CN113912645A

CN113912645A - Preparation method of triphenylphosphine

Info

Publication number: CN113912645A
Application number: CN202111317553.6A
Authority: CN
Inventors: 宋斌; 龚秦丽; 邓伟强
Original assignee: Hunan Jingshi New Material Co ltd
Current assignee: Hunan Jingshi New Material Co ltd
Priority date: 2021-11-09
Filing date: 2021-11-09
Publication date: 2022-01-11
Anticipated expiration: 2041-11-09
Also published as: WO2023082352A1; CN113912645B

Abstract

The invention provides a preparation method of triphenylphosphine, which comprises the following steps: the method comprises the following steps of (1) preparing trimethoxy monoboron sodium, and reacting the trimethoxy monoboron sodium with triphenylphosphine dichloride to obtain triphenylphosphine; further, reacting sodium hydride with trimethyl borate to obtain trimethoxy monoboron sodium reaction solution; dropwise adding the obtained trimethoxy monoboron sodium reaction solution into the first solution to react to obtain triphenylphosphine; the method provided by the invention can realize the advantages of high yield, high purity and more environmental protection of triphenylphosphine.

Description

Preparation method of triphenylphosphine

Technical Field

The invention relates to the technical field of triphenylphosphine preparation, and particularly relates to a preparation method of triphenylphosphine.

Background

Triphenylphosphine is a chemical raw material with wide application, and is widely applied to wittig reaction process, catalyst ligand and the like in the industries of medicine, chemical engineering and the like. After the triphenylphosphine is used for wittig reaction, the triphenylphosphine becomes a byproduct triphenylphosphine oxide; if triphenylphosphine oxide is used as waste residue for treatment, the treatment cost is high, and the content of phosphorus in the three wastes is difficult to be treated below the environmental protection qualified standard. Therefore, the technology of recovering triphenylphosphine by reducing triphenylphosphine oxide has been widely researched and applied.

1.2, at present, there are two main industrial methods for preparing triphenylphosphine by reducing triphenylphosphine oxide.

The first method is to directly reduce triphenylphosphine oxide with 1,1,3, 3-tetramethyldisiloxane, or trichloromonohydroxysilane, etc., to obtain triphenylphosphine, wherein the chemical reaction equation is shown in formula (1):

the first method has the advantage of short process route. The disadvantages are that the market price of the 1,1,3, 3-tetramethyl disiloxane is higher, the large amount of polydimethyl siloxane generated after the reaction needs to be properly treated, and the environmental protection cost is high. The trichlorosilane not only seriously corrodes equipment, but also has small proportion of effective reducing groups (hydrogen atoms) in molecules, so the total consumption is large, and the total cost of raw materials and the equipment is high; a large amount of polydichlorosilane is also generated after the reaction, which needs to be properly treated, and the environmental protection cost is high.

The second method is that triphenylphosphine oxide is treated with oxalyl chloride to obtain triphenylphosphine dichloride; then the triphenylphosphine dichloride is reduced by lithium aluminum hydride, aluminum powder (sheet) and the like to obtain triphenyl phosphine; wherein, the chemical reaction equation is shown as chemical formula (2):

the second method has the advantages that the by-product in the first step is mainly oxalic acid, the by-products in the second step are mainly aluminum trichloride, lithium chloride, hydrochloric acid and the like, and the difficulty of environmental protection treatment is relatively small. The disadvantages are: if the reaction in the second step is reduced by using lithium aluminum hydride, the raw material cost is higher; if aluminum powder (flake) is used for reduction, although the cost is low, the conversion rate is high only if the aluminum powder (flake) needs to be excessive by more than 3 times, and the active aluminum powder (flake) has more residues, is difficult to recycle and apply and can only be treated by adding acid; the waste of active aluminum powder (sheet) is more, hydrogen is generated during acid adding post-treatment, the process danger is larger during enlarged production, a large amount of aluminum salt is generated, and the environment is not friendly enough.

Disclosure of Invention

The invention provides a preparation method of triphenylphosphine, which is used for improving the preparation process of the triphenylphosphine, wherein sodium hydride with lower price is used as an initial raw material, trimethoxy monoboron sodium is prepared firstly, and then the triphenylphosphine is reacted with triphenylphosphine dichloride under the action of catalytic amount of aluminum trichloride or stannous chloride to obtain the triphenylphosphine. The cost of raw materials is lower than that of the two methods, the main three wastes are only sodium chloride, and the solvent and the main auxiliary agent trimethyl borate can be recycled; the process is high in safety and more environment-friendly.

The invention provides a preparation method of triphenylphosphine, which comprises the following steps:

preparing the trimethoxy-boron monohydrogen sodium,

the triphenylphosphine is obtained by the reaction of trimethoxy monoboron sodium and triphenylphosphine dichloride.

Preferably, the method further comprises the following steps:

reacting sodium hydride with trimethyl borate to obtain trimethoxy monoboron sodium reaction solution;

dropwise adding the obtained trimethoxy monoboron sodium reaction solution into the first solution to obtain triphenylphosphine.

Preferably, the first solution is triphenylphosphine dichloride solution containing a catalytic amount of aluminum trichloride or stannous chloride.

Preferably, the method further comprises the following steps:

adding sodium hydride and a solvent A into the first reaction bottle; then, cooling to-50-10 ℃ under the protection of nitrogen, uniformly stirring at the temperature of-50-10 ℃, and then dropwise adding a second solution;

after the dropwise addition, continuously keeping the temperature between 50 ℃ below zero and 10 ℃ and stirring for 1 to 5 hours to generate the trimethoxy-boron-hydrogen-based sodium reaction solution.

Preferably, the solvent A is one or a mixture of more of diethyl ether, tetrahydrofuran, 2-methyltetrahydrofuran and 1, 4-dioxane;

the dosage of the solvent A is 4-6 times of the mass ratio of sodium hydride;

the dosage of the trimethyl borate is 1.1-4.0 times of the equivalent of the sodium hydride;

the second solution is trimethyl borate, or a mixed solution of trimethyl borate and the solvent A.

Preferably, adding triphenylphosphine dichloride and the solution III into the reaction bottle II, and stirring uniformly under the protection of nitrogen until the temperature is-50-10 ℃;

then adding a catalyst, and then dropwise adding trimethoxy monoboron sodium reaction solution;

after the dropwise adding is finished, carrying out heat preservation reaction for 3-15 hours at the temperature of-20-10 ℃;

filtering to remove insoluble substances generated in the reaction and obtain filtrate; wherein the insoluble matter is sodium chloride.

Preferably, the dosage of the triphenylphosphine dichloride is 0.4-0.45 time equivalent of the sodium hydride;

the third solution is a solvent A or a mixture of the solvent A and trimethyl borate; the mixing ratio of the solvent A and trimethyl borate is any ratio;

the dosage of the solution III is 4-8 times of the mass ratio of triphenylphosphine dichloride;

the solvent A is one or a mixture of more of diethyl ether, tetrahydrofuran, 2-methyltetrahydrofuran and 1, 4-dioxane;

the catalyst is one or a mixture of stannous chloride and aluminum trichloride;

the dosage of the catalyst is 0.5 to 5 mass percent of the triphenylphosphine dichloride;

the temperature of the dropping of the trimethoxy monoboron sodium reaction liquid and the temperature of the heat preservation reaction after the dropping are both-20 to 10 ℃; the reaction time after the dropwise addition is 3-15 hours;

the temperature for filtering and removing insoluble substances generated by the reaction is between-20 ℃ and room temperature.

Preferably, the filtrate is decompressed and concentrated, the azeotrope of trimethyl borate and the solvent A is recovered, and the concentrated residue is reserved;

adding a solvent B and dilute hydrochloric acid into the concentrated residues, and hydrolyzing and extracting;

separating the hydrolyzed reactant, washing the obtained organic layer with water to neutrality, and concentrating to remove the solvent B to obtain a crude product of triphenylphosphine;

after purification and drying by a crystallization method, the high-purity triphenylphosphine is obtained.

Preferably, the solvent B is one or a mixture of more of benzene, toluene, xylene, chlorobenzene, anisole, tetrahydrofuran and methyltetrahydrofuran;

the dosage of the solvent B is 3-10 times of the mass ratio of triphenylphosphine dichloride;

the dosage of the hydrochloric acid is 0.3-0.5 time equivalent of the sodium hydride;

in the water washing process, the water washing temperature is 0-50 ℃;

the solvent for crystallizing the crude triphenylphosphine can be ethanol, propanol, isopropanol, ethyl acetate, isopropyl acetate, toluene, petroleum ether and the like, or a mixture of the ethanol, the propanol, the isopropanol, the ethyl acetate, the isopropyl acetate, the toluene and the petroleum ether;

and the dosage of a crystallization solvent when the crude triphenylphosphine product is crystallized by using a crystallization method is 3-10 times of the mass ratio of the crude triphenylphosphine product.

The invention has the following beneficial effects:

the method for preparing the triphenylphosphine by using the sodium hydride as the starting material to prepare the trimethoxy monoboron sodium and then using the trimethoxy monoboron sodium to reduce the triphenylphosphine dichloride to obtain the triphenylphosphine is not disclosed by related documents or technologies at present.

In the prior art, trimethoxy monoboron sodium can not exist stably at the temperature of more than 10 ℃; the reaction of disproportionation and decomposition is easy to occur, and further the reaction is converted into sodium methoxide and various byproducts, such as dimethoxy monohydro borane, methoxy dihydroborane, borane and the like which escape in a gaseous state. In the process scheme for preparing sodium borohydride, due to the adoption of conditions such as excessive sodium hydride, a pressurized system, a reaction temperature of more than 200 ℃ and the like, trimethoxy monoborohydride sodium, dimethoxy monoborohydride, methoxy dihydroborane, borane and the like only exist as intermediates, and can continuously react with sodium hydride at high temperature to finally obtain sodium borohydride, as shown in a chemical reaction equation (3):

the invention preferably adopts another reaction condition, namely, a scheme that the temperature is lower than 10 ℃ and trimethyl borate is excessive is adopted, so that the trimethoxy sodium borohydride is kept to exist stably in the solution; and then directly used for the next reaction.

Further, trimethyl borate is preferably selected in the invention; when the temperature is below 10 ℃, only trimethyl borate can react with sodium hydride to obtain trimethoxy monoboron sodium; similar triethyl borate, tripropyl borate, tributyl borate, etc. do not react similarly.

Meanwhile, in the present invention, sodium hydride is used in a sufficient market, and the effective reducing group (hydrogen atom) has a large specific gravity in the molecule, and the unit cost thereof is lower than that of 1,1,3, 3-tetramethyldisiloxane, trichlorosilane, or lithium aluminum hydride, excessive aluminum flakes (powder), etc. Compared with other existing industrial methods for preparing triphenylphosphine by using triphenylphosphine dichloride, the method has the advantages of lower raw material cost and higher process safety.

In addition, the method adopted by the invention does not generate a large amount of byproducts such as polysilicone, aluminum salt and the like which are difficult to treat or dangerous active aluminum powder (sheet) residues; the main auxiliary materials such as the trimethyl borate, the solvent A, the solvent B and the like can be recycled and reused; is more environment-friendly.

Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention may be realized and attained by the structure particularly pointed out in the written description.

The technical solution of the present invention is further described in detail by the following examples.

Detailed Description

The following description of the preferred embodiments of the present invention is provided for the purpose of illustration and description, and is in no way intended to limit the invention.

The embodiment of the invention provides a preparation method of triphenylphosphine, which comprises the following steps:

the trimethoxy sodium monohydrogenborate is prepared, and the trimethoxy sodium monohydrogenborate is reacted with triphenylphosphine dichloride to obtain triphenylphosphine.

Further comprising: reacting sodium hydride with trimethyl borate to obtain trimethoxyborohydride sodium reaction solution; dropwise adding the obtained trimethoxy monoboron sodium reaction solution into the first solution to obtain triphenylphosphine. The first solution is a triphenylphosphine chloride solution containing a catalytic amount of aluminum trichloride or stannous chloride.

Further comprising: adding sodium hydride and a solvent A into the first reaction bottle; then, cooling to-50-10 ℃ under the protection of nitrogen, uniformly stirring at the temperature of-50-10 ℃, and then dropwise adding a second solution; after the dripping is finished, continuously keeping the temperature between minus 50 ℃ and 10 ℃ and stirring for 1 to 5 hours to generate the trimethoxy monoboron sodium reaction solution.

The solvent A is one or a mixture of more of diethyl ether, tetrahydrofuran, 2-methyltetrahydrofuran and 1, 4-dioxane; the dosage of the solvent A is 4-6 times of the mass ratio of sodium hydride; the dosage of the trimethyl borate is 1.1-4.0 times of the equivalent of the sodium hydride; the second solution is trimethyl borate, or a mixed solution of trimethyl borate and the solvent A.

Further, adding triphenylphosphine dichloride and the solution III into the reaction bottle II, and stirring uniformly under the protection of nitrogen until the temperature is between 50 ℃ below zero and 10 ℃; then adding a catalyst, and then dropwise adding trimethoxy monoboron sodium reaction solution; after the dropwise adding is finished, carrying out heat preservation reaction for 3-15 hours at the temperature of-20-10 ℃; filtering to remove insoluble substances generated in the reaction and obtain filtrate; wherein the insoluble substance is sodium chloride.

Wherein the dosage of the triphenylphosphine dichloride is 0.4-0.45 equivalent of the sodium hydride; the third solution is a solvent A or a mixture of the solvent A and trimethyl borate; the mixing ratio of the solvent A and trimethyl borate is any ratio; the dosage of the solution III is 4-8 times of the mass ratio of triphenyl phosphine dichloride; the solvent A is one or a mixture of more of diethyl ether, tetrahydrofuran, 2-methyltetrahydrofuran and 1, 4-dioxane; the catalyst is one or a mixture of a plurality of stannous chloride and aluminum trichloride; the dosage of the catalyst is 0.5 to 5 mass percent of the triphenylphosphine dichloride; the temperature of the dropping of the trimethoxy monoboron sodium reaction liquid and the temperature of the heat preservation reaction after the dropping are both-20 to 10 ℃; the heat preservation reaction time after dropwise adding is 3-15 hours; the temperature for filtering and removing insoluble substances generated by the reaction is between-20 ℃ and room temperature.

Further, decompressing and concentrating the filtrate, recovering an azeotrope of trimethyl borate and the solvent A, and reserving a concentrated residue; adding a solvent B and dilute hydrochloric acid into the concentrated residues, and hydrolyzing and extracting; separating the hydrolyzed reactant, washing the obtained organic layer with water to neutrality, and concentrating to remove the solvent B to obtain a crude product of triphenylphosphine; after purification and drying by a crystallization method, the high-purity triphenylphosphine is obtained.

Wherein the solvent B is one or a mixture of more of benzene, toluene, xylene, chlorobenzene, anisole, tetrahydrofuran and methyltetrahydrofuran; the dosage of the solvent B is 3-10 times of the mass ratio of triphenyl phosphine dichloride; the dosage of the hydrochloric acid is 0.3-0.5 time equivalent of the sodium hydride; in the water washing process, the water washing temperature is 0-50 ℃; the solvent for crystallizing the crude triphenylphosphine can be ethanol, propanol, isopropanol, ethyl acetate, isopropyl acetate, toluene, petroleum ether and the like, or a mixture of the ethanol, the propanol, the isopropanol, the ethyl acetate, the isopropyl acetate, the toluene and the petroleum ether; and the dosage of a crystallization solvent when the triphenyl phosphine crude product is crystallized by using a crystallization method is 3-10 times of the mass ratio of the triphenyl phosphine crude product.

The preparation method comprises the following steps:

using a one-pot method; firstly, sodium hydride is used for reacting with trimethyl borate to prepare trimethoxy boron sodium hydride; then the reaction liquid is dropped into the triphenylphosphine solution containing the catalytic amount of aluminum trichloride (or stannous chloride), and the triphenylphosphine is obtained after the reaction. Byproducts are sodium chloride and trimethyl borate; wherein trimethyl borate can be recovered and reused together with the solvent, and the corresponding chemical reaction equation (4):

the specific operation steps are as follows:

step 1, adding sodium hydride and a solvent A into a reaction bottle I; and then cooling to-50-10 ℃ under the protection of nitrogen, keeping the temperature at-50-10 ℃, stirring, and dropwise adding trimethyl borate (or a mixed solution of trimethyl borate and a solvent A). After the dropwise addition is finished, continuously keeping the temperature between 50 ℃ below zero and 10 ℃ and stirring for 1 to 5 hours to generate the trimethoxy monoboron sodium reaction solution.

The solvent A can be one of diethyl ether, tetrahydrofuran, 2-methyltetrahydrofuran and 1, 4-dioxane, or a mixture of the diethyl ether, the tetrahydrofuran, the 2-methyltetrahydrofuran and the 1, 4-dioxane;

the dosage of the solvent A can be 4-6 times of the mass ratio of sodium hydride;

the dosage of the trimethyl borate can be 1.1-4.0 times of the equivalent of sodium hydride;

the trimethyl borate (or the mixed solution of the trimethyl borate and the solvent A) can be pure trimethyl borate, or can be a solution of the trimethyl borate and the solvent A mixed in any proportion;

the dropping and heat preservation reaction temperature is between-50 ℃ and 10 ℃;

and the reaction time of heat preservation after the dropwise addition is 1-5 hours.

And 2, adding triphenylphosphine dichloride and a solvent A (or a mixture of the solvent A and trimethyl borate) into the reaction bottle II, and preserving the temperature of-20-10 ℃ under the protection of nitrogen and stirring. Then adding a catalyst, and then dropwise adding trimethoxy monoboron sodium reaction solution. After the dropwise addition is finished, the temperature is kept at-20-10 ℃ for reaction for 3-15 hours. Insoluble matter (sodium chloride) produced by the reaction was then removed by filtration, and a filtrate was obtained.

The dosage of the triphenylphosphine dichloride can be 0.4 to 0.45 equivalent of the sodium hydride;

the solvent A and trimethyl borate are mixed in any proportion;

the dosage of the solvent A (or the mixture of the solvent A and trimethyl borate) can be 4-8 times of the mass ratio of triphenylphosphine dichloride;

the catalyst can be stannous chloride, or aluminum trichloride, or a mixture of the stannous chloride and the aluminum trichloride;

the dosage of the catalyst can be 0.5 to 5 percent of the mass ratio of the triphenylphosphine dichloride;

the dripping operation time has no strict requirement, and the requirements are met on controlling reaction heat release and ensuring the temperature of a reaction solution to be-20-10 ℃;

the temperature of the dropwise addition and the temperature of the dropwise addition-after heat preservation reaction are both-20-10 ℃;

and the heat preservation reaction time after dropwise adding is 3-15 hours.

The temperature during the filtration can be between-20 ℃ and room temperature.

And 3, carrying out reduced pressure concentration on the obtained filtrate, and recovering the azeotrope of trimethyl borate and the solvent A. Adding solvent B and dilute hydrochloric acid into the concentrated residue, and hydrolyzing and extracting; and (3) separating the hydrolyzed reaction, washing the obtained organic layer to be neutral by using water, and concentrating to remove the solvent B to obtain a crude product of the triphenylphosphine. And purifying and drying by using a crystallization method to obtain the high-purity triphenylphosphine.

The solvent B can be benzene, toluene, xylene, chlorobenzene, anisole, tetrahydrofuran, methyltetrahydrofuran and the like, or a mixture of the benzene, the toluene, the xylene, the chlorobenzene, the anisole, the tetrahydrofuran and the methyltetrahydrofuran;

the dosage of the solvent B can be 3-10 times of the mass ratio of triphenylphosphine dichloride;

the concentration of the hydrochloric acid is not strictly required, and the dosage of the hydrochloric acid can be 0.3-0.5 time equivalent of that of sodium hydride;

the dosage of water and the washing times during washing have no strict requirements, and the washing is carried out until the water layer is neutral;

the temperature of the water washing is 0-50 ℃;

the dosage of the solvent during the crystallization of the triphenylphosphine crude product can be 3-10 times of the mass ratio of the triphenylphosphine crude product;

the temperature and times of the crystallization of the crude triphenylphosphine product are not strictly required, and the triphenyl phosphine is purified to a satisfactory purity.

The invention adopts the scheme that the temperature is lower than 10 ℃ and trimethyl borate is excessive, so that the trimethoxy boron-hydrogen sodium can be kept stably in the solution; and then directly used for the next reaction. The situation that the trimethoxy monoboron sodium can not exist stably at the temperature of more than 10 ℃ in the prior art is reduced; and further reducing the unstable condition which causes the trimethoxy-monoboron sodium to be easily subjected to disproportionation, decomposition and other reactions, and further converted into sodium methoxide and various byproducts, such as dimethoxy-monoboron, methoxy-dihydroborane and borane which escape in a gaseous state.

In addition, the method adopted by the invention does not generate a large amount of byproducts such as polysilicone, aluminum salt and the like which are difficult to treat or dangerous active aluminum powder (sheet) residues; the main auxiliary materials such as the trimethyl borate, the solvent A, the solvent B and the like can be recycled and reused; the environment is more friendly;

therefore, the method provided by the invention can realize the advantages of high yield, high purity and more environmental protection of triphenylphosphine.

Experimental example 1

1.1 to a 250ml reaction flask I, 20g (0.5mol) of 60% sodium hydride and 80g of anhydrous tetrahydrofuran were added. Stirring and cooling to 0-10 ℃ under the protection of nitrogen. Then maintaining the nitrogen protection, stirring and liquid temperature at 0-10 ℃, and dropwise adding 57.2g (0.55mol) of trimethyl borate; after the dripping is finished, the temperature is kept between 0 and 10 ℃ and stirring is continued for 1 hour.

1.2, into another 1000ml reaction flask II, 74.9g (0.225mol) of triphenyl phosphine dichloride and 300g of tetrahydrofuran are added, and the temperature is controlled to be 0-10 ℃ under the protection of nitrogen and stirring. Then 0.375g of stannous chloride is added; and then controlling the temperature to be 0-10 ℃, stirring and dropwise adding the reaction mixture obtained by 4.1.1. And after the dropwise addition is finished, continuously preserving the heat at 0-10 ℃ for reaction for 15 hours. Then, the reaction mixture was filtered at room temperature to remove insoluble substances (sodium chloride) produced in the reaction.

1.3, decompressing and concentrating the filtrate obtained in the step 1.2, and recovering the mixed solvent of trimethyl borate and tetrahydrofuran for standby application. 225g of toluene and 110g (0.15mol) of 5% dilute hydrochloric acid were added to the concentrated residue, and after stirring at room temperature for 1 hour, liquid separation was performed; and washing the obtained organic layer at 40-50 ℃ with water to be neutral, and concentrating to remove toluene to obtain about 69g of residue which is a crude product of the triphenylphosphine. The crude product is crystallized for 2 times by using a mixed solvent of 2.8 times of ethanol and 0.2 time of toluene, and then dried to obtain 52.7g of triphenylphosphine, wherein the yield is 89.1 percent, and the liquid chromatography purity is more than or equal to 99.7 percent.

Experimental example 2

2.1 to a 1000ml reaction flask I, 20g (0.5mol) of 60% sodium hydride, and 120g of anhydrous 2-methyltetrahydrofuran were added. Stirring and cooling to-50 to-40 ℃ under the protection of nitrogen. Then maintaining the nitrogen protection, stirring and liquid temperature of-50 to-40 ℃, and dropwise adding a mixture of 208g (2mol) of trimethyl borate and 200g of 2-methyltetrahydrofuran; after the dripping is finished, the temperature is kept between minus 50 ℃ and minus 40 ℃ and the stirring is continued for 5 hours.

2.2 into another 2000ml reaction flask II, 66.6g (0.2mol) of triphenylphosphine dichloride and 533g of a mixture of 2-methyltetrahydrofuran/trimethyl borate are added, and the temperature is controlled to be-20 to-10 ℃ under nitrogen protection and stirring. Then 3.33g of anhydrous aluminum trichloride is added; then controlling the temperature to be minus 20 to minus 10 ℃, stirring and dropwise adding the reaction mixture obtained by 4.2.1. After the dropwise addition is finished, the temperature is kept for 3 hours at minus 20 to minus 10 ℃. Then filtering at-20-10 deg.C to remove insoluble substances (sodium chloride) generated by the reaction.

And 2.3, carrying out reduced pressure concentration on the filtrate obtained in the step 2.2, and recovering the mixed solvent of trimethyl borate and 2-methyltetrahydrofuran for later use. 666g of anisole and 91.3g (0.25mol) of 10% dilute hydrochloric acid are added into the concentrated residues, and after stirring is carried out for 1 hour at the temperature of 0-10 ℃, liquid separation is carried out; and washing the obtained organic layer at 0-10 ℃ with water to be neutral, and concentrating to remove anisole to obtain about 57g of residue which is a triphenylphosphine crude product. The crude product is crystallized for 2 times by using a mixed solvent of 8 times by mass of isopropanol and 2 times by mass of petroleum ether, and then is dried in vacuum, 46.3g of triphenylphosphine is obtained, the yield is 88.3%, and the purity of liquid chromatography is more than or equal to 99.8%.

And (4) conclusion: as is obvious from experimental example 1 and experimental example 2, the yield of triphenylphosphine is at least more than or equal to 88.3%; the purity of liquid chromatogram is at least more than or equal to 99.7%.

Meanwhile, the invention adopts the scheme that the temperature is lower than 10 ℃ and trimethyl borate is excessive, so that the trimethoxy boron-hydrogen sodium can be kept in the solution stably; and then used directly in the next reaction. The situation that the trimethoxy monoboron sodium can not exist stably at the temperature of more than 10 ℃ in the prior art is reduced; and further reducing the unstable condition to cause the trimethoxy monoboron sodium to be easily subjected to disproportionation, decomposition and other reactions, and further converted into sodium methoxide and various byproducts, such as dimethoxy monohydroborane, methoxy dihydroborane and borane which escape in a gaseous state.

It will be apparent to those skilled in the art that various changes and modifications may be made in the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.

Claims

1. The preparation method of triphenylphosphine is characterized by comprising the following steps:

preparing the trimethoxy-boron monohydrogen sodium,

2. The method of claim 1, further comprising:

dropwise adding the obtained trimethoxy monoboron sodium reaction solution into the first solution to react to obtain the triphenylphosphine.

3. The method of claim 2, wherein the first solution is triphenylphosphine dichloride solution containing a catalytic amount of aluminum trichloride or stannous chloride.

4. The method of claim 2, further comprising:

after the dropwise addition is finished, continuously keeping the temperature between 50 ℃ below zero and 10 ℃ and stirring for 1 to 5 hours to generate the trimethoxy monoboron sodium reaction solution.

5. The process according to claim 4, wherein the solvent A is one or more selected from the group consisting of diethyl ether, tetrahydrofuran, 2-methyltetrahydrofuran, and 1, 4-dioxane;

the dosage of the solvent A is 4-6 times of the mass ratio of sodium hydride;

6. The preparation method of triphenylphosphine as claimed in claim 2, wherein triphenylphosphine dichloride and the solution III are added into the reaction bottle II, and the mixture is stirred uniformly under the protection of nitrogen gas at-50 to 10 ℃;

filtering to remove insoluble substances generated in the reaction and obtain filtrate; wherein the insoluble substance is sodium chloride.

7. The method of claim 6, wherein the amount of triphenylphosphine dichloride is 0.4 to 0.45 equivalent of sodium hydride;

the catalyst is one or a mixture of stannous chloride and aluminum trichloride;

the temperature of the dropping of the trimethoxy monoboron sodium reaction liquid and the temperature of the heat preservation reaction after the dropping are both-20 to 10 ℃; the reaction time after dropwise addition is 3-15 hours;

8. The process according to claim 6, wherein the triphenylphosphine,

decompressing and concentrating the filtrate, recovering an azeotrope of trimethyl borate and the solvent A, and reserving a concentrated residue;

9. The method for preparing triphenylphosphine as claimed in claim 8, wherein the solvent B is one or more of benzene, toluene, xylene, chlorobenzene, anisole, tetrahydrofuran, and methyltetrahydrofuran;

in the water washing process, the water washing temperature is 0-50 ℃;

and the amount of a crystallization solvent used for crystallizing the crude triphenylphosphine product by using a crystallization method is 3-10 times of the mass ratio of the crude triphenylphosphine product.