Synthesis method of BDP with low TPP content

Abstract

The invention relates to the technical field of bisphenol A bis (diphenyl phosphate) synthesis, in particular to a synthesis method of BDP with low TPP content, which at least comprises the following steps: taking a phosphoryl chloride reaction solution as a raw material, controlling the dropwise adding temperature and the dropwise adding time, dropwise adding phenol into a container containing the phosphoryl chloride reaction solution, and extracting negative pressure in the dropwise adding process; the method comprises the following steps: dropwise adding TPP, heating after dropwise adding, controlling the degassing pressure and preserving heat to obtain a BDP crude product, and refining the BDP crude product to obtain a BDP product, thereby effectively reducing the TPP content, improving the BDP product quality and better meeting the actual production requirements by optimizing the reaction conditions.

Description

Technical Field

[0001] This invention relates to the field of bisphenol A bis(diphenyl phosphate) synthesis technology, specifically a method for synthesizing BDP with low TPP content. Background Technology

[0002] Bisphenol A bis(diphenyl phosphate), abbreviated as BDP, is an aromatic oligophosphate based on bisphenol A launched by AkzoNobel Chemicals. This product has better thermal stability and hydrolytic stability than other organic aromatic phosphates and is widely used in ABS (acrylonitrile-butadiene-styrene), PC (polycarbonate), PA (polyamide), and SBS (styrene-butadiene-styrene block copolymer), especially in improving the flame retardant properties of PC / ABS blends. Current industrial production methods for BDP, such as the preparation method of the flame retardant bisphenol A bis(diphenyl phosphate) disclosed in Chinese patent application (publication number CN101456879A) and the preparation method of the flame retardant bisphenol A-bis(diphenyl phosphate) disclosed in Chinese patent application (publication number CN109912646A), all involve the following two-step reaction: Step 1: Phosphorus oxychloride reacts with bisphenol A under Lewis acid catalysis, and excess phosphorus oxychloride is removed under reduced pressure to obtain the intermediate phosphorus chloride; Step 2: Phosphorus chloride undergoes a condensation reaction with phenol, and the byproduct hydrogen chloride is removed under high vacuum after the reaction is complete. In this process, because phosphorus oxychloride cannot be completely removed in the first step, residual phosphorus oxychloride reacts with phenol to form triphenyl phosphate (TPP), even under low phosphorus oxychloride residue conditions. Given the adverse effects of TPP on organisms, there is an urgent need for an effective and reasonable method to minimize the TPP content in BDP. Summary of the Invention

[0003] To address the aforementioned issues, this invention provides a method for synthesizing BDP with low TPP content. By optimizing reaction conditions, the TPP content is effectively reduced, thereby improving the quality of BDP products and better meeting actual production needs.

[0004] This invention provides a method for synthesizing BDP with low TPP content, comprising at least the following steps: using phosphoryl chloride reaction solution as raw material, controlling the dropping temperature and dropping time, adding phenol dropwise to a container containing phosphoryl chloride reaction solution, and drawing a negative pressure during the dropping process; after the dropping is completed, raising the temperature, controlling the degassing pressure and keeping the temperature to obtain crude BDP, and refining the crude BDP to obtain the BDP product.

[0005] This invention optimizes the reaction conditions between phosphoryl chloride and phenol, ensuring that phosphoryl chloride and phenol are fully isolated from moisture while negative pressure is applied. This guarantees the yield of BDP product while effectively reducing the TPP content in the product. In particular, controlling the negative pressure to -0.05 to -0.01 MPa effectively balances the product yield and TPP content, increasing the BDP product yield from 94.11% to over 96% while maintaining the TPP content in the product below 0.8%.

[0006] In one embodiment, the phosphoryl chloride reaction solution is obtained by reacting phosphorus oxychloride with bisphenol A under the catalysis of a Lewis acid.

[0007] In one embodiment, the preparation steps of the phosphoryl chloride reaction solution include: adding 200 parts by weight of fresh phosphorus oxychloride to a reaction flask, adding 2.5 parts by weight of aluminum trichloride, heating to 40°C to dissolve, continuously adding 60-75 parts by weight of bisphenol A to the reaction flask through a star-shaped feeder, controlling the reaction temperature at 80-100°C, absorbing the generated hydrogen chloride gas using an absorption bottle, reacting for 4-6 hours, and after the reaction is completed, removing the remaining phosphorus oxychloride under high vacuum conditions to obtain the phosphoryl chloride reaction solution.

[0008] The preparation steps of the phosphoryl chloride reaction solution include: adding 200 parts by weight of fresh phosphorus oxychloride to a reaction flask, adding 1.5-4 parts by weight of aluminum trichloride, heating to 35-45°C to dissolve, continuously adding 68 parts by weight of bisphenol A to the reaction flask through a star-shaped feeder, controlling the reaction temperature at 90°C, absorbing the generated hydrogen chloride gas using an absorption bottle, reacting for 5 hours, and after the reaction is completed, removing the remaining phosphorus oxychloride under high vacuum conditions to obtain the phosphoryl chloride reaction solution.

[0009] In one embodiment, the mass ratio of the phosphoryl chloride reaction solution to phenol is (180-220):(140-180).

[0010] In one embodiment, the mass ratio of the phosphoryl chloride reaction solution to phenol is (200.07-200.44):(160.05-160.14).

[0011] In one embodiment, the dropping temperature is 50-100°C.

[0012] In one embodiment, the dropping temperature is 60-90°C.

[0013] In one embodiment, the dropping temperature can be 60°C, 70°C, 80°C, or 90°C.

[0014] In one embodiment, the dripping time is 1.5-2.5 hours.

[0015] In one embodiment, the dripping time can be 1.5h, 2h, or 2.5h.

[0016] In one embodiment, the pressure at which the negative pressure is extracted is -0.05 to -0.01 MPa.

[0017] In one embodiment, the pressure at which the negative pressure is extracted can be -0.05MPa, -0.04MPa, -0.03MPa, -0.02MPa, or -0.01MPa.

[0018] In one embodiment, the temperature for heating is 140-170°C.

[0019] In one embodiment, the temperature for heating is 145-165°C.

[0020] In one embodiment, the temperature for heating can be 145°C, 150°C, 155°C, 160°C, or 165°C.

[0021] In one embodiment, the degassing pressure is -0.1 to -0.05 MPa.

[0022] In one embodiment, the degassing pressure can be -0.1MPa, -0.09MPa, -0.08MPa, -0.07MPa, -0.06MPa, or -0.05MPa.

[0023] In one embodiment, the heat preservation time is 3-5 hours.

[0024] Furthermore, by comprehensively controlling the dropping temperature, dropping time, heating temperature, and degassing pressure, this invention further improves the yield while reducing the formation of TPP. While maintaining the BDP product yield at 96.46%, the TPP content can be reduced to 0.329%.

[0025] In one embodiment, the refining step includes:

[0026] (1) Add solvent and alkaline solution to crude BDP, stir while controlling the temperature, and take organic phase A after separation;

[0027] (2) Add an alkaline solution to organic phase A, stir while controlling the temperature, and take organic phase B after separation.

[0028] (3) Add water to organic phase B, control the temperature and stir, and take organic phase C in layers;

[0029] (4) Add water to organic phase C, control the temperature and stir, and take organic phase D in layers;

[0030] (5) Organic phase D is subjected to high-temperature desolventizing treatment under negative pressure to obtain BDP product.

[0031] In one embodiment, the amount of solvent added is 20-40% of the crude BDP product.

[0032] In one embodiment, the solvent includes at least toluene and methylcyclohexane.

[0033] In one embodiment, the mass ratio of toluene to methylcyclohexane is (0.5-2):1.

[0034] In one embodiment, the amount of alkaline aqueous solution added in step (1) is 20-40% based on the total mass of crude BDP and solvent.

[0035] In one embodiment, the amount of alkaline aqueous solution added in step (2) is 20-40% based on the mass of organic phase A.

[0036] In one embodiment, the alkaline aqueous solution is a 2-10 wt% sodium hydroxide aqueous solution.

[0037] In one embodiment, the alkaline aqueous solution is a 3-8 wt% sodium hydroxide aqueous solution.

[0038] In one embodiment, the amount of water added in step (3) is 40-60% based on the mass of organic phase B.

[0039] In one embodiment, the amount of water added in step (4) is 40-60% based on the mass of organic phase C.

[0040] In one embodiment, the temperature of the temperature-controlled stirring is 60-80°C, and the time is 20-40 minutes.

[0041] The negative pressure is -0.1 to -0.05 MPa.

[0042] In one embodiment, the temperature of the high-temperature desolventizing treatment is 110-130°C.

[0043] The synthesis method provided by this invention is simple to operate, easy to control, and has high production efficiency, enabling large-scale industrial production.

[0044] Beneficial effects

[0045] 1. This invention provides a method for synthesizing BDP with low TPP content. By optimizing reaction conditions, the TPP content is effectively reduced, the quality of BDP products is improved, and actual production needs are better met.

[0046] 2. This invention optimizes the reaction conditions between phosphoryl chloride and phenol, ensuring that phosphoryl chloride and phenol are fully isolated from moisture while being subjected to negative pressure, thereby guaranteeing the yield of BDP product and effectively reducing the TPP content in the product.

[0047] 3. By controlling the negative pressure of extraction to -0.05 to -0.01 MPa, this invention effectively balances the product yield and the TPP content in the product, thereby increasing the BDP product yield from 94.11% to over 96% while ensuring that the TPP content in the product is below 0.8%.

[0048] 4. By comprehensively controlling the dropping temperature, dropping time, heating temperature and degassing pressure, this invention further improves the yield while reducing the formation of TPP. While maintaining the BDP product yield at 96.46%, the TPP content can be reduced to 0.329%.

[0049] 5. The synthesis method provided by this invention is simple to operate, easy to control, and has high production efficiency, enabling large-scale industrial production. Detailed Implementation

[0050] Example 1

[0051] Example 1 of the present invention provides a method for synthesizing BDP with low TPP content, comprising the following steps:

[0052] Using phosphoryl chloride reaction solution (200.25g) as raw material, phenol (160.07g) was added dropwise to a container containing phosphoryl chloride reaction solution, with the temperature and time controlled. During the dropwise addition, negative pressure was drawn. After the dropwise addition was completed, the temperature was raised and the degassing pressure was controlled to keep the temperature to obtain crude BDP. After the crude BDP was purified, BDP product (262.48g) was obtained.

[0053] The phosphoryl chloride reaction solution is obtained by reacting phosphorus oxychloride with bisphenol A under the catalysis of a Lewis acid.

[0054] The preparation steps of the phosphoryl chloride reaction solution include: adding 200 parts by weight of fresh phosphorus oxychloride to a reaction flask, adding 1.5-4 parts by weight of aluminum trichloride, heating to 35-45°C to dissolve, continuously adding 68 parts by weight of bisphenol A to the reaction flask through a star-shaped feeder, controlling the reaction temperature at 90°C, absorbing the generated hydrogen chloride gas using an absorption bottle, reacting for 5 hours, and after the reaction is completed, removing the remaining phosphorus oxychloride under high vacuum conditions to obtain the phosphoryl chloride reaction solution.

[0055] The dropping temperature is 90°C.

[0056] The dripping time is 2 hours.

[0057] The pressure at which the negative pressure is extracted is -0.04 MPa.

[0058] The temperature for the heating is 155°C.

[0059] The degassing pressure is -0.05 MPa.

[0060] The heat preservation time is 4 hours.

[0061] The refining steps include:

[0062] (1) Add solvent and 8wt% sodium hydroxide aqueous solution to crude BDP, stir at 70℃ for 30 min, and take organic phase A after separation.

[0063] (2) Add 3wt% sodium hydroxide aqueous solution to organic phase A, stir at 70℃ for 30 min, and take organic phase B after separation.

[0064] (3) Add water to organic phase B, control the temperature at 70℃ and stir for 30 min, then separate the organic phase C into layers;

[0065] (4) Add water to organic phase C, control the temperature at 70℃ and stir for 30 min, then separate the organic phase D into layers;

[0066] (5) Organic phase D is subjected to high-temperature desolventizing treatment under negative pressure to obtain BDP product.

[0067] The amount of 8 wt% sodium hydroxide aqueous solution added in step (1) is 30% based on the total mass of crude BDP and solvent.

[0068] Based on the mass of organic phase A, the amount of 3wt% sodium hydroxide aqueous solution added in step (2) is 30%.

[0069] The amount of water added in step (3) is 50% based on the mass of organic phase B.

[0070] The amount of water added in step (4) is 50% based on the mass of organic phase C.

[0071] Example 2

[0072] Example 2 of the present invention provides a method for synthesizing BDP with low TPP content. The specific implementation method is the same as that of Example 1, except that it includes the following steps:

[0073] Using phosphoryl chloride reaction solution (200.13g) as raw material, phenol (160.09g) was added dropwise to a container containing phosphoryl chloride reaction solution, with the dropping temperature and time controlled. During the dropping process, negative pressure was drawn. After the dropping was completed, the temperature was raised, and the degassing pressure was controlled to maintain the temperature to obtain crude BDP. After refining the crude BDP, BDP product (268.17g) was obtained. The pressure of the negative pressure drawn was -0.01MPa.

[0074] Example 3

[0075] Example 3 of the present invention provides a method for synthesizing BDP with low TPP content. The specific implementation method is the same as that of Example 1, except that it includes the following steps:

[0076] Using phosphoryl chloride reaction solution (200.44 g) as raw material, phenol (160.14 g) was added dropwise to a container containing phosphoryl chloride reaction solution, with the dropping temperature and time controlled. During the dropping process, negative pressure was drawn. After the dropping was completed, the temperature was raised and the degassing pressure was controlled to keep the temperature to obtain crude BDP. After refining the crude BDP, BDP product (266.51 g) was obtained. The dropping temperature was 70°C.

[0077] Example 4

[0078] Example 4 of the present invention provides a method for synthesizing BDP with low TPP content. The specific implementation method is the same as that of Example 1, except that it includes the following steps:

[0079] Using phosphoryl chloride reaction solution (200.07g) as raw material, phenol (160.05g) was added dropwise to a container containing phosphoryl chloride reaction solution, with the dropping temperature and time controlled. During the dropping process, negative pressure was drawn. After the dropping was completed, the temperature was raised, and the degassing pressure was controlled to maintain the temperature to obtain crude BDP. After refining the crude BDP, BDP product (264.76g) was obtained. The pressure of the negative pressure drawn was -0.02MPa.

[0080] Comparative Example 1

[0081] Comparative Example 1 of the present invention provides a method for synthesizing BDP with low TPP content. The specific implementation method is the same as that of Example 1, except that it includes the following steps:

[0082] Using phosphoryl chloride reaction solution (200.04 g) and water (0.36 g) as raw materials, phenol (160.07 g) was added dropwise to a container containing phosphoryl chloride reaction solution while controlling the dropping temperature and time. During the dropping process, negative pressure was drawn. After the dropping was completed, the temperature was raised and the degassing pressure was controlled to keep the temperature to obtain crude BDP. After refining the crude BDP, BDP product (257.44 g) was obtained.

[0083] Comparative Example 2

[0084] Comparative Example 2 of the present invention provides a method for synthesizing BDP with low TPP content. The specific implementation method is the same as that of Example 1, except that it includes the following steps:

[0085] Using phosphoryl chloride reaction solution (200.11g) as raw material, phenol (160.27g) was added dropwise to a container containing phosphoryl chloride reaction solution, with controlled dropping temperature and dropping time (no negative pressure extraction step was performed during the dropping process); after the dropping was completed, the temperature was raised and the degassing pressure was controlled to maintain the temperature to obtain crude BDP product. After refining the crude BDP product, BDP product (265.53g) was obtained.

[0086] Comparative Example 3

[0087] Comparative Example 3 of the present invention provides a method for synthesizing BDP with low TPP content. The specific implementation method is the same as that of Example 1, except that it includes the following steps:

[0088] Using phosphoryl chloride reaction solution (200.55g) as raw material, phenol (160.44g) was added dropwise to a container containing phosphoryl chloride reaction solution, with the dropping temperature and time controlled. During the dropping process, negative pressure was drawn. After the dropping was completed, the temperature was raised, and the degassing pressure was controlled to maintain the temperature to obtain crude BDP. After refining the crude BDP, BDP product (256.08g) was obtained. The pressure of the negative pressure drawn was -0.08MPa.

[0089] Comparative Example 4

[0090] Comparative Example 4 of the present invention provides a method for synthesizing BDP with low TPP content. The specific implementation method is the same as that of Example 1, except that it includes the following steps:

[0091] Using phosphoryl chloride reaction solution (200.32g) as raw material, phenol (160.08g) was added dropwise to a container containing phosphoryl chloride reaction solution, with the drop temperature and time controlled. During the dropwise addition, negative pressure was drawn. After the dropwise addition was completed, the temperature was raised, and the degassing pressure was controlled to maintain the temperature to obtain crude BDP. The crude BDP was then purified to obtain BDP product (261.24g). The temperature raised was 125℃.

[0092] Comparative Example 5

[0093] Comparative Example 5 of the present invention provides a method for synthesizing BDP with low TPP content. The specific implementation method is the same as that of Example 1, except that it includes the following steps:

[0094] Using phosphoryl chloride reaction solution (200.17g) as raw material, phenol (160.04g) was added dropwise to a container containing phosphoryl chloride reaction solution, with the dropping temperature and time controlled. During the dropping process, negative pressure was drawn. After the dropping was completed, the temperature was raised and the degassing pressure was controlled to keep the temperature to obtain crude BDP. After the crude BDP was purified, BDP product (263.21g) was obtained. The dropping time was 1 hour.

[0095] Performance testing

[0096] 1. The yields of BDP products obtained in each embodiment and comparative example were calculated based on the following formulas, and the results are shown in Table 1.

[0097] Yield = (mass of phosphoryl chloride reaction solution / average molecular weight of phosphoryl chloride) × average molecular weight of BDP × 100%.

[0098] Among them, the average molecular weight of phosphoryl chloride is 541.39, and the average molecular weight of BDP is 741.19.

[0099] 2. The components of the BDP products obtained in each example and comparative example were analyzed by liquid chromatography, and the results are shown in Table 1.

[0100] Table 1

[0101]

[0102] As can be seen from the data in Table 1, compared with Comparative Examples 1-5, the synthesis method of low TPP content BDP provided in Examples 1-4 achieved a yield of over 96% and a TPP content of less than 8% for the preparation of BDP products.

Claims

1. A method for synthesizing BDP with low TPP content, characterized in that, At least the following steps are included: Using phosphoryl chloride reaction solution as raw material, phenol is added dropwise to a container containing phosphoryl chloride reaction solution by controlling the dropping temperature and dropping time. During the dropping process, negative pressure is drawn. After the dropping is completed, the temperature is raised and the degassing pressure is controlled to keep the temperature to obtain crude BDP. After refining the crude BDP, the BDP product is obtained.

2. The method for synthesizing low TPP content BDP according to claim 1, characterized in that, The pressure at which the negative pressure is extracted is -0.05 to -0.01 MPa.

3. The method for synthesizing low TPP content BDP according to claim 1, characterized in that, The temperature for the heating is 140-170℃.

4. The method for synthesizing low TPP content BDP according to claim 1, characterized in that, The dripping time is 1.5-2.5 hours.

5. The method for synthesizing low TPP content BDP according to claim 4, characterized in that, The dropping temperature is 50-100℃.

6. The method for synthesizing low TPP content BDP according to claim 1, characterized in that, The phosphoryl chloride reaction solution is obtained by reacting phosphorus oxychloride with bisphenol A under the catalysis of a Lewis acid.

7. The method for synthesizing low TPP content BDP according to claim 1, characterized in that, The degassing pressure is -0.1 to -0.05 MPa.

8. The method for synthesizing low TPP content BDP according to claim 1, characterized in that, The refining steps include: (1) Add solvent and alkaline solution to crude BDP, stir while controlling the temperature, and take organic phase A after separation; (2) Add an alkaline solution to organic phase A, stir while controlling the temperature, and take organic phase B after separation. (3) Add water to organic phase B, control the temperature and stir, and take organic phase C in layers; (4) Add water to organic phase C, control the temperature and stir, and take organic phase D in layers; (5) Organic phase D is subjected to high-temperature desolventizing treatment under negative pressure to obtain BDP product.

9. The method for synthesizing low TPP content BDP according to claim 8, characterized in that, The solvent includes at least toluene and methylcyclohexane.

10. The method for synthesizing low TPP content BDP according to claim 9, characterized in that, The mass ratio of toluene to methylcyclohexane is (0.5-2):1.

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