Preparation method of sulfonium salt capable of being used for photoacid generator

Abstract

The invention provides a preparation method of a novel photoacid generator sulfonium salt compound 1, and belongs to the field of organic chemistry. The synthesis method is characterized in that a compound 3 and a compound 4 react in the presence of a cuprous catalyst and an organic solvent to obtain a compound 1, and the synthesis route is as follows: # imgabs0. The high-purity product can be obtained by taking p-tert-butylbenzene which is low in price and easy to obtain as an initial raw material through iodonium reaction and sulfonium reaction. According to the synthesis method, the substrate is cheap and easy to obtain, the route is short, the cost is low, cuprous iodide and other cuprous catalysts are used for replacing copper acetate and other cuprous catalysts, the yield of the sulfonium salt is increased, use of toxic cuprous and toxic reagents is avoided, the residual amount of copper ions is reduced unexpectedly, and the synthesis method is suitable for industrial production. And the method is beneficial to subsequent obtaining of high-quality photoresist, and has relatively good market value and profound practical significance.

Description

Technical Field

[0001] The invention relates to the preparation of sulfonium salt, a photoacid generator, and belongs to the field of organic chemistry. Background Art

[0002] Photoresist, also known as photoresist, is a medium that uses photochemical reactions to transfer patterns. It is a variety of fine chemicals with different properties and extremely wide applications. Photoresist is a light-sensitive mixed liquid composed of three main components: photosensitive resin, sensitizer and solvent. It is used as an anti-corrosion coating material in the photolithography process. Depending on the development method, photoresist is divided into positive photoresist and negative photoresist. The development of positive photoresist is to use a photoacid generator to catalyze the decomposition of the photoresist, change the polarity of the polymer, and achieve positive development or negative development after treatment with the developer. The chemical structure of the anion and cation of the photoacid generator can determine or affect the characteristics and properties of the photoacid generator. Different chemical compositions, shapes and sizes may also lead to significant changes in the solubility, diffusivity, stability, volatility, acidity and catalytic activity of the photoacid generator or its conjugated photoacid. These changes can directly lead to changes in many parameters related to the performance of the photoresist, such as curing efficiency, photosensitivity, sensitivity, post-exposure delay stability, resolution, standing wave, image profile and acid loss.

[0003] Compound 1, chemical name 4-(4-tert-butylphenyl)-1,4-oxathiinane-4-methyl sulfate, is a sulfonium salt that can be used as a photoacid generator. It can provide cations for the production of different photoacid generators, replacing the common triphenylsulfonium salts, and meeting the requirements of photoacid generators under different process conditions.

[0004]

[0005] However, there are few reports on the preparation of this compound, and the compound is unstable during the preparation process and is easier to remove the methyl group. At the same time, during the research process of the present invention, the researchers of the present invention found that the preparation method in the prior art has a large amount of copper ion residue in the obtained product. The control of metal ion content is one of the core contents of photoresist purity control. A trace amount of metal ion content will produce mobile ion contamination, causing the threshold voltage of the device to change, which is unfavorable to the performance of the processed device. The copper ion residue in the photoacid generator exceeds the standard and directly affects the quality of the subsequent photoresist. Excessive metal ions may cause the performance of the photoresist, such as the decrease of resolution and contrast. At the same time, the use of toxic divalent copper catalysts and toxic solvents such as chloroform in the prior art is potentially dangerous and not suitable for industrial scale-up production.

[0006] Therefore, a new preparation method is needed to solve the above problems in the prior art. Summary of the invention

[0007] The present invention provides a preparation method of a novel photoacid generator sulfonium salt compound 1. The present invention uses cheap and readily available p-tert-butylbenzene as a starting material, and obtains a product with a HPLC purity of ≥99% through an iodonium reaction and a sulfonium reaction. The synthesis method of the present invention has the advantages of cheap and readily available substrates, a short route, low cost, avoidance of the use of toxic reagents, stable products, and less residual copper ions.

[0008] The synthesis process route of the present invention is as follows:

[0009]

[0010] The following steps are involved:

[0011] Step 1: Compound 3 reacts with compound 4 in the presence of a monovalent copper catalyst and an organic solvent to obtain compound 1.

[0012] As a further improvement of the present invention, including but not limited to, the monovalent copper catalyst in step 1 is selected from cuprous chloride, cuprous bromide, and cuprous iodide, preferably cuprous iodide.

[0013] As further improvements of the present invention, including but not limited to, the inventors have found that when using cuprous iodide, it is better than other monovalent copper catalysts; when using a divalent copper catalyst, the high copper ion content of compound 1 will have an adverse effect on the quality of the subsequent photoresist. Only when using a monovalent copper catalyst, especially cuprous iodide, can a compound 1 with high purity and low copper ion content be obtained.

[0014] As a further improvement of the present invention, including but not limited to, the molar ratio of compound 3 to the monovalent copper catalyst in step 1 is 1:(0.01-0.5), preferably 1:(0.01-0.3).

[0015] As a further improvement of the present invention, in certain embodiments, the molar ratio of compound 3 in step 1 to the monovalent copper catalyst is 1:(0.01-0.05).

[0016] As a further improvement of the present invention, including but not limited to, the organic solvent in step 1 is chlorobenzene.

[0017] As a further improvement of the present invention, including but not limited to, the reaction temperature of step 1 is 40-90°C, preferably 50-80°C.

[0018] As a further improvement of the present invention, including but not limited to, the reaction time of step 1 is 0.5 to 5 hours, preferably 0.5 to 4 hours.

[0019] As a further improvement of the present invention, including but not limited to, the molar ratio of compound 3 to compound 4 in step 1 is selected from 1:(1-3), preferably 1:(1-2).

[0020] As a further improvement of the present invention, including but not limited to, in certain embodiments, in step 1, compound 3 is dissolved in chlorobenzene, compound 4 and cuprous iodide are added, the temperature is raised to 50-70° C., and the reaction is carried out for 0.5-3 h to obtain compound 1.

[0021] As a further improvement of the present invention, including but not limited to, in certain embodiments, after the reaction of step 1 is completed, the temperature is cooled to room temperature and stirred for a period of time, and compound 1 is obtained by suction filtration. The above compound 1 can be further purified by multiple slurrying or recrystallization; the slurrying solution is, for example, one of methanol and methyl tert-butyl ether.

[0022] As a further improvement of the present invention, including but not limited to, in certain embodiments, after the reaction of step 1 is completed, the temperature is lowered to room temperature and stirred for a period of time, and compound 1 is obtained by suction filtration. After adding methanol to slurry at room temperature for a period of time, the filtrate is filtered and concentrated, and then recrystallized from methyl tert-butyl ether to obtain a pure product of compound 1.

[0023] Furthermore, the compound 3 is prepared by the following method:

[0024]

[0025] The following steps are involved:

[0026] Step 2: Compound 2 reacts in the presence of an acidic reagent and iodate to obtain an intermediate product;

[0027] Step 3: The intermediate product obtained in step 2 is reacted with dimethyl sulfate in an organic solvent to obtain compound 3.

[0028] As a further improvement of the present invention, including but not limited to, the acidic reagent in step 2 is selected from one or more of sulfuric acid, acetic acid, and acetic anhydride.

[0029] As a further improvement of the present invention, including but not limited to, the iodate in step 2 is selected from one or more of potassium iodate, lithium iodate, and sodium iodate, preferably potassium iodate.

[0030] As a further improvement of the present invention, including but not limited to, the reaction temperature of step 2 is -20 to 10°C, preferably -15 to 5°C.

[0031] As a further improvement of the present invention, including but not limited to, the reaction time of step 2 is 12 to 36 hours, preferably 18 to 30 hours.

[0032] As a further improvement of the present invention, including but not limited to, after the reaction of step 2 is completed, quenching with water, filtering, extracting with an organic solvent, combining the organic phases, adding deionized water for extraction, combining the aqueous phases, and cooling to -5 to 5°C to obtain an intermediate product;

[0033] Furthermore, the organic solvent is toluene.

[0034] As a further improvement of the present invention, including but not limited to, in step 3, the intermediate product obtained in step 2 and dimethyl sulfate are refluxed to obtain compound 3.

[0035] As a further improvement of the present invention, including but not limited to, the organic solvent in step 3 is selected from any one or more of methanol, ethanol, and isopropanol, preferably methanol.

[0036] As a further improvement of the present invention, including but not limited to, the reaction time of step 3 is 2 to 18 hours, preferably 2 to 10 hours.

[0037] As a further improvement of the present invention, including but not limited to, in step 3, after the reaction is completed, a post-treatment may be optionally performed, wherein the post-treatment comprises evaporating the solvent under reduced pressure and adding an organic solvent for recrystallization; for example, the organic solvent is tetrahydrofuran.

[0038] The advantages of the method of the present invention mainly lie in:

[0039] 1. The prior art uses toxic divalent copper catalysts and toxic solvents such as chloroform, which are potentially dangerous and not suitable for large-scale industrial production. The divalent copper principle used in the prior art is Lewis acid catalysis, and monovalent copper is a metal catalysis similar to the Ullmann reaction, and the two mechanisms are different. During the invention process, the technical personnel of the present invention unexpectedly discovered that the use of a monovalent copper catalyst, such as cuprous iodide, as a catalyst can efficiently obtain the target sulfonium salt, and the residual copper ion content is low, which has unexpected technical effects. At the same time, it was found that the use of chlorobenzene as a solvent can further increase the yield by 15% while maintaining a low residual copper ion content, and solve the problem of using toxic reagents in the prior art.

[0040] 2. The present invention uses a monovalent copper catalyst, such as cuprous iodide, instead of a divalent copper catalyst such as cupric acetate, which not only improves the yield of the sulfonium salt, but also avoids the use of toxic divalent copper. At the same time, compared with the prior art, the present invention unexpectedly reduces the residual copper ion content of the sulfonium salt by more than 6 times by changing the catalyst, solvent, specific reaction temperature and time, which is conducive to the subsequent high-quality photoresist.

[0041] 3. The present invention uses chlorobenzene instead of chloroform, which can achieve solvent recovery and avoid the use of toxic solvent chloroform, while further improving the yield, which is more in line with the concept of green chemistry. When other conventional aromatic solvents are used, the substrates aggregate and cannot react.

[0042] 4. The present invention provides a new method for preparing compound 1, which has simple operation, safe reaction, short reaction time, and can be scaled up for production on a large scale of 30 kg, and therefore has good market value and far-reaching practical significance. DETAILED DESCRIPTION

[0043] The beneficial effects of the present invention are now further described by the following examples. It should be understood that these examples are only for illustrative purposes and do not limit the scope of the present invention. At the same time, obvious changes and modifications made by ordinary technicians in the field according to the present invention are also included in the scope of the present invention.

[0044] Unless otherwise specified, the raw materials and reagents used in the examples are commercially available.

[0045] The room temperature in the examples refers to 20-30° C. Unless otherwise specified, the reagents were used directly without purification. All solvents were purchased from commercial suppliers, such as Sigma Aldrich, and were used without treatment.

[0046] Example 1: Preparation of Compound 3

[0047]

[0048] Sulfuric acid (4380g) was added to the kettle, mechanically stirred, acetic acid (3040g) and potassium iodate (4786g) were added at -10 to 10°C, acetic anhydride (9120g) and compound 2 (2000g) were added dropwise at -10 to 0°C, and the mixture was kept at -10 to 0°C for 24h. After the reaction was completed, deionized water was added dropwise at -10 to 0°C to quench the mixture, and the addition was completed. The aqueous phase was filtered to obtain the aqueous phase, and toluene was added to extract the mixture twice. The organic phases were combined, and deionized water was added to extract the mixture. The aqueous phases were combined and cooled to 0 to 5°C to precipitate a white solid product. The crude product was filtered and dried to obtain 5846g, which was dissolved in methanol. Dimethyl sulfate (752g) was added dropwise thereto. After the addition, the mixture was heated to reflux for 6h. The reaction was complete after nuclear magnetic resonance detection. Methanol was evaporated under reduced pressure, and tetrahydrofuran was added to dissolve the residue. After the temperature was raised to completely dissolved, the temperature was lowered to 10°C for crystallization to obtain 5260g of a white solid with a yield of 70%.

[0049] Example 2: Preparation of Compound 1

[0050]

[0051] Compound 3 (500 g) was dissolved in chlorobenzene (2 L), and compound 4 (108.3 g) and cuprous iodide (5 g) were added in sequence, and mechanical stirring was performed under nitrogen protection. The oil bath was raised to an internal temperature of 60-65 ° C, and the reaction was performed for 1 h. After the reaction was completed by TLC monitoring, the internal temperature was lowered to 20-25 ° C and stirred for 0.5 h, and 444 g of off-white solid wet product was obtained by suction filtration. Methanol (2.5 L) was added at room temperature to dissolve the wet product, and diatomaceous earth was filtered. The filtrate was concentrated under reduced pressure to obtain a light yellow solid wet product. Methyl tert-butyl ether (2.5 L) was added at room temperature, and the temperature was raised to 45-50 ° C and stirred for 1 h, and then lowered to 20-25 ° C and stirred for 0.5 h. The white solid wet product was filtered and dried at 55-60 ° C to obtain 320.6 g of white solid, with a yield of 97%, a purity of 99.92% by HPLC, and a copper ion content of 361 ppm detected by ICP-MS.

[0052] Comparative Example 1: Preparation of Compound 1

[0053] Compound 3 (250 g) was dissolved in chlorobenzene (1 L), and compound 4 (54.2 g) and copper acetate (2.4 g) were added, and mechanical stirring was performed under nitrogen protection. The oil bath was raised to an internal temperature of 60-65 ° C, and the reaction was performed for 1 h. After the reaction was monitored by TLC, the internal temperature was lowered to 20-25 ° C and stirred for 0.5 h, and 184 g of off-white solid wet product was obtained by suction filtration. Methanol (1 L) was added at room temperature to dissolve the wet product, and diatomaceous earth was filtered. The filtrate was concentrated under reduced pressure at 45-50 ° C to obtain a light yellow solid wet product. Methyl tert-butyl ether (1 L) was added at room temperature, and the temperature was raised to 45-50 ° C and stirred for 1 h, then lowered to room temperature and stirred for 0.5 h, and a white solid wet product was obtained by filtration. The white solid was dried at 55-60 ° C for 24 h, with a yield of 49%, a purity of 99.6% by HPLC, and the copper ion content was 2329 ppm by ICP-MS.

[0054] Comparative Example 2: Preparation of Compound 1

[0055] This comparative example was prepared according to the method in the prior art JP2017057192A.

[0056] Compound 3 (100 g) was dissolved in chloroform (700 ml), compound 4 (20.6 g) was added, stirred at room temperature for 0.5 h, copper acetate (1 g) was added, mechanically stirred, and nitrogen was protected. The oil bath was raised to an internal temperature of 80°C, refluxed for 2 h, and after TLC monitoring, the reaction was complete, the external temperature was 40-45°C, concentrated, 880 ml of methyl tert-butyl ether was added, stirred at room temperature for 0.5 h, then filtered, and dried at 55-60°C to obtain 53 g of a white solid product, with a yield of 70%, HPLC purity of 98%, and ICP-MS detection of copper ion content of 18501 ppm.

[0057] Comparative Example 3: Preparation of Compound 1

[0058] Compound 3 (100 g) was dissolved in chloroform (700 ml), compound 4 (20.6 g) was added, stirred at room temperature for 0.5 h, cuprous iodide (1 g) was added, mechanically stirred, and nitrogen was protected. The oil bath was raised to an internal temperature of 60-65 ° C, and the reaction was carried out for 1 h. The reaction was monitored by TLC. The chloroform was removed by concentration at an external temperature of 40-45 ° C, 400 ml of methanol was added, and after dissolving at room temperature, 50 g of diatomaceous earth was passed through and filtered, the filtrate was collected, and the methanol was removed by vacuum concentration at 40-45 ° C, 500 ml of tertiary methyl ether was added, and the white solid wet product was filtered after stirring at room temperature for 2 h. The white solid product was dried at 55-60 ° C to obtain 53.0 g of a white solid product with a yield of 80%. The copper ion content was 400 ppm detected by ICP-MS.

[0059] The above embodiments are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for preparing compound 1, characterized in that: The following steps are involved: Step 1: Compound 3 reacts with compound 4 in the presence of a monovalent copper catalyst and an organic solvent to obtain compound 1; 2. The preparation method according to claim 1, characterized in that: The monovalent copper catalyst is selected from cuprous chloride, cuprous bromide and cuprous iodide, preferably cuprous iodide.

3. The preparation method according to claim 1, characterized in that: The organic solvent is selected from chlorobenzene.

4. The preparation method according to claim 1, characterized in that: The molar ratio of the compound 3 in step 1 to the monovalent copper catalyst is 1:(0.01-0.5), preferably 1:(0.01-0.3).

5. The preparation method according to claim 1, characterized in that: In the step 1, the reaction temperature is 40 to 90° C., more preferably 50 to 80° C.; the reaction time is selected from 0.5 to 5 hours, more preferably 0.5 to 4 hours.

6. The preparation method according to claim 1, characterized in that: In the step 1, the molar ratio of compound 3 to compound 4 is selected from 1:(1-3), preferably 1:(1-2).

7. The preparation method according to claim 1, characterized in that: Compound 1 is obtained by the following method: dissolving compound 3 in chlorobenzene, adding compound 4 and cuprous iodide, heating to 50-70° C., and reacting for 0.5-3 h.

8. The preparation method according to claim 1, characterized in that: The compound 3 was prepared by the following method: The following steps are involved: Step 2: Compound 2 reacts in the presence of an acidic reagent and iodate to obtain an intermediate product; Step 3: The intermediate product obtained in step 2 is reacted with dimethyl sulfate in an organic solvent to obtain compound 3.

9. The preparation method according to claim 8, characterized in that: Step 2 satisfies at least one of the following conditions: The acidic reagent is selected from one or more of sulfuric acid, acetic acid, and acetic anhydride; And / or, the iodate is selected from one or more of potassium iodate, lithium iodate, and sodium iodate, preferably potassium iodate; and / or, the reaction temperature is -20 to 10°C, preferably -15 to 5°C; and / or, the reaction time is 12 to 36 hours, preferably 18 to 30 hours; And / or, after the reaction is complete, quench with water, filter, extract with an organic solvent, combine the organic phases, add deionized water for extraction, combine the aqueous phases, and cool to -5 to 5° C. to obtain an intermediate product.

10. The preparation method according to claim 8, characterized in that: Step 3 satisfies at least one of the following conditions: The organic solvent is selected from any one or more of methanol, ethanol, and isopropanol, preferably methanol; and / or, the reaction time is 2 to 18 hours, preferably 2 to 10 hours; And / or, after the reaction is completed, a post-treatment may be optionally performed, wherein the post-treatment comprises evaporating the solvent under reduced pressure and adding an organic solvent for recrystallization.

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