Preparation method and application of fluorine oil high-value liquid density standard substance

Abstract

The application discloses a preparation method of fluorine oil high-value liquid density standard substance and application thereof, and comprises the following steps: 1) fluorine gas diluted by inert gas is introduced to make fluorine oil intermediate perform fluorination reaction, and fluorine oil base oil with an acid value less than 0.02 mgKOH / g is obtained; 2) the fluorine oil base oil obtained in the step 1) is subjected to molecular distillation, and fluorine oil base oil with a distillation fraction greater than 230 DEG C is preferentially removed, so that single distillation fraction fluorine oil is obtained; and 3) the single distillation fraction fluorine oil obtained in the step 2) is subjected to adsorption filtration, so that high-cleanliness target fluorine oil is obtained. Through development of a specific preparation method, the application develops a kind of liquid density standard substance which is non-toxic, stable, has high density value and meets uncertainty requirements, so as to match development of domestic full series liquid density standard substances, fill the domestic and international blank, and meet the use requirements of domestic market for liquid density standard substances.

Description

Technical Field

[0001] This invention belongs to the field of density measurement technology, specifically relating to a method for preparing a high-value liquid density standard substance for fluorinated oil and its application. Background Technology

[0002] Density metrology is widely used in numerous fields, including petroleum, chemical, building materials, light industry, medical, trade, defense, and scientific research. Density standard liquids are one of the traceability components in density metrology, serving as the foundation and key substance for ensuring the comparability, consistency, and accuracy of density measurement instrument results. Currently, China lacks a complete range of liquid density standard materials. Countries like Japan, Germany, and the UK possess comprehensive series of liquid density standard materials. China relies heavily on imports for its liquid density standard materials. While there are many international products, their quality varies, and prices are relatively high. Currently, the highest-value international liquid density standard is tetrachloroethylene (1623 kg / cm³). 3 While it can reach 20℃, it is toxic, easily evaporates, and is unstable. This imposes certain limitations on the domestic use of liquid density standard materials in terms of purchasing channels and long-term storage, making it impossible to guarantee the high precision of test results and the comparability and consistency of data between different testing institutions; moreover, in the range of 1630-2000 kg / m³... 3 There is currently a lack of liquid density standard materials within this range, and high-precision measurement of high-density liquids faces certain limitations. Therefore, there is an urgent need in China to develop a complete series of liquid density standard materials (600-2000 kg / m³). 3 This is to meet the domestic demand for liquid density measurement and ensure the accuracy of domestic liquid density measurement. Summary of the Invention

[0003] In view of this, the main objective of this invention is to provide a method for preparing a high-value liquid density standard material of fluorinated oil and its application, so as to obtain a non-toxic, extremely low-volatility, highly stable liquid density standard material with a high density value and meeting international uncertainty requirements (1800-2000 kg / m³). 3 ).

[0004] To achieve the above-mentioned objectives, the present invention adopts the following technical solution: a method for preparing a high-value liquid density standard substance of fluorinated oil, comprising the following steps:

[0005] 1) Fluorine gas diluted with inert gas is introduced to cause the fluorinated oil intermediate to undergo a fluorination reaction, resulting in a fluorinated oil base oil with an acid value of less than 0.02 mg KOH / g;

[0006] 2) Perform molecular distillation on the fluorinated oil base oil obtained in step 1) to obtain a single fraction of fluorinated oil;

[0007] 3) The fluorinated oil from the single fraction obtained in step 2) is subjected to adsorption filtration to obtain the target fluorinated oil with high purity.

[0008] According to the method of the present invention, in step 1), the reaction temperature of the fluorination reaction is 150-250°C, preferably 180-220°C.

[0009] According to the method of the present invention, in step 1), the fluorination reaction can be divided into a two-stage fluorination reaction. The first fluorination reaction time is 80-200 h, preferably 150-190 h, until the acid value is less than 0.05 mg KOH / g. The second fluorination temperature is the same as the first fluorination temperature, and the reaction time is 5-30 h, preferably 10-20 h, finally yielding a fluorinated oil base oil with an acid value of less than 0.02 mg KOH / g. The acid value can characterize unstable groups. Fluorinated oil intermediates contain unstable groups, which need to be removed through fluorination. Due to the presence of fluorine gas, the reaction process is relatively complex, and incomplete removal of unstable groups will affect stability and long-term storage of the product. To ensure that the stringent stability requirements of the liquid density standard substance are met, a two-stage fluorination reaction is preferred. As mentioned above, if higher stability is required, a three-stage fluorination can be performed, with the same fluorination temperature and a fluorination time of 5-20 h, preferably 8-15 h.

[0010] According to the method of the present invention, in step 1), the inert gas can be one of carbon dioxide, nitrogen, or argon; preferably, the concentration of fluorine is 5-80%, more preferably 8-50%, for example 50%, 16%, or 20%.

[0011] According to the method of the present invention, in step 1), the fluorinated oil intermediate can be a perfluoropolyether oil or a chlorofluorocarbon oil, and the molecular structural formula of the chlorofluorocarbon oil is: R—(CF2—CClF). n —R1, where R is CF3 or CClF2, n = 3-100; R1 is COF or COCl, and the perfluoropolyether oil has the structural formula CF3—O—[CF(CF3)—CF2O]. n —(CF2-O) m —[CF(CF3)—O) p —(O) r —R, where R is —COF or —CF2COF or —CF2CF2COF, n=3-80, and m, p, r are generally close to zero; in a specific implementation, a fluorinated oil intermediate can be added to a bubbling tower reactor, and fluorine gas diluted with an inert gas can be introduced to carry out the fluorination reaction.

[0012] According to the method of the present invention, in step 2), by controlling the feed rate, the scraper rotation speed, and the cutting temperature conditions, a single distillation fraction with a suitable viscosity of fluorinated oil is obtained.

[0013] According to the method of the present invention, in step 2), the absolute pressure is 4-8 Pa, the feed rate is 2 kg / h to 15 kg / h, preferably 4 kg / h to 10 kg / h, the scraper rotation speed is 10 r / min to 400 r / min, for example 300 r / min to 380 r / min; the cutting temperature gradient is 10 °C, and the temperature range is 55 to 175 °C, for example 55-65, 65-75, 75-85, etc.

[0014] According to the method of the present invention, in step 2), the preferred single fraction of fluorinated oil with suitable viscosity is: perfluoropolyether oil: 75-85, 85-95 or 95-105; fluorinated chlorinated oil: 105-115, 115-125, 125-135 or 135-145.

[0015] According to the method of the present invention, in step 3), the adsorption filtration process needs to be carried out in a Class 100 clean room, including: selecting activated carbon or activated alumina as the adsorbent material and polytetrafluoroethylene membrane as the filter material, adding the fluorinated oil of the single fraction obtained in step 2) to the adsorbent material, adsorbing it under heating and stirring, and then filtering it through the polytetrafluoroethylene membrane.

[0016] According to the method of the present invention, in step 3), during adsorption, preferably, the amount of adsorbent material is 5% to 20% (mass percentage), based on the total weight of fluorinated oil and adsorbent material as 100%, preferably 10% to 20%, the heating temperature is 25 to 80°C, preferably 30 to 60°C, and the stirring speed is 20 to 50 r / min, preferably 30 to 40 r / min; during filtration, the pore size of the polytetrafluoroethylene membrane is 0.05 to 0.8 μm, preferably 0.1 to 0.8 μm; in specific embodiments, the filtration method can be without external force, relying only on gravity, such as self-filtration.

[0017] In another aspect, this invention also provides a high-value liquid density standard material of fluorinated oil prepared by the above method; its density is 1800-2000 kg / m³. 3 (20℃), kinematic viscosity is 5-25 mm. 2 / s (20℃), acid value less than 0.02mgKOH / g.

[0018] In another aspect, the present invention provides the application of the high-density liquid standard material of fluorinated oil prepared by the above method, using it as a liquid density standard material, especially for the measurement of high-density liquids.

[0019] Compared with the prior art, the present invention has the following advantages:

[0020] This invention obtains a high-purity fluorinated oil fraction with suitable viscosity through a series of processes including deep fluorination, molecular distillation, and deep purification of fluorinated oil intermediates. Therefore, this invention aims to further explore the inherent potential of fluorinated oils, fully utilize their inherent properties, and develop a specific preparation method to produce a non-toxic, stable, high-density liquid density standard (1800-2000 kg / m³) that meets uncertainty requirements. 3 This will support the development of a full range of domestic liquid density standard materials, fill the gaps in both domestic and international markets, meet the domestic market's demand for liquid density standard materials, and ensure the consistency and accuracy of domestic density measurement.

[0021] The high-value liquid density standard material for fluorinated oil of this invention can be widely used in the field of density metrology, including petrochemicals, trade, and scientific research laboratories. It can help improve the accuracy of domestic liquid density metrology and contribute to the research and development and upgrading of high-precision density measuring instruments in China. Detailed Implementation

[0022] The present invention will be further described below with reference to the embodiments. However, the present invention is not limited to the listed embodiments, but should also include equivalent improvements and modifications of the technical solutions defined in the appended claims of the present invention.

[0023] The measurement methods and raw materials involved in the embodiments of the present invention are described below:

[0024] The mechanical impurity content was tested using a HIAC / RoYco 8000A / s particle counter.

[0025] The fluorinated oil intermediate is a product prepared by the applicant company; unless otherwise specified, all raw materials involved in the examples can be obtained from commercially available channels.

[0026] Example 1

[0027] Step 1: The fluorinated oil intermediate (fluorocarbon oil) undergoes a secondary fluorination process. Specifically, the intermediate is added to a bubble column reactor, and nitrogen-diluted fluorine gas is introduced at a concentration of 16%. The reaction temperature is controlled at 220℃, and the primary fluorination reaction is carried out for 190 hours until the acid value meets the requirements (0.04 mg KOH / g). A secondary fluorination is then performed at the same temperature for 16 hours, ultimately yielding a fluorinated oil base oil with an acid value of 0.015 mg KOH / g. The molecular structure of the fluorinated oil intermediate is: R—(CF2—CClF). n —R1, where R is CF3 or CClF2, n = 3-100; R1 is COF or COCl.

[0028] Step 2: Perform molecular distillation on the fluorinated base oil obtained in Step 1, prioritizing the removal of the fluorinated base oil fraction with a temperature greater than 230℃. Control the absolute pressure at 4Pa, the feed rate at 8kg / h, the scraper speed at 300r / min, and the cutting temperature gradient at 10℃. Select the fractions 105-115, 115-125, 125-135, or 135-145 based on the viscosity.

[0029] Step 3: The single-fraction fluorinated oil with suitable viscosity obtained in Step 2 is subjected to a deep purification process. Specifically, the fluorinated oil from Step 2 is added to activated carbon, and adsorption is performed under heating and stirring. Then, it is filtered through a polytetrafluoroethylene (PTFE) membrane. The activated carbon dosage is 10%, the heating temperature is 50℃, and the stirring speed is 30 r / min. The PTFE membrane has a pore size of 0.1 μm, and the filtration method relies solely on gravity for self-filtration without any external force. The entire adsorption and filtration process is carried out in a Class 100 cleanroom, yielding a high-purity fluorinated oil fraction. Its relevant indicators are tested, and the values ​​are shown in Table 1.

[0030] Example 2

[0031] Step 1: The fluorinated oil intermediate (perfluoropolyether oil) undergoes a secondary fluorination process. The specific steps are as follows: The fluorinated oil intermediate is added to a bubble column reactor, and nitrogen-diluted fluorine gas is introduced at a concentration of 70%. The reaction temperature is controlled at 180℃, and the primary fluorination reaction is carried out for 100 hours until the acid value is within acceptable limits (0.04 mg KOH / g). A secondary fluorination is then performed at the same temperature for 14 hours, ultimately yielding a fluorinated oil base oil with an acid value of 0.01 mg KOH / g. The structural formula of the fluorinated oil intermediate is CF3—O—[CF(CF3)—CF2O]. n —(CF2-O) m —[CF(CF3)—O) p —(O) r —R, where R is —COF or —CF2COF or —CF2CF2COF, n = 3-80, and m, p, and r are close to zero.

[0032] Step 2: Perform molecular distillation on the fluorinated base oil obtained in Step 1. Prioritize removing the fluorinated base oil fraction with a temperature greater than 230℃. Control the absolute pressure at 8Pa, the feed rate at 10kg / h, the scraper speed at 350r / min, and the cutting temperature gradient at 10℃. Select the fraction 75-85, 85-95, or 95-105 based on the viscosity.

[0033] Step 3: The single-fraction fluorinated oil with suitable viscosity obtained in Step 2 is subjected to a deep purification process. Specifically, the fluorinated oil from Step 2 is added to activated alumina. After adsorption under heating and stirring, it is then filtered through a polytetrafluoroethylene (PTFE) membrane. The activated alumina dosage is 20%, the heating temperature is 30℃, and the stirring speed is 30 r / min. The PTFE membrane has a pore size of 0.2 μm, and the filtration method relies solely on gravity for self-filtration without any external force. The entire adsorption and filtration process is carried out in a Class 100 cleanroom, yielding a high-purity fluorinated oil fraction. Its relevant indicators are tested, and the values ​​are shown in Table 1.

[0034] Example 3

[0035] Step 1: The fluorinated oil intermediate (fluorocarbon oil) undergoes a secondary fluorination process. The specific steps are as follows: The fluorinated oil intermediate is added to a bubble column reactor, and nitrogen-diluted fluorine gas is introduced at a concentration of 20%. The reaction temperature is controlled at 240℃, and the primary fluorination reaction is carried out for 150 hours until the acid value is acceptable (0.04 mg KOH / g). A secondary fluorination is then performed at the same temperature for 10 hours, ultimately yielding a fluorinated oil base oil with an acid value of 0.005 mg KOH / g.

[0036] Step 2: Perform molecular distillation on the fluorinated base oil obtained in Step 1. Prioritize removing the fluorinated base oil fraction with a temperature greater than 230℃. Control the absolute pressure at 8Pa, the feed rate at 4kg / h, the scraper speed at 380r / min, and the cutting temperature gradient at 10℃. Select the fractions 105-115, 115-125, 125-135, or 135-145 based on the viscosity.

[0037] Step 3: The single-fraction fluorinated oil with suitable viscosity obtained in Step 2 is subjected to a deep purification process. Specifically, the fluorinated oil from Step 2 is added to activated carbon, and adsorption is performed under heating and stirring. Then, it is filtered through a polytetrafluoroethylene (PTFE) membrane. The activated carbon dosage is 15%, the heating temperature is 60℃, and the stirring speed is 30 r / min. The PTFE membrane has a pore size of 0.8 μm, and the filtration method relies solely on gravity for self-filtration without any external force. The entire adsorption and filtration process is carried out in a Class 100 cleanroom, yielding a high-purity fluorinated oil fraction. Its relevant indicators are tested, and the values ​​are shown in Table 1.

[0038] Table 1. Index values ​​of fluorinated oil with single fraction, suitable viscosity, and high purity.

[0039]

[0040]

[0041] The acid value and viscosity in Table 1 indicate that the fluorinated oil product obtained in this embodiment has the advantages of low volatility, high stability, few impurities, high purity, and non-toxicity, and also has a high density (1800-2000 kg / m³). 3 It can be used as a standard reference for the density of a full range of liquids (600-2000 kg / m³). 3 This is to meet the domestic demand for liquid density measurement.

[0042] Comparative Example 1

[0043] Based on Example 1, changing the concentration of fluorine gas to 51% will result in a black, viscous substance. The fluorine concentration is too high, and the oil has carbonized. Normally, it should be a colorless and transparent liquid, which does not meet the requirements.

[0044] Comparative Example 2

[0045] Based on Example 2, the molecular distillation feed rate was changed to 20 kg / h. After distillation range testing, the overlap temperature between adjacent fractions reached 10°C, affecting the stability of the viscosity and density of the fractions.

[0046] Comparative Example 3

[0047] Based on Example 3, the amount of activated carbon was changed to 30%, resulting in a large oil loss and a slow filtration process. The filtered fluorinated oil contained mechanical impurities, with a test result of 10 (0.5 μm) impurities per 100 ml.

[0048] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art can make other variations or modifications based on the above description. It is impossible to exhaustively list all embodiments here. All obvious variations or modifications derived from the technical solutions of the present invention are within the scope of protection of the present invention.

Claims

1. A method for preparing a high-value liquid density standard substance of fluorinated oil, characterized in that: Includes the following steps: 1) Fluorine gas diluted with inert gas is introduced to cause the fluorinated oil intermediate to undergo a fluorination reaction, resulting in a fluorinated oil base oil with an acid value of less than 0.02 mg KOH / g; 2) Perform molecular distillation on the fluorinated oil base oil obtained in step 1) to obtain a single fraction of fluorinated oil; 3) The fluorinated oil from the single fraction obtained in step 2) is subjected to adsorption filtration to obtain the target fluorinated oil with high purity. The fluorination reaction is carried out at a temperature of 150-250℃ and is divided into two fluorination reactions. The first fluorination reaction takes 80-200 hours and continues until the acid value is less than 0.05 mg KOH / g. The second fluorination reaction is carried out at the same temperature as the first fluorination reaction, takes 5-30 hours, and has a fluorine concentration of 8-50%. The fluorinated oil intermediate is a perfluoropolyether oil or a chlorofluorocarbon oil, and the molecular structure of the chlorofluorocarbon oil is: R—(CF2—CClF). n —R1, where R is CF3 or CClF2, R1 is COF or COCl, n = 3-100; the structural formula of the perfluoropolyether oil is CF3—O—[CF(CF3)—CF2O] n —(CF2-O) m —[CF(CF3)—O) p —(O) r —R, where R is —COF or —CF2COF or —CF2CF2COF, n = 3-80, m, p, r are close to zero, and n, m, p, r are all positive integers.

2. The method for preparing the high-value liquid density standard material of fluorinated oil according to claim 1, characterized in that: In step 1), the reaction temperature of the fluorination reaction is 180-220℃.

3. The method for preparing the high-value liquid density standard material of fluorinated oil according to claim 1, characterized in that: In step 1), the primary fluorination reaction time is 150-190 h; the secondary fluorination reaction time is 10-20 h.

4. The method for preparing the high-value liquid density standard material of fluorinated oil according to any one of claims 1-3, characterized in that: In step 1), the inert gas is one of carbon dioxide, nitrogen, or argon.

5. The method for preparing the high-value liquid density standard material of fluorinated oil according to claim 1, characterized in that: In step 2), by controlling the feed rate, the scraper speed, and the cutting temperature, a single distillation fraction with a suitable viscosity of fluorinated oil is obtained.

6. The method for preparing the high-value liquid density standard material of fluorinated oil according to claim 5, characterized in that: In step 2), the absolute pressure is 4-8 Pa, the feeding speed is 2 kg / h to 15 kg / h, the scraper speed is 10 r / min to 400 r / min, the cutting temperature gradient is 10℃, and the temperature range is 55 to 175℃. The suitable single-fraction, viscosity range of fluorinated oil is as follows: perfluoropolyether oil: 75-85, 85-95 or 95-105; chlorofluorocarbon oil: 105-115, 115-125, 125-135 or 135-145.

7. The method for preparing the high-value liquid density standard material of fluorinated oil according to claim 6, characterized in that: In step 2), the feeding rate is 4 kg / h to 10 kg / h.

8. The method for preparing the high-value liquid density standard material of fluorinated oil according to claim 1, characterized in that: In step 3), the adsorption filtration is performed in a Class 100 cleanroom and includes the following steps: selecting activated carbon or activated alumina as the adsorbent material and polytetrafluoroethylene membrane as the filter material; adding the fluorinated oil from the single fraction obtained in step 2) to the adsorbent material; adsorbing the oil under heating and stirring conditions; and then filtering it through the polytetrafluoroethylene membrane.

9. The method for preparing the high-value liquid density standard material of fluorinated oil according to claim 8, characterized in that: In step 3), during adsorption, the total weight of fluorinated oil and adsorbent material is 100%, the amount of adsorbent material is 5% to 20%, the heating temperature is 25 to 80°C, and the stirring speed is 20 to 50 r / min; during filtration, the pore size of the polytetrafluoroethylene membrane is 0.05 to 0.8 μm.

10. The method for preparing the high-value liquid density standard material of fluorinated oil according to claim 9, characterized in that: In step 3), the amount of adsorbent material is 10% to 20%, the heating temperature is 30 to 60°C, and the stirring speed is 30 to 40 r / min; during filtration, the pore size of the polytetrafluoroethylene membrane is 0.1 to 0.8 μm.

11. The high-value liquid density standard material of fluorinated oil prepared by the method according to any one of claims 1-10 has a density of 1800-2000 kg / m³. 3 (20℃), kinematic viscosity is 5-25 mm. 2 / s (20℃), acid value less than 0.02mgKOH / g.

12. The application of the high-value liquid density standard material of fluorinated oil prepared by the method according to any one of claims 1-10, wherein it is used as a liquid density standard material.

13. The application of the high-value liquid density standard material of fluorinated oil according to claim 12, characterized in that: It is used for measuring high-density liquids.

Images