Preparation method of N-triphenyl sulfonium salt based on perfluoroalkyl sulfimide structure

Abstract

The invention discloses a preparation method of N-triphenyl sulfonium salt based on a perfluoroalkyl sulfimide structure, which comprises the following steps: S1, performing first-stage low-temperature reaction on piperazine and alpha-bromo-gamma-butyrolactone in an acetonitrile solution through alkalescent inorganic salt, washing with deionized water, and drying to obtain a polar chain segment containing an active hydrogen group; s2, dissolving the polar chain segment and a disulfonyl fluoride cross-linking agent in tetrahydrofuran, and adding triethylamine for second-stage low-temperature reaction to obtain a reaction solution containing monosulfonyl fluoride and perfluoroalkyl functional chain segments; s3, adding perfluoroalkyl sulfonamide into the reaction liquid, carrying out heat preservation reaction until the reaction is finished, washing with deionized water, and drying, so as to obtain anions containing a perfluoroalkyl sulfonimide structure; and S4, mixing anions and triphenylsulfonium chloride salt, dissolving in a mixed solution of dichloromethane and water, reacting at room temperature until the reaction is finished, washing with water, concentrating, drying, and carrying out column chromatography to obtain the N-triphenylsulfonium salt containing the perfluoroalkyl sulfimide structure.

Description

Technical Field

[0001] This invention relates to the field of organic synthesis technology, and specifically to a method for preparing N-triphenylthionium salts based on perfluoroalkyl sulfonylimide structures. Background Technology

[0002] Triphenylthionium perfluorosulfonate is an important photoresist whose properties directly affect the spectral sensitivity and imaging quality of photoresists. This compound acts as a photoacid generator during photoresist manufacturing, producing acid under radiation. This acid causes a chemical reaction between the active components of the photoresist and the developer, thereby revealing the desired pattern.

[0003] Patent CN113173873A discloses a method for preparing triphenylsulfonium perfluorobutane sulfonate sulfonium salt. While the synthetic route is mature, simple, and low-cost, long-chain perfluoroalkyl (long-chain beyond C3) sulfonates are typical persistent pollutants, posing a risk of accumulation. Sulfonate ions are highly acidic, decomposing through intermolecular electron transfer to release acid. This process is limited by the migration and collision probability of ions in the solid. Acid diffusion control relies on linear fluorocarbon chains, which are approaching physical limits. Extending the fluorocarbon chain to obtain stronger acidity and lower diffusivity directly conflicts with environmental regulations, meaning that increasing the acidity of anions has limitations. This product relies on the strong lipophilic and hydrophobic properties of the fluorocarbon chain, making it incompatible with polar resins. After exposure, the generation of acid is accompanied by a dramatic change in regional polarity, which leads to significant differences in dissolution rates, thus forming a high-contrast image during development. However, the diffusion control of linear fluorocarbon chain acid is limited, and further reduction of line edge roughness is restricted. Moreover, the hydrophobicity of the product before exposure is not compatible with polar resins, which means that the compatibility problem of raw materials needs to be solved when formulating photoresist. Summary of the Invention

[0004] The purpose of this invention is to overcome the defects in the prior art and provide a method for preparing N-triphenylthionium salt based on a perfluoroalkyl sulfonylimide structure. The triphenylthionium chloride salt is provided with a hydrophilic group to improve the initial compatibility with polar resins, and an electron-withdrawing and hydrophobic fluorinated superacid source is introduced to adapt to photoresist rings and achieve high-performance photolithography applications.

[0005] To achieve the above-mentioned process effects, the technical solution of the present invention is as follows: a method for preparing N-triphenylthionium salts based on a perfluoroalkyl sulfonylimide structure, comprising the following steps: S1: Piperazine and α-bromo-γ-butyrolactone were reacted in a weakly alkaline inorganic salt solution at a low temperature in the first stage. After washing and drying with deionized water, a polar chain segment containing an active hydrogen group was obtained. S2: Dissolve the polar segment and the bissulfonyl fluoride crosslinking agent in tetrahydrofuran, and add triethylamine for a second-stage low-temperature reaction to obtain a reaction solution containing monosulfonyl fluoride and perfluoroalkyl functional segments; S3: Add perfluoroalkyl sulfonamide to the reaction solution, keep the reaction at the temperature until the end, wash with deionized water and dry to obtain anion containing perfluoroalkyl sulfonamide structure; S4: The anion and triphenylthionium chloride were mixed and dissolved in a mixed solution of dichloromethane and water. The reaction was carried out at room temperature until the end. After washing with water, the solution was concentrated and dried and then subjected to column chromatography to obtain N-triphenylthionium salt containing a perfluoroalkyl sulfonylimide structure.

[0006] A preferred technical solution is that the weakly alkaline inorganic salt is one or a combination of potassium carbonate, cesium carbonate, and sodium carbonate.

[0007] A preferred technical solution is that the molar ratio of piperazine to α-bromo-γ-butyrolactone is 1:(0.9~1.2), and the molar ratio of the total molar amount of piperazine and α-bromo-γ-butyrolactone to the molar amount of the weakly basic inorganic salt and acetonitrile is 2:(2.0~5.0):50.

[0008] The preferred technical solution is that the first stage low temperature is 20~28℃; the second stage low temperature is 0~25℃.

[0009] A preferred technical solution is that the disulfonyl fluoride crosslinking agent is 1,1,2,2,3,3-hexafluoropropane-1,3-disulfonyl fluoride.

[0010] A preferred technical solution is that the molar ratio of the polar segment and the disulfonyl fluoride crosslinking agent is 1:(1~1.2), and the molar ratio of the total molar amount of the polar segment and the disulfonyl fluoride crosslinking agent to that of triethylamine and tetrahydrofuran is 2:(2~5):50.

[0011] A preferred technical solution is that the molar ratio of the functional chain segment to the perfluoroalkyl sulfonamide is 1:(1~1.5).

[0012] The preferred technical solution is that the molar ratio of the anion to the triphenylthionium chloride is 1:(1~1.5).

[0013] A preferred technical solution is that the mass ratio of dichloromethane to water is 5:(1~5), and the mass ratio of triphenylthionium chloride to dichloromethane is 1:(5~10). Controlling the mass ratio of dichloromethane to water facilitates the dissolution of the triphenylthionium chloride reactant in water and the dissolution of the product in dichloromethane. The reaction process is controlled by adjusting the mass of water; too little water can lead to a slow reaction.

[0014] The advantages and beneficial effects of this invention are as follows: By using piperazine and α-bromo-γ-butyrolactone under the action of weakly alkaline inorganic salts and at low temperature, not only are hydrophilic groups imparted to triphenylthionium chloride salt, improving the initial compatibility with polar resins, but the purity and yield of the final product are also improved. By linking hydrophilic polar segments and perfluoroalkyl sulfonamides with a bissulfonyl fluoride crosslinking agent, a super acid source is introduced to impart and enhance the electron-withdrawing and hydrophobic properties of triphenylthionium chloride, making it compatible with the photoresist environment and enabling high-performance photolithography applications. The preparation method is simple to operate, has mild reaction conditions, high yield, and good purity. It avoids the use of precious metal catalysts and composite solvents, and meets environmental protection requirements. Attached Figure Description

[0015] Figure 1 This is the HPLC spectrum of the product from Example 1; Figure 2 This is the HNMR spectrum of the product from Example 1; Figure 3 This is the FNMR spectrum of the product from Example 1; Figure 4 This is a flowchart of the product preparation process. Detailed Implementation

[0016] The specific embodiments of the present invention will be further described below with reference to examples. These examples are only used to more clearly illustrate the technical solutions of the present invention and should not be construed as limiting the scope of protection of the present invention.

[0017] Polar segments containing active hydrogen groups To improve the initial compatibility (i.e., before exposure) of N-triphenylthionium salt containing perfluoroalkyl sulfonylimide structure with polar resin and prevent precipitation, a hydrophilic group was imparted to its anionic moiety. Piperazine and α-bromo-γ-butyrolactone were dissolved in acetonitrile solution, reacted under the action of a weakly alkaline inorganic salt, and the reaction was carried out at low temperature in the first stage. After washing and drying with deionized water, 3-(piperazin-1-yl)dihydrofuran-2(3H)-one was obtained, which is the polar segment containing active hydrogen groups.

[0018] To control the presence of two identical reactive nitrogen sites in piperazine, it is selectively reacted with an active alkylating agent of α-bromo-γ-butyrolactone to achieve unilateral grafting, successfully obtaining a polar segment containing an active hydrogen group and avoiding the formation of byproducts from bilateral grafting. Furthermore, the weakly basic inorganic salt is one or a combination of potassium carbonate, cesium carbonate, and sodium carbonate; the molar ratio of piperazine, α-bromo-γ-butyrolactone, the weakly basic inorganic salt, and acetonitrile is 1:(0.9~1.2):(2.0~5.0):50. Even further, the first-stage low temperature is 20~28℃.

[0019] Synthetic principle: The carbonyl group of the lactone withdraws electrons, which reduces the electron cloud density of the attached nitrogen atom and the cyclic piperazine, weakens the basicity, and greatly reduces the nucleophilicity, thus generating a single-sided grafted product. The reactivity of the modified piperazine decreases sharply, and its reaction rate with the second α-bromo-γ-butyrolactone molecule is much slower than that of the original piperazine.

[0020] Piperazine serves as both a linking and regulating unit. Nitrogen atoms can act as sites for chemical modification, allowing the introduction of other groups to adjust solubility and compatibility. Furthermore, the six-membered ring structure increases the rigidity and volume of the anionic moiety, which helps suppress acid diffusion and improve image resolution. Moreover, nitrogen atoms can fine-tune the electron distribution of individual anions, thereby precisely controlling the final acid strength of the photoacid.

[0021] Perfluoroalkyl functional segments To enhance the electron-withdrawing and hydrophobic properties of the molecule, the polar segment is reacted with a bissulfonyl fluoride crosslinking agent. The free secondary amine of the polar segment attacks the sulfonyl fluoride to form a sulfonamide bond, resulting in a functional segment containing a monosulfonyl fluoride group and a perfluoroalkyl group.

[0022] To reduce the risk of bioaccumulation, the anionic moiety still provides a strong electron-withdrawing effect (ensuring acidity) and a certain degree of hydrophobicity and oleophobicity. Since the longer the alkane chain and the more fluorine atoms in the disulfonyl fluoride crosslinking agent, the more difficult the product synthesis becomes, the disulfonyl fluoride crosslinking agent is 1,1,2,2,3,3-hexafluoropropane-1,3-disulfonyl fluoride, that is, 3-(piperazin-1-yl)dihydrofuran-2(3H)-one reacts with 1,1,2,2,3,3-hexafluoropropane-1,3-disulfonyl fluoride to obtain 1,1,2,2,3,3-hexafluoro-3-((4-(2-oxotetrahydrofuran-3-yl)piperazin-1-yl)sulfonyl)propane-1-sulfonyl fluoride.

[0023] The disulfonyl fluoride crosslinking agent is disulfonyl fluoride, which may undergo unilateral or bilateral linkage. To control the intermediate where sulfonyl fluoride is grafted at one end while retaining sulfonyl fluoride at the other end, the molar ratio of polar segment, disulfonyl fluoride crosslinking agent, triethylamine, and tetrahydrofuran is further specified as 1:(1~1.2):2~5:50. Furthermore, the second-stage low temperature is 0~25℃.

[0024] Anions containing perfluoroalkyl sulfonyl imide structures The sulfonyl fluoride group retained in the previous step reacts with the amide group of the perfluoroalkyl sulfonamide to form a new sulfonamide bond, thereby introducing a stronger super acid source.

[0025] Furthermore, an amine salt is obtained by reacting a perfluoroalkyl sulfonamide with 1,1,2,2,3,3-hexafluoro-3-((4-(2-oxotetrahydrofuran-3-yl)piperazin-1-yl)sulfonyl)propane-1-sulfonyl fluoride (functional segment) in a molar ratio of (1~1.5):1. Further, the perfluoroalkyl sulfonamide is a trifluoromethanesulfonamide or a perfluoroethanesulfonamide. Even further, the perfluoroalkyl sulfonamide is a trifluoromethanesulfonamide.

[0026] The working principle of the obtained fluorinated superacid anion: Piperazine-α-bromo-γ-butyrolactone intermediate provides a rigid framework and well-defined functionalization sites, imparts crucial solubility regulation through the lactone ring, and adapts to the photoresist environment by connecting hydrophobic fluorocarbon functional groups, thus enabling high-performance photolithography applications.

[0027] N-triphenylthionium salts containing perfluoroalkylsulfonylimide structure The chloride ion in triphenylthionium chloride is a good leaving group, which forms thionium salt with the amino group of the fluorinated superacid anion.

[0028] Example 1 The preparation method based on N-triphenylthionium salt containing a perfluoroalkyl sulfonylimide structure includes the following steps: S1: Piperazine and α-bromo-γ-butyrolactone were reacted with potassium carbonate in acetonitrile solution at 25°C for 16 h. After washing and drying with deionized water, 3-(piperazin-1-yl)dihydrofuran-2(3H)-one was obtained. The synthetic steps are as follows: The ingredients include 100g (1.16mol) piperazine, 190g (1.15mol) α-bromo-γ-butyrolactone, 480g potassium carbonate, and 1000mL acetonitrile.

[0029] S2: 3-(piperazin-1-yl)dihydrofuran-2(3H)-one and triethylamine were dissolved in tetrahydrofuran. After stirring thoroughly at 0°C, 1,1,2,2,3,3-hexafluoropropane-1,3-disulfonyl fluoride was added. The mixture was heated to 25°C and reacted for 16 hours to obtain a reaction solution of 1,1,2,2,3,3-hexafluoro-3-((4-(2-oxotetrahydrofuran-3-yl)piperazin-1-yl)sulfonyl)propane-1-sulfonyl fluoride. The synthesis steps are as follows: The contents include 100g of 3-(piperazin-1-yl)dihydrofuran-2(3H)-one, 187g (0.59mol) of 1,1,2,2,3,3-hexafluoropropane-1,3-disulfonyl fluoride, 120g of triethylamine, and 1000ml of tetrahydrofuran.

[0030] S3: 89 g (0.60 mol) of trifluoromethanesulfonamide was added directly to the reaction solution, and the reaction was maintained at this temperature for 15 h. After washing with deionized water and drying, an anion containing a perfluoroalkylsulfonylimide structure was obtained. The synthesis steps are as follows: S4: 100 g of the anion and 50 g (0.167 mol) of triphenylthionium chloride were mixed and dissolved in a mixed solution of 350 ml dichloromethane and 100 ml water. The reaction was carried out at room temperature for 16 h. After washing with water, the mixture was distilled under reduced pressure using a rotary evaporator, and the N-triphenylthionium salt containing a perfluoroalkyl sulfonylimide structure was obtained by column chromatography. The synthesis steps are as follows: The content of the product is from Figure 1 It can be seen that the result is 98.78%.

[0031] The product is a white, viscous solid, composed of Figure 2 The ¹H NMR (400 MHz, CDCl₃) values ​​are δ 7.81–7.65 (m, 15H), 4.42–4.37 (m, 1H), 4.24–4.18 (m, 1H), 3.61–3.56 (m, 5H), 2.91 (s, 2H), 2.65 (s, 2H), and 2.36–2.25 (m, 2H).

[0032] Depend on Figure 3 It can be seen that, 19 FNMR (400 MHz, CDCl3) δ -78.68 (s), -110.91~-111.01 (m), -112.35~-112.42 (m), -118.56~-118.58 (m).

[0033] Example 2 Example 2 is based on Example 1, except that in step S1, piperazine 1 kg (11.6 mol), α-bromo-γ-butyrolactone 1.9 kg (11.5 mol), potassium carbonate 4.8 kg, and acetonitrile 10 L are used. In step S2, 3-(piperazin-1-yl)dihydrofuran-2(3H)-one 1 kg, 1,1,2,2,3,3-hexafluoropropane-1,3-disulfonyl fluoride 1.870 kg (59 mol), triethylamine 1.2 kg, and tetrahydrofuran 10 L are used. In step S3, 890 g (6.0 mol) of trifluoromethanesulfonamide is added directly. In step S4, 1 kg of anion and 500 g (1.67 mol) of triphenylthionium chloride are mixed and dissolved in 3.5 L of dichloromethane and 1 L of water. The amount of reactants is increased to scale up the experiment. The process remains unchanged.

[0034] Example 3 Example 3 is based on Example 1, except that in step S1, the weakly alkaline inorganic salt is sodium carbonate. All other components and processes remain unchanged.

[0035] Comparative Example 1 Comparative Example 1 is based on Example 1, except that in step S1, the temperature of the first stage reaction is 60°C. The other steps remain the same.

[0036] The yield results for the examples and comparative examples are as follows: The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing N-triphenylthionium salts based on perfluoroalkyl sulfonylimide structures, characterized in that, Includes the following steps: S1: Piperazine and α-bromo-γ-butyrolactone were reacted in a weakly alkaline inorganic salt solution at a low temperature in the first stage. After washing and drying with deionized water, a polar chain segment containing an active hydrogen group was obtained. S2: Dissolve the polar segment and the bissulfonyl fluoride crosslinking agent in tetrahydrofuran, and add triethylamine for a second-stage low-temperature reaction to obtain a reaction solution containing monosulfonyl fluoride and perfluoroalkyl functional segments; S3: Add perfluoroalkyl sulfonamide to the reaction solution, keep the reaction at the temperature until the end, wash with deionized water and dry to obtain anion containing perfluoroalkyl sulfonamide structure; S4: The anion and triphenylthionium chloride were mixed and dissolved in a mixed solution of dichloromethane and water. The reaction was carried out at room temperature until the end. After washing with water, the solution was concentrated and dried and then subjected to column chromatography to obtain N-triphenylthionium salt containing a perfluoroalkyl sulfonylimide structure.

2. The preparation method of N-triphenylthionium salt based on a perfluoroalkyl sulfonylimide structure according to claim 1, characterized in that, The weakly alkaline inorganic salt is one or a combination of potassium carbonate, cesium carbonate, and sodium carbonate.

3. The preparation method of N-triphenylthionium salt based on a perfluoroalkyl sulfonylimide structure according to claim 2, characterized in that, The molar ratio of piperazine to α-bromo-γ-butyrolactone is 1:(0.9~1.2), and the molar ratio of the total molar amount of piperazine and α-bromo-γ-butyrolactone to the weakly basic inorganic salt and acetonitrile is 2:(2.0~5.0):

50.

4. The preparation method of N-triphenylthionium salt based on a perfluoroalkyl sulfonylimide structure according to claim 1 or 2, characterized in that, The first stage low temperature is 20~28℃; the second stage low temperature is 0~25℃.

5. The preparation method of N-triphenylthionium salt based on a perfluoroalkyl sulfonylimide structure according to claim 1, characterized in that, The disulfonyl fluoride crosslinking agent is 1,1,2,2,3,3-hexafluoropropane-1,3-disulfonyl fluoride.

6. The preparation method of N-triphenylthionium salt based on a perfluoroalkyl sulfonylimide structure according to claim 5, characterized in that, The molar ratio of the polar segment to the disulfonyl fluoride crosslinker is 1:(1~1.2), and the molar ratio of the total molar amount of the polar segment and the disulfonyl fluoride crosslinker to the molar amount of triethylamine and tetrahydrofuran is 2:(2~5):

50.

7. The preparation method of N-triphenylthionium salt based on a perfluoroalkyl sulfonylimide structure according to claim 1, characterized in that, The molar ratio of the functional chain segment to the perfluoroalkyl sulfonamide is 1:(1~1.5).

8. The preparation method of N-triphenylthionium salt based on a perfluoroalkyl sulfonylimide structure according to claim 1, characterized in that, The molar ratio of the anion to the triphenylthionium chloride is 1:(1~1.5).

9. The preparation method of N-triphenylthionium salt based on a perfluoroalkyl sulfonylimide structure according to claim 8, characterized in that, The mass ratio of dichloromethane to water is 5:(1~5), and the mass ratio of triphenylthionium chloride to dichloromethane is 1:(5~10).

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