylene glycol and ethylene sulfite;

[0036] S5, tail gas treatment:

[0037] The tail gas treatment adopts secondary alkali absorption, and a tail gas absorption bottle is used to neutralize the hydrogen chloride gas entrained by nitrogen. A 20% sodium hydroxide solution is placed in the tail gas absorption bottle to ensure that the discharged tail gas does not contain acidic gas.

[0038] The ethylene sulfite reaction process sample detection method provided by the embodiment adopts triethylamine neutralization, which ensures the accuracy of the test sample without damaging the original state of the sample. At the same time, this test method can very conveniently monitor the reaction process, reduce the loss of raw materials due to insufficient reaction or excessive addition, and improve the conversion rate of raw materials

[0039] Example 2:

[0040] The ethylene sulfite reaction process sample detection method provided by the embodiment of the application comprises the following steps:

[0041] S1, nitrogen deacidification:

[0042] The sample to be tested is placed in a test bottle, and then the test bottle is tightly screwed and placed on a detection table. The temperature of the detection table is set to the temperature in the reaction kettle at the time of sampling. The nitrogen pipeline is connected to the nitrogen interface of the test bottle, and the tail gas interface is connected to the tail gas treatment device. Then, the nitrogen pressure reducing valve is opened to start nitrogen bubbling. The ventilation rate of nitrogen is controlled at 35L / min, and the pH of the gas outlet is detected every 1.5min using a wet pH test paper until the test paper does not change color, and the nitrogen deacidification is completed.

[0043] S2, deacidification with deacidifying agent:

[0044] After the nitrogen deacidification in S1 is completed, 3.5% of the organic phase by mass of triethylamine is added to the test bottle. When no white crystals are generated in the solution, the pH of the organic phase is tested using a pH test paper. If the pH test paper does not change color, the deacidification is completed. If the pH test paper shows acidity, continue to add triethylamine until the pH of the organic phase is neutral.

[0045] S3, filtration and desalination:

[0046] The salt-containing mixture after deacidification in S2 is filtered by negative pressure filtration to remove salt, and the organic phase is subjected to chromatographic test;

[0047] S4, chromatographic test:

[0048] The gas chromatograph is started in advance, and the preparation work before the chromatographic test is completed according to the control program. After the gas chromatograph is ready, an appropriate amount of neutralized organic phase is taken in the chromatographic bottle, and automatic sampling is selected for testing. After the test is completed, the raw material conversion rate and reaction yield are calculated according to the relative peak area of ethylene glycol and ethylene sulfite;

[0049] S5, tail gas treatment:

[0050] The tail gas treatment adopts secondary alkali absorption, and a tail gas absorption bottle is used to neutralize the hydrogen chloride gas entrained by nitrogen. A 20% sodium hydroxide solution is placed in the tail gas absorption bottle to ensure that the discharged tail gas does not contain acidic gas.

[0051] The ethylene sulfite reaction process sample detection method provided by the embodiment adopts triethylamine neutralization, which ensures the accuracy of the test sample while not damaging the original state of the sample. At the same time, this test method can very conveniently monitor the reaction process, reduce the loss of raw materials due to insufficient reaction or excessive addition, and improve the conversion rate of raw materials.

[0052] Example three:

[0053] The ethylene sulfite reaction process sample detection method provided by the embodiment includes the following steps:

[0054] S1, nitrogen deacidification:

[0055] The test bottle is placed in the test bottle, and then the test bottle is screwed tightly and placed on the detection table. The detection table temperature is set to the temperature in the reaction kettle at the time of sampling. The nitrogen pipeline is connected to the nitrogen interface of the test bottle, and the tail gas interface is connected to the tail gas treatment device. Then, the nitrogen pressure reducing valve is opened to start nitrogen bubbling. The ventilation rate of nitrogen is controlled at 45L / min, and the pH of the gas outlet is detected every 1min using a wet pH test paper until the test paper does not change color. Nitrogen deacidification is completed;

[0056] S2, deacidification with deacidifying agent:

[0057] After the nitrogen deacidification in S1 is completed, 3% pyridine of the organic phase is added to the test bottle. When no white crystals are generated in the solution, the pH of the organic phase is tested using a pH test paper. If the pH test paper does not change color, the deacidification is completed. If the pH test paper shows acidity, continue to add pyridine until the pH of the organic phase is neutral;

[0058] S3, filtration and desalination:

[0059] The salt-containing mixture after deacidification in S2 is filtered by negative pressure filtration to remove salt, and the organic phase is subjected to chromatographic test;

[0060] S4, chromatographic test:

[0061] The gas chromatograph is started in advance, and the preparation work before the chromatographic test is completed according to the control program. After the gas chromatograph is ready, an appropriate amount of neutralized organic phase is taken in the chromatographic bottle, and automatic sampling is selected for testing. After the test is completed, the raw material conversion rate and reaction yield are calculated according to the relative peak area of ethylene glycol and ethylene sulfite;

[0062] S5, tail gas treatment:

[0063] The tail gas treatment adopts secondary alkali absorption, and a tail gas absorption bottle is used to neutralize the hydrogen chloride gas entrained by nitrogen. A 25% sodium hydroxide solution is placed in the tail gas absorption bottle to ensure that the discharged tail gas does not contain acidic gas.

[0064] The ethylene sulfite reaction process sample detection method provided by the embodiment adopts pyridine neutralization, which ensures the accuracy of the test sample without damaging the original state of the sample. At the same time, this test method can very conveniently monitor the reaction process, reduce the loss of raw materials due to insufficient reaction or excessive addition, and improve the conversion rate of raw materials.

[0065] Example Four:

[0066] The ethylene sulfite reaction process sample detection method provided by the embodiment of the application comprises the following steps:

[0067] S1, nitrogen deacidification:

[0068] The sample to be tested is placed in the test bottle, and then the test bottle is tightly screwed and placed on the detection table. The detection table temperature is set to the temperature in the reaction kettle at the time of sampling. The nitrogen pipeline is connected to the nitrogen interface of the test bottle, and the tail gas interface is connected to the tail gas treatment device. Then, the nitrogen pressure reducing valve is opened to start nitrogen bubbling. The nitrogen ventilation rate is controlled at 50L / min, and the pH of the gas outlet is detected every 30s using a wet pH test paper until the test paper does not change color, and the nitrogen deacidification is completed.

[0069] S2, deacidification with deacidifying agent:

[0070] After the nitrogen deacidification in S1 is completed, 2.5% pyridine of the organic phase is added to the test bottle. When no white crystals are generated in the solution, the pH of the organic phase is tested using a pH test paper. If the pH test paper does not change color, the deacidification is completed. If the pH test paper shows acidity, continue to add pyridine until the pH of the organic phase is neutral.

[0071] S3, filtration and desalination:

[0072] The salt-containing mixture after deacidification in S2 is filtered by negative pressure filtration to remove salt, and the organic phase is subjected to chromatographic test;

[0073] S4, chromatographic test:

[0074] The gas chromatograph is started in advance, and the preparation work before chromatographic test is completed according to the control program. After the gas chromatograph is ready, an appropriate amount of neutralized organic phase is taken into the chromatographic bottle, and automatic sampling is selected for testing. After the test is completed, the raw material conversion rate and reaction yield are calculated according to the relative peak areas of ethylene glycol and ethylene sulfite;

[0075] S5, tail gas treatment:

[0076] The tail gas treatment adopts secondary alkali absorption, and a tail gas absorption bottle is used to neutralize the hydrogen chloride gas entrained by nitrogen. A 25% sodium hydroxide solution is placed in the tail gas absorption bottle to ensure that the discharged tail gas does not contain acidic gas.

[0077] The ethylene sulfite reaction process sample detection method provided in the embodiment adopts pyridine neutralization, which ensures the accuracy of the test sample while not damaging the original state of the sample. At the same time, this test method can very conveniently monitor the reaction process, reduce the loss of raw materials due to insufficient reaction or excessive addition, and improve the conversion rate of raw materials

[0078] Although embodiments of the present application have been shown and described, it is to be understood that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present application. The scope of the present application is defined by the appended claims and their equivalents.

Claims

1. A method for detecting samples during the vinyl sulfite reaction process, characterized in that: Includes the following steps: S1, Nitrogen deacidification: Place the sample to be tested in the test bottle, then tighten the stopcock of the test bottle and place it on the testing platform. Set the temperature of the testing platform to the temperature inside the reactor when the sample is taken. Connect the nitrogen pipeline to the nitrogen port of the test bottle, and at the same time connect the tail gas port to the tail gas treatment device. Then open the nitrogen pressure reducing valve to start nitrogen bubbling. Control the nitrogen gas flow rate to 1-200 L / min, and use a moistened pH test paper to detect the pH of the gas outlet every 1-2 minutes until the test paper does not change color, indicating that nitrogen deacidification is complete. S2, deacidification agent: After nitrogen deacidification is completed in step S1, deacidifying agent is added dropwise to the test bottle. When no white crystals are formed in the solution, the pH of the organic phase is tested with pH test paper. If the pH test paper does not change color, the deacidification is complete. If the pH test paper shows acidity, the deacidifying agent is added dropwise until the pH of the organic phase is neutral. The deacidifying agent is an organic base, including one or more of triethylamine, pyridine, and sodium methoxide. S3, Filtration and Desalination: The salt-containing mixture after deacidification in step S2 is filtered and desalted by constant pressure filtration or negative pressure filtration, and the organic phase is taken for chromatographic analysis. S4. Chromatographic detection: Start the gas chromatograph in advance and complete the preparation work before chromatographic detection according to the control program. After the gas chromatograph is ready, take an appropriate amount of neutralized organic phase into the chromatographic bottle, select automatic injection for testing, and calculate the raw material conversion rate and reaction yield based on the relative peak areas of ethylene glycol and vinyl sulfite after the test. S5, Exhaust gas treatment: The exhaust gas treatment adopts a two-stage alkaline absorption method. The hydrogen chloride gas carried by the nitrogen is neutralized by using an exhaust gas absorption bottle, and a 5-32% sodium hydroxide solution is placed in the exhaust gas absorption bottle.

2. The method for detecting samples in the vinyl sulfite reaction process according to claim 1, characterized in that: In step S1, the testing station has a temperature control function, and the top of the test bottle has two gas phase interfaces, one for nitrogen and one for exhaust gas treatment.

3. The method for detecting samples in the vinyl sulfite reaction process according to claim 1, characterized in that: In step S2, the amount of deacidifying agent added is 0.1‰-5% of the mass of the organic phase.