Method for preparing phosphine-based compound based on pyrophosphorous acid

Abstract

The present invention belongs to the field of organic chemical synthesis. Disclosed is a method for preparing a phosphine-based compound based on pyrophosphorous acid. The method comprises selectively adding a reducing agent, i.e. pyrophosphorous acid H4P2O5, which contains or does not contain impurities, to a phosphine oxide (sulfide) compound, fully stirring and mixing same with an elemental halogen X2 or a halide MXXY serving as a catalyst to carry out a reduction reaction, and after the reaction is finished, washing same with water, subjecting same to liquid separation, and extracting and purifying same to obtain the target phosphine-based compound. A cheap and readily available reducing agent, i.e. pyrophosphorous acid H4P2O5, and an extremely low catalytic amount of a catalyst (elemental halogen X2 or halide MXXY) are used for preparing the phosphine-based compound by means of reduction, thereby avoiding the problem of using a large amount of expensive iodine in the current process, and greatly reducing the cost and reducing pollution to the environment during the subsequent treatment of iodine waste; in addition, the production process of the present invention is safe and easy to operate, and the byproducts generated during the reaction process are easy to recover.

Description

A method for preparing phosphine-based compounds based on pyrophosphorous acid Technical Field

[0001] The present invention relates to the field of organic chemical synthesis, and more particularly to a method for preparing phosphine-based compounds based on pyrophosphorous acid. Background Art

[0002] Triphenylphosphine is an important fine chemical with extensive applications in organic synthesis and industrial production. For example, triphenylphosphine can be used as a chemical reagent in the Wittig reaction, Staudinger reaction, Mitsunobu reaction, and Appel reaction. It can also be used as a ligand in various transition metal-catalyzed homogeneous reactions. Industrially, the Wittig reaction using triphenylphosphine to produce vitamins produces triphenylphosphine oxide as a byproduct, with an annual production volume of up to 10,000 tons. Due to its stable chemical properties and low utilization value, large amounts of triphenylphosphine oxide can only be treated as solid waste or incinerated, resulting in a waste of phosphorus resources and environmental pollution. With environmental concerns and the global shortage of phosphorus resources becoming increasingly prominent, the recovery of triphenylphosphine oxide is crucial.

[0003] The methods for recovering triphenylphosphine by reducing triphenylphosphine oxide reported so far are mainly as follows: (1) the BASF phosgene / Fe, Al, Si reduction method that is still used today, however, this process uses highly toxic gases and produces a large amount of chloride solid waste; (2) the reduction method using various silanes represented by trichlorosilane as reducing agents, however, this process produces a large amount of hydrochloric acid and silicon oxide solid waste, etc.; (3) the reduction method using other boranes, aluminum hydride reagents, oxalyl chloride, etc.; (4) the reduction method of iodine element / diphenyl phosphite / trimethyl phosphite system developed in recent years (Métivier, P et al. Angew. Chem. Int. Ed. 2017, 56, 15989-15992), and the previously developed method of reducing phosphine oxide compounds using iodine / phosphorous acid system (Han et al. al.J.Org.Chem.2023,88,3909-3915), achieved good reduction efficiency. However, this method requires the use of an equivalent amount of elemental iodine. Since iodine is expensive and difficult to recover in this reaction system, this method is costly and produces large amounts of iodine waste, making large-scale industrial production almost impossible.

[0004] In summary, whether using the traditional method or the iodine-mediated reduction method, there are problems such as high cost of reducing agents, dangerous production processes, or the reduction process is not environmentally friendly. Among them, the reaction route used by the traditional method is shown in the figure below:

[0005] Traditional methods:

[0006] The reaction pathway used in the iodine-mediated reduction method is shown in the figure below:

[0007] Iodine-mediated reduction method:

[0008] Summary of the Invention

[0009] 1. Technical problems to be solved

[0010] In response to the problems existing in the prior art, the present invention aims to provide a method for preparing phosphine-based compounds based on pyrophosphoric acid. The method uses a cheap and readily available reducing agent, pyrophosphoric acid H4P2O5, and an extremely low catalytic amount of catalyst, iodine I2, to mix with a phosphine oxide (sulfur) compound to prepare the corresponding phosphine-based compound. The method is economical and efficient, simple to operate, and safe to produce, and is particularly suitable for large-scale industrial production.

[0011] 2. Technical solution

[0012] To solve the above problems, the present invention adopts the following technical solutions.

[0013] A method for preparing phosphine-based compounds based on pyrophosphoric acid, wherein a phosphine oxide (sulfur) compound R is selectively added with a reducing agent pyrophosphoric acid H4P2O5 containing or not containing impurities, and reacted with a catalyst elemental halogen X2 or a halide M X X Y Stir and mix thoroughly to carry out reduction reaction. After the reaction is completed, separate, wash and purify to obtain phosphine compound Y. The reaction chemical formula is: The structural formula of pyrophosphorous acid H4P2O5 is

[0014] Wherein, the molar ratio of pyrophosphorous acid H4P2O5 to the phosphine oxide (sulfur) group in the phosphine oxide (sulfur) compound R is 1-20; the catalyst elemental halogen X2 or halide M X X Y The molar ratio of the phosphine oxide (sulfur) group to the phosphine oxide (sulfur) group in the phosphine oxide (sulfur) compound R is 0.001-0.1.

[0015] Preferably, the elemental halogen X2 is chlorine Cl2, bromine Br2 or iodine I2, and the halide M X X Y It is an organic or inorganic halide that does not contain fluorine F.

[0016] Preferably, the halide M X X Y Including LiX, NaX, KX, MgX2, AlX3, FeX2, FeX3, NH4X, R3NH and R3SiX, etc.; wherein R is an alkyl group or an aryl group.

[0017] Preferably, the elemental halogen X2 is iodine I2, and the halide M X XY It is a compound containing iodine I.

[0018] Preferably, the phosphine oxide (sulfur) compound R contains an aromatic group.

[0019] Preferably, the phosphine oxide (sulfur) compound R contains an aromatic group connected to the P atom.

[0020] Preferably, the structural formula of the phosphine oxide (sulfur) compound R is The structural formula of the phosphine compound Y is When

[0021] Or the structural formula of phosphine oxide (sulfur) compound R is The structural formula of the phosphine compound Y is When

[0022] Wherein, Z is selected from O or S; R 1 、R 2 and R 3 Each one is independent; R 1 and R 2 are all aryl groups; R 3 R is selected from cycloalkyl, alkyl, thienyl, ferrocenyl, aryl or alkyl substituted by aryl; 4 Selected from aryl, ferrocenyl or alkyl.

[0023] Preferably, R 1 、R 2 are each independently selected from phenyl, or phenyl substituted by one or more of halogen, alkoxy, trifluoromethyl, cyano and alkyl; R 3 is selected from phenyl, thienyl, ferrocenyl, cycloalkyl or alkyl, or phenyl substituted by one or more of halogen, alkoxy, trifluoromethyl, cyano, alkyl and high molecular weight groups, or alkyl substituted by phenyl or high molecular weight groups; R 4 is phenyl, ferrocenyl or alkyl.

[0024] Preferably, in the impurity-containing pyrophosphorous acid H4P2O5, the impurity components include but are not limited to one or more of carboxylic acid, acyl chloride, phosphorous acid, water and hydrogen chloride.

[0025] Preferably, the impurity content is within 20% of the total mass of the impurity-containing pyrophosphorous acid H4P2O5.

[0026] Preferably, pyrophosphorous acid H4P2O5 and elemental halogen X2 or halide M X X Y Formation of H4P2O5 / X2(M X XY ) system, phosphine oxide (sulfur) compound R in H4P2O5 / X2(M X X Y ) system, the reaction can be carried out under nitrogen conditions or air conditions.

[0027] Preferably, when the reduction reaction is carried out, the reaction temperature is 40-120°C.

[0028] Preferably, the reaction temperature is 80-100°C.

[0029] Preferably, an organic solvent is further added, and the organic solvent is selected from a mixture of one or more of benzene solvents, alkanes and halogenated alkanes.

[0030] Preferably, the organic solvent is selected from a mixture of one or more of benzene, toluene, xylene, hexane, pentane, dichloroethane, tetrachloroethylene and chloroform.

[0031] Preferably, the organic solvent is selected from a mixture of one or more of dichloroethane, tetrachloroethylene and chloroform.

[0032] Preferably, the molar ratio of pyrophosphorous acid H4P2O5 to the phosphine oxide (sulfur) group in the phosphine oxide (sulfur) compound R is 0.0055.

[0033] Preferably, the catalyst is iodine elemental halogen X2 or halide M X X Y The molar ratio of the phosphine oxide (sulfur) group to the phosphine oxide (sulfur) group in the phosphine oxide (sulfur) compound R is 0.0025-0.025.

[0034] Preferably, the final by-product produced during the reaction is orthophosphoric acid H3PO4, which is easy to recover and can be removed by washing with water.

[0035] As a further explanation of the present invention, the synthesis of the pyrophosphorous acid H4P2O5 includes but is not limited to the following steps: under the protection of nitrogen gas, mixing phosphorous acid H3PO3 and phosphorus trichloride PCl3 at a molar ratio of 5:1 at 0°C, then returning to room temperature until the reaction is complete, and removing low-boiling point substances under reduced pressure to obtain pyrophosphorous acid H4P2O5;

[0036] Alternatively, under the protection of nitrogen gas, carboxylic acid and phosphorus trichloride PCl3 are mixed at a molar ratio of 3:1 at 0°C, and then the reaction is restored to room temperature until the reaction is complete. The low-boiling point substances are removed under reduced pressure to obtain pyrophosphorous acid H4P2O5;

[0037] The synthesis of pyrophosphorous acid H4P2O5 can also be prepared by other well-known methods, such as dehydration of phosphorous acid. 3. Beneficial effects

[0038] Compared with the prior art, the advantages of the present invention are:

[0039] (1) The present invention provides a method for preparing a phosphine oxide (sulfur) compound by mixing a cheap and readily available reducing agent, pyrophosphorous acid H4P2O5, and a catalyst elemental halogen X2 or a halide M in an extremely low catalytic amount. X X Y , thereby reducing and preparing phosphine-based compounds; avoiding the problem of using a large amount of expensive iodine in the current process, greatly reducing costs and reducing environmental pollution during subsequent treatment of iodine waste.

[0040] (2) The reducing agent pyrophosphorous acid H4P2O5 used in the present invention can be easily prepared by mixing phosphorous acid with phosphorus trichloride PCl3, or by mixing isobutyryl chloride with phosphorus trichloride PCl3. This method is simple, fast, practical and safe. Moreover, the reducing agent phosphorous acid H4P2O5 used in the present invention may contain impurities, so that in industrial applications, industrial by-product waste phosphoric acid containing a certain amount of pyrophosphorous acid can be used in the reduction catalytic reaction provided by the present invention, and the triphenylphosphine product can still be obtained in a very high yield.

[0041] (3) The byproduct produced during the reaction of the present invention is ultimately orthophosphoric acid H3PO4, which can be removed by washing with water and is easy to recycle.

[0042] (4) In the present invention, the reduction reaction can be carried out under mild conditions using only a catalytic amount of elemental halogen or halide as low as 0.0055 mol%. At the same time, the preparation method adopted by the present invention can be carried out under air conditions and nitrogen conditions, has low requirements on production equipment, and is easy to operate.

[0043] (5) In the present invention, the phosphine oxide (sulfur) compound, the reducing agent and the catalyst can react in the presence of an organic solvent or in the absence of an organic solvent; by avoiding harsh reaction conditions, the preparation method adopted by the present invention is cheap, simple, practical, safe and environmentally friendly. DETAILED DESCRIPTION

[0044] The present invention will be further described below with reference to specific embodiments, but the protection scope of the present invention is not limited thereto.

[0045] Test Example 1:

[0046] Synthesis of pyrophosphorous acid H4P2O5: Under nitrogen protection, phosphorous acid (410g, 5mol, 5 equivalents) was added to a three-necked flask, and phosphorus trichloride PCl3 (137.3g, 1mmol, 1 equivalent) was added dropwise at 0°C, and then the reaction was allowed to proceed to room temperature overnight. After removing low-boiling substances under reduced pressure, yellow solid pyrophosphorous acid H4P2O5 (350.3g, 2.4mol, yield 96%) was obtained. 31P NMR and 1 H NMR purity 99%).

[0047] Example 1:

[0048] Preparation of the phosphine-based compound triphenylphosphine Ph3P: Under nitrogen protection, triphenylphosphine oxide Ph3P(O) (1.0 g, 3.59 mmol, 1 equivalent), iodine I2 (22.8 mg, 0.09 mmol, 0.025 equivalent), pyrophosphorous acid H4P2O5 (5.26 g, 35.9 mmol, 10 equivalents) and toluene (5.0 mL) were placed in a 50 mL Schlenk tube, heated to 100 ° C, and kept warm for 5 hours. After the reaction was completed, water (5 mL) was added to the reaction solution, and then extracted with ethyl acetate to obtain an organic phase. The concentrated organic phase was purified by silica gel column chromatography under nitrogen protection to obtain triphenylphosphine Ph3P (867.7 mg, 3.3 mmol), with a GC content of 99.5%, and a triphenylphosphine Ph3P yield of 92%.

[0049] Example 2-24:

[0050] On the basis of Example 1, different solvents are added or not, iodine I2 or hydrogen iodide HI is added as a catalyst, and the amount of solvent (mL), the molar ratio of pyrophosphorous acid H4P2O5 to triphenylphosphine oxide Ph3P(O), the molar ratio of iodine I2 to triphenylphosphine oxide Ph3P(O), the reaction temperature and the reaction time are adjusted to obtain triphenylphosphine Ph3P.

[0051] The reaction conditions of Examples 1-24 were tabulated to obtain Table 1: Different reaction conditions and yields of triphenylphosphine Ph3P in H4P2O5 / I2 system.

[0052] Table 1: Different reaction conditions and yields of triphenylphosphine Ph3P in H4P2O5 / I2 system;

[0053] Comparing Example 1 with Examples 2-3, under the same conditions, the reaction is basically complete when the reaction time is 5 h, and the reaction will not proceed if the reaction time is further extended.

[0054] Comparing Example 1 with Examples 4-5, under the same conditions, the optimal reaction temperature is 100°C, and lowering the temperature or continuing to increase the temperature cannot improve the yield.

[0055] Comparing Example 1 with Examples 6-9, under the same conditions, the reaction yield decreases with continuous reduction of the amount of pyrophosphoric acid H4P2O5. 1.3 equivalents of pyrophosphoric acid H4P2O5 can only reduce 11% of triphenylphosphine Ph3P. On the basis of 10 equivalents of pyrophosphoric acid H4P2O5, increasing the pyrophosphoric acid H4P2O5 to 15 equivalents no longer improves the yield, but instead decreases from 92% to 90%. It can be inferred that when the phosphine oxide (sulfur) compound is reduced in the H4P2O5 / I2 system, the molar ratio of pyrophosphoric acid H4P2O5 to the phosphine oxide (sulfur) compound is 1-20, and the preferred molar ratio is 8-15. Taking into account economic cost factors, the preferred molar ratio of pyrophosphoric acid H4P2O5 to the phosphine oxide (sulfur) compound is 8-10.

[0056] Comparing Example 1 with Examples 10-13, under the same conditions, it can be seen from Example 10 that increasing the amount of catalytic amount I2 will reduce the reaction yield; it can be seen from Example 11 that when the amount of catalyst I2 is reduced to 0.0055 mol%, the yield is as high as 94%, which is better than the test result of adding 0.025 mol% iodine in Example 1, indicating that appropriately reducing the amount of iodine is more conducive to the reduction reaction; it can be seen from Example 13 that when the amount of catalyst I2 is reduced to 0.0025 mol%, a high yield of 91% can also be maintained; it can be inferred that when the phosphine oxide (sulfur) compound is reduced in the H4P2O5 / I2 system, the molar ratio of iodine I2 to the phosphine oxide (sulfur) compound is 0.001-0.1, and the preferred molar ratio is 0.0025-0.025.

[0057] Comparing Example 1 with Examples 14-15, under the same reaction conditions, the reaction could not proceed without adding the catalyst I2; and the reaction could not proceed when hydrogen iodide HI was used instead of iodine I2.

[0058] Comparing Example 1 with Example 16, under the same reaction conditions, without adding a solvent, the reaction can also be carried out efficiently, and the yield of triphenylphosphine Ph3P reaches 91%.

[0059] Comparing Example 1 with Examples 17-18, it can be seen that under the same reaction conditions, when ethanol or THF polar solvent is selected as the solvent, the reaction does not proceed.

[0060] Comparing Example 1 with Examples 19-21, it can be seen that under the same reaction conditions, when the solvent is a non-polar hydrocarbon solvent such as xylene, trimethylbenzene or n-hexane, the reaction can also proceed well.

[0061] Example 25:

[0062] Preparation of the phosphine-based compound triphenylphosphine Ph3P under air conditions: Under air environment conditions, triphenylphosphine oxide Ph3P(O) (1.0 g, 3.59 mmol, 1 equivalent), iodine I2 (22.8 mg, 0.09 mmol, 0.025 equivalent), pyrophosphorous acid H4P2O5 (5.26 g, 35.9 mmol, 10 equivalents) and toluene (5.0 mL) were placed in a 50 mL Schlenk tube, heated to 100°C, and kept warm for 5 hours. After the reaction was completed, water (5 mL) was added to the reaction solution, and then extracted with ethyl acetate to obtain an organic phase. The concentrated organic phase was purified by silica gel column chromatography under nitrogen protection to obtain triphenylphosphine Ph3P (783.7 mg, 2.99 mmol), with a GC content of 99.5% and a triphenylphosphine Ph3P yield of 83%.

[0063] Comparing Example 1 with Example 25, it can be seen that when triphenylphosphine oxide Ph3P(O) is subjected to a reduction reaction in the H4P2O5 / I2 system, the reaction can be carried out under air or nitrogen conditions, and the yield is not low; however, it can be seen that the yield of triphenylphosphine oxide Ph3P(O) is higher when reacted under anaerobic conditions than under aerobic conditions; thus, it can be inferred that when phosphine oxide (sulfur) compounds are subjected to a reduction reaction in the H4P2O5 / I2 system, the reaction can be carried out under air or nitrogen conditions (under aerobic or anaerobic conditions).

[0064] Example 26:

[0065] Preparation of phosphine compound triphenylphosphine Ph3P using impurity-containing pyrophosphorous acid H4P2O5 mixture: under the protection of nitrogen, triphenylphosphine oxide Ph3P(O) (1.0 g, 3.59 mmol, 1 equivalent), iodine I2 (22.8 mg, 0.09 mmol, 0.025 equivalent), pyrophosphorous acid H4P2O5 mixture (5.3 g, containing 80 wt% of H4P2O5, 15% of H3PO3, 1 wt% of i-BuCO2H, 3 wt% of i-BuCOCl , 0.5wt% HCl and 0.5wt% of an unidentified substance) and toluene (5.0mL) were placed in a 50mL Schlenk tube, heated to 100°C, and kept warm for 5 hours. After the reaction was completed, water (5mL) was added to the reaction solution, followed by extraction with ethyl acetate to obtain an organic phase. The concentrated organic phase was purified by silica gel column chromatography under nitrogen protection to obtain triphenylphosphine Ph3P (848.3mg, 3.2mmol) with a GC content of 99.5%. The yield of triphenylphosphine Ph3P was 90%.

[0066] Comparing Example 1 with Example 26, it can be seen that the phosphine-based compound triphenylphosphine Ph3P was prepared with a yield of 90% using a mixture of pyrophosphorous acid H4P2O5 containing impurities. This shows that the triphenylphosphine product can still be obtained in a very high yield when the waste phosphoric acid (containing 80 wt% pyrophosphorous acid and 8 equivalents of effective pyrophosphorous acid) produced as a by-product in the industrial preparation of isobutyryl chloride from isobutyric acid and PCl3 is used in this reduction catalytic reaction.

[0067] Examples 27-34:

[0068] Different phosphine oxide compounds and phosphine sulfur compounds undergo reduction reactions in the H4P2O5 / I2 system:

[0069] Based on the best example 11 among Examples 1-24, 1 g of different phosphine oxide compounds and phosphine sulfur compounds were selected respectively, and reacted with 0.0055 mol% of iodine I2, 10 equivalents of pyrophosphorous acid H4P2O5 and 5 mL of toluene at 100°C for 5 hours to obtain the corresponding phosphine-based compounds.

[0070] The reactions of Example 11 and Examples 27-34 were tabulated to obtain Table 2: Reactions of different phosphine oxide (sulfur) compounds in the H4P2O5 / I2 system.

[0071] Table 2: Reactions of different phosphine oxide (sulfur) compounds in the H4P2O5 / I2 system;

[0072] It can be seen from Example 11, Examples 27-29, and Examples 31-33 that the yields of different phosphine-based compound products are all above 85%.

[0073] It can be inferred from Example 11 and Examples 27-34 that the phosphine oxide (sulfur) compound contains an aromatic group. Furthermore, the phosphine oxide (sulfur) compound contains an aromatic group connected to the P atom.

[0074] R 1 and R 2 are all aryl groups; R 3 R is selected from cycloalkyl, alkyl, thienyl, ferrocenyl, aryl or alkyl substituted by aryl; 4 is selected from aryl, ferrocenyl or alkyl; R 1 、R 2 and R 3 They can be the same or they can be independent and different.

[0075] Furthermore, R 1 、R 2are each independently selected from phenyl, or phenyl substituted by one or more of halogen, alkoxy, trifluoromethyl, cyano and alkyl; R 3 is selected from phenyl, thienyl, ferrocenyl, cycloalkyl or alkyl, or phenyl substituted by one or more of halogen, alkoxy, trifluoromethyl, cyano, alkyl and high molecular weight groups, or alkyl substituted by phenyl or high molecular weight groups; R 4 is phenyl, ferrocenyl or alkyl.

[0076] It can be inferred from Example 1 and Examples 27-34 that Z can be O or S. Therefore, it can be further inferred that both phosphine oxide compounds and phosphine sulfur compounds can be reduced in the H4P2O5 / I2 system to prepare phosphine-based compounds.

[0077] Examples 35-38:

[0078] Different phosphine oxide compounds containing multiple phosphine oxide bonds undergo reduction reactions in the H4P2O5 / I2 system:

[0079] On the basis of the optimal example 11, 1 g of different phosphine-oxygen compounds and phosphine-sulfur compounds containing multiple phosphine-oxygen bonds were selected respectively, and reacted with 0.0055 mol% of iodine I2, 10 equivalents of pyrophosphorous acid H4P2O5 and 5 mL of toluene at 100°C for 5 hours to obtain the corresponding phosphine-based compounds.

[0080] The reactions of Examples 35-38 were tabulated to obtain Table 3: Reactions of compounds containing multiple phosphine-oxygen bonds in the H4P2O5 / I2 system.

[0081] Table 3: Reactions of compounds containing multiple phosphine-oxygen bonds in the H4P2O5 / I2 system;

[0082] As shown in Examples 35-38, compounds containing two phosphine-oxygen bonds reacted in the H₄P₂O₅ / I₂ system with yields exceeding 97%. This suggests that phosphine-oxygen compounds containing multiple phosphine-oxygen groups can react in the H₄P₂O₅ / I₂ system with good yields.

[0083] Examples 39-41:

[0084] Based on Example 1, 0.18 mmol of different halides M were added. X X Y As a catalyst, the reaction was carried out under the same reaction conditions as in Example 1 to obtain triphenylphosphine Ph3P.

[0085] The reaction conditions of Examples 39-41 were tabulated to obtain Table 4: X X Y Different reaction conditions and yields in the system.

[0086] Table 4: Triphenylphosphine Ph3P in H4P2O5 / M X X Y Different reaction conditions and yields in the system;

[0087] As can be seen from Examples 39-41, the halide M x X y As a catalyst, it can be used to prepare phosphine compounds.

[0088] As can be seen from Example 41, the preparation of phosphine-based compounds can still be achieved by selecting non-iodine-containing halides as catalysts, but the yield is only 3%. Therefore, iodine-containing halides are preferably used as catalysts for the preparation of phosphine-based compounds.

[0089] Comparative Example 1:

[0090] The phosphine compound triphenylphosphine Ph3P was prepared using phosphorous acid H3PO3: Under the protection of nitrogen, triphenylphosphine oxide Ph3P(O) (1.0 g, 3.59 mmol, 1 equivalent), iodine I2 (22.8 mg, 0.09 mmol, 0.025 equivalent), phosphorous acid H3PO3 (5.9 g, 71.87 mmol, 10 equivalents) and toluene (5.0 mL) were placed in a 50 mL Schlenk tube, the temperature was raised to 100°C, and the temperature was kept for 5 hours. No reaction was observed, and the yield was 0%.

[0091] Comparative Example 2:

[0092] Preparation of phosphine-based compound triphenylphosphine Ph3P using phosphorous acid H3PO3: Under the protection of nitrogen, triphenylphosphine oxide Ph3P(O) (1.0 g, 3.59 mmol, 1 equivalent), iodine I2 (22.8 mg, 0.09 mmol, 0.025 equivalent), phosphorous acid H3PO3 (5.9 g, 71.87 mmol, 20 equivalents) and toluene (5.0 mL) were placed in a 50 mL Schlenk tube, heated to 120°C and kept warm for 10 h. No reaction was observed and the yield was 0%.

[0093] Comparative Example 3:

[0094] The phosphine-based compound triphenylphosphine Ph3P was prepared using metaphosphoric acid HPO3: Under the protection of nitrogen, triphenylphosphine oxide Ph3P(O) (1.0 g, 3.59 mmol, 1 equivalent), iodine I2 (22.8 mg, 0.09 mmol, 0.025 equivalent), hypophosphorous acid H2PO3 (4.74 g, 71.87 mmol, 20 equivalents) and toluene (5.0 mL) were placed in a 50 mL Schlenk tube, the temperature was raised to 100°C, and the temperature was kept for 5 hours. No reaction was observed, and the yield was 0%.

[0095] Comparative Example 4:

[0096] The phosphine-based compound triphenylphosphine Ph3P was prepared using metaphosphoric acid HPO3: Under the protection of nitrogen, triphenylphosphine oxide Ph3P(O) (1.0 g, 3.59 mmol, 1 equivalent), iodine I2 (22.8 mg, 0.09 mmol, 0.025 equivalent), metaphosphoric acid HPO3 (3.59 g, 71.87 mmol, 20 equivalents) and toluene (5.0 mL) were placed in a 50 mL Schlenk tube, the temperature was raised to 100°C, and the temperature was kept for 5 hours. No reaction was observed, and the yield was 0%.

[0097] By comparing Examples 1-38 with Comparative Examples 1-4, it can be seen that using a reducing agent such as phosphorous acid, hypophosphorous acid, or metaphosphoric acid cannot react triphenylphosphine oxide Ph3P(O) using the method provided in this case.

[0098] Comparative Example 5:

[0099] Preparation of the phosphine-based compound triphenylphosphine Ph3P without adding a catalyst: Under the protection of nitrogen, triphenylphosphine oxide Ph3P(O) (1.0 g, 3.59 mmol, 1 equivalent), pyrophosphorous acid H4P2O5 (5.26 g, 35.9 mmol, 10 equivalents) and toluene (5.0 mL) were placed in a 50-mL Schlenk tube, the temperature was raised to 100°C, and the reaction was kept warm for 5 hours. After the reaction was completed, water (5 mL) was added to the reaction solution, and then extracted with ethyl acetate to obtain an organic phase. The concentrated organic phase was purified by silica gel column chromatography under the protection of nitrogen to obtain triphenylphosphine Ph3P. The yield of triphenylphosphine Ph3P was less than 1%.

[0100] By comparing Example 1 and Comparative Example 5, it can be seen that without adding catalyst elemental halogen X2 or halide M x X y , it is impossible to effectively obtain the phosphine-based compound triphenylphosphine Ph3P.

[0101] Comparative Example 6:

[0102] The phosphine-based compound triphenylphosphine Ph3P was prepared using sodium fluoride as a catalyst: under the protection of nitrogen, triphenylphosphine oxide Ph3P(O) (1.0 g, 3.59 mmol, 1 equivalent), sodium fluoride NaF (0.19 mmol, 7.6 mg), pyrophosphorous acid H4P2O5 (5.26 g, 35.9 mmol, 10 equivalents) and toluene (5.0 mL) were placed in a 50 mL Schlenk tube, the temperature was raised to 100°C, and the reaction was kept warm for 5 hours. No reaction was observed and the yield was 0%.

[0103] Comparative Example 6 shows that the use of fluorine or fluorine-containing halides as catalysts cannot cause triphenylphosphine oxide Ph3P(O) to react.

Claims

1. A method for preparing phosphino compounds based on pyrophosphorous acid, characterized in that: In the phosphine oxide (sulfur) compound R, a reducing agent pyrophosphorous acid H4P2O5 with or without impurities is selectively added, and it is mixed with a catalyst, elemental halogen X2 or halide M X X Y The mixture is stirred well to carry out a reduction reaction. After the reaction is completed, the phosphino compound Y is obtained through washing with water, liquid separation, extraction, and purification Among them, the molar ratio of pyrophosphorous acid H4P2O5 to the phosphine oxide (sulfide) group in the phosphine oxide (sulfide) compound R is 1 - 20; the catalyst is elemental halogen X2 or halide M X X Y The molar ratio to the phosphine oxide (sulfide) group in the phosphine oxide (sulfide) compound R is 0.001 - 0.

1.

2. The method for preparing a phosphino compound based on pyrophosphorous acid according to claim 1, wherein: The elemental halogen X2 is chlorine Cl2, bromine Br2 or iodine I2, and the halide M X X Y is an organic or inorganic halide that does not contain fluorine F.

3. A method for preparing a phosphino compound based on pyrophosphorous acid according to claim 1, wherein: The elemental halogen X2 is iodine I2, and the halide M X X Y is a compound containing iodine I.

4. The method for preparing phosphino compounds based on pyrophosphorous acid according to claim 1, characterized in that: The phosphine oxide (sulfur) compound R contains a group with aromatic properties.

5. The method for preparing phosphino compounds based on pyrophosphorous acid according to claim 1, wherein: The structural formula of the phosphine oxide (sulfur) compound R is The structural formula of the phosphine compound Y is When, the reaction formula is The structural formula of the phosphine oxide (sulfur) compound R is The structural formula of phosphine compound Y is When, the reaction formula is Among them, Z is selected from O or S; R 1 , R 2 and R 3 are each independent; R 1 and R 2 are both aryl; R 3 is selected from cycloalkyl, alkyl, thienyl, A ferrocenyl group, an aryl group or an alkyl group substituted by an aryl group; R 4 Selected from aryl, ferrocenyl or alkyl.

6. The method for preparing phosphino compounds based on pyrophosphorous acid according to claim 5, wherein: R 1 、R 2 each independently selected from phenyl or phenyl substituted with one or more of halogen, alkoxy, trifluoromethyl, cyano and alkyl; R 3 selected from phenyl, thienyl, ferrocenyl, cycloalkyl or alkyl, or phenyl substituted by one or more of halogen, alkoxy, trifluoromethyl, cyano, alkyl and polymer group, or alkyl substituted by phenyl or containing polymer group; R 4 is phenyl, ferrocenyl or alkyl.

7. A method for preparing phosphino compounds based on pyrophosphorous acid according to claim 1, characterized in that: In the impure pyrophosphorous acid H4P2O5, the impurity components include, but are not limited to, one or more of carboxylic acid, acyl chloride, phosphorous acid, water and hydrogen chloride, and the content of the impurities accounts for within 20% of the total mass of the impure pyrophosphorous acid H4P2O5.

8. A method for preparing a phosphino compound based on pyrophosphorous acid according to claim 1, characterized in that: Pyrophosphorous acid H4P2O5 and elemental halogen X2 or halide M X X Y to form the H4P2O5 / X2(M X X Y ) system. When the phosphine oxide (sulfur) compound R undergoes a reduction reaction in the H4P2O5 / X2(M X X Y ) system, the reaction can be carried out under nitrogen conditions or air conditions.

9. A method for preparing phosphino compounds based on pyrophosphorous acid according to claim 1, characterized in that: An organic solvent is also added, and the organic solvent is selected from one or more mixtures of benzene solvents, alkanes and halogenated alkanes.

10. A method for preparing phosphino compounds based on pyrophosphorous acid according to claim 1, characterized in that: The catalyst is elemental halogen X2 or halide M X X Y The molar ratio of the halogen X2 or halide M to the phosphine oxide (sulfide) group in the phosphine oxide (sulfide) compound R is 0.0025 - 0.025.

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