A preparation method of BDP

Abstract

The present invention provides a method for preparing BDP, comprising the following steps: (a) mixing bisphenol A and excess phosphorus oxychloride in the presence of a catalyst, reacting to prepare a BDP intermediate; and (b) adding phenol to carry out a capping reaction. The structural formula of the catalyst is as follows: wherein M is selected from one or more of iron, copper, iridium, and scandium. The catalyst of the present invention can combine with oxygen more rapidly to increase the esterification reaction rate; the catalyst can also inhibit the ester exchange in the capping reaction to a certain extent, thereby reducing the yield of half esters and preventing the generation of BDP polymers.

Description

Technical Field

[0001] The invention relates to the field of organic synthesis, and in particular to a method for preparing BDP. Background Art

[0002] Phosphate flame retardants are a type of halogen-free, low-smoke, low-toxic environmentally friendly flame retardants. They have good compatibility with polymers and are widely used. However, most phosphates are liquids with small molecular weights, high volatility, and low heat resistance, which affect their flame retardant effects and flame retardant durability. However, condensed bisphosphates with large molecular weights, high phosphorus content, and symmetrical structures can overcome the above defects, gradually showing advantages in applications, and are receiving more and more attention.

[0003] Flame retardant BDP is a plasticizer with flame retardant properties, mainly used in thermoplastic engineering plastics. It has excellent thermal stability and low volatility, is superior to traditional flame retardants such as triphenyl phosphate and alkylphenyl phosphate, and is an important organic phosphorus flame retardant.

[0004] At present, the mainstream industrialization scheme of BDP is generally: first, excess phosphorus oxychloride is reacted with bisphenol A under the catalysis of Lewis acid catalyst to obtain bisphenol A tetrachlorobisphosphate. As shown in Formula I, then the excess phosphorus oxychloride is removed by reduced pressure distillation, and finally phenol is used for end-capping reaction to obtain BDP. For example, the records in the patents CN101348500A, CN1414968A, CN1367788A, and CN101456879A.

[0005]

[0006] The above formula I is the key precursor for synthesizing BDP, and the selectivity of its synthesis reaction directly determines the yield of flame retardant BDP. The prior art mostly uses Lewis acid as a catalyst for esterification reaction, but the applicant found that when using Lewis acid catalysis, although a higher raw material conversion rate can be obtained, it will lead to the production of polymers, thereby affecting the content of BDP monomer. In addition, the use of Lewis acid catalyst will lead to the decomposition of bisphenol A, thereby reducing its chromaticity, and it is very easy to emulsify during the post-processing process, resulting in a large loss of product yield. Summary of the invention

[0007] The purpose of the present invention is to provide a method for preparing BDP to improve product yield and selectivity.

[0008] In order to achieve the above invention object, the technical solution of the present invention is as follows:

[0009] A method for preparing BDP comprises the following steps:

[0010] (a) Mixing bisphenol A and excess phosphorus oxychloride in the presence of a catalyst to react and prepare a BDP intermediate

[0011] (b) Add phenol to carry out end-capping reaction.

[0012] As a preferred solution, the catalyst is a metal amine coordination catalyst.

[0013] As a preferred solution, the structural formula of the catalyst is as follows: Wherein, M is selected from one or more of iron, copper, iridium and scandium.

[0014] The method for preparing the catalyst of the present invention comprises the following steps:

[0015] (1) Reaction of 4-amino-1-butanol with tert-butyldimethylsilyl chloride TBSCl;

[0016] (2) then adding methyl acrylate dropwise to react and obtain a tertiary amine intermediate;

[0017] (3) The tertiary amine intermediate is dissolved in dichloromethane, a metal chloride is added, and the reaction is carried out until no solid is precipitated, and the catalyst is separated.

[0018]

[0019] In a preferred embodiment, in the step (1), the reaction time is 2 to 4 hours, preferably 3 hours.

[0020] In a preferred embodiment, in the step (2), after the reaction is completed, purification is performed using a chromatographic column.

[0021] In a preferred embodiment, the molar ratio of the 4-amino-1-butanol to the tert-butyldimethylsilyl chloride TBSCl is 1 to 3, preferably 1.5 to 2.8.

[0022] In a preferred embodiment, the molar ratio of 4-amino-1-butanol to methyl acrylate is 2 to 6, preferably 3 to 5.5.

[0023] In a preferred embodiment, the molar ratio of the 4-amino-1-butanol to the metal salt is 1-5, preferably 2-4.

[0024] The metal salt described in the present invention includes one or more of ferric chloride, iridium chloride, cupric chloride and scandium chloride.

[0025] In a preferred embodiment, the molar ratio of 4-amino-1-butanol to metal chloride is 1-5 to 2.5, preferably 2 to 4.

[0026] In a preferred embodiment, the molar ratio of the catalyst to bisphenol A is 0.02 to 0.005, preferably 0.01 to 0.003.

[0027] In a preferred embodiment, the molar ratio of phosphorus oxychloride to bisphenol A is 2.5 to 5.0, preferably 2.8 to 4.5.

[0028] In a preferred embodiment, in the step (a), the reaction temperature is 80-110°C.

[0029] In a preferred embodiment, in the step (a), the reaction time is 2 to 10 hours.

[0030] In a preferred embodiment, the step (a) is carried out under a nitrogen atmosphere.

[0031] In a preferred embodiment, in step (a), after the reaction is completed, the excess phosphorus oxychloride is removed by distillation through a conventional process, and the obtained reaction solution is directly used in the next step for end-capping reaction with phenol to obtain the BDP finished product.

[0032] In the preparation method of BDP of the present invention, a large sterically hindered tertiary amine is used to form a new catalyst by complexing with a metal. The catalyst has a positive electron distribution in the electron cloud distribution, and can more rapidly combine with oxygen in the first step of catalyzing the esterification reaction, thereby increasing the esterification reaction rate. The catalyst can also inhibit the ester exchange in the end-capping reaction to a certain extent, thereby reducing the yield of the half ester (bisphenol A (4-hydroxy-2,2-diphenyl phosphate)) and preventing the generation of BDP polymers. In addition, more organic components are not prone to emulsification in the subsequent treatment process, thereby increasing the separation efficiency of the BDP intermediate product, thereby greatly increasing the yield of the BDP intermediate product. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is the NMR spectrum of the dimethyl ester tertiary amine intermediate in the embodiment. DETAILED DESCRIPTION

[0034] In order to better understand the technical solution of the present invention, the content of the present invention is further described below in conjunction with the embodiments, but the content of the present invention is not limited to the following embodiments.

[0035] The following describes some of the raw materials used or may be used in the embodiments:

[0036] Phosphorus oxychloride: Alfa Aesar (China) Chemical Co., Ltd.

[0037] Bisphenol A: Shanghai En Chemical Technology Co., Ltd.

[0038] 4-Amino-1-butanol, TBSCl, methyl acrylate, pyridine: Shanghai MacLean Co., Ltd.;

[0039] Anhydrous scandium chloride, iridium chloride, ferric chloride, copper chloride: Shanghai Aladdin Biochemical Technology Co., Ltd.;

[0040] Liquid chromatograph: Agilent 1260; chromatographic column: ZORBAX SB phenyl; column temperature: 30°C; detector: 275 nm; flow rate: 1.0 ml / min; mobile phase: acetonitrile-water (80:20).

[0041] 1HNMR was measured using a Bruker AVANCE III 500 MHz NMR instrument.

[0042] Example 1

[0043] Add 27.042g 4-amino-1-butanol into a 250ml three-necked flask, heat to 60°C, add 49.74g TBSCl, react for 3h, then add 51.05g propylene formate dropwise, after TLC detection, purify by chromatographic column to obtain dimethyl ester tertiary amine intermediate The dimethyl ester tertiary amine intermediate was dissolved in dichloromethane, 40.34 g of cupric chloride was added, and the reaction was carried out until no solid was precipitated. 131 g of copper amine coordination catalyst was obtained by filtration, with a yield of 86%.

[0044] Add 110.82g of freshly distilled phosphorus oxychloride and 0.0388g of copper amine coordination catalyst to a 500mL four-necked bottle equipped with a stirrer, thermometer, dropper, hydrogen chloride trap and condenser, add 66g of bisphenol A at 75℃, stir, heat the reaction solution to 80℃, and react for 2h. Perform vacuum distillation at a liquid phase temperature of 140℃, and continue distillation at 140℃ for 0.5h when almost no phosphorus oxychloride is evaporated. A light yellow viscous liquid remains in the four-necked bottle. Add 108.83g of molten phenol at about 100℃ at one time, stir, and react at 100℃ for 3h to obtain a crude product. The crude ester was cooled to about 45°C, 98.75g toluene and 59.25g 3wt% hydrochloric acid solution were added, stirred for 0.5h, separated, and then 29.63g 5wt% sodium hydroxide solution was added, stirred and washed at 90°C for 0.5h, the water layer was separated, and the obtained product was washed with 49.38g water at about 80°C until neutral. Water was removed by vacuum distillation to obtain 182.50g of product, with a BDP yield of 91.14%, a BDP monomer content of 89.80%, a half ester content of 0.02%, and a polymer content of 10.18%.

[0045] Example 2

[0046] In a 250 ml three-necked flask, 27.042 g of 4-amino-1-butanol was added, and then heated to 60°C, 90.44 g of TBSCl was added, and the reaction was continued for 3 h. Then 76.57 g of propylene formate was added dropwise. After the reaction was completed by TLC detection, a tertiary amine intermediate was obtained by chromatography purification. The tertiary amine intermediate was dissolved in dichloromethane, and 145.98 g of ferric chloride was added. The reaction was continued until no solid was precipitated, and 121 g of copper amine coordination catalyst was obtained by filtration. The yield was 75%.

[0047] Add 124.12g of freshly distilled phosphorus oxychloride and 0.281g of iron amine coordination catalyst to a 500mL four-necked bottle equipped with a stirrer, thermometer, dropper, hydrogen chloride trap and condenser, add 66g of bisphenol A at 75℃, stir, heat the reaction solution to 90℃, and react for 2.5h. Perform vacuum distillation at a liquid phase temperature of 140℃, and continue distillation at 140℃ for 0.5h when almost no phosphorus oxychloride is evaporated. A light yellow viscous liquid remains in the four-necked bottle. Add 122.43g of molten phenol at about 100℃ at one time, stir, and react at 100℃ for 3.1h to obtain a crude product. The crude ester was cooled to about 45°C, 99.25g of toluene and 59.55g of 3wt% hydrochloric acid solution were added, stirred for 0.5h, separated, and then 29.78g of 5wt% sodium hydroxide solution was added, stirred and washed at 90°C for 0.5h, the water layer was separated, and the obtained product was washed with 49.63g of water at about 80°C until neutral. Water was removed by vacuum distillation to obtain 183.50g of product, with a BDP yield of 91.64%, a BDP monomer content of 88.90%, a half ester content of 0.04%, and a polymer content of 11.06%.

[0048] Example 3

[0049] 27.042g of 4-amino-1-butanol was added to a 250ml three-necked flask, and then heated to 60°C, 126.61g of TBSCl was added, and the reaction was continued for 3h. Then 127.62g of propylene formate was added dropwise. After the reaction was completed by TLC detection, a tertiary amine intermediate was obtained by chromatography purification. The tertiary amine intermediate was dissolved in dichloromethane, and 358.29g of iridium chloride was added. The reaction was continued until no solid was precipitated, and 108g of copper amine coordination catalyst was obtained by filtration. The yield was 53%.

[0050] Add 155.15g of freshly distilled phosphorus oxychloride and 0.258g of iridium amine coordination catalyst to a 500mL four-necked bottle equipped with a stirrer, thermometer, dropper, hydrogen chloride trap and condenser, add 66g of bisphenol A at 75℃, stir, heat the reaction solution to 85℃, and react for 2.2h. Perform vacuum distillation at a liquid phase temperature of 140℃, and continue distillation at 140℃ for 0.5h when almost no phosphorus oxychloride is evaporated. A light yellow viscous liquid remains in the four-necked bottle. Add 190.45g of molten phenol at about 100℃ at one time, stir, and react at 100℃ for 3.5h to obtain a crude product. The crude ester was cooled to about 45°C, 100.75g toluene and 60.455g 3wt% hydrochloric acid solution were added, stirred for 0.5h, separated, and then 30.23g 5wt% sodium hydroxide solution was added, stirred and washed at 90°C for 0.5h, the water layer was separated, and the obtained product was washed with 50.38g water at about 80°C until neutral. Water was removed by vacuum distillation to obtain 186.50g of product, with a BDP yield of 93.14%, a BDP monomer content of 89.20%, a half ester content of 0.03%, and a polymer content of 10.77%.

[0051] Example 4

[0052] In a 250 ml three-necked flask, 27.042 g of 4-amino-1-butanol was added, and then heated to 60°C, 135.66 g of TBSCl was added, and the reaction was continued for 3 h. Then 153.14 g of propylene formate was added dropwise. After the reaction was completed by TLC detection, a tertiary amine intermediate was obtained by chromatography purification. The tertiary amine intermediate was dissolved in dichloromethane, and 220.97 g of scandium chloride was added. The reaction was continued until no solid was precipitated, and 120 g of copper amine coordination catalyst was obtained by filtration. The yield was 76%.

[0053] Add 199.48g of freshly distilled phosphorus oxychloride and 0.437g of scandium amine coordination catalyst to a 500mL four-necked bottle equipped with a stirrer, thermometer, dropper, hydrogen chloride trap and condenser, and add 66g of bisphenol A at 75℃, stir, heat the reaction solution to 100℃, and react for 2.3h. Perform vacuum distillation at a liquid phase temperature of 140℃, and continue distillation at 140℃ for 0.5h when almost no phosphorus oxychloride is evaporated. A light yellow viscous liquid remains in the four-necked bottle. Add 217.66g of molten phenol at about 100℃, stir, and react at 100℃ for 3.6h to obtain a crude product. The crude ester was cooled to about 45°C, 97.40g toluene and 58.44g 3wt% hydrochloric acid solution were added, stirred for 0.5h, separated, and then 29.22g 5wt% sodium hydroxide solution was added, stirred and washed at 90°C for 0.5h, the water layer was separated, and the obtained product was washed with 48.70g water at about 80°C until neutral. Water was removed by vacuum distillation to obtain 179.80g of product, with a BDP yield of 89.79%, a BDP monomer content of 89.25%, a half ester content of 0.03%, and a polymer content of 10.72%.

[0054] Comparative Example 1

[0055] Add 110.82g of freshly distilled phosphorus oxychloride to a 500mL four-necked bottle equipped with a stirrer, thermometer, dropper, hydrogen chloride trap and condenser, and react at 75℃. Add 66g of bisphenol A, stir, heat the reaction solution to 110℃, and react for 5h. Perform vacuum distillation at a liquid phase temperature of 140℃. When almost no phosphorus oxychloride is evaporated, continue distillation at 140℃ for 0.5h. A light yellow viscous liquid remains in the four-necked bottle. Add 108.83g of molten phenol at about 100℃, stir, and react at 130℃ for 10h to obtain a crude product. The crude ester was cooled to about 45°C, 22.5g toluene and 13.5g 3wt% hydrochloric acid solution were added, stirred for 0.5h, separated, and then 6.75g 5wt% sodium hydroxide solution was added, stirred and washed at 90°C for 0.5h, the water layer was separated, and the obtained product was washed with 11.25g water at about 80°C until neutral. Water was removed by vacuum distillation to obtain 30g of product, with a BDP yield of 14.98%, a BDP monomer content of 50%, a half ester content of 6.5%, and a polymer content of 43.5%.

[0056] Comparative Example 2

[0057] Add 110.82g of freshly distilled phosphorus oxychloride and 0.1085g of dimethyl tertiary amine into a 500mL four-necked flask equipped with a stirrer, thermometer, dropper, hydrogen chloride trap and condenser. Add 66g of bisphenol A at 75℃, stir, heat the reaction solution to 110℃, and react for 6h. Perform vacuum distillation at a liquid temperature of 140℃. When almost no phosphorus oxychloride is evaporated, continue distillation at 140℃ for 0.5h. A light yellow viscous liquid remains in the four-necked bottle. Add 108.83g of molten phenol at about 100℃, stir, and react at 130℃ for 11h to obtain a crude product. Cool the crude ester to about 45℃, add 30.3g of toluene and 18.18g of 3wt% hydrochloric acid solution, stir for 0.5h, separate the liquid, then add 9.09g of 5wt% sodium hydroxide solution, stir and wash at 90℃ for 0.5h, separate the water layer, and wash the obtained product with 15.15g of water at about 80℃ until it is neutral. Water was removed by distillation under reduced pressure to obtain 45.6 g of product, with a BDP yield of 22.77%, a BDP monomer content of 60.20%, a half ester content of 5.5%, and a polymer content of 34.30%.

[0058] Comparative Example 3

[0059] Add 110.82g of newly distilled phosphorus oxychloride and 0.011g of copper chloride to a 500mL four-necked bottle equipped with a stirrer, a thermometer, a dropper, a hydrogen chloride trap and a condenser, and react at 75°C. Add 66g of bisphenol A, stir, heat the reaction solution to 110°C, and react for 5.5h. Perform vacuum distillation at a liquid phase temperature of 140°C. When almost no phosphorus oxychloride is evaporated, continue distillation at 140°C for 0.5h. A light yellow viscous liquid remains in the four-necked bottle. Add 108.83g of molten phenol at about 100°C at one time, stir, and react at 130°C for 10h to obtain a crude product. The crude ester was cooled to about 45°C, 41.95g toluene and 25.17g 3wt% hydrochloric acid solution were added, stirred for 0.5h, separated, and then 12.59g 5wt% sodium hydroxide solution was added, stirred and washed at 90°C for 0.5h, the water layer was separated, and the obtained product was washed with 20.98g water at about 80°C until neutral. Water was removed by vacuum distillation to obtain 68.9g of product, with a BDP yield of 34.41%, a BDP monomer content of 49.80%, a half ester content of 5.9%, and a polymer content of 44.30%.

Claims

1. A method for preparing BDP, comprising the following steps: (a) Mixing bisphenol A and excess phosphorus oxychloride in the presence of a catalyst to react and prepare a BDP intermediate (b) adding phenol to carry out end-capping reaction; The structural formula of the catalyst is as follows: Wherein, M is selected from one or more of iron, copper, iridium and scandium.

2. The method according to claim 1, characterized in that: The method for preparing the catalyst comprises the following steps: (1) Reaction of 4-amino-1-butanol with tert-butyldimethylsilyl chloride TBSCl; (2) then adding methyl acrylate dropwise to react and obtain a tertiary amine intermediate; (3) dissolving the tertiary amine intermediate in dichloromethane, adding a metal chloride, reacting until no solid precipitates, and separating to obtain a catalyst; The metal chloride includes one or more of ferric chloride, iridium chloride, copper chloride and scandium chloride.

3. The method according to claim 2, characterized in that The molar ratio of the 4-amino-1-butanol to TBSCl is 1-3.

4. The method according to claim 2, characterized in that: The molar ratio of the 4-amino-1-butanol to TBSCl is 1.5 to 2.

8.

5. The method according to claim 2, characterized in that: The molar ratio of the 4-amino-1-butanol to the methyl acrylate is 2-6.

6. The method according to claim 2, characterized in that The molar ratio of the 4-amino-1-butanol to methyl acrylate is 3 to 5.

5.

7. The method according to claim 2, characterized in that: The molar ratio of the 4-amino-1-butanol to the metal chloride is 1-5 to 2.

5.

8. The method according to claim 2, characterized in that: The molar ratio of the 4-amino-1-butanol to the metal chloride is 2-4.

9. The method according to claim 1, characterized in that: The molar ratio of the catalyst to bisphenol A is 0.02 to 0.

005.

10. The method according to claim 1, characterized in that The molar ratio of the catalyst to bisphenol A is 0.01 to 0.

003.

11. The method according to claim 1, characterized in that: The molar ratio of phosphorus oxychloride to bisphenol A is 2.5-5.

0.

12. The method according to claim 1, characterized in that The molar ratio of phosphorus oxychloride to bisphenol A is 2.8-4.

5.

13. The method according to claim 1, characterized in that In the step (a), the reaction temperature is 80-110° C. and the reaction time is 2-10 h.

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