Environmentally friendly method for preparing triphenylphosphine

Abstract

The present invention relates to a method for preparing triphenylphosphine, comprising performing heat treatment on a chlorodiphenylphosphine raw material at a temperature of 280-480°C to prepare triphenylphosphine, wherein the content of dichlorophenylphosphine in the chlorodiphenylphosphine raw material does not exceed 35 wt%, based on the total weight of the chlorodiphenylphosphine raw material.

Description

A green and environmentally friendly method for preparing triphenylphosphine TECHNICAL FIELD

[0001] The present application relates to a method for preparing triphenylphosphine, which can obtain triphenylphosphine through one-step reaction. TECHNICAL BACKGROUND

[0002] Triphenylphosphine has wide application in the field of chemical industry, which is an important fine chemical synthesis catalyst, a petroleum processing catalyst, a new biological catalysis technology and catalyst, a new and efficient catalyst for environmental protection, a new catalyst for organic synthesis, a new and efficient catalyst for polyolefin, a new material for catalyst carrier and various new catalyst supporting materials, and can also be used as a functional fine chemical, a new papermaking special chemical, a new oil field chemical suitable for protective exploitation and enhanced oil recovery, a new surfactant, a high-performance and water-based functional coating and additive, a new textile dyeing and finishing agent, a high-performance environmentally friendly adhesive, a new safe and environmentally friendly pigment and dye, and a high-performance environmentally friendly leather chemical. Triphenylphosphine can also be used as an intermediate for the synthesis of various important chemical products, such as beta-carotene, cefprozil and cefdinir.

[0003] The main synthesis methods for industrial production of triphenylphosphine include (1) Grignard method (sodium method) metal sodium method, in which the high-speed stirred metal sodium is reacted with chlorobenzene and phosphorus trichloride to obtain triphenylphosphine. This method has high technicality, especially the sodium sand equipment, and the dispersion of sodium needs to be solved, and water should be avoided in the operation because the highly active sodium can react violently with water to cause explosion. Therefore, there is a great safety hazard in the production process, which is highly dangerous. (2) Grignard reagent method (Grignard method), in which phenyl magnesium halide and phosphorus trichloride are used as raw materials, the reactants are heated, and triphenylphosphine can be generated through the reaction of the reactants, accompanied by a small amount of by-product triphenylphosphine oxide. This method has the disadvantages of high cost, low yield and poor economic benefit. (3) Friedel-Crafts method, in which thiophosphoryl chloride reacts with benzene under the action of excess aluminum trichloride to produce triphenylphosphine sulfide, and then iron filings or sodium naphthalene are used for desulfurization (reduction) to obtain triphenylphosphine. However, the triphenylphosphine produced by reduction with iron powder has poor quality and yellow color, and the use of aluminum trichloride and iron powder as catalysts will produce a large amount of solid waste, which is not easy to handle and pollutes the environment. (4) Triphenylphosphine oxide reduction method, but the reducing agent used in the triphenylphosphine oxide reduction method is relatively expensive.

[0004] In summary, it is urgent to develop a green and environmentally friendly, low-cost, high-quality and simple method for synthesizing triphenylphosphine. SUMMARY

[0005] The present application aims to provide a method for preparing triphenylphosphine, which is green, safe, low in cost, high in quality and simple in operation, and raw materials of which are easy to obtain without using solvent or cosolvent.

[0006] The technical solution for achieving the above-mentioned object of the present application can be summarized as follows:

[0007] 1. A method for preparing triphenylphosphine, comprising heat-treating a diphenylphosphine chloride raw material at a temperature of 280-480°C to prepare triphenylphosphine, wherein the content of phenyldichlorophosphine in the diphenylphosphine chloride raw material is not more than 35% by weight, based on the total weight of the diphenylphosphine chloride raw material.

[0008] 2. The method according to embodiment 1, wherein the content of phenyldichlorophosphine in the diphenylphosphine chloride 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 chloride raw material.

[0009] 3. The method according to embodiment 1 or 2, wherein the content of the 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, still 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.

[0010] 4. The method according to any one of embodiments 1-3, wherein the heat-treatment temperature is 300-450°C, preferably 320-400°C, more preferably 330-390°C.

[0011] 5. The method according to embodiment 4, wherein the heat-treatment temperature is especially 340-370°C, particularly 345-360°C, most preferably 345-355°C, for example about 350°C.

[0012] 6. The method according to any one of embodiments 1-5, wherein the maximum pressure (gauge pressure) during the heat-treatment is at least 0.05 MPa, preferably at least 0.08 MPa, for example 0.05-6 MPa, more preferably 0.08-5 MPa, still more preferably 0.1-2 MPa or 0.1-0.3 MPa.

[0013] 7. The method according to any one of embodiments 1-6, wherein the heat-treatment is carried out under autogenous pressure.

[0014] 8. The process according to any one of embodiments 1 to 7, wherein the heat treatment is carried out for a time of at least 0.4 hours, preferably 0.4 to 12 hours, more preferably 0.6 to 8 hours, especially 0.8 to 8 hours, most preferably 1.5 to 2.5 hours, such as about 2 hours.

[0015] 9. The process according to any one of embodiments 1 to 8, wherein the content of phosphorus trichloride in the diphenylchlorophosphine starting material is not more than 5 wt.%, preferably not more than 2 wt.%, more preferably not more than 1 wt.%, such as not more than 0.5 wt.% or not more than 0.1 wt.%, based on the total weight of the diphenylchlorophosphine starting material.

[0016] 10. The process according to any one of embodiments 1 to 9, wherein the heat treatment is carried out under stirring.

[0017] 11. The process according to any one of embodiments 1 to 10, wherein the product mixture obtained from the process comprises triphenylphosphine, phenyldichlorophosphine and diphenylchlorophosphine.

[0018] 12. The process according to embodiment 11, wherein the content of triphenylphosphine in the reaction mixture after completion of the heat treatment is at least 15 wt.%, preferably at least 20 wt.%, such as 15 to 60 wt.% or 20 to 50 wt.%, based on the total weight of triphenylphosphine, phenyldichlorophosphine and diphenylchlorophosphine in the reaction mixture.

[0019] 13. The process according to any one of embodiments 1 to 12, wherein the process comprises heat treating the diphenylchlorophosphine starting material at a temperature of 300 to 450 °C, the maximum pressure (gauge pressure) during the heat treatment is at least 0.05 MPa, the heat treatment is carried out for a time of at least 0.4 hours, and

[0020] the content of diphenylchlorophosphine in the diphenylchlorophosphine starting material is at least 65 wt.%, the content of phenyldichlorophosphine is not more than 30 wt.%, and the content of phosphorus trichloride is not more than 5 wt.%, based on the total weight of the diphenylchlorophosphine starting material.

[0021] 14. The process according to any one of embodiments 1 to 13, wherein the process comprises heat treating the diphenylchlorophosphine starting material at a temperature of 345 to 355 °C, the maximum pressure (gauge pressure) during the heat treatment is 0.15 to 0.3 MPa (preferably the heat treatment is carried out at autogenous pressure), the heat treatment is carried out for a time of 1.5 to 2.5 hours, and

[0022] the content of diphenylchlorophosphine in the diphenylchlorophosphine starting material is at least 98 wt.%, the content of phenyldichlorophosphine is not more than 1 wt.%, and the content of phosphorus trichloride is not more than 0.1 wt.% (preferably the diphenylchlorophosphine starting material is free of phosphorus trichloride), based on the total weight of the diphenylchlorophosphine starting material.

[0023] The advantages of the present application are as follows:

[0024] (1) The method of the present application is green, safe, low cost, high quality and simple to operate.

[0025] (2) The method of the present application uses diphenyl chlorophosphine as a raw material, without the need to add other cosolvents, and the raw material is simple and easy to obtain.

[0026] (3) Diphenyl chlorophosphine is a liquid, easy to operate, without the need to use solvents, avoiding solvent pollution.

[0027] (4) The present application can obtain triphenylphosphine with a higher yield and a higher triphenylphosphine / raw material weight ratio. The price of triphenylphosphine is much higher than that of diphenyl chlorophosphine, so the method of the present application has very high industrial value. DETAILED DESCRIPTION

[0028] The present application relates to a method for preparing triphenylphosphine, comprising heat treating a diphenyl chlorophosphine raw material at a temperature of 280-480°C to prepare triphenylphosphine, wherein the content of phenyldichlorophosphine in the diphenyl chlorophosphine raw material is not more than 35% by weight, based on the total weight of the diphenyl chlorophosphine raw material.

[0029] In one embodiment, the content of phenyldichlorophosphine in the diphenyl chlorophosphine 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, still 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, e.g. not more than 0.5% by weight, based on the total weight of the diphenyl chlorophosphine raw material.

[0030] In one embodiment, the content of the diphenylchlorophosphine in the diphenylchlorophosphine starting material is at least 65 wt.-% (e.g. 68 wt.-%, 70 wt.-%, 75 wt.-%, 80 wt.-%, 85 wt.-%, 88 wt.-%, 90 wt.-%, 91 wt.-%, 92 wt.-%, 93 wt.-%, 95 wt.-%, 98 wt.-%, 99 wt.-%, 99.5 wt.-% or 99.9 wt.-%), preferably at least 70 wt.-%, more preferably at least 80 wt.-%, even more preferably at least 88 wt.-%, still more preferably at least 95 wt.-%, e.g. at least 98 wt.-%, based on the total weight of the diphenylchlorophosphine starting material. For example, the content of the diphenylchlorophosphine in the diphenylchlorophosphine starting material is 65-99.5 wt.-%, 70-99.5 wt.-%, 80-99.5 wt.-%, 80-98 wt.-%, 85-95 wt.-% or 90-95 wt.-%.

[0031] According to the present application, the heat treatment temperature is 280-480 °C, e.g. 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 especially 340-370 °C, in particular 345-360 °C, most preferably 345-355 °C, e.g. about 350 °C.

[0032] In one embodiment, the maximum pressure (gauge pressure) during the heat treatment 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, e.g. 0.05-6 MPa, more preferably 0.08-5 MPa, still more preferably 0.1-4 MPa, 0.1-3 MPa, 0.1-2 MPa, 0.1-1 MPa, 0.1-0.8 MPa, 0.1-0.5 MPa, 0.15-0.3 MPa.

[0033] The reactor can be evacuated prior to the introduction of the reactants, for example to -50 kPa or less (i.e. 50 kPa or less below atmospheric pressure), preferably -80 kPa or less (i.e. 80 kPa or less below atmospheric pressure), so that the maximum pressure during the heat treatment can be reduced. Alternatively, an inert gas, for example nitrogen, can be introduced into the reactor prior to the heat treatment so that the maximum pressure during the heat treatment is increased.

[0034] In a preferred embodiment, the heat treatment is carried out at autogenous pressure.

[0035] In one embodiment, the heat treatment is for a time of 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 to 12 hours, more preferably 0.6 to 8 hours, especially 0.8 to 8 hours, 1 to 7 hours, 1 to 5 hours, 1.5 to 4 hours, most preferably 1.5 to 2.5 hours, for example about 2 hours.

[0036] In one embodiment, the diphenylchlorophosphine starting material has a phosphorus trichloride content of 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 diphenylchlorophosphine starting material. In one embodiment, the diphenylchlorophosphine starting material is free of phosphorus trichloride.

[0037] In one embodiment, the diphenylchlorophosphine starting material has a triphenylphosphine content of 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 diphenylchlorophosphine starting material.

[0038] In one embodiment, the heat treatment is carried out with stirring. The stirring rate can be, for example, 50 to 700 r / min, for example 100 to 600 r / min, or 200 to 500 r / min or 300 to 450 r / min.

[0039] Prior to stirring, the diphenylchlorophosphine starting material can be preheated, for example to 40 to 90 °C, preferably to 50 to 80 °C, for example 60 to 80 °C.

[0040] In one embodiment, the product mixture obtained from the process comprises triphenylphosphine, phenyldichlorophosphine and diphenylchlorophosphine.

[0041] In one embodiment, the content of triphenylphosphine in the reaction mixture after the heat treatment is completed is at least 15 wt.-% (e.g. 16 wt.-%, 18 wt.-%, 20 wt.-%, 25 wt.-%, 30 wt.-%, 35 wt.-%, 40 wt.-%, 45 wt.-%, 50 wt.-%, 55 wt.-% or 60 wt.-%), preferably at least 20 wt.-% or at least 25 wt.-%, even at least 30 wt.-%, e.g. 15-60 wt.-%, 15-50 wt.-%, 20-60 wt.-%, 20-50 wt.-%, 25-40 wt.-%, 25-35 wt.-%, based on the total weight of triphenylphosphine, phenyldichlorophosphine and diphenylchlorophosphine in the reaction mixture.

[0042] In one embodiment, the weight ratio of the amount of triphenylphosphine in the reaction mixture after the heat treatment is completed to the total amount of diphenylchlorophosphine in the diphenylchlorophosphine starting material can be at least 0.15 (e.g. 0.16, 0.18, 0.20, 0.25, 0.30, 0.35, 0.40, 0.45, 0.50, 0.55 or 0.6), preferably at least 0.16 or at least 0.18 or at least 0.2, even at least 0.3, e.g. 0.15-0.6, 0.18-0.6, preferably 0.2-0.5 or 0.25-0.5, 0.25-0.4 or 0.25-0.35.

[0043] In one embodiment, the process comprises heat treating the diphenylchlorophosphine starting material at a temperature of 300-450 °C, the maximum pressure (gauge pressure) during the heat treatment is at least 0.05 MPa, the heat treatment is carried out for a time of at least 0.4 hours, and

[0044] The content of diphenylchlorophosphine in the diphenylchlorophosphine starting material is at least 65 wt.-%, the content of phenyldichlorophosphine is not more than 30 wt.-%, the content of phosphorus trichloride is not more than 5 wt.-%, based on the total weight of the diphenylchlorophosphine starting material.

[0045] In one embodiment, the process comprises heat treating the diphenylchlorophosphine starting material at a temperature of 320-400 °C, the maximum pressure (gauge pressure) during the heat treatment is 0.05-6 MPa, the heat treatment is carried out for a time of 0.4-12 hours, and

[0046] The content of diphenylchlorophosphine in the diphenylchlorophosphine starting material is at least 70 wt.-%, the content of phenyldichlorophosphine is not more than 28 wt.-%, the content of phosphorus trichloride is not more than 2 wt.-%, based on the total weight of the diphenylchlorophosphine starting material.

[0047] In one embodiment, the process comprises heat-treating a diphenylchlorophosphine starting material at a temperature of 330-390°C, the maximum pressure (gauge pressure) during the heat-treatment being 0.08-5 MPa, the heat-treatment being for a time of 0.8-8 hours, and

[0048] the content of diphenylchlorophosphine in the diphenylchlorophosphine starting material being at least 91 wt%, the content of phenyldichlorophosphine being not more than 8 wt%, the content of phosphorus trichloride being not more than 1 wt%, based on the total weight of the diphenylchlorophosphine starting material.

[0049] In one embodiment, the process comprises heat-treating a diphenylchlorophosphine starting material at a temperature of 340-370°C, the maximum pressure (gauge pressure) during the heat-treatment being 0.1-2 MPa, the heat-treatment being for a time of 0.8-8 hours, and

[0050] the content of diphenylchlorophosphine in the diphenylchlorophosphine starting material being at least 95 wt%, the content of phenyldichlorophosphine being not more than 1 wt%, the content of phosphorus trichloride being not more than 0.5 wt%, based on the total weight of the diphenylchlorophosphine starting material.

[0051] In one embodiment, the process comprises heat-treating a diphenylchlorophosphine starting material at a temperature of 345-360°C, the maximum pressure (gauge pressure) during the heat-treatment being 0.15-0.3 MPa, the heat-treatment being for a time of 1-7 hours, and

[0052] the content of diphenylchlorophosphine in the diphenylchlorophosphine starting material being at least 95 wt%, the content of phenyldichlorophosphine being not more than 1 wt%, the content of phosphorus trichloride being not more than 0.1 wt%, based on the total weight of the diphenylchlorophosphine starting material.

[0053] In one embodiment, the process comprises heat-treating a diphenylchlorophosphine starting material at a temperature of 345-355°C, the maximum pressure (gauge pressure) during the heat-treatment being 0.15-0.3 MPa (preferably the heat-treatment is carried out at autogenous pressure), the heat-treatment being for a time of 1.5-2.5 hours, and

[0054] the content of diphenylchlorophosphine in the diphenylchlorophosphine starting material being at least 98 wt%, the content of phenyldichlorophosphine being not more than 1 wt%, the content of phosphorus trichloride being not more than 0.1 wt% (preferably free of phosphorus trichloride), based on the total weight of the diphenylchlorophosphine starting material.

[0055] In one embodiment, the process comprises preheating the diphenylphosphine chloride starting material to 50-90°C, then starting stirring, and subsequently heat-treating the diphenylphosphine chloride starting material at a temperature of 345-355°C, the maximum pressure (gauge pressure) during the heat-treatment being 0.15-0.3 MPa (preferably the heat-treatment is carried out at autogenous pressure), the heat-treatment being carried out for a time of 1.5-2.5 hours, and

[0056] The content of diphenylphosphine chloride in the diphenylphosphine chloride starting material is at least 98% by weight, the content of phenyldichlorophosphine is not more than 1% by weight, and the content of phosphorus trichloride is not more than 0.1% by weight (preferably the diphenylphosphine chloride starting material is free of phosphorus trichloride), based on the total weight of the diphenylphosphine chloride starting material.

[0057] The process of the present application is carried out under the protection of an inert gas, for example nitrogen. Prior to carrying out the process of the present application, the reactor is purged with an inert gas, for example nitrogen, for example 2-5 times, preferably 3-5 times.

[0058] The product mixture of the process of the present application can be separated by post-treatment, for example by rectification.

[0059] In one embodiment, the diphenylphosphine chloride starting material can be prepared by using chlorobenzene and yellow phosphorus as starting materials. The resulting reaction mixture typically comprises light components, such as chlorobenzene and phosphorus trichloride, and phenyldichlorophosphine, diphenylphosphine chloride and triphenylphosphine. In the reaction mixture, the amount of triphenylphosphine is typically not more than 6% by weight, for example 1-6% by weight or 2-6% by weight, based on the total weight of phenyldichlorophosphine, diphenylphosphine chloride and triphenylphosphine. The reaction is carried out at an elevated temperature, for example 300-500°C or 300-400°C, and at an elevated pressure, for example 0.01-8.0 MPa or 0.01-6.0 MPa, preferably at autogenous pressure. The diphenylphosphine chloride starting material of the present application can be prepared by removing chlorobenzene, phosphorus trichloride and most of the phenyldichlorophosphine from the reaction mixture, or can be prepared by additionally adding diphenylphosphine chloride to the product mixture enriched in diphenylphosphine chloride obtained after removing chlorobenzene, phosphorus trichloride and most of the phenyldichlorophosphine from the reaction mixture.

[0060] In this technical solution, since the diphenylphosphine chloride does not need to be specially purified, the purification cost is saved.

[0061] Examples

[0062] The features of the present application are further illustrated by the following examples, which do not limit the present application. In the examples, the specific conditions not mentioned are carried out according to the conventional conditions. In the examples, the reagents or instruments not mentioned the manufacturer are all conventional products which can be purchased on the market. In the examples, the pressure is gauge pressure.

[0063] Raw materials:

[0064] Diphenylchlorophosphine: Hubei Guron Technology Co., Ltd., purity ≥ 99.5%, triphenylphosphine content 0.1%-0.3%, without phosphorus trichloride.

[0065] Phenyl dichlorophosphine: Hubei Guron Technology Co., Ltd., purity ≥ 99.5, biphenyl ≤ 0.2%, without phosphorus trichloride.

[0066] Content determination:

[0067] Gas chromatography was used to analyze each component, and correction normalization method was used for quantification.

[0068] Example 1:

[0069] The 5L synthesis reactor was replaced with nitrogen three times, 300 grams of diphenylchlorophosphine was added into the synthesis reactor, the reactor valve was closed, stirring was started, the stirring rate was 350-400 r / min, then it was heated to a maximum of 340°C for 2.0 hours, the maximum pressure during the reaction was 0.1 MPa, the reaction generated 32.2 grams of product phenyl dichlorophosphine and 87.3 grams of triphenylphosphine, 168.2 grams of diphenylchlorophosphine remained, and the impurity was about 12 grams. Among the three phenyl phosphides obtained, the product triphenylphosphine accounted for 30.3 wt%.

[0070] Example 2:

[0071] The 5L synthesis reactor was replaced with nitrogen three times, 300 grams of diphenylchlorophosphine was added into the synthesis reactor, the reactor valve was closed, stirring was started, the stirring rate was 350-400 r / min, then it was heated to a maximum of 350°C for 2.0 hours, the maximum pressure during the reaction was 0.15 MPa, the reaction generated 39.4 grams of product phenyl dichlorophosphine and 93.2 grams of triphenylphosphine, 154.4 grams of diphenylchlorophosphine remained, and the impurity was about 13 grams. Among the three phenyl phosphides obtained, the product triphenylphosphine accounted for 32.5 wt%.

[0072] Example 3:

[0073] The 5L synthesis reactor was replaced with nitrogen three times, 300 grams of diphenylchlorophosphine was added into the synthesis reactor, the reactor valve was closed, stirring was started, the stirring rate was 350-400 r / min, then it was heated to a maximum of 360°C for 2.0 hours, the maximum pressure during the reaction was 0.25 MPa, the reaction generated 34.0 grams of product phenyl dichlorophosphine and 86.4 grams of triphenylphosphine, 162.9 grams of diphenylchlorophosphine remained, and the impurity was about 16 grams. Among the three phenyl phosphides obtained, the product triphenylphosphine accounted for 30.5 wt%.

[0074] Example 4:

[0075] The 5L synthesis reactor was replaced with nitrogen three times, 300 grams of diphenyl phosphine chloride was added into the synthesis reactor, the reactor valve was closed, the stirring was started with a stirring rate of 350-400 r / min, then the temperature was increased to a maximum of 380°C within 70-80 min and kept for 2.0 hours, the maximum pressure during the reaction was 0.4 MPa, the reaction generated 45.4 grams of product phenyl dichlorophosphine and 75.4 grams of triphenyl phosphine, 153.1 grams of diphenyl phosphine chloride remained, and the impurities were about 26 grams. Among the three phenyl phosphine compounds obtained, the product triphenyl phosphine accounted for 27.5 wt%.

[0076] Example 5:

[0077] The 5L synthesis reactor was replaced with nitrogen three times, 300 grams of diphenyl phosphine chloride was added into the synthesis reactor, the reactor valve was closed, the stirring was started with a stirring rate of 350-400 r / min, then the temperature was increased to a maximum of 350°C within 70-80 min and kept for 1.0 hours, the maximum pressure during the reaction was 0.15 MPa, the reaction generated 32.2 grams of product phenyl dichlorophosphine and 87.0 grams of triphenyl phosphine, 169.0 grams of diphenyl phosphine chloride remained, and the impurities were about 11 grams. Among the three phenyl phosphine compounds obtained, the product triphenyl phosphine accounted for 30.2 wt%.

[0078] Example 6:

[0079] The 5L synthesis reactor was replaced with nitrogen three times, 300 grams of diphenyl phosphine chloride was added into the synthesis reactor, the reactor valve was closed, the stirring was started with a stirring rate of 350-400 r / min, then the temperature was increased to a maximum of 350°C within 70-80 min and kept for 4.0 hours, the maximum pressure during the reaction was 0.2 MPa, the reaction generated 36.9 grams of product phenyl dichlorophosphine and 84.4 grams of triphenyl phosphine, 165.3 grams of diphenyl phosphine chloride remained, and the impurities were about 13 grams. Among the three phenyl phosphine compounds obtained, the product triphenyl phosphine accounted for 29.4 wt%.

[0080] Example 7:

[0081] The 5L synthesis reactor was replaced with nitrogen three times, 300 grams of diphenyl phosphine chloride was added into the synthesis reactor, the reactor valve was closed, the stirring was started with a stirring rate of 350-400 r / min, then the temperature was increased to a maximum of 350°C within 70-80 min and kept for 6.0 hours, the maximum pressure during the reaction was 0.3 MPa, the reaction generated 35.3 grams of product phenyl dichlorophosphine and 85.8 grams of triphenyl phosphine, 164.7 grams of diphenyl phosphine chloride remained, and the impurities were about 14 grams. Among the three phenyl phosphine compounds obtained, the product triphenyl phosphine accounted for 30 wt%.

[0082] Example 8:

[0083] The 5L synthesis reactor was replaced with nitrogen three times, 300 grams of diphenyl phosphine chloride was added into the synthesis reactor, the valve of the reactor was closed, and the pressure was increased to 1.0 MPa after nitrogen was added. Then the stirring was started with a stirring rate of 350-400 r / min. The temperature was increased to 350°C within 70-80 min, and the highest pressure during the reaction was 1.7 MPa. The reaction was kept for 2.0 hours. The generated product phenyl dichlorophosphine was 40.3 grams, triphenyl phosphine was 81.7 grams, and the residual diphenyl phosphine chloride was 166.4 grams. The impurity was about 11 grams. Among the three kinds of phenyl phosphine compounds, the product triphenyl phosphine accounted for 28.3 wt%.

[0084] Example 9:

[0085] The 5L synthesis reactor was replaced with nitrogen three times, 300 grams of diphenyl phosphine chloride was added into the synthesis reactor, the valve of the reactor was closed, and the pressure was increased to 1.0 MPa after nitrogen was added. Then the stirring was started with a stirring rate of 350-400 r / min. The temperature was increased to 350°C within 70-80 min, and the highest pressure during the reaction was 1.7 MPa. The reaction was kept for 2.0 hours. The generated product phenyl dichlorophosphine was 40.3 grams, triphenyl phosphine was 81.7 grams, and the residual diphenyl phosphine chloride was 166.4 grams. The impurity was about 11 grams. Among the three kinds of phenyl phosphine compounds, the product triphenyl phosphine accounted for 28.3 wt%.

[0086] Example 10:

[0087] The 5L synthesis reactor was replaced with nitrogen three times, 300 grams of diphenyl phosphine chloride was added into the synthesis reactor, the valve of the reactor was closed, and the pressure was increased to 1.0 MPa after nitrogen was added. Then the stirring was started with a stirring rate of 350-400 r / min. The temperature was increased to 350°C within 70-80 min, and the highest pressure during the reaction was 1.7 MPa. The reaction was kept for 2.0 hours. The generated product phenyl dichlorophosphine was 40.3 grams, triphenyl phosphine was 81.7 grams, and the residual diphenyl phosphine chloride was 166.4 grams. The impurity was about 11 grams. Among the three kinds of phenyl phosphine compounds, the product triphenyl phosphine accounted for 28.3 wt%.

[0088] Finally, it should be noted that the above content is only used to illustrate the technical solutions of the present application, and is not a limitation on the protection scope of the present application. Simple modifications or equivalent replacements of the technical solutions of the present application made by ordinary skilled in the art do not deviate from the essence and scope of the technical solutions of the present application.

Claims

1. A process for the preparation of triphenylphosphine comprising heat-treating a diphenylphosphine chloride starting material at a temperature of from 280 to 480 °C to produce triphenylphosphine, wherein the content of phenyldichlorophosphine in the diphenylphosphine chloride starting material is not more than 35% by weight, based on the total weight of the diphenylphosphine chloride starting material.

2. The process according to claim 1, wherein the content of phenyldichlorophosphine in the diphenylphosphine chloride starting material is not more than 30% by weight, preferably not more than 28% by weight, more preferably not more than 22% by weight, still more preferably not more than 15% by weight, especially not more than 8% by weight, in particular 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 chloride starting material.

3. The process according to claim 1 or 2, wherein the content of the diphenylphosphine chloride in the diphenylphosphine chloride starting 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, still more preferably at least 95% by weight, for example at least 98% by weight, based on the total weight of the diphenylphosphine chloride starting material.

4. The process according to any one of claims 1 to 3, wherein the heat-treatment temperature is from 300 to 450 °C, preferably from 320 to 400 °C, more preferably from 330 to 390 °C.

5. The process according to claim 4, wherein the heat-treatment temperature is especially from 340 to 370 °C, in particular from 345 to 360 °C, most preferably from 345 to 355 °C, for example about 350 °C.

6. The process according to any one of claims 1 to 5, wherein the maximum pressure (gauge) during the heat-treatment is at least 0.05 MPa, preferably at least 0.08 MPa, for example from 0.05 to 6 MPa, more preferably from 0.08 to 5 MPa, still more preferably from 0.1 to 2 MPa or from 0.1 to 0.3 MPa.

7. The process according to any one of claims 1 to 6, wherein the heat-treatment is carried out at autogenous pressure.

8. The process according to any one of claims 1 to 7, wherein the heat-treatment is for a time of at least 0.4 hours, preferably from 0.4 to 12 hours, more preferably from 0.6 to 8 hours, especially from 0.8 to 8 hours, most preferably from 1.5 to 2.5 hours, for example about 2 hours.

9. The process according to any one of claims 1 to 8, wherein the content of phosphorus trichloride in the diphenylphosphine chloride starting 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 starting material.

10. The process according to any one of claims 1 to 9, wherein the heat-treatment is carried out with stirring.

11. The process according to any one of claims 1 to 10, wherein the product mixture resulting from the process comprises triphenylphosphine, phenyldichlorophosphine and diphenylphosphine chloride.

12. The process according to claim 11, wherein the content of triphenylphosphine in the reaction mixture after the heat treatment is at least 15% by weight, preferably at least 20% by weight, such as 15-60% by weight or 20-50% by weight, based on the total weight of triphenylphosphine, phenyldichlorophosphine and diphenylchlorophosphine in the reaction mixture.

13. The process according to any one of claims 1-12, wherein the process comprises heat treating a diphenylchlorophosphine feedstock at a temperature of 300-450°C, the highest pressure (gauge) during the heat treatment is at least 0.05 MPa, the heat treatment is for a time of at least 0.4 hours, and the diphenylchlorophosphine feedstock has a content of diphenylchlorophosphine of at least 65% by weight, a content of phenyldichlorophosphine of not more than 30% by weight, and a content of phosphorus trichloride of not more than 5% by weight, based on the total weight of the diphenylchlorophosphine feedstock.

14. The process according to any one of claims 1-13, wherein the process comprises heat treating a diphenylchlorophosphine feedstock at a temperature of 345-355°C, the highest pressure (gauge) during the heat treatment is 0.15-0.3 MPa (preferably the heat treatment is carried out at autogenous pressure), the heat treatment is for a time of 1.5-2.5 hours, and the diphenylchlorophosphine feedstock has a content of diphenylchlorophosphine of at least 98% by weight, a content of phenyldichlorophosphine of not more than 1% by weight, and a content of phosphorus trichloride of not more than 0.1% by weight (preferably free of phosphorus trichloride), based on the total weight of the diphenylchlorophosphine feedstock.

15. The process according to any one of claims 1-14, wherein the process comprises heat treating a diphenylchlorophosphine feedstock at a temperature of 345-355°C, the highest pressure (gauge) during the heat treatment is 0.15-0.3 MPa (preferably the heat treatment is carried out at autogenous pressure), the heat treatment is for a time of 1.5-2.5 hours, and the diphenylchlorophosphine feedstock has a content of diphenylchlorophosphine of at least 98% by weight, a content of phenyldichlorophosphine of not more than 1% by weight, and a content of phosphorus trichloride of not more than 0.1% by weight (preferably free of phosphorus trichloride), based on the total weight of the diphenylchlorophosphine feedstock. ​