Method for producing G5-grade electronic-grade isopropanol

Abstract

The invention relates to the technical field of isopropyl alcohol preparation, in particular to a method for producing G5-grade electronic-grade isopropyl alcohol, which comprises the following steps: S1, raw material pretreatment: removing boron by ultrapure water: reducing the content of boron in water to be less than or equal to 0.05 ppb by adopting two-stage serial boron ion selective ion exchange resin and combining a reverse osmosis technology; and propylene hydration reaction: pressurizing process water, namely boron-removed deionized water to 8.4 MPa, respectively exchanging heat with tower kettle water of the azeotropic tower and discharged materials of the reactor, heating to 135 DEG C by a feeding heater to generate a liquid phase, and feeding into the reactor. Through directional boron removal, multi-stage rectification and low-temperature normal-pressure operation, efficient and low-cost production of the electronic grade IPA is achieved, the bottleneck of a traditional process is broken through, and the method is suitable for the ultra-precision manufacturing requirement of the semiconductor industry.

Description

Technical Field

[0001] The present invention relates to the technical field of isopropanol preparation, and in particular to a method for producing G5-level electronic-grade isopropanol. Background Art

[0002] Electronic-grade isopropanol (IPA) is a key solvent for photoresist cleaning and wafer drying in semiconductor manufacturing, and needs to meet the SEMIG5 standard (metal impurities ≤ 0.1 ppb, particles ≤ 5 pieces / mL). Traditional processes mostly use propylene hydration method or acetone hydrogenation method, but there are the following problems:

[0003] Boron pollution: Trace boron (>1 ppb) in raw water is difficult to remove, affecting the chip yield;

[0004] Insufficient purity: Conventional rectification is difficult to separate co-boiling impurities (such as acetone, water, diisopropyl ether, propylene oligomers, high-boiling hydrocarbons, 4-methyl-2-pentanone, 2-pentanone, etc.);

[0005] Complex process: Mostly rely on high-pressure rectification or molecular sieve adsorption, with high cost.

[0006] The process for producing isopropanol by the propylene hydration method is mature, but industrial-grade products (purity 99.5%) contain boron, metal ions and light / heavy components, and need to be purified specifically. The prior art has not solved the problems of boron pollution and efficient separation. Summary of the Invention

[0007] The purpose of the present invention is to provide a method for producing G5-level electronic-grade isopropanol, which solves the problems of boron pollution, insufficient purity and high energy consumption in the traditional process through directional boron removal, propylene hydration method combined with multi-stage purification process, and finally produces electronic-grade isopropanol (IPA) that meets the SEMIG5 standard (metal impurities ≤ 0.1 ppb, particles ≤ 5 pieces / mL), which is applicable to high-precision fields such as semiconductor manufacturing, so as to solve the problems raised in the above background art.

[0008] To achieve the above purpose, the present invention provides the following technical solution: A method for producing G5-level electronic-grade isopropanol, comprising the following steps:

[0009] S1. Raw material pretreatment:

[0010] Boron removal from ultrapure water:

[0011] Adopt two-stage series-connected boron ion-selective ion exchange resin, combined with reverse osmosis technology, to reduce the boron content in water to ≤ 0.05 ppb;

[0012] Propylene hydration reaction:

[0013] Process water, i.e., boron-removed deionized water, after being pressurized to 8.4 MPa and respectively exchanging heat with the water at the bottom of the azeotropic distillation column and the reactor effluent, is further heated to 135 °C by the feed heater to form a liquid phase and then enters the reactor. Propylene, after being pressurized to 8.4 MPa and heated to 135 °C, forms a vapor phase and enters the reactor from the top of the reactor. The vapor-phase propylene and the liquid-phase process water undergo a hydration reaction in the reactor. A stream of cold water at 8.4 MPa from the outlet of the process water high-pressure pump enters between the catalyst beds of each section of the reactor to control the reactor bed temperature at 140 °C to 170 °C), reduce the occurrence of side reactions, with the single-pass conversion rate of propylene being 65% and the yield of the main product being 94%.

[0014] S2. Purification of industrial-grade IPA: The reactor effluent undergoes flash evaporation in a high-pressure separation tank at a pressure of 8.4 MPa. The flashed vapor phase enters the propylene removal column through pressure control. The liquid phase exchanges heat with the reaction feed and then is cooled to 100 °C to 110 °C), and then enters a low-pressure separation tank for flash evaporation at a pressure of 2.4 MPa and a temperature of 100 °C to 110 °C. The flashed vapor phase enters the propylene removal column at a pressure of 1.7 MPa and a temperature of 40 °C - 170 °C. The gas-phase material at the top of the propylene removal column, with a pressure of 1.7 MPa and a temperature of 40 °C to 44 °C, after condensation, discharges the non-condensable gas, with part of it being refluxed and part entering the propane removal column at a pressure of 1.7 MPa and a temperature of 40 °C to 44 °C. The liquid-phase material at the bottom of the propylene removal column, with a temperature of 160 °C to 170 °C, goes to the IPA dehydration column at atmospheric pressure and a temperature of 60 °C - 90 °C.

[0015] The depropanizer separates propylene and propane. After the gaseous propylene at the top of the tower is condensed, the non-condensable gas is discharged, part of it is refluxed, and part of it is withdrawn and sent back to the propylene feed buffer tank in the reaction section. The propane at the bottom of the tower is sent to the propane vaporizer to the fuel gas network. The liquid phase discharged from the low-pressure separation tank enters the azeotropic tower at a pressure of 0.1 MPa to 0.3 MPa and a temperature of 100 °C to 150 °C to separate out a large amount of water. The bottom product is mainly water. After heat exchange with the reaction feed, most of the process water is recycled, and a small amount is discharged as wastewater into the sewage treatment. The top material of the azeotropic tower is mainly IPA, water, DIPE and other side reaction products. This stream of material enters the dehydration tower for dehydration at atmospheric pressure and a temperature of 60 °C - 90 °C. The crude IPA with less water content is obtained at the bottom of the tower. The vapor phase at the top of the tower is cooled by a cooler and then enters the reflux tank. After oil-water separation, the aqueous phase containing part of IPA returns to the azeotropic tower. The oil phase is rich in DIPE and a small amount of water and IPA, and then undergoes extraction and refining to recover DIPE and IPA. The crude IPA withdrawn from the bottom of the dehydration tower is sent to the IPA light component removal tower at atmospheric pressure and a temperature of 70 °C to 90 °C to remove the light components with lower boiling points such as C6. The light components withdrawn from the top of the tower are sent to the light component storage tank. The IPA withdrawn from the bottom of the tower is then sent to the heavy component removal tower at atmospheric pressure and a temperature of 90 °C to 100 °C to remove the heavy components in the IPA. The qualified IPA product is obtained from the top of the heavy component removal tower, and the heavy components withdrawn from the bottom of the tower are sent to the heavy component storage tank. Finally, industrial-grade IPA is obtained through propylene recovery; the purity of crude isopropanol ≥ 95%;

[0016] S3. Refining of electronic-grade IPA:

[0017] The first and second stage packed distillation columns are connected in series at the bottom

[0018] First-stage atmospheric distillation: A packed tower is used, and the light component steam is withdrawn from the top to remove residual light components such as diisopropyl ether, propane, acetaldehyde, acetone and a small amount of water vapor, etc.;

[0019] Second-stage atmospheric rectification side stream withdrawal: The target fraction is withdrawn from the upper-middle part of the tower to avoid the azeotrope, and the purity is increased to ≥ 99.99%;

[0020] Terminal filtration: Filter through a 0.03 μm PTFE hydrophobic membrane to ensure that the particle number ≤ 3 pieces / mL.

[0021] Compared with the prior art, the beneficial effects of the present invention are:

[0022] Boron pollution control: The combination of ion exchange resin and reverse osmosis is used, and the boron residue ≤ 0.03 ppb, which is significantly lower than the SEMIG5 standard.

[0023] Efficient separation: The double-stage rectification synergistic side stream withdrawal technology breaks through the azeotropic limit and reduces impurity entrainment.

[0024] Energy saving and consumption reduction: Low-temperature atmospheric operation replaces high-pressure rectification, the energy consumption is reduced by 40%, and the production cost is optimized;

[0025] The present invention realizes the efficient and low-cost production of electronic-grade IPA through directional boron removal, multi-stage rectification, and low-temperature and atmospheric-pressure operation, breaks through the bottleneck of traditional processes, and is applicable to the ultra-precision manufacturing requirements of the semiconductor industry. Brief Description of the Drawings

[0026] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0027] Figure 1 It is a process flow diagram of a method for producing G5-level electronic-grade isopropyl alcohol according to the present invention;

[0028] Figure 2 It is the industrial-grade IPA gas chromatogram according to the present invention;

[0029] Figure 3 It is the electronic-grade IPA gas chromatogram according to the present invention. Specific Embodiments

[0030] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0031] The water content is measured by a Karl Fischer moisture meter;

[0032] The concentration of a single metal cation is measured by ICP-MS;

[0033] The anion concentration is measured by an anion chromatograph;

[0034] The number of particles (>50 nm) is measured by a particle counter;

[0035] Except as specifically pointed out, various materials can be obtained commercially.

[0036] For the specific embodiments, please refer to Figures 1 to 3 , and a technical solution is provided:

[0037] A method for producing G5-level electronic-grade isopropyl alcohol, comprising the following steps:

[0038] S1. Pretreatment of raw materials:

[0039] Ultra-pure water deboronation:

[0040] Adopt two-stage series-connected boron ion selective ion exchange resin, combined with reverse osmosis technology, to reduce the boron content in water to ≤0.05 ppb;

[0041] Propylene hydration reaction:

[0042] Process water, that is, deboronated deionized water, after being pressurized to 8.4 MPa, exchanges heat with the bottom water of the azeotropic tower and the reactor outlet respectively, and then is heated to 135 °C by the feed heater to generate a liquid phase and enter the reactor. Propylene is pressurized to 8.4 MPa and then heated to 135 °C to generate a vapor phase, which enters the reactor from the top of the reactor. The vapor-phase propylene and the liquid-phase process water carry out a hydration reaction in the reactor. A stream of cold water at 8.4 MPa at the outlet of the process water high-pressure pump enters between the catalyst beds of each section of the reactor to control the reactor bed temperature at 140 °C to 170 °C), reduce the occurrence of side reactions, with a single-pass conversion rate of propylene of 65% and a main product yield of 94%.

[0043] S2. Industrial-grade IPA purification: The reactor outlet is flashed in a high-pressure separation tank at a pressure of 8.4 MPa. The flashed vapor phase enters the propylene removal tower through pressure control. The liquid phase exchanges heat with the reaction feed and then is cooled to 100 °C to 110 °C), and then enters the low-pressure separation tank for flashing at a pressure of 2.4 MPa and a temperature of 100 °C to 110 °C. The flashed vapor phase enters the propylene removal tower at a pressure of 1.7 MPa and a temperature of 40 °C - 170 °C. The gas-phase material at the top of the propylene removal tower has a pressure of 1.7 MPa and a temperature of 40 °C - 44 °C. After condensation, the non-condensable gas is discharged, part is refluxed, and part enters the propane removal tower at a pressure of 1.7 MPa and a temperature of 40 °C to 44 °C. The liquid-phase material at the bottom of the propylene removal tower has a temperature of 160 °C to 170 °C and goes to the IPA dehydration tower at atmospheric pressure and a temperature of 60 °C - 90 °C.

[0044] The depropanizer separates propylene and propane. After the gaseous propylene at the top of the tower is condensed, the non-condensable gas is discharged, part of it is refluxed, and part of it is withdrawn and sent back to the propylene feed buffer tank in the reaction section. The propane at the bottom of the tower is sent to the propane vaporizer to the fuel gas pipeline network. The liquid phase discharged from the low-pressure separation tank enters the azeotropic tower at a pressure of 0.1 MPa to 0.3 MPa and a temperature of 100 °C to 150 °C to separate out a large amount of water. The bottom draw is mainly water. After heat exchange with the reaction feed, most of the process water is recycled, and a small amount is discharged as wastewater into the sewage treatment. The top material of the azeotropic tower is mainly IPA, water, DIPE and other side reaction products. This stream of material enters the dehydration tower for dehydration at atmospheric pressure and a temperature of 60 °C - 90 °C. The crude IPA with low water content is obtained at the bottom of the tower. The vapor phase at the top of the tower is cooled by a cooler and then enters the reflux drum. After oil-water separation, the water phase containing part of IPA returns to the azeotropic tower. The oil phase is rich in DIPE and a small amount of water and IPA, and then is extracted and refined to recover DIPE and IPA. The crude IPA drawn from the bottom of the dehydration tower is sent to the IPA light component removal tower at atmospheric pressure and a temperature of 70 °C to 90 °C to remove the light components with lower boiling points such as C6 light components. The light components drawn from the top of the tower are sent to the light component storage tank. The IPA drawn from the bottom of the tower is then sent to the heavy component removal tower at atmospheric pressure and a temperature of 90 °C to 100 °C to remove the heavy components in the IPA. The qualified IPA product is obtained from the top of the heavy component removal tower, and the heavy components drawn from the bottom of the tower are sent to the heavy component storage tank. Finally, industrial-grade IPA is obtained through propylene recovery; the purity of crude isopropanol ≥ 95%;

[0045] S3. Refining of electronic-grade IPA:

[0046] The first and second-stage packed distillation columns are connected in series at the bottom

[0047] The first-stage atmospheric distillation: A packed tower is used, and the light component steam is withdrawn from the top to remove the residual light components such as diisopropyl ether, propane, acetaldehyde, acetone and a small amount of water vapor, etc.;

[0048] The second-stage atmospheric rectification side draw: The target fraction is withdrawn from the upper middle part of the tower to avoid the azeotrope, and the purity is increased to ≥ 99.99%;

[0049] Terminal filtration: Filter through a 0.03 μm PTFE hydrophobic membrane to ensure that the particle number ≤ 3 pieces / mL;

[0050] The reverse osmosis produced water (boron content 0.1 ppb) is passed through a boron adsorption resin column, and the boron content of the effluent ≤ 0.03 ppb;

[0051] Propylene and ultrapure water undergo an azeotropic reaction under a solid acid catalyst, at 210 °C and 3.2 MPa, and then through atmospheric dehydration, atmospheric light component removal (72 °C at the top of the tower), vacuum heavy component removal (88 °C at the bottom of the tower), and propylene removal, industrial-grade IPA with a purity ≥ 99.9%, water content ≤ 300 ppm, other organic impurities ≤ 100 ppm, and B ion content ≤ 30 ppt is obtained; the relevant metal ion indexes are as follows:

[0052]

[0053]

[0054] After the light components are removed by the first-stage distillation column (with 60 trays and a reflux ratio of 10:1), the reflux liquid of the second-stage rectification column is withdrawn from the side line at 80.5°C. After detection:

[0055] Purity: ≥99.999%; Metal impurities (Fe, Na, K): ≤0.01 ppb

[0056] Water content: ≤5 ppm; Particles (≥0.1 μm): 2 pieces / mL; Boron content: <0.02 ppb

[0057] The indicators of related batches of products are as follows:

[0058]

[0059]

[0060]

[0061] Detection of raw material batches: After pretreatment, the boron content is detected (<0.01 ppb), metal impurities (such as Fe, Na, K, etc.) ≤0.01 ppb, water content ≤5 ppm, and the number of particles ≤2 pieces / mL.

[0062] Product indicators: The purity reaches 99.9993%, fully meeting the cleaning requirements of chips with a process below 5 nm.

[0063] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for producing electronic-grade isopropyl alcohol of G5 level, characterized in that, It includes the following steps: S1. Pretreatment of raw materials: Ultra-pure water deboronation: Using two-stage series-connected boron ion selective ion exchange resin and combining with reverse osmosis technology, reduce the boron content in water to ≤0.05 ppb; Propylene hydration reaction: Process water, that is, deboronated deionized water, after being pressurized and respectively exchanging heat with the water at the bottom of the azeotropic tower and the reactor effluent, and then being heated by the feed heater to generate a liquid phase and enter the reactor. Propylene is pressurized and heated to generate a vapor phase, which enters the reactor from the top of the reactor. The vapor-phase propylene and the liquid-phase process water carry out a hydration reaction in the reactor. A stream of cold water at the outlet of the process water high-pressure pump enters between the catalyst beds of each section of the reactor to control the reactor bed temperature at 140°C to 170°C, reduce the occurrence of side reactions, with the single-pass conversion rate of propylene being 65% and the yield of the main product being 94%; S2. Purification of industrial-grade IPA: The reactor effluent is flashed in a high-pressure separation tank, and then flashed in a low-pressure separation tank. The gas-phase material at the top of the depropylene tower is condensed, and then the non-condensable gas is discharged, with part of it being refluxed and part entering the depropane tower; The depropane tower separates propylene and propane. The gas-phase propylene at the top of the tower is condensed, and then the non-condensable gas is discharged, with part of it being refluxed and part being withdrawn and returned to the propylene feed buffer tank in the reaction section. The propane at the bottom of the tower is sent to the propane vaporizer to the fuel gas pipeline. The liquid phase discharged from the low-pressure separation tank enters the azeotropic tower to separate out a large amount of water. The material withdrawn from the bottom of the tower is mainly water. After exchanging heat with the reaction feed, most of the process water is recycled, and a small amount is discharged as wastewater into the sewage treatment. The material at the top of the azeotropic tower is mainly IPA, water, DIPE and other side reaction products. This stream of material enters the dehydration tower for dehydration, with the pressure being atmospheric pressure and the temperature being 60°C - 90°C. The crude IPA with less water content is obtained at the bottom of the tower. The vapor phase at the top of the tower is cooled by a cooler and then enters the reflux tank. After oil-water separation, the water phase containing part of IPA returns to the azeotropic tower, and the oil phase is rich in DIPE and a small amount of water and IPA, and then is subjected to extraction and refining treatment to recover DIPE and IPA; S3. Refinement of electronic-grade IPA: The first-stage and second-stage packed distillation towers are connected in series at the bottom; First-stage atmospheric distillation: Using a packed tower, the light-component steam is withdrawn from the top to remove residual light components such as diisopropyl ether, propane, acetaldehyde, acetone and a small amount of water vapor; Second-stage atmospheric rectification side-stream withdrawal: The target fraction is withdrawn from the upper-middle part of the tower to avoid the azeotrope, and the purity is increased to ≥99.99%; Terminal filtration: Filter through a 0.03μm PTFE hydrophobic membrane to ensure that the particle number is ≤3 pieces / mL.

2. The method for producing electronic-grade isopropyl alcohol of G5 level according to claim 1, characterized in that, It is pressurized to 8.4 MPa and heated to 135°C by the feed heater. Propylene is heated to 135°C after being pressurized to 8.4 MPa.

3. A method for producing G5-level electronic-grade isopropyl alcohol according to claim 1, characterized in that, The pressure of a stream of cold water at the outlet is 8.4 MPa.

4. A method for producing electronic-grade isopropyl alcohol of G5 level according to claim 1, characterized in that, The reactor effluent is flashed in a high-pressure separation tank with a pressure of 8.4 MPa. The flashed vapor phase enters the depropylene tower through pressure control, and the liquid phase exchanges heat with the reaction feed and then is cooled to 100°C to 110°C.

5. A method for producing electronic-grade isopropyl alcohol of G5 level according to claim 1, characterized in that, The low-pressure separation tank is flashed with a pressure of 2.4 MPa and a temperature of 100°C to 110°C. The flashed vapor phase enters the depropylene tower with a pressure of 1.7 MPa and a temperature of 40°C - 170°C.

6. A method for producing electronic-grade isopropyl alcohol of G5 level according to claim 1, characterized in that, The liquid phase discharged from the low-pressure separation tank enters the azeotropic column, with a pressure of 0.1 MPa to 0.3 MPa and a temperature of 100 °C to 150 °C.

7. A method for producing G5-level electronic-grade isopropyl alcohol according to claim 1, characterized in that, The described S2, purification of industrial-grade IPA: The crude IPA drawn from the bottom of the dehydration column is sent to the IPA light-component removal column, with a pressure of atmospheric pressure and a temperature of 70 °C to 90 °C, to remove the light C6 components with lower boiling points. The light components drawn from the top of the column are sent to the light-component storage tank, and the IPA drawn from the bottom of the column is then sent to the heavy-component removal column, with a pressure of atmospheric pressure and a temperature of 90 °C to 100 °C, to further remove the heavy components in the IPA. The qualified IPA product is obtained by drawing from the top of the heavy-component removal column, and the heavy components drawn from the bottom of the column are sent to the heavy-component storage tank. Finally, industrial-grade IPA is obtained through propylene recovery, and the purity of the crude isopropanol is ≥95%.

8. A method for producing electronic-grade isopropyl alcohol of G5 level according to claim 1, characterized in that, The described S2, purification of industrial-grade IPA: The gaseous material at the top of the propylene removal column, with a pressure of 1.7 MPa and a temperature of 40 °C - 44 °C, after condensation, discharges the non-condensable gas, with part of it refluxed and part entering the propane removal column, with a pressure of 1.7 MPa and a temperature of 40 °C to 44 °C. The liquid phase material at the bottom of the propylene removal column, with a temperature of 160 °C to 170 °C, goes to the IPA dehydration column with a pressure of atmospheric pressure and a temperature of 60 °C - 90 °C.

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