High-selectivity reduction method for preparing triphenylphosphine from triphenylphosphine sulfide
By using toluene solvents and metal sodium reducing agents in a low oxygen environment, combined with the role of additives, triophenyl sulfur sulfur sulfur is highly selectively converted into tritenophyls. The problem has realized the industrialized production of environmental protection and friendship.
Patent Information
- Application Number
- CN202411462988.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-18
- Publication Date
- 2025-01-21
AI Technical Summary
The method of reducing triphenyl sulfoxide to triphenyl phosphine in the prior art has problems of high cost, danger and environmental pollution, and it is difficult to achieve high selective reduction in a low oxygen environment.
In a low oxygen environment, the use of toluene as a solvent, react tritenopene sulfur sulfur with metal reducing agent (such as metal sodium) and additives (such as ethanol, isopropanol, etc.), and control the reaction temperature at 0 ℃ ~ 250 ℃. Filtering and decompression removing the solvent, and purified to obtain tritenophyls.
In the low -oxygen environment, the tria benzene sulfur sulfur is transformed into tritenophyls, which reduces production costs and risks. It is simple, environmentally friendly and friendly, and is suitable for industrialized production.
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of organic synthesis, and more specifically to a highly selective reduction method for preparing triphenylphosphine from triphenylphosphine sulfide. Background Art
[0002] In order to avoid the waste of phosphine resources in triphenylphosphine sulfide, it is often reduced to triphenylphosphine for recovery. The reducing agent currently used is usually a metal hydride, such as sodium hydride, LiAlH4 (Byrne, Peter A. et al. Org. Bio. Chem. 2012, 10, 3531-3537), Raney-Ni (Demchuk, Oleg M. et al. Phosphorus Sulfur Silicon Relat. Elem. 2017, 192, 64-68), Bu3P, etc. (Horner, L. et al, Chemische Berichete 1958, 91, 1583). The above method has the problems of high reducing agent price, dangerous production process and non-green environmental protection. In addition to the above-mentioned metal hydrides, the reducing agent also includes iron powder (Ludwig Maier, HELVETIC ACHIMICA ACT, 1964, 47, 238.). However, the direct reduction of triphenylphosphine sulfide with iron powder requires a high temperature of 370°C, which is too high and difficult to carry out in actual operation.
[0003] In addition to the above method, triphenylphosphine sulfide (Ph3PS) can also be dissolved in tetrahydrofuran (THF) solution and reduced to triphenylphosphine (Ph3P) using NaNaphthalide. The yield of Ph3P prepared by this method can reach about 89% (Horner, L. Chemische Berichete 1959, 92, 2088; Olah, GA et al. J. Org. Chem. 1977, 42, 2190).
[0004] Recently, we discovered that Ph3PS can react with micro-sodium in THF to obtain Ph3P (Zhang, J.-Q. et al. Phosphorus Sulfur Silicon Relat. Elem. 2021, 196, 961-964); however, as Ph3P is produced, Ph3P will also rapidly react with micro-metallic sodium (Ye, J. et al. Organometallics 2020, 39, 2682-2694.) to form by-products. Therefore, this method cannot be used to obtain Ph3P with high selectivity.
[0005] We have recently discovered that in non-polar solvents such as toluene, metallic sodium can efficiently reduce R 1 R2 R 3 PS Manufacturing R 1 R 2 R 3 P (Zhang, J.-Q. et al. Green Chem., 2023; https: / / doi.org / 10.1039 / D3GC03071G). However, this reaction requires strict anaerobic conditions.
[0006] In order to solve the above problems, the document "Reduction of phosphorus compounds with alkali metals" was disclosed in Volume 92, Pages 2088-2094 of Chemische Berichte in 1959. This method uses 5.3 equivalents of metallic sodium to achieve a final product yield of 75%. However, according to the law of conservation of atoms, this reaction only requires 2 equivalents of metallic sodium to complete the reaction; thus, it can be seen that this method increases the final product yield by sacrificing more than double the metallic sodium, which results in a waste of sodium resources and increases the safety risk and production cost of the reaction.
[0007] Therefore, it is necessary to provide a method for reducing triphenylphosphine sulfide under low oxygen conditions, and the method is safe, controllable, environmentally friendly, low-cost, and can reduce triphenylphosphine sulfide with high selectivity. Summary of the invention
[0008] In view of the problems existing in the prior art, the object of the present invention is to provide a method for converting triphenylphosphine sulfide into triphenylphosphine with high selectivity in a low-oxygen environment. The method has a wide range of applications and is simple in process, low in cost, safe and controllable, environmentally friendly, and easy to scale up for industrial production. In addition, triphenylphosphine sulfide can be used to prepare triphenylphosphine with high selectivity, and no other by-products are generated during the reaction.
[0009] To solve the above problems, the present invention adopts the following technical solutions.
[0010] A highly selective reduction method for preparing triphenylphosphine from triphenylphosphine sulfide, wherein triphenylphosphine sulfide, an additive and a metal reducing agent react in toluene at a temperature of 0N250°C under a low oxygen environment with an oxygen content of 5ppm to 2000ppm; after the reaction is completed, the triphenylphosphine is separated and purified to obtain the triphenylphosphine;
[0011] The additive is ethanol, isopropanol, tert-butanol, tetrahydrofuran, diphenyl ether, isopropyl ether or ethyl ether, and the metal reducing agent is selected from one or any combination of Li, Na and K.
[0012] Furthermore, the additive is isopropyl alcohol or diphenyl ether.
[0013] Furthermore, the low oxygen environment is a mixture of oxygen and inert gas, and the oxygen content is 200 ppm.
[0014] Furthermore, the inert gas is argon or nitrogen.
[0015] Furthermore, the metal reducing agent is Na.
[0016] Furthermore, after the reaction is completed and in the presence of toluene solvent and additives, the organic phase is separated by filtration, and the toluene solvent is removed under reduced pressure to obtain triphenylphosphine and unreacted triphenylphosphine sulfide, and finally triphenylphosphine is obtained by an organic synthesis purification method.
[0017] Furthermore, the triphenylphosphine sulfide is a pure substance.
[0018] Furthermore, the triphenylphosphine sulfide contains impurities, which are one or a mixture of any two or more of organic alcohols and organic ethers, and the impurity content is less than 30%; the impurities do not react with triphenylphosphine sulfide, triphenylphosphine and a metal reducing agent.
[0019] The present invention will be further described below:
[0020] A highly selective reduction method for preparing triphenylphosphine from triphenylphosphine sulfide comprises the following steps: placing 2.0 mmol of triphenylphosphine sulfide, 4.0 mmol of metallic sodium, 0.2 mmol of an additive and 1 mL of toluene in a glass tube, heating the tube to 110° C. in an oxygen-containing (200 ppm) nitrogen atmosphere, and keeping the temperature for reaction for 18 hours; after the triphenylphosphine sulfide and metallic sodium are fully reacted, cooling the tube to room temperature, filtering, removing an organic solvent under reduced pressure, and purifying the tube to obtain triphenylphosphine.
[0021] After the reaction is completed, the sodium disulfide and triphenylphosphine are separated by water and an organic solvent. An embodiment is as follows: 2.0 mmol triphenylphosphine sulfide, 4.0 mmol metallic sodium, 0.2 mmol additive, and 1 mL toluene are placed in a glass tube, heated to 110° C. under oxygen-containing nitrogen (oxygen content is 200 ppm), and kept warm for reaction for 18 hours. After triphenylphosphine sulfide and metallic sodium fully react, the temperature is lowered to room temperature, water and an organic solvent are added to the reaction system, and after sufficient shaking, the reaction system is allowed to stand to obtain an organic phase and an aqueous phase. The organic phase and the aqueous phase are separated to obtain an organic phase, and the organic solvent is removed by vacuum rotary evaporation, and the reaction is purified to obtain triphenylphosphine.
[0022] Furthermore, the metal reducing agent is sodium.
[0023] Furthermore, the metal reducing agent is in the form of micron powder, liquid or block.
[0024] Furthermore, the triphenylphosphine sulfide does not react with the metal reducing agent under the conditions of the additive and toluene.
[0025] Furthermore, the triphenylphosphine sulfide is a pure substance.
[0026] Furthermore, the triphenylphosphine sulfide contains impurities, and the impurities are one or a mixture of any of organic alcohols and organic ethers, and the impurity content is less than 30%. Preferably, the impurities can also be R 1 R 2 R 3 PO, solvent, inorganic salt, etc.; the R 1 , R 2 and R 3 are independently selected from aromatic or aliphatic substituents, wherein R 1 , R 2 and R 3 At least one of the substituents is an aromatic substituent.
[0027] Further, the solvent does not react with triphenylphosphine sulfide, and the impurities do not react with triphenylphosphine sulfide, triphenylphosphine and the metal reducing agent.
[0028] Compared with the prior art, the advantages of the present invention are:
[0029] First, the present invention overcomes the influence of oxygen on the metal reducing agent by adding a small amount of additives in the reaction of reducing triphenylphosphine to prepare triphenylphosphine, so that the surface of the metal reducing agent is not easily passivated due to the presence of oxygen, thereby enabling triphenylphosphine to generate triphenylphosphine in a low-oxygen environment; in addition, the addition of the additive reduces the amount of metallic sodium used, greatly reduces the production cost of the method, and reduces the danger in the reaction process, so that the reduction reaction has significant advantages in large-scale industrial production.
[0030] 2. The preparation method provided by the present invention is simple, environmentally friendly, and the product is easy to separate; the sulfide and the unreacted metal reducing agent can be separated by filtering the organic phase, and the organic solvent is removed under reduced pressure and purified to obtain pure triphenylphosphine.
[0031] 3. The method provided by the present invention for reacting triphenylphosphine sulfide with a metal reducing agent to generate triphenylphosphine and sulfide enables triphenylphosphine sulfide, which has no wide application value, to be converted into triphenylphosphine with wide application value, thereby enabling triphenylphosphine sulfide to be effectively utilized. DETAILED DESCRIPTION
[0032] Embodiment 1:
[0033] 2.0 mmol triphenylphosphine sulfide, 4.0 mmol metallic sodium, 0.2 mmol ethanol and 1.0 mL toluene were placed in a glass tube, heated to 110° C. under the protection of oxygen-containing nitrogen (oxygen content of 200 ppm), and kept warm for reaction for 18 hours. After triphenylphosphine sulfide and metallic sodium fully reacted, the temperature was lowered to room temperature, filtered, the organic solvent was removed under reduced pressure, and purified to obtain triphenylphosphine. The yield of triphenylphosphine was 73%.
[0034] Comparative Example 1:
[0035] The conditions of this comparative example are different from those of Example 1 in that no additive is added, and the other conditions are the same as those of Example 1; triphenylphosphine is obtained, and the yield of triphenylphosphine is 33%.
[0036] It can be seen from Example 1 and Comparative Example 1 that the addition of the additive enables triphenylphosphine sulfide to react in a low oxygen environment with an oxygen content of 200 ppm under the action of a small amount of metal reducing agent to prepare triphenylphosphine, and the yield of triphenylphosphine is significantly higher than the yield without using the additive.
[0037] Embodiment 2:
[0038] 2.0 mmol triphenylphosphine sulfide, 4.0 mmol metallic sodium, 0.2 mmol isopropanol and 1.0 mL toluene were placed in a glass tube, heated to 110° C. under the protection of oxygen-containing nitrogen (oxygen content of 200 ppm), and kept warm for reaction for 18 hours. After triphenylphosphine sulfide and metallic sodium fully reacted, the temperature was lowered to room temperature, filtered, the organic solvent was removed under reduced pressure, and purified to obtain triphenylphosphine. The yield of triphenylphosphine was 88%.
[0039] Embodiment 3:
[0040] 2.0 mmol triphenylphosphine sulfide, 4.0 mmol sodium metal, 0.2 mmol tert-butanol and 1.0 mL toluene were placed in a glass tube, heated to 110° C. under the protection of oxygen-containing nitrogen (oxygen content of 200 ppm), and kept warm for reaction for 18 hours. After triphenylphosphine sulfide and sodium metal fully reacted, the temperature was lowered to room temperature, filtered, the organic solvent was removed under reduced pressure, and purified to obtain triphenylphosphine. The yield of triphenylphosphine was 76%.
[0041] Embodiment 4:
[0042] 2.0 mmol triphenylphosphine sulfide, 4.0 mmol sodium metal, 0.2 mmol tetrahydrofuran and 1.0 mL toluene were placed in a glass tube, heated to 110° C. under the protection of oxygen-containing nitrogen (oxygen content of 200 ppm), and kept warm for reaction for 18 hours. After triphenylphosphine sulfide and sodium metal fully reacted, the temperature was lowered to room temperature, filtered, the organic solvent was removed under reduced pressure, and purified to obtain triphenylphosphine. The yield of triphenylphosphine was 77%.
[0043] Embodiment 5:
[0044] 2.0 mmol triphenylphosphine sulfide, 4.0 mmol sodium metal, 0.2 mmol diphenyl ether and 1.0 mL toluene were placed in a glass tube, heated to 110° C. under the protection of oxygen-containing nitrogen (oxygen content of 200 ppm), and kept warm for reaction for 18 hours. After triphenylphosphine sulfide and sodium metal fully reacted, the temperature was lowered to room temperature, filtered, the organic solvent was removed under reduced pressure, and purified to obtain triphenylphosphine. The yield of triphenylphosphine was 88%.
[0045] Embodiment 6:
[0046] 2.0 mmol triphenylphosphine sulfide, 4.0 mmol sodium metal, 0.2 mmol isopropyl ether and 1.0 mL toluene were placed in a glass tube, heated to 110° C. under the protection of oxygen-containing nitrogen (oxygen content is 200 ppm), and kept warm for reaction for 18 hours. After triphenylphosphine sulfide and sodium metal fully reacted, the temperature was lowered to room temperature, filtered, the organic solvent was removed under reduced pressure, and purified to obtain triphenylphosphine. The yield of triphenylphosphine was 65%.
[0047] Embodiment 7:
[0048] 2.0 mmol triphenylphosphine sulfide, 4.0 mmol sodium metal, 0.2 mmol ether and 1.0 mL toluene were placed in a glass tube, heated to 110° C. under the protection of oxygen-containing nitrogen (oxygen content of 200 ppm), and kept warm for reaction for 18 hours. After triphenylphosphine sulfide and sodium metal fully reacted, the temperature was lowered to room temperature, filtered, the organic solvent was removed under reduced pressure, and purified to obtain triphenylphosphine. The yield of triphenylphosphine was 83%.
[0049] It can be seen from Examples 1 to 7 that when the metal reducing agent is sodium metal and the oxygen content in the oxygen-containing nitrogen is 200 ppm, the additive can overcome the inhibitory effect of oxygen on the reaction during the reaction, thereby increasing the yield of the product. When the additive is isopropanol or diphenyl ether, the effect of overcoming the inhibitory effect of oxygen on the reaction is the greatest.
[0050] Comparative Example 2:
[0051] The conditions of this comparative example are different from those of Example 1 in that no additive is added, and the oxygen content in the oxygen-containing nitrogen is 5 ppm. Other conditions are the same as those of Example 1. Triphenylphosphine is prepared, and the yield of triphenylphosphine is 98%.
[0052] Comparative Example 3:
[0053] The conditions of this comparative example are different from those of Example 1 in that no additive is added, and the oxygen content in the oxygen-containing nitrogen is 2000 ppm. The other conditions are the same as those of Example 1. Triphenylphosphine is obtained, and the yield of triphenylphosphine is 2%.
[0054] Embodiment 8:
[0055] 2.0 mmol triphenylphosphine sulfide, 4.0 mmol sodium metal, 0.2 mmol ethanol and 1.0 mL toluene were placed in a glass tube, heated to 110° C. under the protection of oxygen-containing nitrogen (oxygen content of 2000 ppm), and kept warm for reaction for 18 hours. After triphenylphosphine sulfide and sodium metal fully reacted, the temperature was lowered to room temperature, filtered, the organic solvent was removed under reduced pressure, and purified to obtain triphenylphosphine. The yield of triphenylphosphine was 45%.
[0056] It can be seen from Comparative Examples 1, 2 and 3 that, in the absence of additives, as the oxygen content increases, the yield of the final product decreases significantly; especially when the oxygen content is 2000 ppm, the yield of the final product is as low as 2%, and triphenylphosphine sulfide and the metal reducing agent hardly react.
[0057] It can be seen from Example 1, Example 8, Comparative Example 1, Comparative Example 2 and Comparative Example 3 that when the oxygen content is 200ppm, after adding the additive, the yield of triphenylphosphine will be significantly increased, and the yield of triphenylphosphine can reach 73%, which is significantly higher than the yield of the final product when no additive is added; when the oxygen content is 2000ppm, when no additive is added, the yield of the final product is 2%, and metallic sodium and triphenylphosphine sulfide hardly react, but after adding the additive, the yield of the final product can reach 45%, and the yield improvement effect is most obvious compared with not adding the additive.
[0058] Embodiment 9:
[0059] 2.0mmol of 90% pure triphenylphosphine sulfide (other main components of the raw material: 15-crown ether-5, 3%, 18-crown ether-6, 2%, naphthalene, 5%), 4.0mmol of metallic sodium, 0.2mmol of ethanol and 1.0mL of toluene were placed in a glass tube, heated to 110°C under the protection of oxygen-containing nitrogen (oxygen content of 200ppm), and kept warm for reaction for 18h. After triphenylphosphine sulfide and metallic sodium fully reacted, the temperature was lowered to room temperature, filtered, the organic solvent was removed under reduced pressure, and purified to obtain triphenylphosphine. The yield of triphenylphosphine was 77%.
[0060] Comparative Example 4:
[0061] This comparative example is different from Example 9 in that no additive is added; other conditions are the same as those in Example 9, and triphenylphosphine is obtained, and the yield of triphenylphosphine is 35%.
[0062] It can be seen from Example 9 and Comparative Example 4 that after adding the additive, the triphenylphosphine sulfide containing impurities can still react with the metal reducing agent in a low-oxygen environment to obtain the corresponding triphenylphosphine, and the yield of the final product is significantly higher than the yield without adding the additive. Therefore, the additive can overcome the inhibitory effect of oxygen on the reaction, so that the triphenylphosphine sulfide containing impurities can react with a small amount of metal reducing agent, thereby improving the yield of the final product triphenylphosphine.
Claims
1. A highly selective reduction method for preparing triphenylphosphine from triphenylphosphine sulfide, characterized in that: In a low oxygen environment with an oxygen content of 5ppm to 2000ppm, triphenylphosphine sulfide, an additive and a metal reducing agent react in toluene at a temperature of 0 to 250°C; after the reaction is completed, triphenylphosphine is separated and purified to obtain; The additive is ethanol, isopropanol, tert-butanol, tetrahydrofuran, diphenyl ether, isopropyl ether or ethyl ether, and the metal reducing agent is selected from one or any combination of Li, Na and K.
2. The highly selective reduction method for preparing triphenylphosphine from triphenylphosphine sulfide according to claim 1, characterized in that: The additive is isopropyl alcohol or diphenyl ether.
3. The highly selective reduction method for preparing triphenylphosphine from triphenylphosphine sulfide according to claim 1, characterized in that: The low oxygen environment is a mixture of oxygen and inert gas, and the oxygen content is 200 ppm.
4. The highly selective reduction method for preparing triphenylphosphine from triphenylphosphine sulfide according to claim 3, characterized in that: The inert gas is argon or nitrogen.
5. The highly selective reduction method for preparing triphenylphosphine from triphenylphosphine sulfide according to claim 1, characterized in that: The molar content of the additive relative to triphenylphosphine sulfide is 5N150%.
6. The highly selective reduction method for preparing triphenylphosphine from triphenylphosphine sulfide according to claim 1, characterized in that: The molar ratio of the metal reducing agent to triphenylphosphine sulfide is 1-2:
1.
7. The highly selective reduction method for preparing triphenylphosphine from triphenylphosphine sulfide according to claim 1, characterized in that: The metal reducing agent is Na.
8. The highly selective reduction method for preparing triphenylphosphine from triphenylphosphine sulfide according to claim 1, characterized in that: After the reaction is completed and toluene solvent and additives are present, the organic phase is separated by filtration, and the toluene solvent is removed under reduced pressure to obtain triphenylphosphine and unreacted triphenylphosphine sulfide, and finally triphenylphosphine is obtained by an organic synthesis purification method.
9. The highly selective reduction method for preparing triphenylphosphine from triphenylphosphine sulfide according to claim 1, characterized in that: The triphenylphosphine sulfide is a pure substance.
10. The highly selective reduction method for preparing triphenylphosphine from triphenylphosphine sulfide according to claim 1, characterized in that: The triphenylphosphine sulfide contains impurities, which are one or a mixture of any two or more of organic alcohols and organic ethers, and the impurity content is less than 30%; the impurities do not react with triphenylphosphine sulfide, triphenylphosphine and a metal reducing agent.