Synthesis method of methyl diphenyl phosphate
By using a composite catalyst of phenol salt and metal oxide for transesterification, the safety risks and high temperature and pressure problems in the synthesis of methyl diphenyl phosphate were solved, achieving a synthesis effect with high purity and high yield.
Patent Information
- Application Number
- CN202510914162.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-03
- Publication Date
- 2025-10-17
AI Technical Summary
Existing methods for synthesizing methyl diphenyl phosphate suffer from problems such as harsh reaction conditions, low yields, and safety risks associated with the use of alkyl halides.
A composite catalyst of phenol salt and metal oxide was used to replace haloalkanes for the transesterification reaction of triphenyl phosphite and trimethyl phosphite, avoiding the use of haloalkanes, reducing the reaction temperature, and ensuring high purity and yield.
The synthesis of methyl diphenyl phosphate, characterized by high safety, mild reaction conditions, and high product purity and yield, has been achieved, overcoming the safety risks and high temperature and pressure problems of existing technologies.
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Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of organic synthesis, and particularly relates to a synthesis method of methyl diphenyl phosphate. BACKGROUND
[0002] Methyl diphenyl phosphate is widely used as a flame retardant or an industrial intermediate in various industries. Its early synthesis method is that A. Michaelis and R. Kaehne reported in 1898 that trialkyl phosphite and iodoalkane were heated to generate dihydrocarbyl phosphate, that is, Michaelis-Arbuzov reaction. However, the early reaction may have problems such as harsh reaction conditions and low yield.
[0003] Secondly, phenylmethanol and triphenylphosphine are reacted under alkaline conditions to generate phenyl methyl phosphate, and then the phenyl methyl phosphate is reacted with methyl halide to generate methyl diphenyl phosphate. This method may have better selectivity and yield than the traditional method, and the reaction conditions are relatively mild. However, methyl halide has safety risks.
[0004] Finally, triphenyl phosphite and trimethyl phosphite are subjected to ester exchange reaction in the presence of methyl halide to prepare methyl diphenyl phosphate. The method has high purity of the synthesized product, but also has problems such as safety risks of methyl halide and high reaction temperature (250-300℃).
[0005] At present, methyl diphenyl phosphate is mostly synthesized by the latter two methods. However, due to the problems of expensive catalyst, safety risks of halogenated alkane and high reaction temperature in the existing methods, it is necessary to develop a preparation method of methyl diphenyl phosphate with high safety, relatively mild reaction conditions and high purity. SUMMARY
[0006] To solve the above technical problems, the present application provides a synthesis method of methyl diphenyl phosphate. The preparation method provided by the present application can avoid the use of halogenated alkane by using a compounded catalyst, the reaction temperature is relatively mild, and the purity is not lower than that of the prior art, thereby solving the problems of the existing preparation methods, such as more by-products, high reaction temperature and safety risks of halogenated alkane as a catalyst.
[0007] To achieve the above purpose, the present application adopts the following technical solutions:
[0008] The present application provides a synthesis method of methyl diphenyl phosphate, which comprises the following steps: mixing triphenyl phosphite, trimethyl phosphite, phenol salt and metal oxide, and performing ester exchange reaction to obtain the methyl diphenyl phosphate.
[0009] The present application introduces phenolate and metal oxide as a complex catalyst to catalyze the ester exchange reaction of triphenyl phosphite and trimethyl phosphite to obtain methyl diphenyl phosphate. The method avoids the use of halogenated alkane, improves the safety of the reaction, reduces the temperature of the reaction, and at the same time ensures that the reaction has high yield and purity, and has good application prospect.
[0010] Preferably, the phenolate is selected from sodium phenolate and / or tetraphenylphosphonium phenolate.
[0011] Preferably, the metal oxide is selected from any one or a combination of at least two of zinc oxide, magnesium oxide or dibutyl tin oxide.
[0012] Preferably, the molar ratio of triphenyl phosphite, trimethyl phosphite, phenolate and metal oxide is 1:(0.5-0.7):(0.0005-0.0015):(0.001-0.003).
[0013] For example, (0.5-0.7) can be 0.5, 0.55, 0.6, 0.65, 0.7, etc.; (0.0005-0.0015) can be 0.0005, 0.0008, 0.001, 0.0012, 0.0015, etc.; (0.001-0.003) can be 0.001, 0.0015, 0.002, 0.0025, 0.003, etc.
[0014] For example, the molar ratio of triphenyl phosphite, trimethyl phosphite, phenolate and metal oxide can be 1:0.6:0.001:0.002, 1:0.5:0.0005:0.003, 1:0.7:0.0015:0.001, 1:0.6:0.0012:0.002, etc.
[0015] Preferably, the ester exchange reaction is carried out in the absence of a solvent.
[0016] Preferably, the temperature of the ester exchange reaction is 170-250℃ (for example, it can be 170℃, 180℃, 200℃, 220℃, 240℃, 250℃, etc.), and the time is 6-12h (for example, it can be 6h, 8h, 9h, 10h, 11h, 12h, etc.).
[0017] Preferably, the temperature of the ester exchange reaction is 200-230℃, and the time is 6-10h.
[0018] The present application can reduce the temperature of the ester exchange reaction in the traditional preparation process of methyl diphenyl phosphate to a certain extent, and the reaction conditions are relatively mild.
[0019] Preferably, the transesterification reaction is followed by a post-treatment step.
[0020] Preferably, the post-treatment step comprises recrystallization.
[0021] Preferably, the recrystallization employs a solvent selected from the group consisting of ester solvents and / or ether solvents.
[0022] Preferably, the recrystallization employs a solvent selected from the group consisting of ethyl acetate, methyl formate or methyl tert-butyl ether.
[0023] On the basis of common general knowledge in the art, the above-mentioned preferred conditions can be combined in any manner, i.e. to obtain preferred embodiments of the present application.
[0024] Compared with the prior art, the present application has at least the following beneficial effects:
[0025] The present application provides a synthesis method of methyl diphenyl phosphate, which replaces halogenated alkane with a complex catalyst of phenolate and metal oxide, overcomes the shortcomings of halogenated alkane, such as safety risk, multiple by-products, harsh reaction conditions, low yield, etc., and to some extent reduces the required reaction temperature, and the method can obtain a product with high purity. BRIEF DESCRIPTION OF DRAWINGS
[0026] Figure 1 is the H NMR spectrum of the methyl diphenyl phosphate in Example 1. 1 H NMR spectrum.
[0027] Figure 2 is the H NMR spectrum of the methyl diphenyl phosphate in Example 2. 1 H NMR spectrum. DETAILED DESCRIPTION
[0028] In order to facilitate the understanding of the present application, the present application is illustrated by the following examples. It should be understood by those skilled in the art that the examples are only to help understand the present application, and should not be regarded as specific limitations of the present application.
[0029] The purity in the present application is measured by liquid chromatography.
[0030] Example 1
[0031] The present embodiment provides a synthesis method of methyl diphenyl phosphate:
[0032] In a 250 mL three-necked flask equipped with a stirrer, triphenyl phosphite (60 g, 0.19 mol), trimethyl phosphite (16.13 g, 0.13 mol), tetraphenylphosphonium phenoxide (0.06 g, 0.00015 mol), and zinc oxide (0.015 g, 0.00019 mol) were added. The mixture was heated to 200 °C under nitrogen protection and kept for 7 h. The reaction was monitored by liquid chromatography until the raw material was substantially converted. The mixture was cooled to 70 °C, and ethyl acetate was added for recrystallization. The mixture was filtered while hot, and then cooled for crystallization. The mixture was filtered to obtain white methyl diphenyl phosphate crystals (63.49 g) with a yield of 85.02% and a purity of 97.49%.
[0033] Synthesis of methyl diphenyl phosphate 1 The H NMR (400 MHz, chloroform-d) spectrum is shown in Figure 1
[0034] Example 2
[0035] This example provides a method for synthesizing methyl diphenyl phosphate:
[0036] In a 250 mL three-necked flask equipped with a stirrer, triphenyl phosphite (50 g, 0.16 mol), trimethyl phosphite (10.00 g, 0.081 mol), sodium phenoxide (0.025 g, 0.00014 mol), and zinc oxide (0.013 g, 0.00016 mol) were added. The mixture was heated to 200 °C under nitrogen protection and kept for 7 h. The reaction was monitored by liquid chromatography until the raw material was substantially converted. The mixture was cooled to 70 °C, and ethyl acetate was added for recrystallization. The mixture was filtered while hot, and then cooled for crystallization. The mixture was filtered to obtain white methyl diphenyl phosphate crystals (51.78 g) with a yield of 81.66% and a purity of 96.49%.
[0037] Synthesis of methyl diphenyl phosphate 1 The H NMR (400 MHz, chloroform-d) spectrum is shown in Figure 2
[0038] Example 3
[0039] This example provides a method for synthesizing methyl diphenyl phosphate:
[0040] Into a 250 mL three-necked flask equipped with a stirrer, triphenyl phosphite (60 g, 0.19 mol), trimethyl phosphite (16.13 g, 0.13 mol), tetraphenylphosphonium phenoxide (0.08 g, 0.00019 mol), magnesium oxide (0.015 g, 0.00038 mol) were added, and the mixture was heated to 200 °C under nitrogen protection and kept for 6 h. The reaction was monitored by liquid chromatography until the starting material was substantially converted. The mixture was cooled to 70 °C, and ethyl acetate was added for recrystallization. The mixture was filtered while hot, and then cooled to crystallize. The product was filtered to obtain white crystals of methyl diphenyl phosphate (65.55 g, 87.05% yield, 97.03% purity).
[0041] Example 4
[0042] This example provides a method for synthesizing methyl diphenyl phosphate, which differs from Example 1 only in that tetraphenylphosphonium phenoxide is replaced by an equimolar amount of sodium phenoxide. The other conditions are the same as in Example 1. Methyl diphenyl phosphate (64.77 g) is obtained in a yield of 86.01% and a purity of 96.56%.
[0043] Example 5
[0044] This example provides a method for synthesizing methyl diphenyl phosphate, which differs from Example 1 only in that zinc oxide is replaced by an equimolar amount of magnesium oxide. The other conditions are the same as in Example 1. Methyl diphenyl phosphate (63.85 g) is obtained in a yield of 84.79% and a purity of 98.14%.
[0045] Example 6
[0046] This example provides a method for synthesizing methyl diphenyl phosphate, which differs from Example 1 only in that zinc oxide is replaced by an equimolar amount of dibutyl tin oxide. The other conditions are the same as in Example 1. Methyl diphenyl phosphate (60.14 g) is obtained in a yield of 79.86% and a purity of 97.56%.
[0047] Comparative Example 1
[0048] This comparative example provides a method for synthesizing methyl diphenyl phosphate, which differs from Example 1 only in that tetraphenylphosphonium phenoxide is not added, and its molar amount is distributed to zinc oxide. The other conditions are the same as in Example 1. Methyl diphenyl phosphate (41.49 g) is obtained in a yield of 55.10% and a purity of 96.44%.
[0049] Comparative Example 2
[0050] This comparative example provides a method for synthesizing methyl diphenyl phosphate, which differs from Example 1 only in that zinc oxide is not added, and its molar amount is distributed to tetraphenylphosphonium sodium salt. The other conditions are the same as in Example 1. Methyl diphenyl phosphate (45.37 g) is obtained in a yield of 60.25% and a purity of 97.24%.
[0051] The yield and purity of the above examples and comparative examples are summarized in Table 1.
[0052] Table 1
[0053] Group Purity (%) Yield (%) Example 1 95.49 85.02 Example 2 96.49 81.66 Example 3 97.03 87.05 Example 4 96.56 86.01 Example 5 98.14 84.79 Example 6 97.56 79.86 Comparative Example 1 96.44 55.10 Comparative Example 2 97.24 60.25
[0054] As can be seen from the data in Table 1, the application uses a complex catalyst of phenolate and metal oxide to replace the halogenated alkane catalyst, which not only improves the safety of the synthesis reaction, but also ensures a high yield and purity.
[0055] The applicant states that the above is only a specific embodiment of the application, but the protection scope of the application is not limited thereto. It should be understood by those skilled in the art that any changes or replacements within the technical scope disclosed by the application can be easily thought of by those skilled in the art, and all fall within the protection scope and disclosure scope of the application.
Claims
1. A method for synthesizing methyl diphenyl phosphate, characterized in that: The synthesis method comprises the following steps: mixing triphenyl phosphite, trimethyl phosphite, phenolate and metal oxide, and performing an ester exchange reaction to obtain the methyl diphenyl phosphate.
2. The synthesis method according to claim 1, wherein The phenolate is selected from sodium phenolate and / or tetraphenylphosphine phenolate.
3. The synthesis method according to claim 1 or 2, characterized in that The metal oxide is selected from any one of zinc oxide, magnesium oxide or dibutyltin oxide, or a combination of at least two thereof.
4. The synthesis method according to any one of claims 1 to 3, characterized in that The molar ratio of triphenyl phosphite, trimethyl phosphite, phenolate and metal oxide is 1:(0.5-0.7):(0.0005-0.0015):(0.001-0.003).
5. The synthesis method according to any one of claims 1 to 4, characterized in that The transesterification reaction is carried out in the absence of a solvent.
6. The synthesis method according to any one of claims 1 to 5, characterized in that The temperature of the transesterification reaction is 170-250° C., and the time is 6-12 hours.
7. The synthesis method according to claim 6, characterized in that The temperature of the transesterification reaction is 200-230° C., and the time is 6-10 hours.
8. The synthesis method according to any one of claims 1 to 7, characterized in that The transesterification reaction further includes a post-processing step; Preferably, the post-treatment step comprises recrystallization.
9. The synthesis method according to claim 8, characterized in that The solvent used in the recrystallization is an ester solvent and / or an ether solvent.
10. The synthesis method according to claim 9, characterized in that The solvent used in the recrystallization is selected from any one of ethyl acetate, methyl formate and methyl tert-butyl ether, or a combination of at least two thereof.