A process for the preparation of triphenylphosphine
By using catalysts such as ferric chloride and metallic iron reducing agents to reduce triphenylphosphine sulfur or triphenylphosphine selenium under mild conditions, the problems of high reaction temperature and high cost in existing technologies have been solved, achieving efficient and safe preparation of triphenylphosphine, which is suitable for industrial production.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SUN YAT SEN UNIV
- Filing Date
- 2026-04-07
- Publication Date
- 2026-06-09
AI Technical Summary
Existing methods for reducing triphenylphosphine sulfur or triphenylphosphine selenium suffer from problems such as high reaction temperatures, high costs, and safety concerns, making them unsuitable for large-scale industrial production.
The reduction reaction of triphenylphosphine sulfur or triphenylphosphine selenide is carried out under mild conditions using catalysts such as ferric chloride, ferrous chloride, and ferric bromide, and metallic iron or iron powder as reducing agents, combined with an appropriate Lewis alkaline solvent.
This method enables the efficient preparation of triphenylphosphine at lower temperatures, reducing production costs, improving safety, and making it suitable for large-scale industrial applications.
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Figure CN122167482A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of organic synthesis technology, and in particular to a method for preparing triphenylphosphine. Background Technology
[0002] Triphenylphosphine plays a crucial role in organic synthesis and chemical production due to its significant nucleophilicity and coordination properties; it can participate in reactions as a substrate or act as a catalyst or ligand to promote reactions. Because of its importance in industrial production, research on the reduction of triphenylphosphine via phosphorus-oxygen and phosphorus-sulfur compounds has attracted considerable attention. However, the reduction of phosphorus-sulfur compounds presents several challenges: the high bond energy of the P=S bonds in phosphorus-sulfur compounds endows them with high stability; furthermore, sulfur is less electronegative than oxygen, making phosphorus-sulfur bonds less polarizable than phosphorus-oxygen bonds and more difficult to activate, thus posing a significant challenge to the reduction of phosphorus-sulfur compounds.
[0003] Compared to the reduction of phosphorus oxides, there are relatively few methods for reducing phosphorus sulfur compounds. Currently, methods for directly reducing phosphorus sulfur compounds all have certain problems. Using sodium or Raney nickel as reducing agents for the reduction of phosphorus sulfur compounds poses significant safety risks and is highly dangerous in large-scale industrial production, while also being costly. Another common reducing agent, hexachlorodisilane, is expensive and also unsuitable for large-scale industrial production. Furthermore, iron powder can only reduce triphenylphosphine sulfur at extremely high temperatures of 370 °C, but this temperature is too high, consumes a lot of energy, and has stringent requirements for reaction equipment, making it undesirable as well.
[0004] In view of the above-mentioned problems in the existing technology, there is an urgent need to develop a method for preparing triphenylphosphine from triphenylphosphine sulfur or triphenylphosphine selenium. Summary of the Invention
[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a catalyst for preparing triphenylphosphine from triphenylphosphine sulfur or triphenylphosphine selenium.
[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:
[0007] This invention provides a method for preparing triphenylphosphine, wherein the raw materials used in the method comprise a catalyst, triphenylphosphine sulfur or triphenylphosphine selenium, and a reducing agent; The catalyst is ferric chloride, aluminum chloride, ferrous chloride, ferric bromide, aluminum bromide, ferrous bromide, ferrous iodide, aluminum triiodide, iodine, liquid bromine, chlorine, and other substances that can react with metallic iron or aluminum to produce the above catalysts on site. The reducing agent is metallic iron or a metallic material containing iron.
[0008] According to a preferred method of the present invention, the catalyst comprises one of ferric chloride, ferrous chloride, ferric bromide, ferrous bromide, ferrous iodide, bromine or iodine, preferably anhydrous ferric chloride, anhydrous ferrous chloride, anhydrous ferric bromide, anhydrous ferrous bromide, liquid bromine or iodine, and more preferably anhydrous ferric chloride, anhydrous ferrous chloride, anhydrous ferric bromide or anhydrous ferrous bromide.
[0009] According to a preferred method of the present invention, the reducing agent is iron powder.
[0010] According to a preferred method of the present invention, the raw materials further include a solvent.
[0011] According to a preferred method of the present invention, wherein the method employs at least one of the following (I)-(V): (I) The solvent system contains at least one Lewis basic solvent with suitable coordination ability; (II) The molar ratio of phosphorus or selenium in the triphenylphosphine sulfur or triphenylphosphine selenium to the catalyst is greater than or equal to 1:0.2 and less than or equal to 1:0.01; (III) The molar ratio of phosphorus or selenium in the triphenylphosphine sulfur or triphenylphosphine selenium to the reducing agent is greater than or equal to 1:10 and less than or equal to 1:1, preferably greater than or equal to 1:6 and less than or equal to 1:1.5; (IV) The ratio of the moles of phosphorus or selenium in the triphenylphosphine sulfur or triphenylphosphine selenium to the volume of the solvent is greater than or equal to 1 mole: 4 L and less than or equal to 1 mole: 0.5 L.
[0012] According to a preferred method of the present invention, the method further comprises the following steps: under dry nitrogen, adding the triphenylphosphine sulfur or triphenylphosphine selenium, the catalyst and the reducing agent to the solvent for reaction, and after the reaction system is cooled to room temperature, performing post-processing to obtain the triphenylphosphine.
[0013] According to a preferred method of the present invention, in the case of triphenylphosphine sulfide, the synthetic route of the method is shown in the following formula: , In the case of triphenylphosphine selenium, the synthetic route of the method is the same as above, except that triphenylphosphine selenium replaces triphenylphosphine sulfur.
[0014] According to a preferred method of the present invention, the reaction temperature is 100-135 °C and the reaction time is 12-24 h; the solvent system comprises benzonitrile, phenylacetonitrile, acetonitrile, triethylene glycol dimethyl ether, diethylene glycol monoethyl ether, diethylene glycol dimethyl ether, N,N-dimethylformamide, a mixed solvent of acetonitrile and p-xylene, a mixed solvent of N,N-dimethylformamide and p-xylene, a mixed solvent of 1,3-dimethyl-2-imidazolinone and p-xylene, and a mixed solvent of N,N-dimethylformamide and toluene.
[0015] According to a preferred method of the present invention, the post-processing includes extraction, drying, and purification.
[0016] The method of this invention employs a suitable, highly efficient catalyst, reducing agent, and solvent system to activate triphenylphosphine sulfur. Therefore, a suitable, highly efficient catalyst, reducing agent, and solvent system are key factors of focus in this invention. Furthermore, compared to other reducing agents (such as zinc, aluminum powder, and hexachlorodisilane), the iron used in this invention has low production costs, abundant resources, and stable prices, making it suitable for large-scale industrial production with an industrial yield of 60% or higher. In short, compared to existing technologies, the method of this invention is simple, mild, cost-controllable, and safe to operate. Attached Figure Description
[0017] Figure 1 This is a process flow diagram of the method for preparing triphenylphosphine from triphenylphosphine sulfur according to the present invention. Detailed Implementation
[0018] To better illustrate the purpose, technical solution, and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments.
[0019] In a first aspect, the present invention provides a method for preparing triphenylphosphine from triphenylphosphine sulfur or triphenylphosphine selenium, wherein the catalyst is ferric chloride, aluminum chloride, ferrous chloride, ferric bromide, aluminum bromide, ferrous bromide, ferrous iodide, aluminum triiodide, iodine, liquid bromine, chlorine, and other substances that can react with metallic iron or aluminum to produce the above-mentioned catalyst in situ.
[0020] This invention utilizes the aforementioned catalyst in the reaction to prepare triphenylphosphine from triphenylphosphine sulfur or triphenylphosphine selenium, overcoming the following shortcomings of existing reducing agents: high reaction temperature, high cost, and high risk in the reduction of triphenylphosphine sulfur or triphenylphosphine selenium. Through extensive experimental research, the inventors have achieved the reduction of triphenylphosphine sulfur or triphenylphosphine selenium under relatively mild conditions, resulting in a high yield of triphenylphosphine.
[0021] Preferably, the catalyst is one of ferric chloride, ferrous chloride, ferric bromide, ferrous bromide, ferrous iodide, bromine, or iodine, preferably anhydrous ferric chloride, anhydrous ferrous chloride, anhydrous ferric bromide, anhydrous ferrous bromide, liquid bromine, or iodine, and more preferably anhydrous ferric chloride, anhydrous ferrous chloride, anhydrous ferric bromide, or anhydrous ferrous bromide.
[0022] More preferably, the catalyst is anhydrous ferric chloride. Using the above catalyst not only provides excellent catalytic performance, resulting in a high yield of triphenylphosphine prepared by this invention, but also offers low cost and good industrial application value.
[0023] Secondly, in this invention, the raw materials for preparing triphenylphosphine include the catalyst described in the first aspect.
[0024] Preferably, the raw materials for preparing triphenylphosphine further include triphenylphosphine sulfur, a reducing agent, a catalyst, and a solvent.
[0025] The structural formula of triphenylphosphine thio is shown below: .
[0026] More preferably, the reducing agent is metallic iron, or a metal containing iron such as iron powder. Through extensive experiments, the inventors have discovered that the use of a catalyst enables metallic iron or a metal containing iron, which has a low reducing capacity, to carry out the reaction of this invention under mild conditions, and the reducing agent is also more cost-effective, thus possessing greater practical value.
[0027] More preferably, the solvent is benzonitrile, phenylacetonitrile, acetonitrile, triethylene glycol dimethyl ether, diethylene glycol monoethyl ether, diethylene glycol dimethyl ether, N,N-dimethylformamide, a mixed solvent of acetonitrile and p-xylene, a mixed solvent of N,N-dimethylformamide and p-xylene, a mixed solvent of 1,3-dimethyl-2-imidazolinone and p-xylene, a mixed solvent of N,N-dimethylformamide and toluene, and most preferably anhydrous dried acetonitrile.
[0028] Most preferably, in the catalyst, the molar ratio of phosphorus or selenium in triphenylphosphine sulfur or triphenylphosphine selenium to the catalyst is greater than or equal to 1:0.2 and less than or equal to 1:0.01. Through extensive experiments, the inventors have discovered that under these conditions, the yield of the final triphenylphosphine is maximized, while simultaneously saving experimental costs.
[0029] Most preferably, the molar ratio of phosphorus or selenium in the triphenylphosphine sulfur or triphenylphosphine selenium to the reducing agent is greater than or equal to 1:10 and less than or equal to 1:1, preferably greater than or equal to 1:6 and less than or equal to 1:1.5, and more preferably 1:3, thereby achieving the lowest amount of reducing agent while ensuring that the yield is not reduced.
[0030] Most preferably, the ratio of the moles of phosphorus or selenium in the triphenylphosphine sulfur or triphenylphosphine selenium to the volume of the solvent is 1 mole: (0.5-1.0) mL, thus achieving the most suitable solvent concentration without reducing the yield.
[0031] The method for preparing triphenylphosphine provided by the present invention includes the following steps: under a dry atmosphere, triphenylphosphine sulfur or triphenylphosphine selenium, a catalyst and a reducing agent are added to a solvent to react. After cooling to room temperature, the reaction is quenched, extracted, dried and purified to obtain the triphenylphosphine.
[0032] In the case of triphenylphosphine sulfide, the specific synthetic route of the method is as follows: , In the case of triphenylphosphine selenium, the synthetic route of the method is the same as above, except that triphenylphosphine selenium replaces triphenylphosphine sulfur.
[0033] In a preferred embodiment of the method for preparing triphenylphosphine according to the present invention, the drying atmosphere is dry nitrogen.
[0034] Through extensive exploratory experiments, the inventors discovered that the following points should be noted when using the catalyst described in this invention: 1. The catalyst needs to have a certain degree of acidity, but its acidity cannot be too strong; otherwise, the catalytic cycle will not be possible. 2. Pay attention to the dryness of the catalyst and solvent. Excessive water content in the catalyst and solvent will lead to a decrease in catalytic efficiency. 3. The catalyst needs to be quenched after use because triphenylphosphine is easily oxidized to triphenylphosphine oxide in an oxygen atmosphere after the experiment. 4. Pay attention to the dryness of the raw materials. If the raw materials contain other solvents such as dichloromethane or methanol, it will lead to a decrease in catalytic efficiency.
[0035] According to a preferred embodiment of the method of the present invention, the reaction temperature is 135 °C and the reaction time is 6-12 h.
[0036] According to a preferred embodiment of the method of the present invention, the specific post-processing steps are as follows: adding an aqueous sodium hydroxide solution to the solution cooled to room temperature, then adding an appropriate amount of ethyl acetate, followed by filtration, and extracting the organic phase with ethyl acetate, then drying the organic phase with anhydrous sodium sulfate, and finally purifying the dried organic phase by column chromatography, and obtaining the triphenylphosphine after solvent removal.
[0037] Compared with the prior art, the present invention achieves the following beneficial technical effects: The present invention provides a catalyst for preparing triphenylphosphine from triphenylphosphine sulfide or triphenylphosphine selenide. The catalyst is used in the reaction to prepare triphenylphosphine from triphenylphosphine sulfide or triphenylphosphine selenide, and metallic iron or iron-containing metal materials are used as reducing agents to achieve the reduction of triphenylphosphine sulfide or triphenylphosphine selenide at a temperature of 135°C or below, resulting in a high yield of triphenylphosphine. The present invention overcomes the problem in the prior art where the reduction of triphenylphosphine sulfide or triphenylphosphine selenide is limited by the high reaction temperature. Furthermore, the raw materials used in the present invention are inexpensive and readily available, and do not use expensive reagents such as silane or borane, resulting in a significant cost advantage. Moreover, each step of the preparation method of the present invention is safer and more suitable for large-scale industrial application. Example
[0038] The preferred embodiments of the present invention will be described in more detail below through specific examples, but the present invention is not limited thereto. Unless otherwise specified, all reagents or instruments used in the present invention are commercially available conventional products; the experimental methods described are conventional methods unless otherwise specified. Unless otherwise stated, all yields mentioned below are NMR yields.
[0039] The parameters of the reducing agent used in this invention are as follows: reduced iron powder (100-200 mesh, 99%).
[0040] In embodiments of the present invention, the molar percentage of the reducing agent or catalyst is the molar percentage of 1 equivalent of phosphorus.
[0041] In one embodiment of the method for preparing triphenylphosphine from triphenylphosphine sulfide according to the present invention, the reaction formula and preparation process of the triphenylphosphine are as follows: .
[0042] Under a nitrogen atmosphere, 0.5 mmol (1 equivalent) of triphenylphosphine sulfide as described above was dissolved in 0.5 mL of 5 mol% ferric chloride in acetonitrile, followed by the addition of 3.0 equivalents of iron powder (100 mesh, 99%). The reaction was carried out at 135 °C for 12 h. After the reaction was complete, the mixture was cooled to room temperature and then quenched with 0.5 mL of 3M sodium hydroxide solution. The NMR yield was 91%. The structural characterization data of the obtained product are as follows: 31 P NMR (162 MHz, CDCl3, 7.27 ppm) δ: -5.23. Examples 1-2 to 1-7
[0043] The only difference between Examples 1-2 to 1-7 and Example 1 is the type, concentration, and amount of catalyst used; all other steps are the same as in Example 1. The type, concentration, and amount of catalyst used in Examples 1-2 to 1-7, as well as the product yields, are shown in Table 1 below. (All yields in the table are NMR yields.)
[0044] Table 1 Example 2-45
[0045] The only difference between Examples 2-45 and Example 1 is the type of solvent used, as well as the type, concentration, and amount of catalyst. All other steps are the same as in Example 1. The types of solvents used, the type, concentration, and amount of catalyst used in Examples 2-45, and the yields of the products are shown in Table 2 below. (All yields in the table are NMR yields.)
[0046] Table 2 Examples 46-50
[0047] The only difference between Examples 46-50 and Example 1 is that the type, concentration, and amount of catalyst are different, while the other steps are the same as in Example 1. The type, concentration, amount of catalyst and yield of product used in Examples 46-50 are shown in Table 3 below.
[0048] Table 3 Examples 51-56
[0049] The only differences between Examples 51-56 and Example 1 are: the reduction dosage, the amount and type of catalyst, and the reaction time. All other steps are the same as in Example 1. The reduction dosage, the amount and type of catalyst, the reaction time, and the product yield used in Examples 51-56 are shown in Table 4 below.
[0050] Table 4 Examples 57-59
[0051] The only differences between Examples 57-59 and Example 1 are: the amount and type of water and triphenylphosphine added, the amount and type of catalyst, and the reaction time. All other steps are the same as in Example 1. The types of catalysts used in Examples 57-59 and the conversion rates of the products are shown in Table 5 below.
[0052] Table 5 Examples 60-64
[0053] The only differences between Examples 60-64 and Example 1 are: the type of reducing agent, the amount and type of catalyst, the reaction temperature and concentration are different, and the rest of the steps are the same as those in Example 1. The type of reducing agent, the amount and type of catalyst, the reaction temperature and concentration and the yield of the product used in Examples 60-64 are shown in Table 6 below.
[0054] Table 6 Examples 65-67
[0055] The only differences between Examples 65-67 and Example 1 are: the reduction dosage, the amount and type of catalyst, the reaction temperature and the solvent. All other steps are the same as in Example 1. The reduction dosage, the amount and type of catalyst, the reaction temperature and the solvent and the product yield used in Examples 65-67 are shown in Table 7 below.
[0056] Table 7 Examples 68-77
[0057] The only difference between Examples 68-77 and Example 1 is that the amount and type of raw materials and catalysts used in the preparation are different; the rest of the steps are the same as those in Example 1. The amount and type of raw materials and catalysts used in Examples 68-77 and the conversion rate of the products are shown in Table 8 below.
[0058] Table 8 Examples 78-79
[0059] The only difference between Examples 78-79 and Example 1 is that the amount, concentration, and temperature of the raw materials and catalysts are different, while the other steps are the same as those in Example 1. The amount, concentration, and temperature of the raw materials and catalysts used in Examples 78-79 and the conversion rate of the products are shown in Table 9 below.
[0060] Table 9
[0061] According to the structural characterization data of the triphenylphosphine prepared in the above embodiments of the present invention, the present invention successfully prepared triphenylphosphine with a high yield, and under specific raw material conditions, it can reduce pentavalent phosphorus compounds with iron powder at 100-135 °C; at the same time, it can be seen from Examples 57-59 that the product triphenylphosphine and water are unfavorable to the reaction, and ferric chloride will combine with triphenylphosphine, causing ferric chloride to lose its catalytic activity.
[0062] In summary, this invention overcomes the problem of the high reaction temperature limiting the reduction of triphenylphosphine sulfur in existing technologies. The raw materials used in this invention are inexpensive and readily available, and it does not use expensive reagents such as silane or borane, which has a significant cost advantage. At the same time, it does not use highly reactive and dangerous metals, making it safer and suitable for large-scale industrial applications.
[0063] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.
Claims
1. A method for preparing triphenylphosphine, characterized in that, The raw materials used in the method include a catalyst, triphenylphosphine sulfide or triphenylphosphine selenide, and a reducing agent; The catalyst is ferric chloride, aluminum chloride, ferrous chloride, ferric bromide, aluminum bromide, ferrous bromide, ferrous iodide, aluminum triiodide, iodine, liquid bromine, chlorine, and other substances that can react with metallic iron or aluminum to produce the above catalysts on site. The reducing agent is metallic iron or a metallic material containing iron.
2. The method as described in claim 1, characterized in that, The raw materials for preparation include triphenylphosphine sulfur or triphenylphosphine selenium, a reducing agent, and a catalyst; the catalyst includes one of ferric chloride, ferrous chloride, ferric bromide, ferrous bromide, ferrous iodide, bromine, or iodine, preferably anhydrous ferric chloride, anhydrous ferrous chloride, anhydrous ferric bromide, anhydrous ferrous bromide, liquid bromine, or iodine, and more preferably anhydrous ferric chloride, anhydrous ferrous chloride, anhydrous ferric bromide, or anhydrous ferrous bromide.
3. The method as described in claim 1, characterized in that, The reducing agent is iron powder.
4. The method as described in claim 1, characterized in that, The raw materials used in the preparation also include solvents.
5. The method as described in claim 4, characterized in that, The method employs at least one of the following (Ⅰ)-(Ⅴ): (I) The solvent system contains at least one Lewis basic solvent with suitable coordination ability; (II) The molar ratio of phosphorus or selenium in the triphenylphosphine sulfur or triphenylphosphine selenium to the catalyst is greater than or equal to 1:0.2 and less than or equal to 1:0.01; (III) The molar ratio of phosphorus or selenium in the triphenylphosphine sulfur or triphenylphosphine selenium to the reducing agent is greater than or equal to 1:10 and less than or equal to 1:1, preferably greater than or equal to 1:6 and less than or equal to 1:1.5; (IV) The ratio of the moles of phosphorus or selenium in the triphenylphosphine sulfur or triphenylphosphine selenium to the volume of the solvent is greater than or equal to 1 mole: 4 L and less than or equal to 1 mole: 0.5 L.
6. The method as described in claim 4 or 5, characterized in that, The method further includes the following steps: under dry nitrogen, the triphenylphosphine sulfur or triphenylphosphine selenium, the catalyst and the reducing agent are added to the solvent to react, and after the reaction system is cooled to room temperature, post-processing is performed to obtain the triphenylphosphine.
7. The method as described in claim 6, characterized in that, In the case of triphenylphosphine sulfide, the synthetic route of the method is shown below: ， In the case of triphenylphosphine selenium, the synthetic route of the method is the same as above, except that triphenylphosphine selenium replaces triphenylphosphine sulfur.
8. The method as described in claim 6, characterized in that, The reaction temperature is 100-135 ℃, and the reaction time is 12-24 h; the solvent system includes benzonitrile, phenylacetonitrile, acetonitrile, triethylene glycol dimethyl ether, diethylene glycol monoethyl ether, diethylene glycol dimethyl ether, N,N-dimethylformamide, a mixed solvent of acetonitrile and p-xylene, a mixed solvent of N,N-dimethylformamide and p-xylene, a mixed solvent of 1,3-dimethyl-2-imidazolinone and p-xylene, and a mixed solvent of N,N-dimethylformamide and toluene.
9. The method as described in claim 7, characterized in that, The post-processing includes extraction, drying, and purification.