Electrochemical preparation method of tri (1, 1, 1, 3, 3, 3-hexafluoro-2-propyl) phosphite

Abstract

The invention discloses an electrochemical preparation method of tris (1, 1, 1, 3, 3, 3-hexafluoro-2-propyl) phosphite, and belongs to the technical field of electrolysis processes for producing compounds. The method comprises the following steps: mixing white phosphorus, hexafluoroisopropanol, an activation additive, an organic alkali, an electrolyte and an organic solvent to form an electrolytic reaction solution; the electrolytic reaction solution is electrolyzed under the action of direct current, white phosphorus is oxidized at an anode and then subjected to nucleophilic attack by hexafluoroisopropanol to generate tri (1, 1, 1, 3, 3, 3-hexafluoro-2-propyl) phosphite, and hydrogen atoms are reduced at a cathode to form hydrogen. The method has the advantages of simplicity, convenience, rapidness, high safety, few byproducts, high utilization value and low cost; the method is high in atom utilization rate and weak in corrosion to devices, meets the requirements of green and safe production, and has a good industrial application prospect.

Description

Technical Field

[0001] The invention relates to the technical field of electrolytic process for producing compounds, and in particular to an electrochemical preparation method of tris(1,1,1,3,3,3-hexafluoro-2-propyl)phosphite. Background Art

[0002] Trivalent organic phosphides are an important class of organic compounds that are widely used in many fields. These compounds usually have three organic groups connected to the phosphorus atom to form sp 3 Hybridized trigonal pyramid configuration. Due to the unique electronic structure of phosphorus atoms, trivalent organic phosphides exhibit rich chemical properties, including electrophilicity, amphiphilicity and diene-philicity. These properties enable trivalent organic phosphides to participate in a variety of organic reactions as effective ligands or catalysts. Based on these characteristics, trivalent organic phosphides are an extremely important class of bulk chemicals, widely used in flame retardants, ligands, plasticizers, etc., and also used in the synthesis of pesticides, dyes, medicines and other organic chemical products.

[0003] The existing methods for synthesizing trivalent organic phosphides, such as those provided in the literature (Donath, M., Schwedtmann, K., Schneider, T. et al. Direct conversion of white phosphorus to versatilephosphorus transfer reagents via oxidative onioation. Nat. Chem. 14, 384–391(2022). https: / / doi.org / 10.1038 / s41557-022-00913-4), generally involve synthesizing organic phosphorus transfer reagents such as phosphorus trichloride or phosphine, which are then attacked by nucleophilic reagents to generate the target product. However, this process inevitably results in a loss of yield due to the need for multiple steps, and both phosphine and chlorine required to generate phosphorus trichloride are toxic gases, which pose a high threat to operators and the environment. At the same time, the process releases a large amount of hydrogen chloride, which also causes serious pollution to the environment and corrosion to the equipment.

[0004] Tris(1,1,1,3,3,3-hexafluoro-2-propyl)phosphite is a trivalent organic phosphite containing a hexafluoro group. It has specific chemical and physical properties and has potential application value in many fields. Tris(1,1,1,3,3,3-hexafluoro-2-propyl)phosphite can be used as a chemical additive, involving the processing and modification of materials such as coatings, plastics, and rubber. In addition, due to its special chemical structure, it also has flame retardant and anti-corrosion functions, and has broad application prospects in the battery field. The synthesis of tris(1,1,1,3,3,3-hexafluoro-2-propyl)phosphite also has the above-mentioned technical problems of synthesizing trivalent organic phosphites.

[0005] In order to solve the defects in the synthesis process of tris(1,1,1,3,3,3-hexafluoro-2-propyl)phosphite, a Chinese invention patent with publication number CN114075240A discloses a method for synthesizing tris(1,1,1,3,3,3-hexafluoro-2-propyl)phosphite. The method comprises the following steps: 1. Adding hexafluoroisopropanol, triphenyl phosphite and inorganic strong base into a reaction vessel under the protection of inert gas throughout the process; 2. Stirring at 30-35 ℃ for 16-20 h; then adding water and organic solvent for extraction, taking the organic layer for direct distillation to obtain the target product. Compared with the traditional method, it has the advantages of simple process route, high safety and high product yield. However, the invention uses triphenyl phosphite as a phosphorus source, which is still highly toxic to aquatic organisms and is easy to cause long-term adverse effects in the aquatic environment; it is irritating to the skin and eyes, and the operator needs to take additional protective measures. Not only that, from the perspective of raw material procurement, the production cost of triphenyl phosphite is relatively high. This scheme has a long reaction time during the synthesis process and produces a large amount of by-products such as benzene compounds and sodium salts. These by-products are difficult to recycle and reuse, resulting in a waste of raw materials, which is also not conducive to reducing production costs.

[0006] In summary, a different synthesis route of tris(1,1,1,3,3,3-hexafluoro-2-propyl)phosphite is provided outside the prior art, which meets the requirements of reducing costs, improving safety, being simple and fast, having few by-products and having high utilization value, and is of great significance for expanding the application of tris(1,1,1,3,3,3-hexafluoro-2-propyl)phosphite. Summary of the invention

[0007] In view of the above-mentioned defects of the prior art, in the first aspect of the present invention, a simple, fast, safe, low-by-product, high-utilization-value, low-cost electrochemical preparation method of tris(1,1,1,3,3,3-hexafluoro-2-propyl)phosphite is provided, comprising the following steps: White phosphorus, hexafluoroisopropanol, an organic base, an electrolyte, and an organic solvent are mixed to form an electrolytic reaction solution; the electrolytic reaction solution is electrolyzed under the action of direct current, and the white phosphorus is oxidized at the anode and then attacked by hexafluoroisopropanol to generate tris(1,1,1,3,3,3-hexafluoro-2-propyl)phosphite, and the hydrogen atoms are reduced at the cathode to form hydrogen gas; The overall reaction equation for electrolysis is as follows: .

[0008] Preferably, in the electrolytic reaction solution, the amount of white phosphorus added is 1-50 mmol; the amount of hexafluoroisopropanol added is 1-10 mL; the amount of organic base added is 0.5-5 mmol; the amount of electrolyte added is 0.2-3 mmol; and the amount of organic solvent added is 1-10 mL.

[0009] In order to promote the activation of white phosphorus and reduce polymerization, an activation additive can be added to the electrolytic reaction solution. The activation additive can be a Lewis acid, including an acid or a salt that ionizes in a solution environment to be acidic, such as sulfuric acid, sulfonic acid, acetic acid and lithium salt, which are all suitable types of selection.

[0010] Preferably, the electrolytic reaction solution is further added with an activation additive, and the activation additive includes at least one of sulfuric acid, p-toluenesulfonic acid, sulfonic acid, acetic acid, lithium iodide, lithium chloride and lithium sulfate.

[0011] Further preferably, the molar ratio of the activation additive to white phosphorus is 1:0.2-10.

[0012] The organic base plays a role in promoting alcohol dehydrogenation by nucleophilic attack during the electrolysis process. For example, pyridine base compounds, potassium tert-butoxide, and triethylamine are all suitable types of organic bases for the present invention.

[0013] Preferably, the organic base includes at least one of 4-methoxypyridine, 4-methylpyridine, potassium tert-butoxide, 4-dimethylaminopyridine and triethylamine.

[0014] In the electrolysis process, the function of the electrolyte is to improve the conductivity of the electrolyte, and the function of the organic solvent is to promote the dispersion of substances and create a suitable solution environment for the reaction. The electrolyte and the organic solvent should be chemically inert relative to the substrate or the product formed by the reaction and do not react with it. Based on the reaction type of the present invention, the electrolyte can be selected from tetraethylammonium iodide, tetraethylammonium bromide, tetrabutylammonium iodide, potassium iodide, sodium iodide, sodium bromide, tetrabutylammonium bromide, tetrabutylammonium chloride, etc. Taking into account the solubility of the raw materials of the present invention and the polarity of the solvent, the organic solvent can be selected from compounds such as dimethyl sulfoxide, acetonitrile, toluene, tetrahydrofuran, chloroform, dichloromethane, and dichloroethane.

[0015] Preferably, the electrolyte includes at least one of tetraethylammonium iodide, tetraethylammonium bromide, tetrabutylammonium iodide, potassium iodide, sodium iodide, sodium bromide, tetrabutylammonium bromide, and tetrabutylammonium chloride.

[0016] Preferably, the organic solvent includes at least one of dimethyl sulfoxide, acetonitrile, toluene, tetrahydrofuran, chloroform, dichloromethane and dichloroethane.

[0017] The implementation of this method does not require specialized equipment, and the purpose of synthesis can be achieved by using a common electrolysis device in the field, such as an integrated electrolysis cell equipped with a stirrer and electrodes. Therefore, this method has good prospects for scale-up production and industrial preparation. No high voltage or strong current is required during the electrolysis process, the atomic utilization rate of the substrate is high, and the target product is synthesized under mild conditions.

[0018] Preferably, the current intensity of the direct current is 50-500 mA.

[0019] Preferably, the electrolysis temperature is 0-40° C., and the electrolysis time is 40 min-4 h.

[0020] The cathode and anode required for electrolysis are various, and those skilled in the art can use common electrode forms. For example, carbon sheets, graphite felt, carbon cloth, platinum sheets, etc. are used as anodes, and iron sheets, carbon cloth, nickel sheets, copper sheets, foamed nickel, foamed copper, etc. are used as cathodes. It should be noted that, as presented in one or more embodiments of the present invention, the synthesis yield under different electrode selection forms has certain differences, but generally all can meet the synthesis requirements.

[0021] Preferably, the anode includes one of a carbon sheet, graphite felt, carbon cloth, and a platinum sheet; the cathode includes one of an iron sheet, carbon cloth, a nickel sheet, a copper sheet, foamed nickel, and foamed copper.

[0022] Based on the above technical scheme, the inventive concept and principle of the present invention is to use hexafluoroisopropanol and cheap white phosphorus as raw materials and perform electrolysis under electrochemical conditions. During the electrolysis process, white phosphorus is oxidized at the anode under the action of direct current, causing the phosphorus-phosphorus bond (PP) to break, and then hexafluoroisopropanol reacts with it through nucleophilic attack to obtain tris(1,1,1,3,3,3-hexafluoro-2-propyl)phosphite. The electron-withdrawing group in the tris(1,1,1,3,3,3-hexafluoro-2-propyl)phosphite molecule can ensure that it is not easily peroxidized. During the nucleophilic attack process, the hydrogen atoms derived from hexafluoroisopropanol are reduced at the cathode to form hydrogen. The entire reaction process obtains the target product in one step with high Faraday efficiency, and the only by-product is hydrogen with high added value. Its low solubility in organic solvents and gaseous form are also conducive to the separation and recovery of by-products.

[0023] Compared with the prior art, the present invention has the following advantages and beneficial effects: The invention provides an electrochemical preparation method of tris(1,1,1,3,3,3-hexafluoro-2-propyl)phosphite, which has the advantages of being simple, fast, highly safe, having few by-products, having high utilization value and low cost; the method has high atomic utilization rate, weak corrosion to equipment, meets the requirements of green and safe production, and has good prospects for industrial application. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 The nuclear magnetic resonance (NMR) of tris(1,1,1,3,3,3-hexafluoro-2-propyl)phosphite of Example 1 is 31 P) Spectral data graph; Figure 2 The nuclear magnetic resonance hydrogen ( 1 H) Spectral data graph; Figure 3 The NMR carbon of tris(1,1,1,3,3,3-hexafluoro-2-propyl)phosphite of Example 1 is ( 13 C) Spectral data graph; Figure 4 The NMR fluorine ( 19 F) Spectral data plot. DETAILED DESCRIPTION

[0025] The present invention is further described below by way of examples, but the present invention is not limited to the scope of the examples. The experimental methods in the following examples without specifying specific conditions are carried out according to conventional methods and conditions, or selected according to the product specifications.

[0026] Example 1 The electrochemical preparation method of tris(1,1,1,3,3,3-hexafluoro-2-propyl)phosphite comprises the following steps: ; In an argon atmosphere, 3 mmol white phosphorus, 2 mL hexafluoroisopropanol (HFIP), 3 mmol 4-dimethylaminopyridine (DMAP), 1 mmol tetrabutylammonium iodide (TBAI), and 6 mL acetonitrile (MeCN) were added into a reaction tube and mixed to form an electrolytic reaction solution; A carbon plate (CP) was used as an anode and nickel foam (Ni Foam) was used as a cathode. The electrolytic reaction solution was electrolyzed at room temperature (rt) for 3 h under a direct current of 100 mA, and the flow of the electrolytic reaction solution was maintained by rotating a stirrer during the process. After the electrolysis was completed, tris(1,1,1,3,3,3-hexafluoro-2-propyl)phosphite was obtained by distillation and purification.

[0027] The product NMR phosphorus spectrum, hydrogen spectrum, carbon spectrum, and fluorine spectrum data of tris(1,1,1,3,3,3-hexafluoro-2-propyl)phosphite are shown in the following order: Figure 1-4 As shown, the target product was synthesized. The content corresponding to the 140 ppm peak was quantitatively measured by nuclear magnetic resonance phosphorus spectrum, and was 0.96 mmol. The yield of this example was 32%.

[0028] Example 2 The electrochemical preparation method of tris(1,1,1,3,3,3-hexafluoro-2-propyl)phosphite in this embodiment is basically the same as that in Example 1, except that graphite felt of the same specifications is used as the anode in this embodiment. The target product is synthesized by the same method, and the yield of this embodiment is 42%.

[0029] Example 3 The electrochemical preparation method of tris(1,1,1,3,3,3-hexafluoro-2-propyl)phosphite in this embodiment is basically the same as that in Example 1, except that carbon cloth of the same specification is used as the anode in this embodiment. The target product is synthesized by the same method, and the yield of this embodiment is 44%.

[0030] Example 4 The electrochemical preparation method of tris(1,1,1,3,3,3-hexafluoro-2-propyl)phosphite in this embodiment is basically the same as that in Example 1, except that a platinum sheet of the same specification is used as an anode in this embodiment. The target product is synthesized by the same method, and the yield of this embodiment is 40%.

[0031] The use of different types of anodes commonly used in the art for electrolysis has a certain impact on the yield, which may be caused by the different transmission efficiency and resistivity of each electrode for electric energy, but overall it still achieves the purpose of synthesizing tris (1,1,1,3,3,3-hexafluoro-2-propyl) phosphite. Among them, the embodiment using carbon cloth shows the highest yield, and carbon cloth has low cost and wide sources, and is a particularly suitable type for this method.

[0032] Example 5 The electrochemical preparation method of tris(1,1,1,3,3,3-hexafluoro-2-propyl)phosphite comprises the following steps: ; In an argon atmosphere, 3 mmol white phosphorus, 2 mL hexafluoroisopropanol, 3 mmol potassium t-butoxide (t-BuOK), 1 mmol tetrabutylammonium iodide, and 6 mL acetonitrile were added to a reaction tube and mixed to form an electrolytic reaction solution; Carbon cloth (CC) was used as the anode and nickel foam was used as the cathode. The electrolytic reaction solution was electrolyzed at room temperature for 3 h under a direct current of 100 mA, and the flow of the electrolytic reaction solution was maintained by rotating the stirrer during the process. After the electrolysis was completed, tri(1,1,1,3,3,3-hexafluoro-2-propyl)phosphite was obtained by distillation and purification.

[0033] The target product was synthesized using the method described in Example 1, and the yield of this example was 42%.

[0034] Example 6 The electrochemical preparation method of tris(1,1,1,3,3,3-hexafluoro-2-propyl)phosphite in this embodiment is basically the same as that in Example 5, except that the organic base type in this embodiment is triethylamine. The target product is synthesized by the same method, and the yield in this embodiment is 50%.

[0035] Example 7 The electrochemical preparation method of tris(1,1,1,3,3,3-hexafluoro-2-propyl)phosphite in this embodiment is basically the same as that in Example 5, except that the organic base type in this embodiment is 4-methoxypyridine. The target product was synthesized by the same method, and the yield in this embodiment was 31%.

[0036] Example 8 The electrochemical preparation method of tris(1,1,1,3,3,3-hexafluoro-2-propyl)phosphite in this embodiment is basically the same as that in Example 5, except that the organic base type in this embodiment is 4-methylpyridine. The target product was synthesized by the same method, and the yield in this embodiment was 56%.

[0037] Different organic bases have different effects on the yield. In addition to meeting the requirements for synthesizing the target product, the embodiment using 4-methylpyridine showed the highest yield, and it is suitable to use it as an organic base to further optimize the yield of electrolysis.

[0038] Example 9 The electrochemical preparation method of tris(1,1,1,3,3,3-hexafluoro-2-propyl)phosphite comprises the following steps: ; In an argon atmosphere, 3 mmol white phosphorus, 2 mL hexafluoroisopropanol, 0.5 mmol sulfuric acid, 3 mmol 4-methylpyridine, 1 mmol tetrabutylammonium iodide, and 6 mL acetonitrile were added to a reaction tube and mixed to form an electrolytic reaction solution; Carbon cloth was used as the anode and nickel foam was used as the cathode. The electrolytic reaction solution was electrolyzed at room temperature for 3 hours under a direct current of 100 mA, and the flow of the electrolytic reaction solution was maintained by rotating the stirrer during the process. After the electrolysis was completed, tris(1,1,1,3,3,3-hexafluoro-2-propyl)phosphite was obtained by distillation and purification.

[0039] The target product was synthesized using the method described in Example 1, and the yield of this example was 60%.

[0040] Example 10 The electrochemical preparation method of tris(1,1,1,3,3,3-hexafluoro-2-propyl)phosphite in this embodiment is basically the same as that in embodiment 9, except that the activation additive type in this embodiment is lithium chloride. The target product is synthesized by the same method, and the yield in this embodiment is 44%.

[0041] Embodiment 11 The electrochemical preparation method of tris(1,1,1,3,3,3-hexafluoro-2-propyl)phosphite in this embodiment is basically the same as that in embodiment 9, except that the activation additive type in this embodiment is lithium iodide. The target product is synthesized by the same method, and the yield in this embodiment is 45%.

[0042] The yield is reduced to a certain extent after adding lithium halide, which may be due to the use of high-purity white phosphorus in the examples. The addition of this type of Lewis acid promotes the activation of white phosphorus, while the nucleophilic attack rate is limited, resulting in more white phosphorus being polymerized and deactivated at the cathode. In some cases, such as for white phosphorus raw materials with more impurities or lower activity, the addition of lithium halide may be more likely to increase the yield.

[0043] Example 12 The electrochemical preparation method of tris(1,1,1,3,3,3-hexafluoro-2-propyl)phosphite in this embodiment is basically the same as that in embodiment 9, except that the activation additive type in this embodiment is p-toluenesulfonic acid. The target product is synthesized by the same method, and the yield in this embodiment is 70%.

[0044] Adding activation additives can help promote the activation of white phosphorus and reduce polymerization, which is beneficial to improving the quality of the product. Some activation additives, such as acids, can also increase the yield, among which toluenesulfonic acid has a more significant effect.

[0045] Embodiment 13 The electrochemical preparation method of tris(1,1,1,3,3,3-hexafluoro-2-propyl)phosphite comprises the following steps: ; In an argon atmosphere, 3 mmol white phosphorus, 2 mL hexafluoroisopropanol, 0.5 mmol sulfuric acid, 3 mmol 4-methylpyridine, 1 mmol tetrabutylammonium iodide, and 6 mL of a mixed solution of acetonitrile and tetrahydrofuran (THF) in a volume ratio of 2:1 were added to a reaction tube to form an electrolytic reaction solution; Carbon cloth was used as the anode and nickel foam was used as the cathode. The electrolytic reaction solution was electrolyzed at room temperature for 3 hours under a direct current of 100 mA, and the flow of the electrolytic reaction solution was maintained by rotating the stirrer during the process. After the electrolysis was completed, tris(1,1,1,3,3,3-hexafluoro-2-propyl)phosphite was obtained by distillation and purification.

[0046] The target product was synthesized using the method described in Example 1, and the yield of this example was 76%.

[0047] Embodiment 14 The electrochemical preparation method of tris(1,1,1,3,3,3-hexafluoro-2-propyl)phosphite in this embodiment is basically the same as that in embodiment 13, except that the organic solvent in this embodiment is a mixed solution of acetonitrile and toluene in a volume ratio of 2:1. The target product was synthesized by the same method, and the yield in this embodiment was 83%.

[0048] Embodiment 15 The electrochemical preparation method of tris(1,1,1,3,3,3-hexafluoro-2-propyl)phosphite in this embodiment is basically the same as that in Example 13, except that the organic solvent in this embodiment is a mixed solution of acetonitrile and dichloromethane in a volume ratio of 2:1. The target product was synthesized using the same method, and the yield in this embodiment was 78%.

[0049] Example 16 The electrochemical preparation method of tris(1,1,1,3,3,3-hexafluoro-2-propyl)phosphite in this embodiment is basically the same as that in embodiment 13, except that the organic solvent in this embodiment is a mixed solution of acetonitrile and dichloroethane in a volume ratio of 2:1. The target product was synthesized by the same method, and the yield in this embodiment was 81%.

[0050] Compared with a single solvent type, a mixed solvent shows a better yield improvement effect. This may be because a mixed solvent can provide a wider dissolution window than a single solvent, which helps dissolve the substrate; or by changing the degree of solvation to adjust the reaction rate and direction, it can sometimes reduce the activation energy of the reaction, thereby accelerating the reaction process. The mixed solvent used in Example 14 shows a higher yield, and its source is wide and the separation difficulty is low, making it suitable as an organic solvent for electrolysis.

[0051] Embodiment 17 The electrochemical preparation method of tris(1,1,1,3,3,3-hexafluoro-2-propyl)phosphite comprises the following steps: ; In an argon atmosphere, 3 mmol white phosphorus, 2 mL hexafluoroisopropanol, 0.5 mmol sulfuric acid, 3 mmol 4-methylpyridine, 1 mmol tetrabutylammonium bromide (TBAB), and 6 mL of a mixed solution of acetonitrile and toluene (PhMe) in a volume ratio of 2:1 were added to a reaction tube to form an electrolytic reaction solution; Carbon cloth was used as the anode and nickel foam was used as the cathode. The electrolytic reaction solution was electrolyzed at room temperature for 3 hours under a direct current of 100 mA, and the flow of the electrolytic reaction solution was maintained by rotating the stirrer during the process. After the electrolysis was completed, tris(1,1,1,3,3,3-hexafluoro-2-propyl)phosphite was obtained by distillation and purification.

[0052] The target product was synthesized using the method described in Example 1, and the yield of this example was 73%.

[0053] Embodiment 18 The electrochemical preparation method of tris(1,1,1,3,3,3-hexafluoro-2-propyl)phosphite in this embodiment is basically the same as that in Example 17, except that the electrolyte type in this embodiment is tetrabutylammonium chloride. The target product was synthesized using the same method, and the yield in this embodiment was 62%.

[0054] Embodiment 19 The electrochemical preparation method of tris(1,1,1,3,3,3-hexafluoro-2-propyl)phosphite in this embodiment is basically the same as that in Example 17, except that the electrolyte type in this embodiment is sodium iodide. The target product was synthesized using the same method, and the yield in this embodiment was 85%.

[0055] Embodiment 20 The electrochemical preparation method of tris(1,1,1,3,3,3-hexafluoro-2-propyl)phosphite in this embodiment is basically the same as that in Example 17, except that the electrolyte type in this embodiment is sodium bromide. The target product was synthesized using the same method, and the yield in this embodiment was 82%.

[0056] Embodiment 21 The electrochemical preparation method of tris(1,1,1,3,3,3-hexafluoro-2-propyl)phosphite in this embodiment is basically the same as that in Example 1, except that the current intensity of the direct current in this embodiment is 50 mA, the electrolysis temperature is 0° C., and the electrolysis time is 4 h. The target product is synthesized by the same method.

[0057] Embodiment 22 The electrochemical preparation method of tris(1,1,1,3,3,3-hexafluoro-2-propyl)phosphite in this embodiment is basically the same as that in Example 1, except that the current intensity of the direct current in this embodiment is 500 mA, the electrolysis temperature is 40° C., and the electrolysis time is 40 min. The target product is synthesized by the same method.

[0058] Comparative Example 1 This comparative example studies the effect of synthesizing tris (1,1,1,3,3,3-hexafluoro-2-propyl) phosphite when using other solvent types. The preparation method of this comparative example is basically the same as that of Example 13, except that the organic solvent of this example is a mixed solution of acetonitrile and cyclohexane formed in a volume ratio of 2: 1. The synthesis of tris (1,1,1,3,3,3-hexafluoro-2-propyl) phosphite was measured using the method as in Example 1, but the yield of this comparative example is only 8%. The reason for the low yield may be that the polarity gap between the two solvents is too large, and the solubility is poor, which is not conducive to the smooth progress of the synthesis of the target product.

[0059] Comparative Example 2 This comparative example studies the effect of synthesizing tris (1,1,1,3,3,3-hexafluoro-2-propyl) phosphite when using other electrolyte types. The preparation method of this comparative example is basically the same as that of Example 13, except that the electrolyte of this example is tetrabutylammonium tetrafluoroborate. The synthesis of tris (1,1,1,3,3,3-hexafluoro-2-propyl) phosphite was measured using the method of Example 1, but the yield of this comparative example was only 7%. The reason for this result may be that tetrabutylammonium tetrafluoroborate is reactive, which participates in the process of the electrolysis reaction and generates by-products, etc., resulting in a reduced yield.

[0060] In the electrolysis process of the present invention, white phosphorus is oxidized at the anode under the action of direct current, so that the phosphorus-phosphorus bond is broken, and then hexafluoroisopropanol reacts with it through nucleophilic attack to obtain tris(1,1,1,3,3,3-hexafluoro-2-propyl)phosphite. The electron-withdrawing group in the tris(1,1,1,3,3,3-hexafluoro-2-propyl)phosphite molecule can ensure that it is not easily peroxidized. During the nucleophilic attack process, the hydrogen atoms derived from hexafluoroisopropanol are reduced at the cathode to form hydrogen. The entire reaction process obtains the target product in one step with high Faraday efficiency, and the only byproduct is hydrogen with high added value, and its low solubility in organic solvents and gaseous form are also conducive to the separation and recovery of byproducts.

[0061] The maximum yield of the electrochemical preparation method of tri(1,1,1,3,3,3-hexafluoro-2-propyl)phosphite in the embodiment can reach 85%, which is slightly higher than the optimal level of the prior art (CN114075240A); but in terms of reaction time, the method only takes 3 hours to electrolyze the target product under mild conditions, while the prior art requires more than 15 hours. Therefore, the present invention is applied to industrial production, and has the advantages of being simple, fast, safe, having few by-products, high utilization value, and low cost; the method has high atomic utilization rate, weak corrosion to the device, meets the requirements of green and safe production, can greatly improve the production capacity of tri(1,1,1,3,3,3-hexafluoro-2-propyl)phosphite, and has good prospects for industrial application.

[0062] The preferred specific embodiments of the present invention are described in detail above. It should be understood that a person skilled in the art can make many modifications and changes based on the concept of the present invention without creative work. Therefore, any technical solution that can be obtained by a person skilled in the art through logical analysis, reasoning or limited experiments based on the concept of the present invention on the basis of the prior art should be within the scope of protection determined by the claims.

Claims

1. An electrochemical preparation method of tris(1,1,1,3,3,3-hexafluoro-2-propyl)phosphite, characterized in that: The steps include: White phosphorus, hexafluoroisopropanol, an organic base, an electrolyte, and an organic solvent are mixed to form an electrolytic reaction solution; the electrolytic reaction solution is electrolyzed under the action of direct current, and the white phosphorus is oxidized at the anode and then attacked by hexafluoroisopropanol to generate tris(1,1,1,3,3,3-hexafluoro-2-propyl)phosphite, and the hydrogen atoms are reduced at the cathode to form hydrogen gas; The electrolyte includes at least one of tetraethylammonium iodide, tetraethylammonium bromide, tetrabutylammonium iodide, potassium iodide, sodium iodide, sodium bromide, tetrabutylammonium bromide, and tetrabutylammonium chloride; The organic solvent includes at least one of dimethyl sulfoxide, acetonitrile, toluene, tetrahydrofuran, chloroform, dichloromethane, and dichloroethane; The overall reaction equation for electrolysis is as follows: 。 2. The electrochemical preparation method of tris(1,1,1,3,3,3-hexafluoro-2-propyl)phosphite according to claim 1, characterized in that: In the electrolytic reaction solution, the addition amount of white phosphorus is 1-50 mmol; the addition amount of hexafluoroisopropanol is 1-10 mL; the addition amount of organic base is 0.5-5 mmol; the addition amount of electrolyte is 0.2-3 mmol; and the addition amount of organic solvent is 1-10 mL.

3. The electrochemical preparation method of tris(1,1,1,3,3,3-hexafluoro-2-propyl)phosphite according to claim 1, characterized in that: The electrolytic reaction solution is further added with an activation additive, and the activation additive includes at least one of sulfuric acid, p-toluenesulfonic acid, sulfonic acid, acetic acid, lithium iodide, lithium chloride and lithium sulfate.

4. The electrochemical preparation method of tris(1,1,1,3,3,3-hexafluoro-2-propyl)phosphite according to claim 3, characterized in that: The molar ratio of the activation additive to white phosphorus is 1:0.2-10.

5. The electrochemical preparation method of tris(1,1,1,3,3,3-hexafluoro-2-propyl)phosphite according to claim 1, characterized in that: The organic base includes at least one of 4-methoxypyridine, 4-methylpyridine, potassium tert-butoxide, 4-dimethylaminopyridine and triethylamine.

6. The electrochemical preparation method of tris(1,1,1,3,3,3-hexafluoro-2-propyl)phosphite according to claim 1, characterized in that: The current intensity of the direct current is 50-500 mA.

7. The electrochemical preparation method of tris(1,1,1,3,3,3-hexafluoro-2-propyl)phosphite according to claim 1, characterized in that: The electrolysis temperature is 0-40°C, and the electrolysis time is 40 min-4 h.

8. The electrochemical preparation method of tris(1,1,1,3,3,3-hexafluoro-2-propyl)phosphite according to claim 1, characterized in that: The anode includes one of a carbon sheet, graphite felt, carbon cloth, and a platinum sheet; the cathode includes one of an iron sheet, carbon cloth, a nickel sheet, a copper sheet, foamed nickel, and foamed copper.

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