Method for preparing triphenylphosphine by multiple heat treatments of diphenylphosphonium chloride and removal of phenylphosphonium dichloride intermediate

Abstract

The invention relates to a method for preparing triphenylphosphine, which comprises the following steps: 1) carrying out first heat treatment on a diphenyl phosphine chloride raw material at the temperature of 280-480 DEG C to obtain a first heat treatment mixture containing phenyl dichlorophosphine, diphenyl phosphine chloride and triphenylphosphine, wherein the content of phenyldichlorophosphine in the diphenyl phosphine chloride raw material is not more than 35 wt% based on the total weight of the diphenyl phosphine chloride raw material; 2) removing phenylphosphine dichloride from the first heat-treated mixture to obtain a phenylphosphine dichloride-depleted mixture wherein the content of phenylphosphine dichloride in the phenylphosphine dichloride-depleted mixture is not more than 8% by weight based on the total weight of the phenylphosphine dichloride-depleted mixture; and (3) carrying out second heat treatment on the mixture obtained in the step (2) at the temperature of 280-480 DEG C to obtain a second heat-treated mixture containing phenyldichlorophosphine, diphenylphosphonium chloride and triphenylphosphine.

Description

Technical Field

[0001] This invention relates to a method for preparing triphenylphosphine, wherein triphenylphosphine is prepared by repeatedly heat-treating diphenylphosphine chloride and removing the intermediate product of phenylphosphine dichloride. Technical Background

[0002] Triphenylphosphine has a wide range of applications in the chemical industry. It is an important catalyst for the synthesis of fine chemicals; a catalyst for petroleum processing; a novel biocatalytic technology and catalyst; a novel and efficient catalyst for environmental protection; a novel catalyst for organic synthesis; a novel and efficient catalyst for polyolefins; a new material for catalyst supports and various novel co-catalytic materials; it can also be used as a functional fine chemical; a novel papermaking chemical; a novel oilfield chemical suitable for protective extraction and enhanced oil recovery; a novel surfactant; a high-performance, water-based functional coating and auxiliaries; a novel textile dyeing and finishing auxiliaries; a high-performance environmentally friendly adhesive; a novel safe and environmentally friendly pigment and dye; and a high-performance environmentally friendly leather chemical. Triphenylphosphine can also serve as an intermediate in the chemical synthesis of various important chemical products, such as β-carotene, cefprozil, and cefdinir.

[0003] The main methods for industrial production of triphenylphosphine include (1) the Grignard method (sodium method): using metallic sodium, which is stirred at high speed, to react with chlorobenzene and phosphorus trichloride to produce triphenylphosphine. This method is technically demanding, especially the sodium sand equipment. It is necessary to solve the problem of sodium dispersion and avoid the presence of water during operation, as highly reactive sodium is prone to violent reaction with water and explosion. Therefore, there are significant safety hazards and high risk in the production process. (2) the Grignard reagent method (Grignard method): this method uses phenyl magnesium halide and phosphorus trichloride as raw materials. The reactants are heated to produce triphenylphosphine through the reaction, accompanied by a small amount of byproduct - triphenylphosphine oxide. This method has disadvantages such as high cost, low yield, and poor economic benefits. (3) the Friedel-Cloughs method: this method uses thiophosphonochloride to react with benzene in the presence of excess aluminum trichloride to produce triphenylphosphine sulfur, which is then desulfurized (reduced) with iron filings or sodium naphthalene to obtain triphenylphosphine. However, the triphenylphosphine product reduced by iron powder is of poor quality and has a yellowish color. Furthermore, the use of aluminum trichloride and iron powder as catalysts will generate a large amount of solid waste that is difficult to treat and will cause environmental pollution. (4) Triphenylphosphine oxide reduction method, but the reducing agent used in the triphenylphosphine oxide reduction method is relatively expensive.

[0004] In conclusion, there is an urgent need to develop a green, environmentally friendly, low-cost, high-yield, and simple method for synthesizing triphenylphosphine. Summary of the Invention

[0005] The purpose of this invention is to provide a method for preparing triphenylphosphine, which is green, environmentally friendly, safe, low-cost, high-yield, and simple to operate. Furthermore, this method does not require the use of solvents or co-solvents and the raw materials are readily available.

[0006] The technical solution for achieving the above-mentioned objectives of this invention can be summarized as follows:

[0007] 1. A method for preparing triphenylphosphine, comprising:

[0008] 1) A first heat treatment is performed on diphenylphosphine chloride raw material at a temperature of 280-480°C to obtain a first heat treatment mixture containing phenylphosphine dichloride, diphenylphosphine chloride and triphenylphosphine, wherein the content of phenylphosphine dichloride in the diphenylphosphine chloride raw material does not exceed 35% by weight, based on the total weight of the diphenylphosphine chloride raw material;

[0009] 2) Remove phenyl dichloride from the first heat-treated mixture to obtain a phenyl dichloride-deficient mixture, wherein the phenyl dichloride content in the phenyl dichloride-deficient mixture does not exceed 8% by weight, based on the total weight of the phenyl dichloride-deficient mixture; and

[0010] 3) The mixture obtained in step 2) is subjected to a second heat treatment at a temperature of 280-480°C to obtain a second heat-treated mixture containing phenylphosphine dichloride, diphenylphosphine chloride and triphenylphosphine.

[0011] 2. According to the method of embodiment 1, the content of phenyl dichloride in the diphenylphosphine raw material is not more than 30% by weight, preferably not more than 28% by weight, more preferably not more than 22% by weight, even more preferably not more than 15% by weight, especially not more than 8% by weight, particularly not more than 3% by weight, most preferably not more than 1% by weight, for example not more than 0.5% by weight, based on the total weight of the diphenylphosphine raw material.

[0012] 3. According to the method of embodiment 1 or 2, wherein the content of phenyl dichloride in the mixture depleted in step 2) is not more than 5% by weight, preferably not more than 4% by weight, more preferably not more than 2% by weight, and even more preferably not more than 1% by weight, based on the total weight of the mixture depleted in phenyl dichloride.

[0013] 4. The method according to any one of embodiments 1-3, wherein the content of diphenylphosphine chloride in the diphenylphosphine chloride raw material is at least 65% by weight, preferably at least 70% by weight, more preferably at least 80% by weight, even more preferably at least 88% by weight, and even more preferably at least 95% by weight, for example at least 98% by weight, based on the total weight of the diphenylphosphine chloride raw material.

[0014] 5. The method according to any one of embodiments 1-4, wherein the content of diphenylphosphine chloride in the mixture containing phenylphosphine chloride in step 2) is at least 45% by weight, preferably 50-85% by weight, more preferably 55-80% by weight, and even more preferably 55-70% by weight, based on the total weight of the diphenylphosphine chloride raw material.

[0015] 6. The method according to any one of embodiments 1-5, wherein the triphenylphosphine content in the mixture of phenylphosphine-depleted dichloride in step 2) is 12-40% by weight, preferably 15-38% by weight, more preferably 20-35% by weight, based on the total weight of the mixture of phenylphosphine-depleted dichloride.

[0016] 7. The method according to any one of embodiments 1-6, wherein the first and second heat treatment temperatures are 300-450°C, preferably 320-400°C, and more preferably 330-390°C.

[0017] 8. The method according to embodiment 7, wherein the first and second heat treatment temperatures are in particular 340-370°C, especially 345-360°C, most preferably 345-355°C, for example about 350°C.

[0018] 9. The method according to any one of embodiments 1-8, wherein the highest pressure (gauge pressure) in the first and second heat treatment processes is at least 0.05 MPa, preferably at least 0.08 MPa, for example 0.05-6 MPa, more preferably 0.08-5 MPa, and even more preferably 0.1-2 MPa or 0.1-1 MPa.

[0019] 10. The method according to any one of embodiments 1-9, wherein the first and second heat treatments are performed under autogenous pressure.

[0020] 11. The method according to any one of embodiments 1-10, wherein the time for the first and second heat treatments is at least 0.4 hours, preferably 0.4-12 hours, more preferably 0.6-8 hours, especially 0.8-8 hours, most preferably 1.5-2.5 hours, for example about 2 hours.

[0021] 12. The method according to any one of embodiments 1-11, wherein the phosphorus trichloride content in the diphenylphosphine chloride raw material is not more than 5% by weight, preferably not more than 2% by weight, more preferably not more than 1% by weight, for example not more than 0.5% by weight or not more than 0.1% by weight, based on the total weight of the diphenylphosphine chloride raw material.

[0022] 13. The method according to any one of embodiments 1-12, wherein the first and second heat treatments are performed under stirring.

[0023] 14. The method according to any one of embodiments 1-13, wherein step 2) further comprises adding additional diphenylphosphine chloride to the mixture leaning against phenylphosphine chloride, preferably the amount of added diphenylphosphine chloride is at least 5% by weight, preferably at least 10% by weight or at least 20% by weight, for example 10-80% by weight, based on the total weight of the mixture leaning against phenylphosphine chloride. In this case, the mixture in step 3) undergoing the second heat treatment is a mixture with additional diphenylphosphine chloride added.

[0024] 15. The method according to any one of embodiments 1-14, wherein the removal of phenylphosphine dichloride in step 2) is carried out by flash evaporation or distillation, preferably distillation, especially rectification.

[0025] 16. The method according to any one of embodiments 1-15, wherein the method further comprises repeating steps 2) and 3) once or more.

[0026] 17. The method according to any one of embodiments 1-16, wherein the diphenylphosphine chloride raw material in step 1) is derived from a reaction mixture obtained by reacting chlorobenzene and yellow phosphorus, wherein chlorobenzene, phosphorus trichloride and most of the phenylphosphine dichloride are removed from the reaction mixture to obtain the diphenylphosphine chloride raw material.

[0027] 18. The method according to any one of embodiments 1-17, wherein the first and second heat treatments are performed at a temperature of 300-450°C, the maximum pressure (gauge pressure) during the first and second heat treatments is at least 0.05 MPa, and the duration of the first and second heat treatments is at least 0.4 hours.

[0028] The diphenylphosphine chloride raw material contains at least 65% by weight of diphenylphosphine chloride, no more than 30% by weight of phenyl diphosphine chloride, and no more than 5% by weight of phosphorus trichloride, based on the total weight of the diphenylphosphine chloride raw material.

[0029] In step 2), the content of diphenylphosphine chloride in the mixture depleted of phenylphosphine chloride is at least 45% by weight, the content of phenylphosphine chloride is no more than 5% by weight, and the content of triphenylphosphine is 12-40% by weight, based on the total weight of the mixture depleted of phenylphosphine chloride.

[0030] 19. The method according to any one of embodiments 1-18, wherein the first and second heat treatments are performed at a temperature of 345-355°C, the maximum pressure (gauge pressure) during the first and second heat treatments is 0.15-1 MPa (preferably the first and second heat treatments are performed under autogenous pressure), and the duration of the first and second heat treatments is 1.5-2.5 hours.

[0031] The diphenylphosphine chloride raw material contains at least 98% by weight of diphenylphosphine chloride, no more than 1% by weight of phenylphosphine dichloride, and no more than 0.1% by weight of phosphorus trichloride (preferably free of phosphorus trichloride), based on the total weight of the diphenylphosphine chloride raw material.

[0032] In step 2), the content of diphenylphosphine chloride in the phenylphosphine-deficient mixture is at least 55-80% by weight, the content of phenylphosphine chloride is no more than 2% by weight, and the content of triphenylphosphine is 20-35% by weight, based on the total weight of the phenylphosphine-deficient mixture.

[0033] Step 2) further includes adding additional diphenylphosphine chloride to the mixture that is lean against phenylphosphine dichloride, and the amount of diphenylphosphine chloride added is at least 20% by weight based on the total weight of the mixture that is lean against phenylphosphine dichloride.

[0034] The beneficial effects of this invention are as follows:

[0035] (1) The method of the present invention is green, environmentally friendly, safe, low-cost, high-quality and simple to operate.

[0036] (2) The method of the present invention uses diphenylphosphine chloride as raw material, without the need to add other co-solvents, and the raw material is simple and easy to obtain.

[0037] (3) Diphenylphosphine chloride is a liquid, which is easy to handle and does not require the use of solvents, thus avoiding solvent pollution.

[0038] (4) This invention can obtain triphenylphosphine with a high yield and a high triphenylphosphine / raw material weight ratio. The price of triphenylphosphine is much higher than that of diphenylphosphine chloride, therefore the method of this invention has extremely high industrial value. Detailed Implementation

[0039] This invention relates to a method for preparing triphenylphosphine, comprising:

[0040] 1) A first heat treatment is performed on diphenylphosphine chloride raw material at a temperature of 280-480°C to obtain a first heat treatment mixture containing phenylphosphine dichloride, diphenylphosphine chloride and triphenylphosphine, wherein the content of phenylphosphine dichloride in the diphenylphosphine chloride raw material does not exceed 35% by weight, based on the total weight of the diphenylphosphine chloride raw material;

[0041] 2) Remove phenyl dichloride from the first heat-treated mixture to obtain a phenyl dichloride-deficient mixture, wherein the phenyl dichloride content in the phenyl dichloride-deficient mixture does not exceed 8% by weight, based on the total weight of the phenyl dichloride-deficient mixture; and

[0042] 3) The mixture obtained in step 2) is subjected to a second heat treatment at a temperature of 280-480°C to obtain a second heat-treated mixture containing phenylphosphine dichloride, diphenylphosphine chloride and triphenylphosphine.

[0043] In one embodiment, the content of phenyl dichloride in the diphenylphosphine raw material is not more than 30% by weight (e.g., 28% by weight, 26% by weight, 25% by weight, 22% by weight, 20% by weight, 18% by weight, 15% by weight, 12% by weight, 10% by weight, 8% by weight, 5% by weight, 3% by weight, 2% by weight, 1% by weight, 0.5% by weight, or 0.1% by weight), preferably not more than 28% by weight, more preferably not more than 22% by weight, even more preferably not more than 15% by weight, especially not more than 8% by weight, particularly not more than 3% by weight, most preferably not more than 1% by weight, for example not more than 0.5% by weight, based on the total weight of the diphenylphosphine raw material.

[0044] In one embodiment, the content of diphenylphosphine chloride in the diphenylphosphine chloride feedstock is at least 65% by weight (e.g., 68% by weight, 70% by weight, 75% by weight, 80% by weight, 85% by weight, 88% by weight, 90% by weight, 91% by weight, 92% by weight, 93% by weight, 95% by weight, 98% by weight, 99% by weight, 99.5% by weight, or 99.9% by weight), preferably at least 70% by weight, more preferably at least 80% by weight, even more preferably at least 88% by weight, and even more preferably at least 95% by weight, for example at least 98% by weight, based on the total weight of the diphenylphosphine chloride feedstock. The content of diphenylphosphine chloride in the diphenylphosphine chloride feedstock is 65-99.5% by weight, 70-99.5% by weight, 80-99.5% by weight, 80-98% by weight, 85-95% by weight, or 90-95% by weight.

[0045] According to the present invention, the first and second heat treatment temperatures are 280-480°C, for example 280°C, 290°C, 300°C, 310°C, 320°C, 330°C, 340°C, 345°C, 350°C, 355°C, 360°C, 370°C, 380°C, 390°C, 400°C, 410°C, 420°C, 430°C, 440°C, or 450°C. In one embodiment, the heat treatment temperature is 290-450°C, 300-450°C, preferably 320-400°C or 330-390°C, more preferably 330-380°C. In a preferred embodiment, the heat treatment temperature is particularly 340-370°C, especially 345-360°C, most preferably 345-355°C, for example, about 350°C. The first and second heat treatment temperatures may be the same or different.

[0046] In one embodiment, the highest pressure (gauge pressure) during the first and second heat treatment processes is at least 0.05 MPa (e.g., 0.08 MPa, 0.1 MPa, 0.15 MPa, 0.2 MPa, 0.25 MPa, 0.3 MPa, 0.5 MPa, 0.8 MPa, 1 MPa, 2 MPa, 3 MPa, 4 MPa, 5 MPa, 6 MPa), preferably at least 0.08 MPa, for example 0.05-6 MPa, more preferably 0.08-5 MPa, and even more preferably 0.1-4 MPa, 0.1-3 MPa, 0.1-2 MPa, 0.1-1 MPa, 0.1-0.8 MPa, 0.15-0.8 MPa, 0.2-0.6 MPa. The highest pressure during the first and second heat treatment processes may be the same or different.

[0047] Before feeding materials, the reactor can be evacuated, for example to -50 kPa or lower (i.e., 50 kPa or lower than atmospheric pressure), preferably -80 kPa or lower (i.e., 80 kPa or lower than atmospheric pressure), thereby reducing the maximum pressure during the heat treatment process. Alternatively, an inert gas, such as nitrogen, can be introduced into the reactor before heat treatment to increase the maximum pressure during the process.

[0048] In a preferred embodiment, the first and second heat treatments are performed under autogenous pressure.

[0049] In one embodiment, the duration of the first and second heat treatments is at least 0.4 hours (e.g., 0.5 hours, 0.8 hours, 1 hour, 1.2 hours, 1.5 hours, 1.8 hours, 2 hours, 2.2 hours, 2.5 hours, 3 hours, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, 9 hours, 10 hours, 11 hours, or 12 hours), preferably 0.4-12 hours, more preferably 0.6-8 hours, especially 0.8-8 hours, 1-7 hours, 1-5 hours, 1.5-4 hours, and most preferably 1.5-2.5 hours, for example, about 2 hours. The durations of the first and second heat treatments can be the same or different.

[0050] In one embodiment, the phosphorus trichloride content in the diphenylphosphine chloride feedstock is no more than 5% by weight (e.g., 4% by weight, 3% by weight, 2% by weight, 1% by weight, 0.5% by weight, 0.2% by weight, 0.1% by weight, or 0.05% by weight), preferably no more than 2% by weight, more preferably no more than 1% by weight, for example, no more than 0.5% by weight or no more than 0.1% by weight, based on the total weight of the diphenylphosphine chloride feedstock. In one embodiment, the diphenylphosphine chloride feedstock is free of phosphorus trichloride.

[0051] In one embodiment, the triphenylphosphine content in the diphenylphosphine chloride feedstock is no more than 6% by weight (e.g., 5% by weight, 4% by weight, 3% by weight, 2% by weight, 1% by weight, 0.5% by weight, 0.2% by weight or 0.1% by weight), preferably no more than 5% by weight, more preferably no more than 1% by weight, for example no more than 0.5% by weight or no more than 0.1% by weight, based on the total weight of the diphenylphosphine chloride feedstock.

[0052] In one embodiment, the diphenylphosphine chloride feedstock in step 1) may be derived from a reaction mixture obtained by reacting chlorobenzene and yellow phosphorus. This reaction mixture typically contains light components such as chlorobenzene and phosphorus trichloride, as well as phenylphosphine dichloride, diphenylphosphine chloride, and triphenylphosphine. The reaction is carried out at high temperatures (e.g., 300-500°C or 300-400°C) and elevated pressures (e.g., 0.01-8.0 MPa or 0.01-6.0 MPa, preferably autogenous pressure). The diphenylphosphine chloride feedstock of the present invention can be prepared by removing chlorobenzene, phosphorus trichloride, and most of the phenylphosphine dichloride from the reaction mixture, or by additionally adding diphenylphosphine chloride to a diphenylphosphine-rich product mixture obtained after removing chlorobenzene, phosphorus trichloride, and most of the phenylphosphine dichloride from the reaction mixture.

[0053] In this technical solution, purification costs are saved because there is no need to purify diphenylphosphine chloride.

[0054] According to the present invention, the reaction mixture may comprise phenylphosphine dichloride, diphenylphosphine chloride, triphenylphosphine, chlorobenzene, and phosphorus trichloride. In the reaction mixture, the amount of triphenylphosphine typically does not exceed 6% by weight, for example, 1-6% by weight or 2-6% by weight, based on the total weight of phenylphosphine dichloride, diphenylphosphine chloride, and triphenylphosphine.

[0055] In step 2) of the present invention, phenyl dichloride is removed from the first heat-treated mixture to obtain a mixture depleted in phenyl dichloride.

[0056] In step 2), the removal of phenylphosphine dichloride is carried out by flash evaporation or distillation, preferably distillation, especially rectification, such as atmospheric distillation or vacuum distillation.

[0057] In one embodiment, the content of phenyl dichloride in the mixture depleted of phenyl dichloride in step 2) is no more than 5% by weight, preferably no more than 4% by weight or 3% by weight, more preferably no more than 2% by weight, and even more preferably no more than 1% by weight, based on the total weight of the mixture depleted of phenyl dichloride. In another embodiment, the content of phenyl dichloride in the mixture depleted of phenyl dichloride in step 2) is 0.5-5% by weight, preferably 1-4% by weight, more preferably 2-3% by weight, based on the total weight of the mixture depleted of phenyl dichloride.

[0058] In one embodiment, the content of diphenylphosphine chloride in the mixture containing phenylphosphine chloride in step 2) is at least 45% by weight (e.g., 50% by weight, 55% by weight, 60% by weight, 65% by weight, 70% by weight, 75% by weight or 80% by weight), preferably 50-85% by weight, more preferably 55-80% by weight, and even more preferably 55-70% by weight, based on the total weight of the diphenylphosphine chloride raw material.

[0059] In one embodiment, the triphenylphosphine content in the phenylphosphine-poor mixture in step 2) is 12-40% by weight (e.g., 15% by weight, 18% by weight, 20% by weight, 25% by weight, 30% by weight or 35% by weight), preferably 15-38% by weight, more preferably 20-35% by weight, based on the total weight of the phenylphosphine-poor mixture.

[0060] In one embodiment, the phosphorus trichloride content in the phenyl dichloride-poor mixture in step 2) is no more than 1 wt%, preferably no more than 0.5 wt%, and even more preferably no more than 0.1 wt%, based on the total weight of the phenyl dichloride-poor mixture. In one embodiment, the phenyl dichloride-poor mixture does not contain phosphorus trichloride.

[0061] In one embodiment, the first and second heat treatments are performed under stirring. The stirring rate can be, for example, 50-700 r / min, such as 100-600 r / min, or 200-500 r / min or 300-450 r / min.

[0062] Before stirring, the diphenylphosphine chloride feedstock can be preheated, for example to 40-90°C, preferably to 50-80°C, such as 60-80°C.

[0063] In one embodiment, step 2) further comprises adding additional diphenylphosphine chloride to the phenylphosphine-poor mixture, preferably in an amount of at least 5% by weight (e.g., 8%, 10%, 12%, 15%, 20%, 30%, 40%, 50%, 80%, or 100% by weight), more preferably at least 10% or at least 20% by weight, based on the total weight of the phenylphosphine-poor mixture. In this case, the mixture undergoing the second heat treatment in step 3) is the mixture with the additional addition of diphenylphosphine chloride. In one embodiment, the amount of added diphenylphosphine chloride is 5-100% by weight, preferably 10-80% by weight, or 20-50% by weight, based on the total weight of the phenylphosphine-poor mixture. Adding diphenylphosphine chloride to the phenylphosphine-poor mixture can further increase the triphenylphosphine content in the product.

[0064] In one embodiment, the method further includes repeating steps 2) and 3) once or more, for example, once or twice, after step 3). For example, if repeated once, the repeated step 2) can be named step 2'), and the repeated step 3) can be named step 3'). In this case, the method of the present invention includes steps 1), 2), 3), 2'), and 3'). The conditions in step 2') are as described for step 2), and the conditions in step 3') are as described for step 3).

[0065] In one embodiment, the content of triphenylphosphine in the final product mixture obtained by the method of the present invention is at least 28% by weight (e.g., 30% by weight, 32% by weight, 35% by weight, 40% by weight, 50% by weight, 60% by weight or 70% by weight), preferably at least 30% by weight or at least 35% by weight, or even at least 40% by weight, for example 28-70% by weight, 30-70% by weight, 35-60% by weight, 35-50% by weight, 40-50% by weight, based on the total weight of the final product mixture.

[0066] In one embodiment, the weight ratio of the amount of triphenylphosphine in the final product mixture to the total amount of diphenylphosphine chloride in all diphenylphosphine chloride feedstocks can be at least 0.2 (e.g., 0.22, 0.25, 0.3, 0.35, 0.38, 0.4, 0.45, 0.5, 0.6, or 0.7), preferably at least 0.25 or at least 0.3, even at least 0.38, for example 0.2-0.7 or 0.2-0.6, preferably 0.25-0.7 or 0.25-0.6 or 0.25-0.5, more preferably 0.3-0.7 or 0.3-0.6 or 0.3-0.5, even 0.35-0.7 or 0.35-0.6 or 0.35-0.5 or 0.35-0.45.

[0067] Those skilled in the art will understand that the final product mixture is the second heat-treated mixture, or, where the method of the present invention further includes repeating steps 2) and 3) once or more, the final product mixture is the final product mixture obtained after repeating them once or more.

[0068] In one embodiment, the first and second heat treatments are performed at a temperature of 300-450°C, the highest pressure (gauge pressure) during the first and second heat treatments is at least 0.05 MPa, and the duration of the first and second heat treatments is at least 0.4 hours.

[0069] The diphenylphosphine chloride raw material contains at least 65% by weight of diphenylphosphine chloride, no more than 30% by weight of phenyl diphosphine chloride, and no more than 5% by weight of phosphorus trichloride, based on the total weight of the diphenylphosphine chloride raw material.

[0070] In step 2), the content of diphenylphosphine chloride in the mixture depleted of phenylphosphine chloride is at least 45% by weight, the content of phenylphosphine chloride is no more than 5% by weight, and the content of triphenylphosphine is 12-40% by weight, based on the total weight of the mixture depleted of phenylphosphine chloride.

[0071] In one embodiment, the first and second heat treatments are performed at a temperature of 320-400°C, the highest pressure (gauge pressure) during the first and second heat treatments is at least 0.05-6 MPa, and the duration of the first and second heat treatments is 0.4-12 hours.

[0072] The diphenylphosphine chloride raw material contains at least 70% by weight of diphenylphosphine chloride, no more than 28% by weight of phenylphosphine dichloride, and no more than 2% by weight of phosphorus trichloride, based on the total weight of the diphenylphosphine chloride raw material; and

[0073] In step 2), the content of diphenylphosphine chloride in the mixture depleted of phenylphosphine chloride is 50-85% by weight, the content of phenylphosphine chloride is no more than 4% by weight, and the content of triphenylphosphine is 15-38% by weight, based on the total weight of the mixture depleted of phenylphosphine chloride.

[0074] In one embodiment, the first and second heat treatments are performed at a temperature of 330-390°C, the highest pressure (gauge pressure) during the first and second heat treatments is at least 0.08-5 MPa, and the duration of the first and second heat treatments is 0.8-8 hours.

[0075] The diphenylphosphine chloride raw material contains at least 91% by weight of diphenylphosphine chloride, no more than 8% by weight of phenyl diphosphine chloride, and no more than 1% by weight of phosphorus trichloride, based on the total weight of the diphenylphosphine chloride raw material; and

[0076] In step 2), the content of diphenylphosphine chloride in the mixture depleted of phenylphosphine chloride is 55-80% by weight, the content of phenylphosphine chloride is no more than 3% by weight, and the content of triphenylphosphine is 20-35% by weight, based on the total weight of the mixture depleted of phenylphosphine chloride.

[0077] In one embodiment, the first and second heat treatments are performed at a temperature of 340-370°C, the highest pressure (gauge pressure) during the first and second heat treatments is at least 0.1-2 MPa, and the duration of the first and second heat treatments is 0.8-8 hours.

[0078] The diphenylphosphine chloride raw material contains at least 95% by weight of diphenylphosphine chloride, no more than 1% by weight of phenylphosphine dichloride, and no more than 0.5% by weight of phosphorus trichloride, based on the total weight of the diphenylphosphine chloride raw material; and

[0079] In step 2), the content of diphenylphosphine chloride in the mixture depleted of phenylphosphine chloride is 55-70% by weight, the content of phenylphosphine chloride is no more than 2% by weight, and the content of triphenylphosphine is 20-35% by weight, based on the total weight of the mixture depleted of phenylphosphine chloride.

[0080] In one embodiment, the first and second heat treatments are performed at a temperature of 340-370°C, the highest pressure (gauge pressure) during the first and second heat treatments is at least 0.1-2 MPa, and the duration of the first and second heat treatments is 0.8-8 hours.

[0081] The diphenylphosphine chloride raw material contains at least 95% by weight of diphenylphosphine chloride, no more than 1% by weight of phenylphosphine dichloride, and no more than 0.5% by weight of phosphorus trichloride, based on the total weight of the diphenylphosphine chloride raw material.

[0082] In step 2), the content of diphenylphosphine chloride in the phenylphosphine-deficient mixture is 55-70% by weight, the content of phenylphosphine chloride is no more than 2% by weight, and the content of triphenylphosphine is 20-35% by weight, based on the total weight of the phenylphosphine-deficient mixture; and

[0083] Step 2) further includes adding additional diphenylphosphine chloride to the mixture that is deficient in phenylphosphine dichloride.

[0084] In one embodiment, the first and second heat treatments are performed at a temperature of 345-360°C, the highest pressure (gauge pressure) during the first and second heat treatments is at least 0.1-2 MPa (preferably the first and second heat treatments are performed under autogenous pressure), and the duration of the first and second heat treatments is 0.8-6 hours.

[0085] The diphenylphosphine chloride raw material contains at least 95% by weight of diphenylphosphine chloride, no more than 1% by weight of phenylphosphine dichloride, and no more than 0.1% by weight of phosphorus trichloride, based on the total weight of the diphenylphosphine chloride raw material.

[0086] In step 2), the content of diphenylphosphine chloride in the phenylphosphine-deficient mixture is 55-70% by weight, the content of phenylphosphine chloride is no more than 2% by weight, and the content of triphenylphosphine is 20-35% by weight, based on the total weight of the phenylphosphine-deficient mixture; and

[0087] Step 2) further includes adding additional diphenylphosphine chloride to the mixture that is deficient in phenylphosphine dichloride.

[0088] In one embodiment, the first and second heat treatments are performed at a temperature of 345-360°C, the highest pressure (gauge pressure) during the first and second heat treatments is at least 0.15-1 MPa (preferably the first and second heat treatments are performed under autogenous pressure), and the duration of the first and second heat treatments is 1-4 hours;

[0089] The diphenylphosphine chloride raw material contains at least 95% by weight of diphenylphosphine chloride, no more than 1% by weight of phenylphosphine dichloride, and no more than 0.1% by weight of phosphorus trichloride, based on the total weight of the diphenylphosphine chloride raw material.

[0090] In step 2), the content of diphenylphosphine chloride in the phenylphosphine-deficient mixture is 55-70% by weight, the content of phenylphosphine chloride is no more than 2% by weight, and the content of triphenylphosphine is 20-35% by weight, based on the total weight of the phenylphosphine-deficient mixture; and

[0091] Step 2) further includes adding additional diphenylphosphine chloride to the mixture that is depleted of phenylphosphine dichloride, and the amount of diphenylphosphine chloride added is at least 10% by weight based on the total weight of the mixture that is depleted of phenylphosphine dichloride.

[0092] In one embodiment, the first and second heat treatments are performed at a temperature of 345-355°C, the highest pressure (gauge pressure) during the first and second heat treatments is 0.15-1 MPa (preferably the first and second heat treatments are performed under autogenous pressure), and the duration of the first and second heat treatments is 1.5-2.5 hours.

[0093] The diphenylphosphine chloride raw material contains at least 98% by weight of diphenylphosphine chloride, no more than 1% by weight of phenylphosphine dichloride, and no more than 0.1% by weight of phosphorus trichloride (preferably free of phosphorus trichloride), based on the total weight of the diphenylphosphine chloride raw material.

[0094] In step 2), the content of diphenylphosphine chloride in the phenylphosphine-deficient mixture is at least 55-80% by weight, the content of phenylphosphine chloride is no more than 2% by weight, and the content of triphenylphosphine is 20-35% by weight, based on the total weight of the phenylphosphine-deficient mixture.

[0095] Step 2) further includes adding additional diphenylphosphine chloride to the mixture that is lean against phenylphosphine dichloride, and the amount of diphenylphosphine chloride added is at least 20% by weight based on the total weight of the mixture that is lean against phenylphosphine dichloride.

[0096] In one embodiment, the first and second heat treatments are performed at a temperature of 345-355°C, the highest pressure (gauge pressure) during the first and second heat treatments is 0.15-1 MPa (preferably the first and second heat treatments are performed under autogenous pressure), and the duration of the first and second heat treatments is 1.5-2.5 hours.

[0097] The diphenylphosphine chloride raw material contains at least 98% by weight of diphenylphosphine chloride, no more than 1% by weight of phenylphosphine dichloride, and no more than 0.1% by weight of phosphorus trichloride (preferably free of phosphorus trichloride), based on the total weight of the diphenylphosphine chloride raw material.

[0098] In step 2), the content of diphenylphosphine chloride in the phenylphosphine-deficient mixture is at least 55-80% by weight, the content of phenylphosphine chloride is no more than 2% by weight, and the content of triphenylphosphine is 20-35% by weight, based on the total weight of the phenylphosphine-deficient mixture.

[0099] Step 2) further comprises adding additional diphenylphosphine chloride to the mixture leaning against phenylphosphine dichloride, wherein the amount of diphenylphosphine chloride added is at least 20% by weight based on the total weight of the mixture leaning against phenylphosphine dichloride; and

[0100] The method further includes repeating steps 2) and 3) once after step 3).

[0101] In one embodiment, the method includes preheating the diphenylphosphine chloride feedstock to 50-90°C, then starting stirring, and subsequently heat-treating the diphenylphosphine chloride feedstock at a first heat treatment temperature.

[0102] The method of the present invention is carried out under the protection of an inert gas, such as nitrogen. Before carrying out the method of the present invention, the reactor is purged with an inert gas (such as nitrogen), for example, purging 2-5 times, preferably 3-5 times.

[0103] The product mixture of the method of the present invention can be separated by post-processing, such as distillation.

[0104] Example

[0105] The features of the present invention are further illustrated below through examples, but these examples do not constitute a limitation thereof. Unless otherwise specified, specific conditions were applied in the examples. Reagents or instruments used, unless otherwise specified, are all commercially available products. Pressures mentioned in the examples are gauge pressures.

[0106] raw material:

[0107] Diphenylphosphine chloride: Hubei Gurun Technology Co., Ltd., purity ≥99.5%, triphenylphosphine content 0.1%-0.3%, does not contain phosphorus trichloride.

[0108] Content determination:

[0109] Gas chromatography was used to analyze each component, and quantification was performed using the correction and normalization method.

[0110] Example 1:

[0111] 1865g of reaction solution prepared by reacting chlorobenzene and yellow phosphorus (which contains light components (phosphorus trichloride and chlorobenzene), phenylphosphine dichloride, diphenylphosphine chloride and triphenylphosphine) was subjected to vacuum distillation (vacuum degree of -0.1MPa, distillation temperature at the top of the column of about 120℃) to remove light components and most of phenylphosphine dichloride, yielding 830g of bottom material, which contains 25g of phenylphosphine dichloride, 705g of diphenylphosphine chloride, 65g of triphenylphosphine and 35g of impurities.

[0112] Add the 830g base material to the synthesis reactor, close the reactor valve, turn on the stirrer at a stirring rate of 350-400r / min, and then heat it to a maximum of 350℃ for 70-80min and hold it for 2.0h. The maximum pressure during the reaction process is 0.5MPa, and the reaction produces 803g of reaction liquid.

[0113] The above 803g reaction liquid was subjected to vacuum distillation (vacuum degree of -0.1MPa, distillation temperature at the top of the column of about 120℃) to remove light components and most of the phenyl dichloride. The remaining 638g bottom material (containing 5g phenyl dichloride, 417g diphenyl chloride, 158g triphenyl phosphine, and 58g impurities) was added to the synthesis reactor. The reactor valve was closed, and stirring was started at a stirring rate of 350-400r / min. After 70-80min, the temperature was raised to the maximum of 350℃ and held for 2.0h. The maximum pressure during the reaction was 0.4MPa. The reaction yielded 586g of reaction liquid, of which 62g phenyl dichloride, 254g diphenyl chloride, and 202g triphenyl phosphine accounted for 34.5%, and there were also 68g of impurities.

[0114] Example 2:

[0115] 1974g of reaction solution (prepared from chlorobenzene and yellow phosphorus, containing light components (phosphorus trichloride and chlorobenzene), phenyl dichloride, diphenyl phosphine chloride, and triphenylphosphine) was subjected to vacuum distillation (vacuum degree of -0.1MPa, distillation temperature at the top of the column of approximately 120°C) to remove the light components and most of the phenyl dichloride, yielding 874g of bottom material, which contained 13g of phenyl dichloride, 743g of diphenyl phosphine chloride, 87g of triphenylphosphine, and 31g of impurities.

[0116] The 874g base material and 126g diphenylphosphine chloride were added to a 5L synthesis reactor. The reactor valve was closed, and the stirring was started at a rate of 350-400r / min. The temperature was then raised to a maximum of 350℃ and held for 2.0h after 70-80min. The maximum pressure during the reaction was 0.4MPa, and 995g of reaction liquid was produced.

[0117] The above 995g reaction liquid was subjected to vacuum distillation (vacuum degree of -0.1MPa, distillation temperature at the top of the column of about 120℃) to remove light components and most of the monobenzene. The remaining 803g bottom material (containing 10g phenyl dichloride, 531g diphenyl chloride, 250g triphenylphosphine, and 12g impurities) and 197g diphenyl chloride were added to the synthesis reactor. The reactor valve was closed, and stirring was started at a stirring rate of 350-400r / min. After 70-80min, the temperature was raised to a maximum of 350℃ and held for 2.0h. The maximum pressure during the reaction was 0.4MPa. The reaction produced 980g reaction liquid, which contained 111g phenyl dichloride, 436g diphenyl chloride, 427g triphenylphosphine, and 6g impurities. Triphenylphosphine accounted for 43.6wt%.

[0118] Example 3:

[0119] The 5L synthesis reactor was purged with nitrogen three times. 1000g of diphenylphosphine chloride was added to the synthesis reactor, the reactor valve was closed, and the stirring was started at a rate of 350-400 r / min. After 70-80 min, the temperature was raised to a maximum of 350℃ and held for 2.0 h. The maximum pressure during the reaction was 0.3 MPa, and 970g of reaction liquid was produced.

[0120] The above 970g reaction liquid was subjected to vacuum distillation (vacuum degree of -0.1MPa, distillation temperature at the top of the column of about 120℃) to remove light components and most of the phenyl dichloride. The remaining 800g bottom material (containing 21g phenyl dichloride, 492g diphenyl chloride, 278g triphenyl chloride and 9g impurities) and 200g diphenyl chloride were added to the synthesis reactor. The reactor valve was closed and the stirring was turned on at a stirring rate of 350-400r / min. After 70-80min, the temperature was raised to the maximum of 350℃ and held for 2.0h. The maximum pressure during the reaction was 0.3MPa. The reaction yielded 978g of reaction liquid.

[0121] The above 978g reaction liquid was subjected to vacuum distillation (vacuum degree of -0.1MPa, distillation temperature at the top of the column of about 120℃) to remove light components and phenyl dichloride. The remaining 880g bottom material (containing 457g diphenyl chloride, 414g triphenyl phosphine and 9g impurities) and 120g diphenyl chloride were added to the synthesis reactor. The reactor valve was closed and the stirring was turned on at a stirring rate of 350-400r / min. After 70-80min, the temperature was raised to the maximum of 350℃ and held for 2.0h. The maximum pressure during the reaction was 0.3MPa. The reaction produced 980g reaction liquid, which contained 38g phenyl dichloride, 461g diphenyl chloride and 446g triphenyl phosphine, with triphenyl phosphine accounting for 45.5wt%.

[0122] Finally, it should be noted that the above content is only used to illustrate the technical solution of the present invention, and is not intended to limit the scope of protection of the present invention. Simple modifications or equivalent substitutions made by those skilled in the art to the technical solution of the present invention do not depart from the essence and scope of the technical solution of the present invention.

Claims

1. A method for preparing triphenylphosphine, comprising: 1) A first heat treatment is performed on diphenylphosphine chloride raw material at a temperature of 280-480°C to obtain a first heat treatment mixture containing phenylphosphine dichloride, diphenylphosphine chloride and triphenylphosphine, wherein the content of phenylphosphine dichloride in the diphenylphosphine chloride raw material does not exceed 35% by weight, based on the total weight of the diphenylphosphine chloride raw material; 2) Remove phenyl dichloride from the first heat-treated mixture to obtain a phenyl dichloride-deficient mixture, wherein the phenyl dichloride content in the phenyl dichloride-deficient mixture does not exceed 8% by weight, based on the total weight of the phenyl dichloride-deficient mixture; and 3) The mixture obtained in step 2) is subjected to a second heat treatment at a temperature of 280-480°C to obtain a second heat-treated mixture containing phenylphosphine dichloride, diphenylphosphine chloride and triphenylphosphine.

2. The method according to claim 1, wherein the content of phenyl dichloride in the diphenylphosphine raw material is not more than 30% by weight, preferably not more than 28% by weight, more preferably not more than 22% by weight, even more preferably not more than 15% by weight, especially not more than 8% by weight, particularly not more than 3% by weight, most preferably not more than 1% by weight, for example not more than 0.5% by weight, based on the total weight of the diphenylphosphine raw material.

3. The method according to claim 1 or 2, wherein the content of phenyl dichloride in the mixture depleted in step 2) is no more than 5% by weight, preferably no more than 4% by weight, more preferably no more than 2% by weight, and even more preferably no more than 1% by weight, based on the total weight of the mixture depleted in phenyl dichloride.

4. The method according to any one of claims 1-3, wherein the content of diphenylphosphine chloride in the diphenylphosphine chloride raw material is at least 65% by weight, preferably at least 70% by weight, more preferably at least 80% by weight, even more preferably at least 88% by weight, and even more preferably at least 95% by weight, for example at least 98% by weight, based on the total weight of the diphenylphosphine chloride raw material.

5. The method according to any one of claims 1-4, wherein the content of diphenylphosphine chloride in the mixture containing phenylphosphine chloride in step 2) is at least 45% by weight, preferably 50-85% by weight, more preferably 55-80% by weight, and even more preferably 55-70% by weight, based on the total weight of the diphenylphosphine chloride raw material.

6. The method according to any one of claims 1-5, wherein the triphenylphosphine content in the mixture depleted of phenyl dichloride in step 2) is 12-40% by weight, preferably 15-38% by weight, more preferably 20-35% by weight, based on the total weight of the mixture depleted of phenyl dichloride.

7. The method according to any one of claims 1-6, wherein the first and second heat treatment temperatures are 300-450°C, preferably 320-400°C, and more preferably 330-390°C.

8. The method of claim 7, wherein the first and second heat treatment temperatures are in particular 340-370°C, especially 345-360°C, most preferably 345-355°C, for example about 350°C.

9. The method according to any one of claims 1-8, wherein the highest pressure (gauge pressure) during the first and second heat treatment processes is at least 0.05 MPa, preferably at least 0.08 MPa, for example 0.05-6 MPa, more preferably 0.08-5 MPa, and even more preferably 0.1-2 MPa or 0.1-1 MPa.

10. The method according to any one of claims 1-9, wherein the first and second heat treatments are performed under autogenous pressure.

11. The method according to any one of claims 1-10, wherein the first and second heat treatments are performed for at least 0.4 hours, preferably 0.4-12 hours, more preferably 0.6-8 hours, especially 0.8-8 hours, most preferably 1.5-2.5 hours, for example about 2 hours.

12. The method according to any one of claims 1-11, wherein the phosphorus trichloride content in the diphenylphosphine chloride raw material is not more than 5% by weight, preferably not more than 2% by weight, more preferably not more than 1% by weight, for example not more than 0.5% by weight or not more than 0.1% by weight, based on the total weight of the diphenylphosphine chloride raw material.

13. The method according to any one of claims 1-12, wherein the first and second heat treatments are performed under stirring.

14. The method according to any one of claims 1-13, wherein step 2) further comprises adding additional diphenylphosphine chloride to the mixture leaning against phenylphosphine chloride, preferably the amount of added diphenylphosphine chloride being at least 5% by weight, preferably at least 10% by weight or at least 20% by weight, for example 10-80% by weight, in which case the mixture undergoing the second heat treatment in step 3) is a mixture with additional added diphenylphosphine chloride.

15. The method according to any one of claims 1-14, wherein the removal of phenylphosphine dichloride in step 2) is carried out by flash evaporation or distillation, preferably distillation, particularly rectification.

16. The method according to any one of claims 1-15, the method further comprising repeating steps 2) and 3) once or more.

17. The method according to any one of claims 1-16, wherein the diphenylphosphine chloride raw material in step 1) is derived from a reaction mixture obtained by reacting chlorobenzene and yellow phosphorus, wherein chlorobenzene, phosphorus trichloride and most of the phenylphosphine dichloride are removed from the reaction mixture to obtain the diphenylphosphine chloride raw material.

18. The method according to any one of claims 1-17, wherein the first and second heat treatments are performed at a temperature of 300-450°C, the highest pressure (gauge pressure) during the first and second heat treatments is at least 0.05 MPa, and the duration of the first and second heat treatments is at least 0.4 hours. The diphenylphosphine chloride raw material contains at least 65% by weight of diphenylphosphine chloride, no more than 30% by weight of phenyl diphosphine chloride, and no more than 5% by weight of phosphorus trichloride, based on the total weight of the diphenylphosphine chloride raw material. In step 2), the content of diphenylphosphine chloride in the mixture depleted of phenylphosphine chloride is at least 45% by weight, the content of phenylphosphine chloride is no more than 5% by weight, and the content of triphenylphosphine is 12-40% by weight, based on the total weight of the mixture depleted of phenylphosphine chloride.

19. The method according to any one of claims 1-18, wherein the first and second heat treatments are performed at a temperature of 345-355°C, the maximum pressure (gauge pressure) during the first and second heat treatments is 0.15-1 MPa (preferably the first and second heat treatments are performed under autogenous pressure), and the duration of the first and second heat treatments is 1.5-2.5 hours. The diphenylphosphine chloride raw material contains at least 98% by weight of diphenylphosphine chloride, no more than 1% by weight of phenylphosphine dichloride, and no more than 0.1% by weight of phosphorus trichloride (preferably free of phosphorus trichloride), based on the total weight of the diphenylphosphine chloride raw material. In step 2), the content of diphenylphosphine chloride in the phenylphosphine-deficient mixture is at least 55-80% by weight, the content of phenylphosphine chloride is no more than 2% by weight, and the content of triphenylphosphine is 20-35% by weight, based on the total weight of the phenylphosphine-deficient mixture. Step 2) further includes adding additional diphenylphosphine chloride to the mixture that is lean against phenylphosphine dichloride, and the amount of diphenylphosphine chloride added is at least 20% by weight based on the total weight of the mixture that is lean against phenylphosphine dichloride.