Purification method of bisphenol A-bis (diphenyl phosphate)

Abstract

The invention relates to the technical field of flame retardant purification, in particular to a purification method of bisphenol A-bis (diphenyl phosphate). Comprising the following steps: adding a solvent into a bisphenol A-bis (diphenyl phosphate) crude product, and stirring and mixing to obtain a mixed solution; adding the mixed solution into a washing kettle, adding a washing solution into the washing kettle, heating and stirring to wash the mixed solution, pumping the organic phase in the washing kettle into a desolventizing kettle through a delivery pump after an upper organic phase and a lower water layer appear in the washing kettle and the lower water layer in the washing kettle is discharged, stirring, heating and desolventizing to obtain a desolventizing solution; the refined bisphenol A-bis (diphenyl phosphate) is obtained. The obvious emulsification phenomenon in the washing process can be improved, and the yield of the bisphenol A-bis (diphenyl phosphate) washing section is increased.

Description

Technical Field

[0001] The invention relates to the technical field of flame retardant purification, and in particular to a method for purifying bisphenol A-bis(diphenyl phosphate). Background Art

[0002] Bisphenol A-bis(diphenyl phosphate) is an aromatic oligomeric phosphate based on bisphenol A. Compared with other aromatic phosphates, it has higher thermal stability and hydrolysis stability and is a highly efficient flame retardant plasticizer that is not easy to volatilize. It is often used in polyphenylene ether, polycarbonate (PC / ABS) blends, high-impact polystyrene (PPO / HIPS) blends or used alone in HIPS. Bisphenol A-bis(diphenyl phosphate) can show better physical properties, and its flame retardant properties are mainly exerted in the condensed phase. During thermal decomposition, phosphorus is easily accumulated in the solid residue. At present, phosphorus oxychloride and bisphenol A are reacted under Lewis acid catalysis, and the excess phosphorus oxychloride is removed under reduced pressure to obtain a phosphorus oxychloride intermediate, and then the phosphorus oxychloride is condensed with phenol to remove the byproduct hydrogen chloride. Finally, the crude product is dissolved in toluene and then washed and desolventized to obtain the finished product; however, when the washing effect is not good, the product is prone to emulsification during the water washing process, which will cause process product loss due to difficulty in stratification.

[0003] A Chinese patent with the patent publication number CN117946157A discloses a method for synthesizing bisphenol A-bis(diphenyl phosphate), but the yield of bisphenol A-bis(diphenyl phosphate) obtained by washing, purifying and distilling the crude product of bisphenol A-bis(diphenyl phosphate) under negative pressure is less than 95%.

[0004] Therefore, providing a method for purifying bisphenol A-bis(diphenyl phosphate) with high yield and stable purification performance is a major technical problem that needs to be solved at present. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides a method for purifying bisphenol A-bis(diphenyl phosphate), comprising the following steps:

[0006] The solvent is added to the crude product of bisphenol A-bis(diphenyl phosphate) and stirred to obtain a mixed liquid; the mixed liquid is added to a washing kettle, and the washing liquid is added to the washing kettle and then heated and stirred to wash the mixed liquid, an upper organic phase and a lower water layer appear in the washing kettle, and after the lower water layer in the washing kettle is drained, the organic phase in the washing kettle is pumped into a desolventizing kettle through a delivery pump, stirred, heated, and then desolventized to obtain refined bisphenol A-bis(diphenyl phosphate).

[0007] In one embodiment, the crude bisphenol A-bis(diphenyl phosphate) is a crude product obtained by condensation reaction of phosphorus oxychloride and phenol, and the mass content of phenol in the crude bisphenol A-bis(diphenyl phosphate) is 2-3%.

[0008] In one embodiment, the solvent comprises toluene and cyclohexane.

[0009] In one embodiment, the mass ratio of toluene to cyclohexane is (0.8-1.2):1.

[0010] In order to improve the emulsification phenomenon in the washing process of the mixed solution and increase the yield of bisphenol A-bis(diphenyl phosphate), the inventors found in the experimental process that when the mass ratio of toluene and cyclohexane of a specific solvent is (0.8-1.2):1, the obvious emulsification phenomenon in the water washing process can be improved; the inventors found in the experimental process that increasing the polarity of the solvent can improve the emulsification problem in the water washing process of bisphenol A-bis(diphenyl phosphate), and the solvent polarity is ethyl acetate, cyclohexane, and toluene from large to small. The inventors also found that although ethyl acetate is used as the solvent, the polarity of the solvent is greatly improved and the emulsification problem in the water washing process is solved, the yield of bisphenol A-bis(diphenyl phosphate) obtained is lower than the purification yield after toluene and cyclohexane cooperate. The main reason is that the boiling point of ethyl acetate is low and the process loss is large. In particular, when the mass ratio of toluene and cyclohexane is (0.8-1.2):1, the yield of bisphenol A-bis(diphenyl phosphate) can be increased to more than 95%, and the obvious emulsification phenomenon in the water washing process can be avoided.

[0011] In one embodiment, the mass ratio of the solvent to the crude bisphenol A-bis(diphenyl phosphate) is (1.5-2.5):1.

[0012] In one embodiment, the mass ratio of the solvent to the crude bisphenol A-bis(diphenyl phosphate) is 2:1.

[0013] In one embodiment, the mass ratio of the washing liquid to the crude bisphenol A-bis(diphenyl phosphate) is 5.5-6.5.

[0014] In one embodiment, the mass ratio of the washing liquid to the crude bisphenol A-bis(diphenyl phosphate) is 6.

[0015] In one embodiment, the washing solution includes acid solution, alkali solution and water.

[0016] In one embodiment, the mass ratio of the acid solution, the alkali solution and the water is 1:2:1.

[0017] In one embodiment, the acid solution comprises an aqueous solution of hydrochloric acid with a mass concentration of 2-3%.

[0018] In one embodiment, the alkali solution comprises an aqueous sodium hydroxide solution with a mass concentration of 3-5%.

[0019] In one embodiment, the water is pure water.

[0020] In one embodiment, the method of washing the mixed solution comprises sequentially performing acid washing, alkali washing, and water washing.

[0021] In one embodiment, the acid washing comprises adding acid solution into the washing kettle, heating it to 60°C and stirring it for 30 minutes to acid wash the mixed solution, after which an upper organic phase and a lower water layer appear in the washing kettle, and the lower water layer is discharged.

[0022] In one embodiment, the alkali washing comprises adding alkali solution into a washing kettle and stirring the mixture to perform alkali washing, an upper organic phase and a lower water layer appear in the washing kettle, and the lower water layer is discharged.

[0023] In one embodiment, the alkali washing includes a primary alkali washing and a secondary alkali washing, the primary alkali washing and the secondary alkali washing use the same amount of alkali solution, the temperature is maintained at 60° C. during the primary alkali washing and the secondary alkali washing, and stirring is performed for 30 minutes.

[0024] In one embodiment, the alkali solution used in the first alkali washing is a sodium hydroxide aqueous solution with a mass concentration of 5%.

[0025] In one embodiment, the alkali solution used in the secondary alkali washing is a sodium hydroxide aqueous solution with a mass concentration of 3%.

[0026] In one embodiment, the water washing comprises adding water into a washing kettle and then stirring to wash the mixed solution with water, an upper organic phase and a lower aqueous layer appear in the washing kettle, and the lower aqueous layer is discharged.

[0027] In one embodiment, the purification method of bisphenol A-bis(diphenyl phosphate) comprises the following steps: adding a solvent to a crude bisphenol A-bis(diphenyl phosphate) product and stirring and mixing in a reaction kettle to obtain a mixed solution; adding the mixed solution to a washing kettle through a delivery pump, and adding an acid solution to the washing kettle and stirring the mixture at a higher temperature to perform acid washing on the mixed solution, wherein an upper organic phase and a lower aqueous layer appear in the washing kettle after the acid washing, and the lower aqueous layer is discharged; then adding an alkali solution to the washing kettle and stirring the mixture to perform an alkali washing on the organic phase, and washing the mixture after the alkali washing. An upper organic phase and a lower aqueous layer appear in the washing kettle, and the lower aqueous layer is discharged; alkali solution is then added to the washing kettle and stirred to perform secondary alkali washing on the organic phase. After the secondary alkali washing, an upper organic phase and a lower aqueous layer appear in the washing kettle, and the lower aqueous layer is discharged; water is then added to the washing kettle and stirred to wash the organic phase. After washing, an upper organic phase and a lower aqueous layer appear in the washing kettle, and the lower aqueous layer is discharged. The organic phase in the washing kettle is pumped into a desolventizing kettle through a delivery pump, stirred, and heated for desolventizing to obtain refined bisphenol A-bis(diphenyl phosphate).

[0028] In one embodiment, the organic phase in the washing kettle is pumped into the desolventizing kettle through a delivery pump, stirred, heated to 101-110°C, and desolventized for 1-5 hours under a negative pressure of -110 to -90 kPa to obtain refined bisphenol A-bis(diphenyl phosphate).

[0029] In one embodiment, the organic phase in the washing kettle is pumped into a desolventizing kettle through a delivery pump, stirred, heated to 105° C., and desolventized at a negative pressure of -100 kPa for 3 hours to obtain refined bisphenol A-bis(diphenyl phosphate).

[0030] Beneficial Effects

[0031] 1. The purification method of bisphenol A-bis(diphenyl phosphate) provided in the present application can obtain bisphenol A-bis(diphenyl phosphate) with higher purity.

[0032] 2. The purification method of bisphenol A-bis(diphenyl phosphate) provided in the present application can use a single solvent to solve the problems of emulsification, oil-water separation, and yield reduction during the water washing process. The yield is increased from 92.13% of a single solvent to 96.7%.

[0033] 3. The purification method of bisphenol A-bis(diphenyl phosphate) provided in the present application can improve the yield of bisphenol A-bis(diphenyl phosphate) and the performance of the purification process is stable.

[0034] 4 The purification method of bisphenol A-bis(diphenyl phosphate) provided in the present application uses a specific solvent of toluene and cyclohexane in a mass ratio of (0.8-1.2):1, which can improve the obvious emulsification phenomenon in the water washing process.

[0035] 5. The purification method of bisphenol A-bis(diphenyl phosphate) provided in the present application can better solve the emulsification problem while improving the yield of the bisphenol A-bis(diphenyl phosphate) washing section. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 A schematic flow chart of a method for purifying bisphenol A-bis(diphenyl phosphate) provided in Examples 1-3 and Comparative Examples 1-3.

[0037] Figure 2 This is a state diagram of the comparative example 1 in which obvious emulsification phenomenon occurs during the water washing process. DETAILED DESCRIPTION

[0038] Example 1

[0039] The present embodiment provides a method for purifying bisphenol A-bis(diphenyl phosphate), comprising the following steps: adding 26140 kg of solvent to 13070 kg of bisphenol A-bis(diphenyl phosphate) crude product and stirring and mixing in a reaction kettle to obtain a mixed solution; adding the mixed solution to a washing kettle through a delivery pump, adding 19605 kg of acid solution to the washing kettle, heating the temperature to 60° C. and stirring for 30 min to acid-wash the mixed solution, after which an upper organic phase and a lower water layer appear in the washing kettle, and the lower water layer is discharged; then adding 19605 kg of alkali solution to the washing kettle, maintaining the temperature at 60° C., and stirring for 30 min to perform an alkali wash on the organic phase, and washing the mixture after the alkali wash. An upper organic phase and a lower aqueous layer appeared in the kettle, and the lower aqueous layer was discharged; 19605 kg of alkali solution was added to the washing kettle and the temperature was maintained at 60°C, and the organic phase was stirred for a second alkali wash. After the second alkali wash, an upper organic phase and a lower aqueous layer appeared in the washing kettle, and the lower aqueous layer was discharged; 19605 kg of water was added to the washing kettle and stirred to wash the organic phase. After washing, an upper organic phase and a lower aqueous layer appeared in the washing kettle, and the lower aqueous layer was discharged. The organic phase in the washing kettle was pumped into the desolventizing kettle through a delivery pump, stirred, and heated to 105°C. The negative pressure was pumped to -100 kPa for desolventizing for 3 hours to obtain 10919 kg of refined bisphenol A-bis(diphenyl phosphate).

[0040] The crude bisphenol A-bis(diphenyl phosphate) is a crude product obtained by condensation reaction of phosphorus oxychloride and phenol, and the mass content of phenol in the crude bisphenol A-bis(diphenyl phosphate) is 2.3%.

[0041] The solvent is toluene and cyclohexane, and the mass ratio of toluene to cyclohexane is 1:1.

[0042] The acid solution is a hydrochloric acid aqueous solution with a concentration of 2%.

[0043] The alkali solution used in the first alkali washing is a sodium hydroxide aqueous solution with a mass concentration of 5%.

[0044] The alkali solution used in the secondary alkali washing is a sodium hydroxide aqueous solution with a mass concentration of 3%.

[0045] The water is pure water.

[0046] Figure 1 Provided is a schematic flow diagram of a method for purifying bisphenol A-bis(diphenyl phosphate).

[0047] Example 2

[0048] The present embodiment provides a method for purifying bisphenol A-bis(diphenyl phosphate), comprising the following steps: adding 25300 kg of solvent to 12650 kg of bisphenol A-bis(diphenyl phosphate) crude product and stirring and mixing in a reaction kettle to obtain a mixed solution; adding the mixed solution to a washing kettle through a delivery pump, adding 18975 kg of acid solution to the washing kettle, heating the temperature to 60° C. and stirring for 30 min to acid-wash the mixed solution, after which an upper organic phase and a lower water layer appear in the washing kettle, and the lower water layer is discharged; then adding 18975 kg of alkali solution to the washing kettle, maintaining the temperature at 60° C., and stirring for 30 min to perform an alkali wash on the organic phase, and washing the mixture after the alkali wash. An upper organic phase and a lower aqueous layer appeared in the kettle, and the lower aqueous layer was discharged; 18,975 kg of alkali solution was added to the washing kettle and the temperature was maintained at 60°C, and the organic phase was stirred for a second alkali wash. After the second alkali wash, an upper organic phase and a lower aqueous layer appeared in the washing kettle, and the lower aqueous layer was discharged; 18,975 kg of water was added to the washing kettle and stirred to wash the organic phase. After washing, an upper organic phase and a lower aqueous layer appeared in the washing kettle, and the lower aqueous layer was discharged. The organic phase in the washing kettle was pumped into the desolventizing kettle through a delivery pump, stirred, and heated to 105°C. The negative pressure was pumped to -100 kPa for desolventizing for 3 hours to obtain 12,080 kg of refined bisphenol A-bis(diphenyl phosphate).

[0049] The crude bisphenol A-bis(diphenyl phosphate) is a crude product obtained by condensation reaction of phosphorus oxychloride and phenol, and the mass content of phenol in the crude bisphenol A-bis(diphenyl phosphate) is 2.1%.

[0050] The solvent is toluene and cyclohexane, and the mass ratio of toluene to cyclohexane is 0.8:1.

[0051] The acid solution is a hydrochloric acid aqueous solution with a concentration of 2%.

[0052] The alkali solution used in the first alkali washing is a sodium hydroxide aqueous solution with a mass concentration of 5%.

[0053] The alkali solution used in the secondary alkali washing is a sodium hydroxide aqueous solution with a mass concentration of 3%.

[0054] The water is pure water.

[0055] Figure 1 Provided is a schematic flow diagram of a method for purifying bisphenol A-bis(diphenyl phosphate).

[0056] Example 3

[0057] The present embodiment provides a method for purifying bisphenol A-bis(diphenyl phosphate), comprising the following steps: adding 28180 kg of solvent to 14090 kg of bisphenol A-bis(diphenyl phosphate) crude product and stirring and mixing in a reaction kettle to obtain a mixed solution; adding the mixed solution to a washing kettle through a delivery pump, adding 21135 kg of acid solution to the washing kettle, heating the temperature to 60° C. and stirring for 30 min to acid-wash the mixed solution, after which an upper organic phase and a lower water layer appear in the washing kettle, and the lower water layer is discharged; then adding 21135 kg of alkali solution to the washing kettle, maintaining the temperature at 60° C., and stirring for 30 min to perform an alkali wash on the organic phase, and washing the mixture after the alkali wash. An upper organic phase and a lower aqueous layer appeared in the kettle, and the lower aqueous layer was discharged; 21,135 kg of alkali solution was added to the washing kettle and the temperature was maintained at 60°C, and the organic phase was stirred for a second alkali wash. After the second alkali wash, an upper organic phase and a lower aqueous layer appeared in the washing kettle, and the lower aqueous layer was discharged; 21,135 kg of water was added to the washing kettle and stirred to wash the organic phase. After washing, an upper organic phase and a lower aqueous layer appeared in the washing kettle, and the lower aqueous layer was discharged. The organic phase in the washing kettle was pumped into the desolventizing kettle through a transfer pump, stirred, and heated to 105°C. The negative pressure was pumped to -100 kPa for desolventizing for 3 hours to obtain 10,919 kg of refined bisphenol A-bis(diphenyl phosphate).

[0058] The crude bisphenol A-bis(diphenyl phosphate) is a crude product obtained by condensation reaction of phosphorus oxychloride and phenol, and the mass content of phenol in the crude bisphenol A-bis(diphenyl phosphate) is 2.3%.

[0059] The solvent is toluene and cyclohexane, and the mass ratio of toluene to cyclohexane is 1.2:1.

[0060] The acid solution is a hydrochloric acid aqueous solution with a concentration of 2%.

[0061] The alkali solution used in the first alkali washing is a sodium hydroxide aqueous solution with a mass concentration of 5%.

[0062] The alkali solution used in the secondary alkali washing is a sodium hydroxide aqueous solution with a mass concentration of 3%.

[0063] The water is pure water.

[0064] Figure 1 Provided is a schematic flow diagram of a method for purifying bisphenol A-bis(diphenyl phosphate).

[0065] Comparative Example 1

[0066] The present comparative example provides a method for purifying bisphenol A-bis(diphenyl phosphate), comprising the following steps: adding 24630 kg of solvent to 12315 kg of bisphenol A-bis(diphenyl phosphate) crude product and stirring and mixing in a reaction kettle to obtain a mixed solution; adding the mixed solution to a washing kettle through a delivery pump, adding 18472 kg of acid solution to the washing kettle, heating the temperature to 60° C. and stirring for 30 min to acid-wash the mixed solution, wherein an upper organic phase and a lower water layer appear in the washing kettle after acid washing, and the lower water layer is discharged; then adding 18472 kg of alkali solution to the washing kettle, maintaining the temperature at 60° C., and stirring for 30 min to perform an alkali washing on the organic phase, and washing the mixture after the alkali washing. An upper organic phase and a lower aqueous layer appeared in the washing kettle, and the lower aqueous layer was discharged; 18472 kg of alkali solution was added to the washing kettle and the temperature was maintained at 60°C, and the organic phase was stirred for a second alkali washing. After the second alkali washing, an upper organic phase and a lower aqueous layer appeared in the washing kettle, and the lower aqueous layer was discharged; 18472 kg of water was added to the washing kettle and stirred to wash the organic phase. After washing, an upper organic phase and a lower aqueous layer appeared in the washing kettle, and the lower aqueous layer was discharged. The organic phase in the washing kettle was pumped into the desolventizing kettle through a transfer pump, stirred, and heated to 105°C. The negative pressure was pumped to -100 kPa for desolventizing for 3 hours to obtain 11305 kg of refined bisphenol A-bis(diphenyl phosphate).

[0067] The crude bisphenol A-bis(diphenyl phosphate) is a crude product obtained by condensation reaction of phosphorus oxychloride and phenol. The mass content of phenol in the crude bisphenol A-bis(diphenyl phosphate) is 2.42%.

[0068] The solvent is toluene.

[0069] The acid solution is a hydrochloric acid aqueous solution with a concentration of 2%.

[0070] The alkali solution used in the first alkali washing is a sodium hydroxide aqueous solution with a mass concentration of 5%.

[0071] The alkali solution used in the secondary alkali washing is a sodium hydroxide aqueous solution with a mass concentration of 3%.

[0072] The water is pure water.

[0073] Figure 1 Provided is a schematic flow diagram of a method for purifying bisphenol A-bis(diphenyl phosphate).

[0074] Comparative Example 2

[0075] The present comparative example provides a method for purifying bisphenol A-bis(diphenyl phosphate), comprising the following steps: adding 23150 kg of solvent to 11575 kg of bisphenol A-bis(diphenyl phosphate) crude product and stirring and mixing in a reaction kettle to obtain a mixed solution; adding the mixed solution to a washing kettle through a delivery pump, adding 17362 kg of acid solution to the washing kettle, heating the temperature to 60° C. and stirring for 30 min to acid-wash the mixed solution, after which an upper organic phase and a lower water layer appear in the washing kettle, and the lower water layer is discharged; then adding 17362 kg of alkali solution to the washing kettle, maintaining the temperature at 60° C., and stirring for 30 min to perform an alkali wash on the organic phase, and washing the mixture once after the alkali wash. An upper organic phase and a lower aqueous layer appeared in the washing kettle, and the lower aqueous layer was discharged; 17362 kg of alkali solution was added to the washing kettle and the temperature was maintained at 60°C, and the organic phase was stirred for a second alkali washing. After the second alkali washing, an upper organic phase and a lower aqueous layer appeared in the washing kettle, and the lower aqueous layer was discharged; 17362 kg of water was added to the washing kettle and stirred to wash the organic phase. After washing, an upper organic phase and a lower aqueous layer appeared in the washing kettle, and the lower aqueous layer was discharged. The organic phase in the washing kettle was pumped into the desolventizing kettle through a transfer pump, stirred, and heated to 105°C. The negative pressure was pumped to -100 kPa for desolventizing for 3 hours to obtain 10919 kg of refined bisphenol A-bis(diphenyl phosphate).

[0076] The crude bisphenol A-bis(diphenyl phosphate) is a crude product obtained by condensation reaction of phosphorus oxychloride and phenol, and the mass content of phenol in the crude bisphenol A-bis(diphenyl phosphate) is 2.12%.

[0077] The solvent is ethyl acetate.

[0078] The acid solution is a hydrochloric acid aqueous solution with a concentration of 2%.

[0079] The alkali solution used in the first alkali washing is a sodium hydroxide aqueous solution with a mass concentration of 5%.

[0080] The alkali solution used in the secondary alkali washing is a sodium hydroxide aqueous solution with a mass concentration of 3%.

[0081] The water is pure water.

[0082] Figure 1 Provided is a schematic flow diagram of a method for purifying bisphenol A-bis(diphenyl phosphate).

[0083] Comparative Example 3

[0084] The present comparative example provides a method for purifying bisphenol A-bis(diphenyl phosphate), comprising the following steps: adding 21150 kg of solvent to 10575 kg of bisphenol A-bis(diphenyl phosphate) crude product and stirring and mixing in a reaction kettle to obtain a mixed solution; adding the mixed solution to a washing kettle through a delivery pump, adding 15860 kg of acid solution to the washing kettle, heating the temperature to 60° C. and stirring for 30 min to acid-wash the mixed solution, after which an upper organic phase and a lower water layer appear in the washing kettle, and the lower water layer is discharged; then adding 15860 kg of alkali solution to the washing kettle, maintaining the temperature at 60° C., and stirring for 30 min to perform an alkali wash on the organic phase, and washing the mixture after the alkali wash. An upper organic phase and a lower aqueous layer appeared in the kettle, and the lower aqueous layer was discharged; 15,860 kg of alkali solution was added to the washing kettle and the temperature was maintained at 60°C, and the organic phase was stirred for a second alkali wash. After the second alkali wash, an upper organic phase and a lower aqueous layer appeared in the washing kettle, and the lower aqueous layer was discharged; 15,860 kg of water was added to the washing kettle and stirred to wash the organic phase. After washing, an upper organic phase and a lower aqueous layer appeared in the washing kettle, and the lower aqueous layer was discharged. The organic phase in the washing kettle was pumped into the desolventizing kettle through a delivery pump, stirred, and heated to 105°C. The negative pressure was pumped to -100 kPa for desolventizing for 3 hours to obtain 10,919 kg of refined bisphenol A-bis(diphenyl phosphate).

[0085] The crude bisphenol A-bis(diphenyl phosphate) is a crude product obtained by condensation reaction of phosphorus oxychloride and phenol, and the mass content of phenol in the crude bisphenol A-bis(diphenyl phosphate) is 2.12%.

[0086] The solvent is toluene and cyclohexane, and the mass ratio of toluene to cyclohexane is 0.5:1.

[0087] The acid solution is a hydrochloric acid aqueous solution with a concentration of 2%.

[0088] The alkali solution used in the first alkali washing is a sodium hydroxide aqueous solution with a mass concentration of 5%.

[0089] The alkali solution used in the secondary alkali washing is a sodium hydroxide aqueous solution with a mass concentration of 3%.

[0090] The water is pure water.

[0091] Figure 1 Provided is a schematic flow diagram of a method for purifying bisphenol A-bis(diphenyl phosphate).

[0092] Performance Testing

[0093] 1. Yield test

[0094] The yield of the refined bisphenol A-bis(diphenyl phosphate) provided by Examples 1-3 and Comparative Examples 1-3 was tested. The test results are shown in Table 1.

[0095] Yield % = mass of refined bisphenol A-bis(diphenyl phosphate) / (mass of crude bisphenol A-bis(diphenyl phosphate) - mass of phenol)*100%.

[0096] 2. Acid value test

[0097] The purified bisphenol A-bis(diphenyl phosphate) provided in Examples 1-3 and Comparative Examples 1-3 were subjected to an acid value test. The test results are shown in Table 1.

[0098] Acid value test method:

[0099] Reagents and solutions: sodium hydroxide standard titration solution: c (NaOH = 0.05 mol / L), 10 g / L phenolphthalein indicator.

[0100] Main instruments: Micro-alkaline burette: 5mL, graduation value 0.02mL, analytical balance (accurate to 0.01g); conical flask: 250mL.

[0101] Determination steps:

[0102] Weigh 50 g of the sample (accurate to 0.01 g) and place it in a 250 mL conical flask. Add 50 mL of neutralized ethanol and 2 to 4 drops of 10 g / L phenolphthalein indicator. Titrate with 0.05 mol / L sodium hydroxide standard titration solution until it turns pink. The end point is when the color does not fade for 5 seconds.

[0103] The acid value X is the amount of potassium hydroxide (mg) required to neutralize the acidic substances in 1g of the sample, and the unit is mgKOH / g. It is calculated according to formula (1):

[0104]

[0105] In formula (1): V–00 – the volume of sodium hydroxide standard titration solution consumed by the sample, in milliliters (mL); V0 – the volume of sodium hydroxide standard titration solution consumed by the blank, in milliliters (mL);

[0106] c––––the concentration of sodium hydroxide standard titration solution, in moles per liter (mol / L);

[0107] M – molar mass of potassium hydroxide, in grams per mole (g / mol) [M = 56.11];

[0108] m––––The mass of the sample, in grams (g).

[0109] 3. Moisture test

[0110] The refined bisphenol A-bis(diphenyl phosphate) provided in Examples 1-3 and Comparative Examples 1-3 was tested for moisture content. The test results are shown in Table 1.

[0111] Carry out according to the method specified in GB / T 6283-2008.

[0112] 4. Solvent quantitative test

[0113] The refined bisphenol A-bis(diphenyl phosphate) provided in Examples 1-3 and Comparative Examples 1-3 were subjected to a solvent quantitative test, and the test results are shown in Table 1.

[0114] Test method: Use liquid chromatography to quantitatively analyze the solvent: weigh about 0.02g (accurate to 0.0002g) of the solvent standard into a 100mL volumetric flask, dilute to the scale with the mobile phase, pipette 5.00mL of the solution into a 50mL volumetric flask, dilute to the scale with the mobile phase, and shake well.

[0115] Preparation of sample solution: weigh about 2g of sample into a 50mL volumetric flask, dilute to scale with mobile phase, shake well and set aside. Under the above operating conditions, after the instrument baseline is stable, continuously inject several injections of standard solution, and calculate the mass fraction of phenol in the sample W1 (%) according to formula (2):

[0116]

[0117] In formula (2):

[0118] r1 - the average value of the solvent peak area in the standard solution;

[0119] r2 - the average value of the solvent peak area in the sample solution;

[0120] m1 - the mass of the solvent standard (g);

[0121] m2 – mass of the sample (g);

[0122] p──mass fraction of solvent in standard sample (%).

[0123] The qualified standards for refined bisphenol A-bis(diphenyl phosphate) are shown in Table 2.

[0124] 5. Quality analysis test

[0125] The contents of the refined bisphenol A-bis(diphenyl phosphate) provided in Examples 1-3 and Comparative Examples 1-3 were analyzed using a high performance liquid chromatograph with a variable wavelength ultraviolet detector, the detection wavelength being 254 nm; the test results are shown in Tables 3-8.

[0126] 6. Washing status test

[0127] Record whether emulsification occurs during the washing process in the purification method of bisphenol A-bis(diphenyl phosphate) provided in Examples 1-3 and Comparative Examples 1-3. The recorded results are shown in Table 1. The emulsification state is shown in Table 2. Figure 2 .

[0128] Table 1

[0129]

[0130] It can be seen from the test data in Table 1 that in the present application, by using a specific solvent of toluene and cyclohexane in a mass ratio of (0.8-1.2):1, the obvious emulsification phenomenon in the water washing process can be improved.

[0131] Table 2

[0132]

[0133] Table 3

[0134]

[0135] Table 4

[0136]

[0137]

[0138] Table 5

[0139]

[0140] Table 6

[0141]

[0142] Table 7

[0143]

[0144] Table 8

[0145]

[0146]

[0147] It can be seen from the experimental test results in the above table that the purification method of bisphenol A-bis(diphenyl phosphate) provided in the present application can obtain bisphenol A-bis(diphenyl phosphate) with higher purity.

Claims

1. A method for purifying bisphenol A-bis(diphenyl phosphate), characterized in that: The following steps are involved: The solvent is added to the crude product of bisphenol A-bis(diphenyl phosphate) and stirred to obtain a mixed liquid; the mixed liquid is added to a washing kettle, and the washing liquid is added to the washing kettle and then heated and stirred to wash the mixed liquid, an upper organic phase and a lower water layer appear in the washing kettle, and after the lower water layer in the washing kettle is drained, the organic phase in the washing kettle is pumped into a desolventizing kettle through a delivery pump, stirred, heated, and then desolventized to obtain refined bisphenol A-bis(diphenyl phosphate).

2. The method for purifying bisphenol A-bis(diphenyl phosphate) as claimed in claim 1, characterized in that: The crude bisphenol A-bis(diphenyl phosphate) is a crude product obtained by condensation reaction of phosphorus oxychloride and phenol.

3. The method for purifying bisphenol A-bis(diphenyl phosphate) as claimed in claim 1, characterized in that: The solvent includes toluene and cyclohexane, and the mass ratio of toluene to cyclohexane is (0.8-1.2):

1.

4. The method for purifying bisphenol A-bis(diphenyl phosphate) as claimed in claim 3, characterized in that: The mass ratio of the solvent to the crude bisphenol A-bis(diphenyl phosphate) is (1.5-2.5):

1.

5. The method for purifying bisphenol A-bis(diphenyl phosphate) as claimed in claim 1, characterized in that: The washing liquid includes acid solution, alkali solution and water.

6. The method for purifying bisphenol A-bis(diphenyl phosphate) as claimed in claim 5, characterized in that: The method of washing the mixed liquid includes acid washing, alkali washing and water washing in sequence.

7. The method for purifying bisphenol A-bis(diphenyl phosphate) as claimed in claim 6, characterized in that: The acid washing comprises adding acid solution into the washing kettle and then heating and stirring to acid wash the mixed solution, an upper organic phase and a lower water layer appear in the washing kettle, and the lower water layer is discharged.

8. The method for purifying bisphenol A-bis(diphenyl phosphate) as claimed in claim 6, characterized in that: The alkali washing comprises adding alkali solution into the washing kettle and stirring the mixture to perform alkali washing, an upper organic phase and a lower water layer appear in the washing kettle, and the lower water layer is discharged.

9. The method for purifying bisphenol A-bis(diphenyl phosphate) as claimed in claim 6, characterized in that: The water washing includes adding water into the washing kettle and stirring to wash the mixed liquid, an upper organic phase and a lower water layer appear in the washing kettle, and the lower water layer is discharged.

10. The method for purifying bisphenol A-bis(diphenyl phosphate) according to claim 1, characterized in that: The organic phase in the washing kettle is pumped into the desolventizing kettle through a delivery pump for stirring, the temperature is raised to 101-110° C., and the negative pressure is pumped to -110 to -90 kPa for desolventizing for 1-5 hours to obtain refined bisphenol A-bis(diphenyl phosphate).

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