Refining method of ultra-dry electronic-grade n-octane

Abstract

The invention discloses a refining method of ultra-dry electronic-grade n-octane, and belongs to the technical field of chemical purification. Comprising the following steps: S1, dewatering commercially available n-octane by using a 4A molecular sieve; s2, filtering to remove solid particles in the n-octane; s3, introducing n-octane into a rectifying still, keeping the pressure in the rectifying still at-60kPa to-85kPa, starting heating to set the temperature in the rectifying still at 120-160 DEG C, starting to receive a front fraction when the tower top temperature rises to 100-115 DEG C, receiving a main fraction when the front fraction accounts for 5%-10% of the mass of the n-octane, and collecting the front fraction and the main fraction respectively, wherein the main fraction accounts for 80%-90% of the mass of the n-octane; the main fraction is the ultra-dry electronic-grade n-octane. According to the method, efficient separation of trace water and components is realized through cooperation of molecular sieve water removal and high-vacuum rectification. The yield of the main fraction reaches 80-90%, and the water content is 1t; the component purity is greater than or equal to 99.5%, and the metal purity can reach the 7N standard, so that the requirements of electronic-grade products are met.

Description

Technical Field

[0001] The present invention belongs to the technical field of chemical purification, and particularly relates to a refining method for ultra-dry electronic-grade n-octane. Background Art

[0002] Ultra-dry electronic-grade n-octane is a high-purity organic solvent, with its purity usually reaching over 99.5% and the water content being extremely low, usually at the ppm level.

[0003] In the electronics and semiconductor industries, ultra-dry electronic-grade n-octane has extremely wide applications. First of all, in the semiconductor manufacturing process, the cleanliness of the wafer directly affects the quality and performance of the final product; the high purity and low residue characteristics of ultra-dry electronic-grade n-octane make it an ideal solvent for cleaning wafers, capable of effectively removing organic pollutants and particles on the wafer surface and ensuring the high cleanliness of the wafer. Secondly, it also plays an important role in photoresist removal. Photoresist is a key material in semiconductor manufacturing, but it needs to be completely removed after completing its function. Traditional removal methods may cause damage or residue on the wafer surface, while using ultra-dry electronic-grade n-octane can efficiently and safely remove the photoresist without causing any damage to the wafer surface. In addition, it is also used as a cleaning agent. In the cleaning process of chemical equipment and pipelines, the high purity and low residue characteristics of ultra-dry electronic-grade n-octane make it an ideal cleaning agent, capable of effectively removing the residues inside the equipment and pipelines and ensuring the cleanliness and safety of the production process.

[0004] However, there are also many difficulties in the process of preparing ultra-dry electronic-grade n-octane, such as it is difficult to reduce the water content to below 10 ppm, the process cost is high and the time consumption is long. For example, Chinese Patent CN114940642A discloses a preparation method for semiconductor-grade n-octane, which includes steps such as using P2O5 to adsorb and remove the water in n-octane, using molecular sieves to adsorb impurities, rectifying to remove inorganic metal ions, and pressure filtration to remove particles. Although it shows that the water content can reach below 2 ppm, its operation mainly relies on P2O5 for water removal and requires multiple feeding steps and waiting for 24 h for continuous testing. These steps are cumbersome and time-consuming and are not suitable for industrial production applications.

[0005] Therefore, it has high application value to develop a new n-octane treatment process to reduce the water content of n-octane, improve the purity and yield, and shorten the treatment time. Summary of the Invention

[0006] The purpose of the present invention is to provide a refining method for ultra-dry electronic-grade n-octane to reduce the water content of n-octane, improve the yield and purity, and shorten the process duration.

[0007] The purpose of the present invention can be achieved through the following technical solutions:

[0008] A refining method for ultra-dry electronic-grade n-octane, comprising the following steps:

[0009] S1. Using 4A molecular sieve to remove water from commercially available n-octane;

[0010] S2. Filtering to remove solid particles in the n-octane;

[0011] S3. Feeding the n-octane into a distillation kettle, maintaining the pressure in the distillation kettle at -60 kPa to -85 kPa, turning on the heating, setting the temperature in the distillation kettle at 120 - 160 °C, starting to collect the fore-fraction when the temperature at the top of the column rises to 100 - 115 °C, the mass of the fore-fraction accounting for 5% - 10% of the n-octane, and then collecting the main fraction after the fore-fraction ends, the mass of the main fraction accounting for 80% - 90% of the n-octane, collecting the fore-fraction and the main fraction respectively, and the main fraction is the ultra-dry electronic-grade n-octane.

[0012] Further, the water content in the commercially available n-octane is ≤ 60 ppm, preferably ≤ 50 ppm, and the component purity is ≥ 98%. The component purity is tested by gas chromatography (GC) method, and the component purity value is the percentage of the peak area value of n-octane in the peak area values of all components.

[0013] Further, the mass ratio of the 4A molecular sieve to the n-octane is 1:(10 - 23), preferably 1:(15 - 20).

[0014] Further, the 4A molecular sieve is of the 4A sodium type molecular sieve specification.

[0015] Further, the mixing time of the 4A molecular sieve and the n-octane in S1 is not less than 24 h, preferably 24 - 48 h.

[0016] Further, after the water removal in S1, the water content in the n-octane is ≤ 15 ppm, preferably ≤ 10 ppm.

[0017] Further, the pore size specification of the filter used in S2 is 0.5 - 5 μm, and at least one of 5 μm, 4 μm, 3 μm, 2.5 μm, 2 μm, 1.5 μm, 1 μm, 0.5 μm, etc. can be selected.

[0018] Further, the pressure in the distillation kettle is -60 to -80 kPa, more preferably -70 to -80 kPa.

[0019] Further, in S3, turn on the heating and set the temperature in the distillation kettle at 145 - 150 °C.

[0020] Further, the receiving speed of the fore-fraction is 10 - 15 g / min.

[0021] Further, the receiving speed of the main fraction is 20 - 45 g / min.

[0022] Furthermore, the height of the rectification column is ≥ 1.0 m, and optionally, it can be any one of 1.0 m, 1.2 m, 1.5 m, 2.0 m, 2.5 m, 2.7 m, 3.0 m, etc.

[0023] Furthermore, the rectification column is filled with stainless steel structured packing, and optionally, it can be FC-4 stainless steel structured packing with a tray height of 45 - 55 mm.

[0024] Furthermore, the low-temperature condensation temperature during rectification is -45 to -30 °C.

[0025] Furthermore, the remaining n-octane in the kettle is drawn out as kettle residue.

[0026] Furthermore, the water content of the ultra-dry electronic-grade n-octane is < 5 ppm, and more preferably ≤ 2 ppm; the component purity is ≥ 99.5%.

[0027] Furthermore, the ultra-dry electronic-grade n-octane needs to be stored in an environment isolated from water and oxygen.

[0028] Furthermore, the fore-fraction can be used as a raw material for n-octane and continue the purification process.

[0029] Advantages of the present invention:

[0030] (1) Through deep synergistic water removal and high-precision separation, the present invention realizes the ultra-purification of commercially available n-octane. Pretreatment with 4A sodium-type molecular sieve reduces the water content to the specified value; subsequent rectification is carried out under high vacuum and precise temperature control, combined with ultra-low temperature condensation and high-efficiency structured packing, realizing the separation of trace water, light components (fore-fraction) and heavy components (kettle residue); significantly improving the purity and dryness of n-octane, the water content of the prepared product can be ≤ 2 ppm, the component purity is ≥ 99.5%, and the metal purity is ≥ 99.99999% (7N standard), meeting the stringent requirements of the electronic grade, and the process is stable and controllable.

[0031] (2) The present invention optimally integrates the advantages of physical adsorption and vacuum rectification and sets key process parameters. Molecular sieve pretreatment can greatly reduce the initial water load; a specific high vacuum range effectively reduces the boiling point of n-octane and adjusts the volatility of different components, allowing efficient separation at a relatively low and safe temperature, reducing the generation of thermally sensitive impurities and energy consumption. By precisely controlling the receiving speed of the fore-fraction and the main fraction, combined with high-efficiency packing, the clarity of fraction cutting and the high yield of the main product are ensured. In addition, the recyclable design of the fore-fraction reduces raw material waste and improves the economy and environmental protection of the overall process. Description of the Drawings

[0032] The following further describes the present invention in conjunction with the drawings.

[0033] Figure 1 It is the GC chromatogram of the ultra-dry electronic-grade n-octane refined in Example 1 of the present invention;

[0034] Figure 2 It is the GC chromatogram of the ultra-dry electronic-grade n-octane refined in Example 2 of the present invention;

[0035] Figure 3 It is the GC chromatogram of the ultra-dry electronic-grade n-octane refined in Example 3 of the present invention;

[0036] Figure 4 It is the GC comparison chromatogram of the ultra-dry electronic-grade n-octane refined in Example 1 of the present invention and commercially available n-octane. Detailed Embodiments

[0037] The following is a detailed description of the specific embodiments of the present invention, but it should be understood that the protection scope of the present invention is not limited by the specific embodiments.

[0038] Example 1

[0039] This example provides a refining method for ultra-dry electronic-grade n-octane, including the following steps:

[0040] S1. Use 4A sodium molecular sieve and commercially available n-octane to be configured in a mass ratio of 1:17.5 and placed for more than 24 hours for water treatment;

[0041] Among them, the water content of the commercially available n-octane is 41 ppm, and the component purity is 98.5%; the water content of the n-octane after water treatment is 10 ppm;

[0042] S2. Use a raw material filter with a pore size specification of 2 μm to remove solid particles in the n-octane;

[0043] S3. Keep the pressure of the stainless steel distillation column kettle for leak detection. After the result is normal, evacuate the kettle to a negative pressure (-100 kPa) and purge the feed pipeline with nitrogen, and then pump in 10 kg of n-octane;

[0044] Control the pressure in the kettle to -75 kPa, turn on the heating to set the temperature in the kettle to 145 °C, turn on the low-temperature cooling circulation pump, and set the condensation reflux temperature to -40 °C. When the top temperature rises to 105 °C and the reflux ratio is 0.3:8, start receiving the fore fraction, with a receiving speed of 10 g / min. The mass of the fore fraction accounts for 5% of the commercially available n-octane. After the collection of the fore fraction is completed, receive the main fraction, with a receiving speed of 35 g / min. The mass of the main fraction accounts for 85% of the commercially available n-octane. After the completion, draw out the remaining n-octane in the kettle as the kettle residue, and collect the fore fraction and the main fraction respectively. The main fraction is the ultra-dry electronic-grade n-octane;

[0045] Among them, the rectifying column is filled with 2.5 m high FC-4 stainless steel structured packing, and the packing tray has a height of 50 mm.

[0046] The GC spectrum of the ultra-dry electronic grade n-octane obtained above is as Figure 1 shown; calculated according to the peak area, the component purity of the ultra-dry electronic grade n-octane is 99.864%.

[0047] The GC comparison spectrum of the ultra-dry electronic grade n-octane and the commercially available n-octane obtained above is as Figure 4 shown; compared with the commercially available n-octane, the GC curve of the ultra-dry electronic grade n-octane obtained by the method of the present application has fewer impurity peaks and higher product component purity.

[0048] Example 2

[0049] The difference between this example and Example 1 is that the process parameters are adjusted, and the specific implementation steps are as follows:

[0050] S1. Use 4A sodium molecular sieve and commercially available n-octane to be configured in a mass ratio of 1:10 and placed for more than 24 h for water treatment;

[0051] Among them, the water content of the commercially available n-octane is 41 ppm, and the component purity is 98.5%; the water content of the n-octane after water treatment is 15 ppm;

[0052] S2. Use a raw material filter with a pore size of 2 μm to remove solid particles in the n-octane;

[0053] S3. Keep the stainless steel distillation column kettle under pressure for leak detection. After the result is normal, evacuate the kettle to a negative pressure (-100 kPa) and purge the feed pipeline with nitrogen, and then draw in 20 kg of n-octane.

[0054] Control the pressure in the distillation kettle to -80 kPa, turn on the heating, set the temperature in the distillation kettle to 120 °C, turn on the low-temperature cooling circulation pump, and set the condensation reflux temperature to -40 °C. When the top temperature rises to 100 °C and the reflux ratio is 0.2:8, start receiving the fore fraction at a receiving speed of 12 g / min. The mass of the fore fraction accounts for 10% of the n-octane. After the collection of the fore fraction is completed, start receiving the main fraction at a receiving speed of 30 g / min. The mass of the main fraction accounts for 80% of the n-octane. After completion, draw out the remaining n-octane in the kettle as the kettle residue, and collect the fore fraction and the main fraction respectively. The main fraction is the ultra-dry electronic grade n-octane.

[0055] Among them, the rectifying column is filled with 2.5 m high FC-4 stainless steel structured packing, and the packing tray has a height of 50 mm.

[0056] The remaining raw materials and the preparation process are the same as those in Example 1.

[0057] The GC spectrum of the ultra-dry electronic grade n-octane obtained above is asFigure 2 As shown, based on the peak area calculation, the component purity of the ultra-dry electronic-grade n-octane is 99.776%.

[0058] Example 3

[0059] This example is different from Example 1 in that the process parameters are adjusted. The specific implementation steps are as follows:

[0060] S1. Use 4A sodium-type molecular sieve and commercially available n-octane to configure according to the mass ratio of 1:23 and place for more than 24 hours for water treatment;

[0061] Among them, the water content of the commercially available n-octane is 41 ppm, and the component purity is 98.5%; the water content of the n-octane after water treatment is 9 ppm;

[0062] S2. Use a raw material filter with a pore size specification of 2 μm to remove solid particles in the n-octane;

[0063] S3. Keep the stainless-steel distillation column kettle under pressure to check for leaks. After the result is normal, evacuate the kettle to a negative pressure (-100 kPa) and purge the feed pipeline with nitrogen, and then draw in 25 kg of n-octane;

[0064] Control the pressure in the distillation kettle to -70 kPa, turn on the heating, set the temperature in the distillation kettle to 160 °C, turn on the low-temperature cooling circulation pump, and set the condensation reflux temperature to -30 °C. When the top temperature rises to 115 °C and the reflux ratio is 0.3:8, start receiving the fore-fraction at a receiving speed of 15 g / min. The mass of the fore-fraction accounts for 7% of the n-octane. After the collection of the fore-fraction is completed, receive the main fraction at a receiving speed of 40 g / min. The mass of the main fraction accounts for 82% of the n-octane. After the end, draw out the remaining n-octane in the kettle as the kettle residue, and collect the fore-fraction and the main fraction separately. The main fraction is the ultra-dry electronic-grade n-octane.

[0065] Among them, the distillation column is filled with 2.5 m high TC-4 stainless-steel structured packing, and the height of the packing tray is 50 mm.

[0066] The remaining raw materials and the preparation process are the same as those in Example 1.

[0067] The GC chromatogram of the above-obtained ultra-dry electronic-grade n-octane is as Figure 3 shown. Based on the peak area calculation, the component purity of the ultra-dry electronic-grade n-octane is 99.853%.

[0068] Example 4

[0069] This example is different from Example 1 in that the process parameters are adjusted. The specific implementation steps are as follows:

[0070] S1. Configure 4A sodium-type molecular sieve and commercially available n-octane in a mass ratio of 1:15 and place for more than 24 hours for water treatment;

[0071] Among them, the water content of commercially available n-octane is 41 ppm, and the component purity is 98.5%; the water content of n-octane after water treatment is 10 ppm;

[0072] S2. Use a raw material filter with a pore size specification of 2 μm to remove solid particles in n-octane;

[0073] S3. Keep the pressure of the stainless steel distillation column kettle for leak detection. After the result is normal, evacuate the kettle to negative pressure (-100 kPa) and purge the feed pipeline with nitrogen, and then draw in 15 kg of n-octane;

[0074] Control the pressure in the kettle to -75 kPa, turn on the heating to set the temperature in the kettle to 130 °C, turn on the low-temperature cooling circulation pump, and set the condensation reflux temperature to -40 °C. When the top temperature rises to 108 °C and the reflux ratio is 0.3:8, start receiving the fore fraction at a receiving speed of 11 g / min. The mass of the fore fraction accounts for 6% of n-octane. After the collection of the fore fraction is completed, receive the main fraction at a receiving speed of 20 g / min. The mass of the main fraction accounts for 81% of n-octane. After completion, draw out the remaining n-octane in the kettle as the kettle residue, collect the fore fraction and the main fraction respectively, and the main fraction is the ultra-dry electronic-grade n-octane;

[0075] Among them, the distillation column is filled with 2.5 m high FC-4 stainless steel structured packing, and the height of the packing tray is 50 mm.

[0076] The remaining raw materials and preparation process are the same as those in Example 1. The component purity of the ultra-dry electronic-grade n-octane tested by GC is 99.746%.

[0077] Example 5

[0078] Compared with Example 1, this example is different in that the process parameters are adjusted, and the specific implementation steps are as follows:

[0079] S1. Configure 4A sodium-type molecular sieve and commercially available n-octane in a mass ratio of 1:20 and place for more than 24 hours for water treatment;

[0080] Among them, the water content of commercially available n-octane is 41 ppm, and the component purity is 98.5%; the water content of n-octane after water treatment is 12 ppm;

[0081] S2. Use a raw material filter with a pore size specification of 2 μm to remove solid particles in n-octane;

[0082] S3. Keep the pressure of the stainless steel distillation column kettle for leak detection. After the result is normal, evacuate the kettle to negative pressure (-100 kPa) and purge the feed pipeline with nitrogen, and then draw in 22.5 kg of n-octane;

[0083] Control the pressure in the bottom of the column to -75 kPa, turn on the heating and set the temperature in the column to 155 °C, turn on the low-temperature cooling circulation pump, and set the condensation reflux temperature to -40 °C. When the temperature at the top of the column rises to 112 °C and the reflux ratio is 0.3:8, start receiving the fore fraction at a receiving speed of ............

[0084] Among them, the rectifying column is filled with 2.5 m high FC-4 stainless steel structured packing, and the height of the packing tray is 50 mm.

[0085] The remaining raw materials and the preparation process are the same as those in Example 1. The purity of the components of the ultra-dry electronic grade n-octane tested by GC is 99.806%.

[0086] Comparative Example 1

[0087] Compared with Example 1, the difference in this comparative example is that the pressure in the bottom of the column is adjusted to -50 kPa. The specific implementation steps are as follows:

[0088] S1. Use 4A sodium molecular sieve and commercially available n-octane to configure according to the mass ratio of 1:17.5 and place for more than 24 h for water treatment;

[0089] Among them, the water content of the commercially available n-octane is 41 ppm, and the component purity is 98.5%; the water content of the n-octane after water treatment is 10 ppm;

[0090] S2. Use a raw material filter with a pore size of 2 μm to remove solid particles in the n-octane;

[0091] S3. Keep the pressure of the stainless steel rectifying column bottom for leak detection. After the result is normal, evacuate the column bottom to negative pressure (-100 kPa) and purge the feed pipeline with nitrogen, and then draw in 10 kg of n-octane;

[0092] Control the pressure in the bottom of the column to -50 kPa, turn on the heating and set the temperature in the column to 145 °C, turn on the low-temperature cooling circulation pump, and set the condensation reflux temperature to -40 °C. When the temperature at the top of the column rises to 105 °C and the reflux ratio is 0.3:8, start receiving the fore fraction at a receiving speed of 10 g / min, the mass of the fore fraction accounts for ............

[0093] The remaining raw materials and the preparation process are the same as those in Example 1. The purity of the components of the ultra-dry electronic-grade n-octane tested by GC is 98.611%.

[0094] Comparative Example 2

[0095] Compared with Example 1, the difference in this comparative example is that the temperature in the kettle is adjusted to 100 °C by turning on the heating. The specific implementation steps are as follows:

[0096] S1. Use 4A sodium molecular sieve and commercially available n-octane to configure according to the mass ratio of 1:17.5 and place for more than 24 hours for water treatment;

[0097] Among them, the water content of the commercially available n-octane is 41 ppm, and the component purity is 98.5%; the water content of the n-octane after water treatment is 10 ppm;

[0098] S2. Use a raw material filter with a pore size of 2 μm to remove solid particles in the n-octane;

[0099] S3. Keep the pressure of the stainless steel distillation column kettle for leak detection. After the result is normal, evacuate the kettle to a negative pressure (-100 kPa) and purge the feed pipeline with nitrogen, and then draw in 10 kg of n-octane;

[0100] Control the pressure in the kettle to -75 kPa, turn on the heating to set the temperature in the kettle to 100 °C, turn on the low-temperature cooling circulation pump, and set the condensation reflux temperature to -40 °C. When the top temperature rises to 85 °C and the reflux ratio is 0.3:8, start receiving the fore-fraction at a receiving speed of 10 g / min. The mass of the fore-fraction accounts for 5% of the n-octane. After the collection of the fore-fraction is completed, receive the main fraction at a receiving speed of 35 g / min. The mass of the main fraction accounts for 85% of the n-octane. After the completion, draw out the remaining n-octane as the kettle residue, and collect the fore-fraction and the main fraction respectively. The main fraction is the ultra-dry electronic-grade n-octane;

[0101] The remaining raw materials and the preparation process are the same as those in Example 1. The purity of the components of the ultra-dry electronic-grade n-octane tested by GC is 98.561%.

[0102] Comparative Example 3

[0103] Compared with Example 1, the difference in this comparative example is that the receiving speed of the fore-fraction is adjusted to 20 g / min. The specific implementation steps are as follows:

[0104] S1. Use 4A sodium molecular sieve and commercially available n-octane to configure according to the mass ratio of 1:17.5 and place for more than 24 hours for water treatment;

[0105] Among them, the water content of the commercially available n-octane is 41 ppm, and the component purity is 98.5%; the water content of the n-octane after water treatment is 10 ppm;

[0106] S2. Remove solid particulate matter in n-octane using a raw material filter with a pore size specification of 2 μm;

[0107] S3. Keep the pressure of the stainless-steel distillation column kettle for leak detection. After the result is normal, evacuate the kettle to a negative pressure (-100 kPa) and purge the feed pipeline with nitrogen. Then, draw in 10 kg of n-octane;

[0108] Control the pressure in the kettle to -75 kPa, turn on the heating to set the temperature in the kettle to 145 °C, turn on the low-temperature cooling circulation pump, and set the condensation reflux temperature to -40 °C. When the top temperature rises to 105 °C and the reflux ratio is 0.3:8, start receiving the fore fraction at a receiving speed of 10 g / min. The mass of the fore fraction accounts for 5% of the n-octane. After the collection of the fore fraction is completed, receive the main fraction at a receiving speed of 20 g / min. The mass of the main fraction accounts for 85% of the n-octane. After completion, draw out the remaining n-octane in the kettle as the kettle residue. Collect the fore fraction and the main fraction separately. The main fraction is the ultra-dry electronic grade n-octane;

[0109] The remaining raw materials and the preparation process are the same as those in Example 1. The purity of the components of the ultra-dry electronic grade n-octane tested by GC is 98.738%.

[0110] Comparative Example 4

[0111] Compared with Example 1, the difference in this comparative example is that the mass of the fore fraction accounts for 2% of the n-octane, and the mass of the main fraction accounts for 95% of the n-octane. The specific implementation steps are as follows:

[0112] S1. Configure 4A sodium-type molecular sieve and commercially available n-octane in a mass ratio of 1:17.5 and place them for more than 24 h for water treatment;

[0113] Among them, the water content of the commercially available n-octane is 41 ppm, and the component purity is 98.5%; the water content of the n-octane after water treatment is 10 ppm;

[0114] S2. Remove solid particulate matter in n-octane using a raw material filter with a pore size specification of 2 μm;

[0115] S3. Keep the pressure of the stainless-steel distillation column kettle for leak detection. After the result is normal, evacuate the kettle to a negative pressure (-100 kPa) and purge the feed pipeline with nitrogen. Then, draw in 10 kg of n-octane;

[0116] Control the pressure in the bottom of the column to -75 kPa, turn on the heating and set the temperature in the column to 145 °C, turn on the low-temperature cooling circulation pump, and set the condensation reflux temperature to -40 °C. When the top temperature rises to 105 °C and the reflux ratio is 0.3:8, start receiving the fore-fraction at a rate of 10 g / min. The mass of the fore-fraction accounts for 2% of n-octane. After the collection of the fore-fraction is completed, start receiving the main fraction at a rate of 35 g / min. The mass of the main fraction accounts for 95% of n-octane. After completion, draw out the remaining n-octane in the column as the residue at the bottom of the column. Collect the fore-fraction and the main fraction separately. The main fraction is the ultra-dry electronic-grade n-octane;

[0117] The remaining raw materials and the preparation process are the same as those in Example 1. The purity of the components of the ultra-dry electronic-grade n-octane tested by GC is 98.563%.

[0118] Comparative Example 5

[0119] Compared with Example 1, the difference in this comparative example is that the water content of the commercially available n-octane is 80 ppm and the component purity is 97.55%. The specific implementation steps are as follows:

[0120] S1. Configure 4A sodium-type molecular sieve and commercially available n-octane in a mass ratio of 1:17.5 and place them for more than 24 h for water treatment;

[0121] Among them, the water content of the commercially available n-octane is 80 ppm and the component purity is 97.55%; the water content of the n-octane after water treatment is 10 ppm;

[0122] S2. Use a raw material filter with a pore size of 2 μm to remove solid particles in n-octane;

[0123] S3. Keep the pressure of the stainless-steel distillation column bottom for leak detection. After the result is normal, evacuate the column bottom to a negative pressure (-100 kPa) and purge the feed pipeline with nitrogen, and then draw in 10 kg of n-octane;

[0124] Control the pressure in the bottom of the column to -75 kPa, turn on the heating and set the temperature in the column to 145 °C, turn on the low-temperature cooling circulation pump, and set the condensation reflux temperature to -40 °C. When the top temperature rises to 105 °C and the reflux ratio is 0.3:8, start receiving the fore-fraction at a rate of 10 g / min. The mass of the fore-fraction accounts for 5% of n-octane. After the collection of the fore-fraction is completed, start receiving the main fraction at a rate of 35 g / min. The mass of the main fraction accounts for 85% of n-octane. After completion, draw out the remaining n-octane as the residue at the bottom of the column. Collect the fore-fraction and the main fraction separately. The main fraction is the ultra-dry electronic-grade n-octane;

[0125] The remaining raw materials and the preparation process are the same as those in Example 1. The purity of the components of the ultra-dry electronic-grade n-octane tested by GC is 98.211%.

[0126] Statistically analyze the performance test results of the ultra-dry electronic-grade n-octane prepared in Examples 1-5 and Comparative Examples 1-5. Among them, the water content was measured using a moisture tester (Karl Fischer method), the component purity was measured using the GC method, and the value was the percentage of the n-octane peak area in the total peak area of the components. The yield was the percentage of the actual mass of n-octane in the theoretical mass. The results are shown in Table 1:

[0127] Table 1

[0128]

[0129] As can be seen from Table 1, the water content of the refined n-octane in Example 1 was 2.5 ppm, the GC purity measured was 99.864%, and the yield was 85%. Figure 4 In the GC comparison spectrum of the n-octane in Example 1 and the commercially available n-octane, the disappearance of miscellaneous peaks was also shown in the n-octane of Example 1; the water content of the n-octane in Examples 2-5 could reach below 5 ppm, the yield was above 80%, the component purity reached above 99.5%, and the metal purity could reach the 7N standard (ICP-MS method), and the process took a short time.

[0130] It can be seen from the comparison of Comparative Examples 1-5 with Example 1 that the adjustment results of process parameters showed a decrease in purity and yield. Although the yield in Comparative Example 4 was relatively high, its water content was too high and the purity was low, making it unable to be used subsequently.

[0131] In summary, the refining method of ultra-dry electronic-grade n-octane provided by the present invention obtains ultra-dry electronic-grade n-octane with low water content and high purity. The refining method has a high yield, simple process operation, and good application prospects.

[0132] The above discloses only several specific embodiments of the present invention. However, the embodiments of the present invention are not limited thereto, and any changes that can be thought of by those skilled in the art should fall within the protection scope of the present invention.

Claims

1. A refining method for ultra-dry electronic-grade n-octane, characterized in that, It includes the following steps: S1. Use 4A molecular sieve to remove water from commercially available n-octane; S2. Filter to remove solid particles in n-octane; S3. Feed n-octane into a distillation kettle, keep the pressure in the distillation kettle at -60 kPa to -85 kPa, turn on the heating, set the temperature in the distillation kettle at 120 - 160 °C, start receiving the fore-fraction when the top temperature rises to 100 - 115 °C, the mass of the fore-fraction accounts for 5% - 10% of n-octane, after the fore-fraction ends, receive the main fraction, the mass of the main fraction accounts for 80% - 90% of n-octane, collect the fore-fraction and the main fraction respectively, and the main fraction is the ultra-dry electronic grade n-octane.

2. The refining method of super-dry electronic grade n-octane according to claim 1, characterized in that, The water content in the commercially available n-octane is ≤ 60 ppm, and the component purity is ≥ 98%.

3. A refining method of super-dry electronic-grade n-octane according to claim 1, characterized in that The mass ratio of the 4A molecular sieve to n-octane is 1:(10 - 23).

4. The refining method of super-dry electronic grade n-octane according to claim 1, characterized in that, After water removal in S1, the water content in n-octane is ≤ 15 ppm.

5. The refining method of super-dry electronic-grade n-octane according to claim 1, wherein The aperture specification of the filter used in S2 is 0.5 - 5 μm.

6. The refining method of a super-dry electronic-grade n-octane according to claim 1, characterized in that, The pressure in the distillation kettle is -60 to -80 kPa; in S3, turn on the heating and set the temperature in the distillation kettle at 145 - 150 °C.

7. A refining method for ultra-dry electronic-grade n-octane according to claim 1, characterized in that, The receiving speed of the fore-fraction is 10 - 15 g / min.

8. A refining method for super-dry electronic-grade n-octane according to claim 1, characterized in that, The receiving speed of the main fraction is 20 - 45 g / min.

9. A refining method of super-dry electronic-grade n-octane according to claim 1, characterized in that, The height of the distillation column is ≥ 1.0 m, and the distillation column is filled with stainless steel structured packing.

10. A refining method of ultra-dry electronic-grade n-octane according to claim 1, characterized in that, The water content of the ultra-dry electronic grade n-octane is < 5 ppm, and the component purity is ≥ 99.5%.

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