Preparation method of diphenyl phenylphosphonate
阅读说明：本技术 一种苯基膦酸二苯酯的制备方法 (Preparation method of diphenyl phenylphosphonate ) 是由 吕云兴 高洪明 王秋伟 于 2020-07-02 设计创作，主要内容包括：本发明属于有机合成技术领域,提供了一种苯基膦酸二苯酯的制备方法,先在雷尼镍催化和保护气氛条件下,以溴化苯为引发剂,将亚磷酸三苯酯进行异构化反应,将反应料液进行减压蒸馏和固液分离,将所得分离液和苯基膦酰二氯混合进行酯化反应,得到苯基膦酸二苯酯；亚磷酸三苯酯和溴化苯的摩尔比为1:0.5～2；异构化反应的温度为220～260℃。本发明通过控制溴化苯用量,显著降低了异构化反应温度；异构化反应产生的杂质为苯酚,本发明将第一步生成的杂质与苯基膦酰二氯反应,转换成目标产物苯基膦酸二苯酯,从而提高合成方法的收率,且所得产物纯度高。此外,本发明的方法中溴化苯和雷尼镍均可回收套用,反应成本低,环境污染小。(The invention belongs to the technical field of organic synthesis, and provides a preparation method of diphenyl phenylphosphonate, which comprises the steps of firstly, under the conditions of Raney nickel catalysis and protective atmosphere, using bromobenzene as an initiator, carrying out isomerization reaction on triphenyl phosphite, carrying out reduced pressure distillation and solid-liquid separation on reaction feed liquid, mixing the obtained separation liquid and phenylphosphonic dichloride, and carrying out esterification reaction to obtain diphenyl phenylphosphonate; the molar ratio of triphenyl phosphite to benzene bromide is 1: 0.5-2; the temperature of the isomerization reaction is 220-260 ℃. The invention obviously reduces the isomerization reaction temperature by controlling the dosage of the bromobenzene; the impurity generated by isomerization reaction is phenol, and the impurity generated in the first step reacts with phenylphosphonic dichloride to be converted into a target product, namely the diphenyl phenylphosphonate, so that the yield of the synthesis method is improved, and the purity of the obtained product is high. In addition, in the method, the benzene bromide and the Raney nickel can be recycled, so that the reaction cost is low and the environmental pollution is small.)
1. The preparation method of diphenyl phenylphosphonate is characterized by comprising the following steps:
(1) under the conditions of Raney nickel catalysis and protective atmosphere, benzene bromide is used as an initiator, triphenyl phosphite is subjected to isomerization reaction, and the obtained reaction liquid is subjected to reduced pressure distillation and solid-liquid separation in sequence to obtain separation liquid;
(2) mixing the separation solution and phenylphosphonic dichloride for esterification reaction to obtain diphenyl phenylphosphonate;
wherein the molar ratio of triphenyl phosphite to benzene bromide is 1 (0.5-2); the isomerization reaction temperature is 220-260 ℃.
2. The method according to claim 1, wherein the Raney nickel is used in an amount of 1-3% by weight based on the weight of triphenyl phosphite.
3. The preparation method of claim 1, wherein the benzene bromide is added into the mixture of triphenyl phosphite and raney nickel in a dropwise manner, and the dropwise addition time is 1-2 hours.
4. The method according to claim 1, wherein the vacuum degree of the reduced pressure distillation is 2 to 5mmHg and the temperature is 130 to 160 ℃.
5. The preparation method according to claim 1, wherein the solid obtained by the solid-liquid separation is Raney nickel, and the Raney nickel is recycled.
6. The preparation method according to claim 1, wherein the esterification reaction temperature is 120-140 ℃, and the reaction is carried out until the content of phenol in the feed liquid is less than 0.5 wt%.
7. The preparation method according to claim 1, wherein the molar ratio of the phenylphosphoryl dichloride to the phenol in the separated liquid is (0.45-0.5): 1.
8. The method of claim 1, wherein the esterification reaction is carried out under catalysis of a catalyst, wherein the catalyst is a lewis catalyst; the dosage of the catalyst is 0.1-0.5% of the mass of triphenyl phosphite.
9. The method according to claim 8, wherein the Lewis catalyst is one or more selected from titanium tetrachloride, butyl titanate, aluminum trichloride and magnesium chloride.
10. The preparation method according to claim 1 or 8, wherein after the esterification reaction is completed, the method further comprises the steps of carrying out high vacuum reduced pressure distillation on the obtained esterification reaction feed liquid, and collecting fractions at 220-240 ℃ to obtain diphenyl phenylphosphonate; the vacuum degree of the high vacuum reduced pressure distillation is 0.5-2 mmHg.
Technical Field
The invention relates to the technical field of organic synthesis, in particular to a preparation method of diphenyl phenylphosphonate.
Background
Aryl phosphate belongs to halogen-free phosphate, is mainly applied to flame retardant plasticizers of engineering plastics and phenolic resin laminated plates and can be used as a halogen-free environment-friendly flame retardant, diphenyl phenylphosphonate belongs to a special form of aryl phosphate, and the English name is as follows: benzen phosphonicidi-phenvlester, structural formula as follows:
CAS: 3049-24-9, formula: c18H15O3P, physical and chemical properties are as follows: white, odorless crystalline powder, slightly deliquescent; steam pressure 0.01kPa/20 ℃; a flash point of 220 ℃; the melting point is 58-62 ℃; boiling point 370 ℃; solubility: insoluble in water, slightly soluble in alcohol, soluble in benzene, chloroform and acetone, and easily soluble in diethyl ether; relative density (water ═ 1): 1.21; relative steam density (air ═ 1): 9.42. the diphenyl phenylphosphonate belongs to one of aryl phosphate, and has a special structure, the structure has a P-C bond, and the other is a P-O-C bond, so that the diphenyl phenylphosphonate has higher stability and hydrolysis resistance than triphenyl phosphate due to the existence of the P-C bond. As diphenyl phenylphosphonate has high stability and is not easy to decompose corrosive chemical substances, the application field prospect is wider than that of triphenyl phosphate, and triphenyl phosphate can be possibly substituted.
At present, the synthesis method of diphenyl phenylphosphonate is as follows:
U.S. Pat. No. 3,430,3807 describes heating triphenyl phosphite to above 200 ℃ in the presence of a metal halide and benzene iodide to obtain a portion of diphenyl phenylphosphonate, but the yield is low and the production of benzene iodide is too high to be industrially feasible.
In 1983, Bayer corporation improved the method, a small amount of benzene bromide was added into triphenyl phosphite to initiate reaction, Raney nickel was used as a catalyst, and isomerization reaction was carried out at a high temperature of 300-320 ℃ to obtain diphenyl phenylphosphonate with a yield of more than 90%. However, in the method, a metal catalyst Raney nickel is used, and the Raney nickel is easy to ignite at high temperature, but the method is difficult to react at the temperature of less than 300 ℃, a byproduct phenol exists in a reaction product, the byproduct is required to be treated, and environmental pollution is caused in the treatment process.
Yao and Levchik (Tetrahedron Letters,47(2006)277-281) in 2006 added halogenated benzene and triethyl phosphite to triphenyl phosphite, and the catalysis reaction was carried out by using anhydrous nickel chloride as a catalyst, the triphenyl phosphite and triethyl phosphite were firstly subjected to transesterification, and then subjected to isomerization reaction, and after the transesterification process, a large amount of diphenyl ethylphosphate impurities (about 10%) existed, and the impurities were difficult to separate from the target product, and if the impurities were refined, the refining treatment process would increase the synthesis cost and make industrial production difficult.
Disclosure of Invention
In view of this, the present invention provides a method for preparing diphenyl phenylphosphonate. The preparation method provided by the invention has the advantages of low reaction temperature, little environmental pollution, high product yield, high purity and low cost.
In order to achieve the above object, the present invention provides the following technical solutions:
a preparation method of diphenyl phenylphosphonate comprises the following steps:
(1) under the conditions of Raney nickel catalysis and protective atmosphere, benzene bromide is used as an initiator, triphenyl phosphite is subjected to isomerization reaction, and the obtained reaction liquid is subjected to reduced pressure distillation and solid-liquid separation in sequence to obtain separation liquid;
(2) mixing the separation solution and phenylphosphonic dichloride for esterification reaction to obtain diphenyl phenylphosphonate;
wherein the molar ratio of triphenyl phosphite to benzene bromide is 1 (0.5-2); the isomerization reaction temperature is 220-260 ℃.
Preferably, the dosage of the raney nickel is 1-3% of the weight of triphenyl phosphite.
Preferably, the benzene bromide is added into the mixture of triphenyl phosphite and raney nickel in a dropwise manner, and the dropwise addition time is 1-2 h.
Preferably, the vacuum degree of the reduced pressure distillation is 2-5 mmHg, and the temperature is 130-160 ℃.
Preferably, the solid obtained by the solid-liquid separation is Raney nickel, and the Raney nickel is recycled and reused.
Preferably, the esterification reaction temperature is 120-140 ℃, and the reaction is carried out until the content of phenol in the feed liquid is less than 0.5 wt%.
Preferably, the molar ratio of the phenylphosphoryl dichloride to the phenol in the separation liquid is (0.45-0.5): 1.
Preferably, the esterification reaction is carried out under the catalysis of a catalyst, and the catalyst is a Lewis catalyst; the dosage of the catalyst is 0.1-0.5% of the mass of triphenyl phosphite.
Preferably, the lewis catalyst is one or more of titanium tetrachloride, butyl titanate, aluminum trichloride and magnesium chloride.
Preferably, after the esterification reaction is finished, carrying out high vacuum reduced pressure distillation on the obtained esterification reaction feed liquid, and collecting fractions at 220-240 ℃ to obtain diphenyl phenylphosphonate; the vacuum degree of the high vacuum reduced pressure distillation is 0.5-2 mmHg.
Has the advantages that:
(1) according to the invention, the molar ratio of triphenyl phosphite to benzene bromide is controlled to be 1 (0.5-2), and the reaction is promoted by increasing the amount of the benzene bromide (the isomerization reaction is instantaneous, the benzene bromide can provide phenyl, so that the reaction is carried out in the positive direction), so that the reaction is carried out at the temperature lower than 300 ℃, and the problem that raney nickel is easy to ignite at high temperature is avoided.
(2) The isomerization reaction temperature is 220-260 ℃, compared with the scheme that the reaction is carried out at 310-320 ℃ in the traditional method, the method can avoid the oxidation of triphenyl phosphite at high temperature, thereby avoiding the increase of triphenyl phosphate impurities.
(3) At the reaction temperature of the invention, the main impurity generated by isomerization reaction is phenol, the invention adopts phenylphosphonic dichloride and phenol to react to generate the target product of phenylphosphonic acid diphenyl ester, because the reaction of phenylphosphonic dichloride and phenol is easy to carry out and almost completely quantitative reaction, the invention converts the impurity generated in the first step into the target product of phenylphosphonic acid diphenyl ester, thereby improving the yield of the synthesis method. The implementation result shows that the yield of the diphenyl phenylphosphonate prepared by the method can reach 96.77 percent, and the purity can reach 99.35 percent.
(4) The invention can recycle benzene bromide and Raney nickel, has little environmental pollution and low cost, can obtain high-purity products by high vacuum reduced pressure distillation, and has simple post-treatment.
Detailed Description
The invention provides a preparation method of diphenyl phenylphosphonate, which comprises the following steps:
(1) under the conditions of Raney nickel catalysis and protective atmosphere, benzene bromide is used as an initiator, triphenyl phosphite is subjected to isomerization reaction, and the obtained reaction liquid is subjected to reduced pressure distillation and solid-liquid separation in sequence to obtain separation liquid;
(2) mixing the separation solution and phenylphosphonic dichloride for esterification reaction to obtain diphenyl phenylphosphonate;
wherein the molar ratio of triphenyl phosphite to benzene bromide is 1 (0.5-2); the isomerization reaction temperature is 220-260 ℃.
In the invention, triphenyl phosphite is subjected to isomerization reaction by taking benzene bromide as an initiator under the conditions of raney nickel catalysis and protective atmosphere. In the present invention, the protective atmosphere is preferably nitrogen; the molar ratio of triphenyl phosphite to benzene bromide is 1 (0.5-2), preferably 1 (1-1.5); the benzene bromide is preferably added into the mixture of triphenyl phosphite and raney nickel in a dropwise manner, and the dropwise addition time is preferably 1-2 h; the temperature of the isomerization reaction is 220-260 ℃, and preferably 230-250 ℃. The method preferably determines the end point of the isomerization reaction by liquid phase monitoring, and stops the reaction when the reaction is completed until the triphenyl phosphite in the feed liquid reacts, and in the specific embodiment of the invention, the reaction is stopped when the mass fraction of the triphenyl phosphite in the reaction feed liquid is less than or equal to 0.2%; in the embodiment of the invention, the incubation reaction is preferably continued for 30min after the completion of the dropwise addition of the bromobenzene. Triphenyl phosphite is isomerized to diphenyl phenylphosphonate under the initiation of benzene bromide and catalysis of raney nickel, and a part of phenol by-product is formed at the same time.
In the invention, the dosage of the raney nickel is preferably 1-3% of the weight of triphenyl phosphite, and more preferably 1.5-2.5%; the dosage of the raney nickel is calculated by the weight of wet raney nickel; the particle size of the Raney nickel is preferably 50 μm; in the specific embodiment of the invention, the commercially available raney nickel is stored in water in a sealed manner, and when the method is applied, the commercially available raney nickel is preferably added into a four-neck flask firstly, water is removed under the vacuum reduced pressure condition, triphenyl phosphite is added after the raney nickel is dried, then the temperature is slowly raised to the isomerization reaction temperature under the nitrogen protection condition, and then the dropwise addition of the bromobenzene is started. In the invention, the conditions for dehydrating under the vacuum reduced pressure condition are specifically as follows: heating to 120-125 ℃ under the condition of a vacuum degree of 2-3 mmHg, and dehydrating for 2 hours in vacuum.
In the present invention, the reaction formula of the isomerization reaction is shown as formula I:
after the isomerization reaction is finished, the obtained reaction liquid is subjected to reduced pressure distillation and solid-liquid separation in sequence to obtain a separation liquid. In the invention, the vacuum degree of the reduced pressure distillation is preferably 2-5 mmHg, and more preferably 2-3 mmHg; the temperature of the reduced pressure distillation is preferably 130-160 ℃, and more preferably 140-160 ℃; the solid-liquid separation method is preferably nitrogen filter pressing, and the temperature of the nitrogen filter pressing is preferably 60-65 ℃; in the specific embodiment of the invention, preferably, after the temperature of the reaction feed liquid is reduced to 70-80 ℃, the reduced pressure distillation is started, the temperature is gradually increased to the reduced pressure distillation temperature, and after the reduced pressure distillation is finished, the temperature is reduced to 60-65 ℃ for nitrogen pressure filtration. The invention removes the residual bromobenzene in the reaction feed liquid by reduced pressure distillation. The brominated benzene obtained by reduced pressure distillation can be reused.
In the invention, the solid obtained by solid-liquid separation is Raney nickel, and the Raney nickel is preferably recycled and reused; filtering to obtain liquid as separation liquid; the main components of the separation liquid are diphenyl phenylphosphonate and phenol.
After the separation liquid is obtained, the separation liquid and phenylphosphonic dichloride are mixed for esterification reaction to obtain the phenylphosphonic acid diphenyl ester. In the invention, the molar ratio of the phenylphosphoryl dichloride to the phenol in the separation liquid is preferably (0.45-0.5): 1; the temperature of the esterification reaction is preferably 120-140 ℃, more preferably 125-135 ℃, the invention preferably uses a liquid phase to monitor the reaction progress, and the reaction can be stopped until the content of phenol in the feed liquid is less than 0.5 wt%.
In the invention, the esterification reaction is preferably carried out under the catalysis of a catalyst, the catalyst is preferably a Lewis catalyst, and the Lewis catalyst is preferably one or more of titanium tetrachloride, butyl titanate, aluminum trichloride and magnesium chloride; the dosage of the catalyst is preferably 0.1-0.5% of the mass of triphenyl phosphite.
In the present invention, the reaction formula of the esterification reaction is shown as formula II:
after the esterification reaction is finished, preferably, carrying out high vacuum reduced pressure distillation on the obtained esterification reaction material liquid, and collecting fractions at 220-240 ℃ to obtain diphenyl phenylphosphonate; the degree of vacuum of the high vacuum reduced pressure distillation is preferably 0.5 to 2mmHg, and more preferably 1 to 1.5 mmHg.
The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention.