A method for preparing chlorophosphoranes based on tetrachlorosilane

Abstract

This invention discloses a method for preparing chlorophosphine compounds based on tetrachlorosilane, belonging to the field of organic synthesis technology. The method involves preparing chlorophosphine oxide R... 1 R 2 P(O)H, when dissolved in an organic solvent, reacts with tetrachlorosilane SiCl4 to give chlorophosphine compound R. 1 R 2 The present invention features a short reaction time, requiring only a few minutes to successfully complete the conversion of chlorine atoms with a high yield. The reaction conditions are mild, and the reaction can be completed at room temperature. The present invention uses tetrachlorosilane for the reaction, which, compared to the use of phosphorus trichloride or acetyl chloride reagents in the prior art, solves the problem of long reaction time in the preparation of chlorophosphine compounds, while also reducing the amount of tetrachlorosilane used.

Description

Technical Field

[0001] This invention relates to the field of organic synthesis technology, and more specifically, to a method for preparing chlorophosphine compounds based on tetrachlorosilane. Background Technology

[0002] Phosphine chlorides are important key intermediates in organic synthesis, widely used in the synthesis of various trivalent (chiral) phosphine ligands, phosphate esters, phosphoramides, phosphine oxide flame retardants, and acylphosphine oxide photoinitiators. Taking diphenylphosphine chloride as an example, the industrial synthesis of phosphine chlorides involves a Friedel-Crafts reaction of benzene and phosphorus trichloride under heating with an saturation of aluminum trichloride, followed by decomplexing and distillation. This process is inefficient and generates large amounts of waste (such as hydrogen chloride, aluminum trichloride, and decomplexing agents used to decomplex diphenylphosphine chloride from aluminum trichloride), causing significant pollution. In the laboratory, relatively stable and commercially available phosphine oxides (R0) are typically used. 1 R 2 Phosphine chloride R was synthesized from P(O)H as a raw material. 1 R 2 PCl. It has been previously reported that, under mild conditions, phosphine oxide R... 1 R 2 P(O)H can react with PCl3 to give R 1 R 2 PCl, this method has been widely used to prepare rare chiral phosphine ligands. However, the preparation using this method requires the use of large amounts of PCl3 (equivalent to R). 1 R 2 It has 10 times the equivalent of P(O)H (PCl3 is used as a solvent), and it is difficult to obtain a pure product with a yield of no more than 80% (RE Montgomery, LD Quin, J. Org. Chem. 1965, 30, 2393-2395). Its chemical reaction formula (II) is as follows:

[0003]

[0004] To address the above issues, the invention patent (authorization number: CN110922428B) uses acetyl chloride (AcCl), which has lower toxicity and corrosiveness and requires a smaller dosage, to replace PCl3 in the reaction with phosphine oxides, thereby obtaining product R. 1 R 2 PCl. However, in this method, when the amount of AcCl is 1 eq, a relatively long reaction time is required for the reaction to be complete. The chemical reaction formula (III) is as follows:

[0005]

[0006] Therefore, there is an urgent need for a more efficient process route. Summary of the Invention

[0007] 1. Technical problems to be solved

[0008] To address the problems existing in the prior art, the present invention aims to provide a method for preparing chlorophosphine compounds based on tetrachlorosilane. By dissolving phosphine oxide in an organic solvent and reacting it with tetrachlorosilane for 5-60 minutes, the product chlorophosphine compounds can be obtained, which greatly shortens the reaction time.

[0009] 2. Technical Solution

[0010] To solve the above problems, the present invention adopts the following technical solution.

[0011] A method for preparing phosphine chlorides based on tetrachlorosilane involves, under an inert gas atmosphere, reacting phosphine oxide R... 1 R 2 P(O)H dissolves in an organic solvent and reacts with tetrachlorosilane SiCl4 at a reaction temperature of -20℃ to 100℃ for 5 to 60 minutes to yield phosphine chloride R. 1 R 2 PCl, its chemical reaction formula (I) is as follows:

[0012]

[0013] Where R 1 R 2 Each can independently represent either aryl or alkyl.

[0014] Furthermore, the organic solvent is selected from one or more of tetrahydrofuran, 1,4-dioxane, toluene, dichloromethane, dichloroethane, and ethyl acetate.

[0015] Furthermore, the organic solvent is tetrahydrofuran.

[0016] Furthermore, the reaction temperature is 0℃-25℃.

[0017] Furthermore, the reaction temperature is 25°C.

[0018] Furthermore, the amount of tetrachlorosilane SiCl4 used is equal to that of phosphine oxide R. 1 R 2 0.25-2 times the equivalent of P(O)H.

[0019] Furthermore, the amount of tetrachlorosilane SiCl4 used is equal to that of phosphine oxide R. 1 R 2 0.5 times the equivalent of P(O)H.

[0020] Furthermore, the reaction time is 10 minutes.

[0021] Furthermore, after the reaction is complete, the chlorophosphine compound R is subjected to... 1 R 2 PCl was subjected to vacuum distillation at room temperature to remove low-boiling substances, and then heated and vacuum distilled to obtain the pure product.

[0022] Furthermore, the phosphine oxide is an aryl phosphine oxide.

[0023] 3. Beneficial effects

[0024] Compared with the prior art, the advantages of this invention are:

[0025] (1) The present invention uses tetrachlorosilane to react with phosphine oxide to obtain the product chlorophosphine. The conversion can be completed smoothly in a few minutes at room temperature, which greatly shortens the reaction time.

[0026] (2) When the phosphine oxide in this invention reacts with tetrachlorosilane, the amount of tetrachlorosilane used is R. 1 R 2 The amount of P(O)H is 0.5 times the equivalent, which reduces the amount of reactants required.

[0027] (3) The reaction conditions of the present invention are mild and can be completed at room temperature.

[0028] (4) The reaction yield and conversion rate of the present invention are high. All four chlorine atoms of tetrachlorosilane can be utilized and converted into chlorophosphine molecules. Detailed Implementation

[0029] The present invention will be further described below with reference to specific embodiments, but the scope of protection of the present invention is not limited thereto.

[0030] Example 1:

[0031] Under nitrogen protection, 1 mmol of diphenylphosphine oxide and 5 mL of tetrahydrofuran were added to a 25 mL Schleck tube. After stirring thoroughly, 0.5 mmol of tetrachlorosilane was added dropwise. The reaction was carried out at 25 °C for 0.5 h. The organic phase was concentrated under reduced pressure to remove solvents and other volatiles, yielding an oily crude product. After reduced pressure distillation, 0.99 mmol of liquid Ph2PCl was obtained, with a yield of 99%.

[0032] Example 2:

[0033] Under nitrogen protection, 1 mmol of diphenylphosphine oxide and 5 mL of tetrahydrofuran were added to a 25 mL Schleck tube. After stirring thoroughly, 0.25 mmol of tetrachlorosilane was added dropwise. The reaction was carried out at 25 °C for 0.5 h. The organic phase was concentrated under reduced pressure to remove solvents and other volatiles, yielding an oily crude product. After reduced pressure distillation, 0.92 mmol of liquid Ph2PCl was obtained, with a yield of 92%.

[0034] Example 2 illustrates that all four chlorine atoms of tetrachlorosilane can be utilized and converted into diphenylphosphine chloride molecules.

[0035] Example 3:

[0036] Under nitrogen protection, 1 mmol of diphenylphosphine oxide and 5 mL of tetrahydrofuran were added to a 25 mL Schleck tube. After stirring thoroughly, 1.0 mmol of tetrachlorosilane was added dropwise. The reaction was carried out at 25 °C for 10 min. The organic phase was concentrated under reduced pressure to remove solvents and other volatiles, yielding an oily crude product. After reduced pressure distillation, 0.99 mmol of liquid Ph2PCl was obtained, with a yield of 99%.

[0037] Example 4:

[0038] Under nitrogen protection, 1 mmol of diphenylphosphine oxide and 5 mL of 1,4-dioxane were added to a 25 mL Schleck tube. After stirring thoroughly, 0.5 mmol of tetrachlorosilane was added dropwise. The reaction was carried out at 25 °C for 0.5 h. The organic phase was concentrated under reduced pressure to remove solvents and other volatiles, yielding an oily crude product. After reduced pressure distillation, 0.97 mmol of liquid Ph2PCl was obtained, with a yield of 97%.

[0039] Example 5:

[0040] Under nitrogen protection, 1 mmol of di(p-methylphenyl)phosphine oxide and 5 mL of tetrahydrofuran were added to a 25 mL Schleck tube. After stirring thoroughly, 0.5 mmol of tetrachlorosilane was added dropwise. The reaction was carried out at 25 °C for 0.5 h. The organic phase was concentrated under reduced pressure to remove solvents and other volatiles, yielding an oily crude product. After reduced pressure distillation, 0.98 mmol of liquid di(p-methylphenyl)phosphine chloride was obtained, with a yield of 98%.

[0041] Example 6:

[0042] Under nitrogen protection, 1 mmol of di(p-methoxyphenyl)phosphine oxide and 5 mL of tetrahydrofuran were added to a 25 mL Schleck tube. After stirring thoroughly, 0.5 mmol of tetrachlorosilane was added dropwise. The reaction was carried out at 25 °C for 0.5 h. The organic phase was concentrated under reduced pressure to remove solvents and other volatiles, yielding an oily crude product. After reduced pressure distillation, 0.96 mmol of liquid di(p-methoxyphenyl)phosphine chloride was obtained, with a yield of 96%.

[0043] Example 7:

[0044] Under nitrogen protection, 1 mmol of di(p-trifluoromethylphenyl)phosphine oxide and 5 mL of tetrahydrofuran were added to a 25 mL Schleck tube. After stirring thoroughly, 0.5 mmol of tetrachlorosilane was added dropwise. The reaction was carried out at 25 °C for 10 min. The organic phase was concentrated under reduced pressure to remove solvents and other volatiles, yielding an oily crude product. After reduced pressure distillation, 0.99 mmol of liquid di(p-trifluoromethylphenyl)phosphine chloride was obtained, with a yield of 99%.

[0045] Example 8:

[0046] Under nitrogen protection, 1 mmol of phenylbutylphosphine oxide and 5 mL of tetrahydrofuran were added to a 25 mL Schleck tube and stirred thoroughly. Then, 0.5 mmol of tetrachlorosilane was added dropwise. After reacting at 25 °C for 1 h, the organic phase was concentrated under reduced pressure to remove solvents and other volatiles, yielding an oily crude product. After reduced pressure distillation, 0.94 mmol of liquid phenylbutylphosphine chloride was obtained, with a yield of 94%.

[0047] Example 9:

[0048] Under nitrogen protection, 1 mmol of dibutylphosphine oxide and 5 mL of tetrahydrofuran were added to a 25 mL Schleck tube. After stirring thoroughly, 0.5 mmol of tetrachlorosilane was added dropwise. The reaction was carried out at 25 °C for 1 h. The organic phase was concentrated under reduced pressure to remove solvents and other volatiles, yielding an oily crude product. After reduced pressure distillation, 0.86 mmol of liquid dibutylphosphine chloride was obtained, with a yield of 86%.

[0049] As can be seen from Examples 1-9, the chlorination yield of arylphosphine oxides is higher than that of alkylphosphine oxides.

[0050] Example 10:

[0051] Under nitrogen protection, 1 mmol of diphenylphosphine oxide and 5 mL of tetrahydrofuran were added to a 25 mL Schleck tube. After stirring thoroughly, 0.5 mmol of tetrachlorosilane was added dropwise. The reaction was carried out at 0 °C for 0.5 h. The organic phase was concentrated under reduced pressure to remove solvents and other volatiles, yielding an oily crude product. After reduced pressure distillation, 0.97 mmol of liquid Ph2PCl was obtained, with a yield of 97%.

[0052] Example 11:

[0053] Under nitrogen protection, 1 mmol of diphenylphosphine oxide and 5 mL of tetrahydrofuran were added to a 25 mL Schleck tube. After stirring thoroughly, 0.5 mmol of tetrachlorosilane was added dropwise. The reaction was carried out at 100 °C for 0.5 h. The organic phase was concentrated under reduced pressure to remove solvents and other volatiles, yielding an oily crude product. After reduced pressure distillation, 0.91 mmol of liquid Ph2PCl was obtained, with a yield of 91%.

[0054] Example 12:

[0055] Under nitrogen protection, 1 mmol of diphenylphosphine oxide and 5 mL of tetrahydrofuran were added to a 25 mL Schleck tube. After stirring thoroughly, 0.5 mmol of tetrachlorosilane was added dropwise. The reaction was carried out at -20 °C for 0.5 h. The organic phase was concentrated under reduced pressure to remove solvents and other volatiles, yielding an oily crude product. After reduced pressure distillation, 0.96 mmol of liquid Ph2PCl was obtained, with a yield of 96%.

[0056] As can be seen from the comparison of Examples 1 and Examples 10-12, 25°C is the optimal reaction temperature, that is, the present invention can fully react phosphine oxide and tetrachlorosilane under normal temperature conditions.

[0057] Example 13:

[0058] Under nitrogen protection, 1 mmol of diphenylphosphine oxide and 5 mL of tetrahydrofuran were added to a 25 mL Schleck tube. After stirring thoroughly, 0.5 mmol of tetrachlorosilane was added dropwise. The reaction was carried out at 25 °C for 10 min. The organic phase was concentrated under reduced pressure to remove solvents and other volatiles, yielding an oily crude product. After reduced pressure distillation, 0.99 mmol of liquid Ph2PCl was obtained, with a yield of 99%.

[0059] Example 14:

[0060] Under nitrogen protection, 1 mmol of diphenylphosphine oxide and 5 mL of tetrahydrofuran were added to a 25 mL Schleck tube. After stirring thoroughly, 0.5 mmol of tetrachlorosilane was added dropwise. The reaction was carried out at 25 °C for 5 min. The organic phase was concentrated under reduced pressure to remove solvents and other volatiles, yielding an oily crude product. After reduced pressure distillation, 0.97 mmol of liquid Ph2PCl was obtained, with a yield of 97%.

[0061] Example 15:

[0062] Under nitrogen protection, 1 mmol of diphenylphosphine oxide and 5 mL of tetrahydrofuran were added to a 25 mL Schleck tube. After stirring thoroughly, 0.5 mmol of tetrachlorosilane was added dropwise. The reaction was carried out at 25 °C for 1 h. The organic phase was concentrated under reduced pressure to remove solvents and other volatiles, yielding an oily crude product. After reduced pressure distillation, 0.99 mmol of liquid Ph2PCl was obtained, with a yield of 99%.

[0063] As can be seen from the comparison of Examples 1 and Examples 13-15, a reaction time of 10 min is sufficient to achieve a complete reaction between phosphine oxide and tetrachlorosilane.

[0064] Example 16:

[0065] Under nitrogen protection, 1 mmol of diphenylphosphine oxide and 5 mL of tetrahydrofuran were added to a 25 mL Schleck tube. After stirring thoroughly, 1 mmol of tetrachlorosilane was added dropwise. The reaction was carried out at 25 °C for 0.5 h. The organic phase was concentrated under reduced pressure to remove solvents and other volatiles, yielding an oily crude product. After reduced pressure distillation, 0.99 mmol of liquid Ph2PCl was obtained, with a yield of 99%.

[0066] Example 17:

[0067] Under nitrogen protection, 1 mmol of diphenylphosphine oxide and 5 mL of tetrahydrofuran were added to a 25 mL Schleck tube. After stirring thoroughly, 2 mmol of tetrachlorosilane was added dropwise. The reaction was carried out at 25 °C for 0.5 h. The organic phase was concentrated under reduced pressure to remove solvents and other volatiles, yielding an oily crude product. After reduced pressure distillation, 0.99 mmol of liquid Ph2PCl was obtained, with a yield of 99%.

[0068] As can be seen from the comparison of Examples 1-2 and Examples 16-17, the amount of tetrachlorosilane used is only 0.5 times the equivalent of phosphine oxide to achieve a full reaction between phosphine oxide and tetrachlorosilane.

[0069] As can be seen from Examples 1-17, considering factors such as cost, yield, and reaction conditions, the optimal technical solution of this invention is to use aryl phosphine oxide, tetrahydrofuran as the organic solvent, tetrachlorosilane at a dosage of 0.5 times the equivalent of the phosphine oxide, a reaction temperature of 25°C, and a reaction time of 10 min.

[0070] Comparative Example 1:

[0071] In a sealed NMR tube filled with argon, Ph₂P(O)H (0.05 mmol) was dissolved in 0.5 mL of tetrahydrofuran, acetyl chloride (twice the equivalent of Ph₂P(O)H) was added, and the mixture was reacted at 25 °C for 12 hours, with a yield of 95%.

[0072] Comparative Example 2:

[0073] In a sealed NMR tube filled with argon, Ph₂P(O)H (0.05 mmol) was dissolved in 0.5 mL of tetrahydrofuran, acetyl chloride (1.2 equivalents of Ph₂P(O)H) was added, and the mixture was reacted at 100 °C for 12 hours, with a yield of 99%.

Claims

1. A method for preparing chlorophosphine compounds based on tetrachlorosilane, characterized in that: Under an inert gas atmosphere, phosphine oxide R 1 R 2 P(O)H dissolves in an organic solvent and reacts with tetrachlorosilane SiCl4 at a reaction temperature of -20℃ to 100℃ for 5 to 60 minutes to give the product phosphine chloride R. 1 R 2 PCl; Where R 1 R 2 Each can independently represent either aryl or alkyl.

2. The method for preparing chlorophosphine compounds based on tetrachlorosilane according to claim 1, characterized in that: The organic solvent is selected from one or more of tetrahydrofuran, 1,4-dioxane, toluene, dichloromethane, dichloroethane, and ethyl acetate.

3. The method for preparing chlorophosphine compounds based on tetrachlorosilane according to claim 2, characterized in that: The organic solvent is tetrahydrofuran.

4. The method for preparing chlorophosphine compounds based on tetrachlorosilane according to claim 1, characterized in that: The reaction temperature is 0℃-25℃.

5. The method for preparing chlorophosphine compounds based on tetrachlorosilane according to claim 4, characterized in that: The reaction temperature is 25°C.

6. The method for preparing chlorophosphine compounds based on tetrachlorosilane according to claim 1, characterized in that: The amount of tetrachlorosilane SiCl4 used is the amount of phosphine oxide R. 1 R 2 0.25-2 times the equivalent of P(O)H.

7. The method for preparing chlorophosphine compounds based on tetrachlorosilane according to claim 6, characterized in that: The amount of tetrachlorosilane SiCl4 used is the amount of phosphine oxide R. 1 R 2 0.5 times the equivalent of P(O)H.

8. The method for preparing chlorophosphine compounds based on tetrachlorosilane according to claim 1, characterized in that: The reaction time is 10 minutes.

9. The method for preparing chlorophosphine compounds based on tetrachlorosilane according to claim 1, characterized in that: After the reaction is complete, the phosphine chloride R is subjected to... 1 R 2 PCl was subjected to vacuum distillation at room temperature to remove low-boiling substances, and then heated and vacuum distilled to obtain the pure product.

10. The method for preparing chlorophosphine compounds based on tetrachlorosilane according to claim 1, characterized in that: Phosphine oxide is aryl phosphine oxide.

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