CN114478232B - Recovery processing method of 3,3', 4' -diphenyl ether tetracarboxylic acid refining mother liquor - Google Patents
Recovery processing method of 3,3', 4' -diphenyl ether tetracarboxylic acid refining mother liquor Download PDFInfo
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Abstract
The invention relates to the technical field of recovery treatment of organic synthesis refined mother liquor, in particular to a recovery treatment method of 3,3', 4' -diphenyl ether tetracarboxylic acid refined mother liquor. The recovery processing method provided by the invention comprises the following steps: mixing 3,3', 4' -diphenyl ether tetracarboxylic acid refined mother liquor with inorganic base to obtain alkali-soluble mother liquor, wherein the pH value of the alkali-soluble mother liquor is more than or equal to 7, and carrying out solid-liquid separation on the alkali-soluble mother liquor to obtain impurity-removed mother liquor; filtering the impurity-removed mother liquor by using a nanofiltration membrane to obtain nanofiltration concentrated solution, wherein the nanofiltration concentrated solution is 3,3', 4' -diphenyl ether tetracarboxylic acid salt solution; and mixing the nanofiltration concentrated solution with inorganic acid for acid precipitation to obtain the 3,3', 4' -diphenyl ether tetracarboxylic acid. The recovery processing method provided by the invention can realize the effective separation of the 3,3', 4' -diphenyl ether tetracarboxylic acid and inorganic salt, and realize the high-efficiency recovery and utilization of the 3,3', 4' -diphenyl ether tetracarboxylic acid.
Description
Technical Field
The invention relates to the technical field of organic synthesis, in particular to a recovery processing method of 3,3', 4' -diphenyl ether tetracarboxylic acid refined mother liquor.
Background
3,3', 4' -diphenyl ether tetracarboxylic acid is an intermediate for producing 3,3', 4' -diphenyl ether dianhydride, 3', 4' -diphenyl ether dianhydride is used as a high-end electronic chemical and is an important raw material of a polyimide material, and polyimide synthesized by using the diphenyl ether dianhydride as the raw material has excellent hot processing performance, high temperature resistance of more than 400 ℃ and high insulating performance. With the development of digitalization, intellectualization and touch screen, the usage amount of polyimide as a high-end electronic material for a display screen is rapidly increased.
In the synthesis process of 3,3', 4' -diphenyl ether dianhydride, the intermediate 3,3', 4' -diphenyl ether tetracarboxylic acid needs to be refined for several times, and a large amount of refined mother liquor is generated. The mother liquor contains a large amount of water, a small amount of 3,3', 4' -diphenyl ether tetracarboxylic acid and a small amount of inorganic acid, so that the cost for directly treating the waste water is high, and the mother liquor contains the 3,3', 4' -diphenyl ether tetracarboxylic acid, so that the yield loss is caused by directly treating the waste water, therefore, the recovery treatment of the refined mother liquor is very important for realizing the recovery of the 3,3', 4' -diphenyl ether tetracarboxylic acid.
The conventional method for recovering 3,3', 4' -diphenylether tetracarboxylic acid from a refined mother liquor of 3,3', 4' -diphenylether dianhydride is a steam concentration method, which utilizes the principle of concentration difference between organic and inorganic salts, but 0.09-0.11% of 3,3', 4' -diphenylether tetracarboxylic acid remains in the final mother liquor, and the recovery rate of 3,3', 4' -diphenylether dianhydride is low.
Disclosure of Invention
In view of this, the invention provides a recovery processing method of 3,3', 4' -diphenyl ether tetracarboxylic acid refining mother liquor, and the recovery processing method provided by the invention can realize the recovery and utilization of 3,3', 4' -diphenyl ether tetracarboxylic acid in the refining mother liquor and improve the yield of 3,3', 4' -diphenyl ether dianhydride products.
In order to achieve the above object, the present invention provides the following technical solutions:
the invention provides a recovery processing method of refined mother liquor of 3,3', 4' -diphenyl ether tetracarboxylic acid, which comprises the following steps:
mixing 3,3', 4' -diphenyl ether tetracarboxylic acid refined mother liquor and inorganic base to obtain alkali-soluble mother liquor, wherein the pH value of the alkali-soluble mother liquor is not less than 7, and carrying out solid-liquid separation on the alkali-soluble mother liquor to obtain impurity-removed mother liquor;
filtering the impurity-removed mother liquor by using a nanofiltration membrane to obtain nanofiltration concentrated liquor, wherein the molecular weight cut-off of the nanofiltration membrane is more than or equal to 100;
and mixing the nanofiltration concentrated solution and inorganic acid for acid precipitation to obtain the 3,3', 4' -diphenyl ether tetracarboxylic acid.
Preferably, the nanofiltration membrane is used for filtering to obtain nanofiltration dialysate, the nanofiltration membrane is used for filtering the nanofiltration dialysate through a reverse osmosis membrane to obtain reverse osmosis concentrated solution and reverse osmosis water, the molecular weight cut-off of the reverse osmosis membrane is more than or equal to 50, the reverse osmosis concentrated solution is an inorganic salt solution, and the reverse osmosis water is used for refining the 3,3', 4' -diphenyl ether tetracarboxylic acid.
Preferably, the nanofiltration membrane is an aromatic polyamide composite nanofiltration membrane, and the molecular weight cut-off of the nanofiltration membrane is 100-1000.
Preferably, the membrane inlet pressure of the nanofiltration membrane is 2-25 bar, the concentration multiple of the nanofiltration membrane is 5-15 times, and the temperature of the impurity removal mother liquor is 10-40 ℃ during filtration of the nanofiltration membrane.
Preferably, the nanofiltration membrane filtration is to circularly carry out nanofiltration membrane filtration on the obtained concentrated solution until the dialysis capacity of the nanofiltration membrane is less than or equal to 1.0m 3 And h, obtaining the nanofiltration concentrated solution.
Preferably, the pH value of the acid precipitation liquid obtained by mixing the nanofiltration concentrated liquid and the inorganic acid is less than or equal to 2, the heat preservation temperature of the acid precipitation is 70-90 ℃, and the heat preservation time of the acid precipitation is 0.5-1 h.
Preferably, the reverse osmosis membrane is a polyamide reverse osmosis membrane, and the molecular weight cut-off of the reverse osmosis membrane is 50-200.
Preferably, the membrane inlet pressure of the reverse osmosis membrane is 20-40 bar, the concentration multiple of the reverse osmosis is 4-10 times, and the temperature of the nanofiltration dialysate is 20-40 ℃ during filtration of the reverse osmosis membrane.
Preferably, the reverse osmosis membrane filtration is to perform reverse osmosis membrane filtration on the obtained concentrated solution circularly until the membrane entry pressure of the reverse osmosis membrane filtration is not less than 40bar to obtain the reverse osmosis concentrated solution, and combine the dialysate filtered by the reverse osmosis membrane each time to obtain reverse osmosis water.
Preferably, the reverse osmosis concentrated solution is concentrated by mechanical steam to recover inorganic salt.
The invention provides a recovery processing method of refined mother liquor of 3,3', 4' -diphenyl ether tetracarboxylic acid, which comprises the following steps: mixing 3,3', 4' -diphenyl ether tetracarboxylic acid refined mother liquor with inorganic base to obtain alkali-soluble mother liquor, wherein the pH value of the alkali-soluble mother liquor is more than or equal to 7, and carrying out solid-liquid separation on the alkali-soluble mother liquor to obtain impurity-removed mother liquor; filtering the impurity-removed mother liquor by using a nanofiltration membrane to obtain nanofiltration concentrated solution; and mixing the nanofiltration concentrated solution with inorganic acid for acid precipitation to obtain the 3,3', 4' -diphenyl ether tetracarboxylic acid. The method comprises the steps of firstly adjusting alkali of refined mother liquor, converting 3,3', 4' -diphenyl ether tetracarboxylic acid in the refined mother liquor into soluble 3,3', 4' -diphenyl ether tetraformate, filtering to remove insoluble impurities, and then feeding the obtained product into a nanofiltration membrane for concentration and filtration, wherein the intercepted molecular weight of the nanofiltration membrane is controlled to be more than or equal to 100, so that nanofiltration concentrated solution of 3,3', 4' -diphenyl ether tetracarboxylic acid salt solution is obtained, the 3,3', 4' -diphenyl ether tetracarboxylic acid in the refined mother liquor is effectively separated from inorganic salt, and the recovery rate of the 3,3', 4' -diphenyl ether tetracarboxylic acid is improved. Therefore, the recovery processing method provided by the invention can realize the effective separation of the 3,3', 4' -diphenyl ether tetracarboxylic acid and inorganic salt, and realize the high-efficiency recovery and utilization of the 3,3', 4' -diphenyl ether tetracarboxylic acid, thereby improving the yield of the 3,3', 4' -diphenyl ether dianhydride product.
The recovery processing method provided by the invention has the advantages of high operation efficiency, energy conservation, improvement of the yield of 3,3', 4' -diphenyl ether dianhydride products, clean and environment-friendly production process and suitability for industrial production.
Drawings
FIG. 1 is a process flow diagram of the recovery processing method of mother liquor for refining diphenyl ether tetracarboxylic acid 3,3', 4' -in the example of the present invention.
Detailed Description
The invention provides a recovery processing method of 3,3', 4' -diphenyl ether tetracarboxylic acid refined mother liquor, which comprises the following steps:
mixing 3,3', 4' -diphenyl ether tetracarboxylic acid refined mother liquor and inorganic base to obtain alkali-soluble mother liquor, wherein the pH value of the alkali-soluble mother liquor is not less than 7, and carrying out solid-liquid separation on the alkali-soluble mother liquor to obtain impurity-removed mother liquor;
filtering the impurity-removed mother liquor by using a nanofiltration membrane to obtain nanofiltration concentrated solution, wherein the nanofiltration concentrated solution is 3,3', 4' -diphenyl ether tetracarboxylic acid salt solution, and the intercepted molecular weight of the nanofiltration membrane is more than or equal to 100;
and mixing the nanofiltration concentrated solution with inorganic acid for acid precipitation to obtain the 3,3', 4' -diphenyl ether tetracarboxylic acid.
In the present invention, all the raw materials are commercially available products well known to those skilled in the art, unless otherwise specified.
The method comprises the steps of mixing 3,3', 4' -diphenyl ether tetracarboxylic acid refined mother liquor with inorganic base (hereinafter referred to as first mixing) to obtain alkali-soluble mother liquor, wherein the pH value of the alkali-soluble mother liquor is not less than 7, and carrying out solid-liquid separation on the alkali-soluble mother liquor to obtain impurity-removed mother liquor.
In a specific embodiment of the present invention, the 3,3', 4' -diphenyl ether tetracarboxylic acid refining mother liquor has a mass percentage content of 3,3', 4' -diphenyl ether tetracarboxylic acid of preferably 0.09 to 0.11%.
In a specific embodiment of the present invention, the mass percentage content of the total formic acid in the 3,3', 4' -diphenyl ether tetracarboxylic acid refined mother liquor is preferably 0.1 to 1%.
In the present invention, the inorganic base preferably includes a hydroxide, and more preferably includes sodium hydroxide and/or potassium hydroxide.
In a specific embodiment of the present invention, the first mixing is preferably performed by dissolving the inorganic base in the 3,3', 4' -diphenylether tetracarboxylic acid purification mother liquor.
In the present invention, the pH of the alkali solution mother liquor is preferably 7 to 9, more preferably 7 to 8, and most preferably 8.
In the present invention, preferably, 3', 4' -diphenyl ether tetracarboxylic acid refined mother liquor is mixed with inorganic base, and the 3,3', 4' -diphenyl ether tetracarboxylic acid reacts with the inorganic base to obtain soluble 3,3', 4' -diphenyl ether tetraformate.
In a specific embodiment of the present invention, when the inorganic base is sodium hydroxide, the reaction equation of the 3,3', 4' -diphenyl ether tetracarboxylic acid and the sodium hydroxide is shown in formula 1:
in the present invention, the solid-liquid separation is preferably filtration, and the filtration is preferably a bag filter, a titanium rod filter or a folded membrane filter, and more preferably a bag filter.
In a specific embodiment of the invention, the filter pore size of the bag filter is preferably 5 μm.
In the present invention, the 3,3', 4' -diphenylethertetracarboxylic acid purification mother liquor is preferably filtered to remove insoluble matter.
After the impurity-removed mother liquor is obtained, the impurity-removed mother liquor is filtered by a nanofiltration membrane to obtain nanofiltration concentrated solution, wherein the nanofiltration concentrated solution is 3,3', 4' -diphenyl ether tetracarboxylic acid salt solution, and the intercepted molecular weight of the nanofiltration membrane is more than or equal to 100.
In the invention, the nanofiltration membrane is preferably an aromatic polyamide composite nanofiltration membrane.
In the present invention, the nanofiltration membrane preferably has a molecular weight cut-off of 100 to 1000, more preferably 200 to 500.
In the invention, the membrane entrance pressure of the nanofiltration membrane is preferably 2-25 bar, and more preferably 15-20 bar.
According to the invention, the impurity removal mother liquor is preferably conveyed by adding a pump, and is added at the same time.
In the present invention, the concentration ratio of the nanofiltration membrane is preferably 5 to 15 times, more preferably 8 to 12 times, and most preferably 10 times.
In the present invention, the dialysis amount of the nanofiltration membrane is preferably 2 to 3m 3 /h。
In the invention, the temperature of the impurity-removing mother liquor is preferably 10-40 ℃ and more preferably 20-30 ℃ during the nanofiltration.
In the invention, the nanofiltration membrane filtration is preferably performed by circularly performing nanofiltration membrane filtration on the obtained concentrated solution until the dialysis capacity of the nanofiltration membrane is preferably less than or equal to 1.0m 3 H, more preferably 0.7m or less 3 And h, obtaining nanofiltration concentrated solution, and preferably combining dialysate filtered by the nanofiltration membrane each time to obtain nanofiltration dialysate.
After the nanofiltration concentrate is obtained, the nanofiltration concentrate is mixed with an inorganic acid (hereinafter referred to as a second mixture) and acid-precipitated to obtain 3,3', 4' -diphenyl ether tetracarboxylic acid.
In the present invention, the inorganic acid is preferably hydrochloric acid or sulfuric acid.
In a specific embodiment of the present invention, the content of the hydrochloric acid is preferably 30% or 36% by mass.
In the specific embodiment of the present invention, the mass percentage of the sulfuric acid is preferably 96% or 92%.
In the present invention, the second mixing is preferably performed by adding the inorganic acid to the nanofiltration concentrate.
In the invention, the nanofiltration concentrated solution and the inorganic acid are mixed for the second time to obtain the acid-out solution, the acid-out solution is subjected to acid-out to obtain 3,3', 4' -diphenyl ether tetracarboxylic acid, the pH value of the acid-out solution during acid-out is preferably less than or equal to 2, the heat preservation temperature of the acid-out solution during acid-out is preferably 70-90 ℃, and the heat preservation time of the acid-out solution during acid-out is preferably 0.5-1 h.
In the present invention, the reaction equation of the acid precipitation is shown in formula 2:
in the present invention, the pH value of the acid-out liquid during acid-out is preferably not more than 2, more preferably 1 to 2.
In the present invention, the temperature for keeping the acid precipitation liquid at the time of acid precipitation is preferably 70 to 90 ℃, and more preferably 75 to 85 ℃.
In the present invention, the incubation time in the acidification of the acidification liquid is preferably 0.5 to 1 hour, and more preferably 0.6 to 0.8 hour.
In the present invention, the acid precipitation mother liquor is obtained after the acid precipitation, and in the present invention, the acid precipitation mother liquor is preferably subjected to a post-treatment to obtain the 3,3', 4' -diphenyl ether tetracarboxylic acid. In the present invention, the post-treatment preferably includes: and sequentially carrying out cooling and solid-liquid separation. In the present invention, the temperature of the cooled acid precipitation mother liquor is preferably 0 to 10 ℃, and more preferably 1 to 5 ℃. In the present invention, it is preferable to perform solid-liquid separation on the cooled acidified mother liquor, and in the present invention, it is preferable to perform centrifugation. The invention has no special requirements for the specific implementation process of the centrifugation.
To obtain 3,3', 4' -diphenyl ether tetracarboxylic acid, the present invention preferably returns the 3,3', 4' -diphenyl ether tetracarboxylic acid to the production line to produce the target product 3,3', 4' -diphenyl ether dianhydride, and the equation of the 3,3', 4' -diphenyl ether tetracarboxylic acid to produce the target product 3,3', 4' -diphenyl ether dianhydride is shown in formula 3:
in the invention, the nanofiltration membrane is used for filtering to obtain nanofiltration dialysate, and after the nanofiltration membrane is used for filtering, the invention preferably also comprises the step of filtering the nanofiltration dialysate by a reverse osmosis membrane to obtain reverse osmosis concentrated solution and reverse osmosis water, wherein the molecular weight cut-off of the reverse osmosis membrane is more than or equal to 50.
In the present invention, the reverse osmosis membrane is preferably a polyamide reverse osmosis membrane.
In the present invention, the reverse osmosis membrane preferably has a molecular weight cut-off of 50 to 200.
In the invention, the membrane inlet pressure of the reverse osmosis membrane filtration is preferably 20-40 bar, and more preferably 25-35 bar.
In the present invention, the concentration ratio of the reverse osmosis filtration is preferably 4 to 10 times, and more preferably 4.5 to 8 times.
In the present invention, the temperature of the nanofiltration dialysate is preferably 20 to 40 ℃, more preferably 25 to 35 ℃ during the reverse osmosis membrane filtration.
In the invention, the reverse osmosis membrane filtration is preferably to perform reverse osmosis membrane filtration on the obtained concentrated solution in a circulating way until the membrane entry pressure of the reverse osmosis membrane filtration is preferably more than or equal to 40bar so as to obtain reverse osmosis concentrated solution, and the dialysate filtered by the reverse osmosis membrane at each time is combined to obtain reverse osmosis water.
In the present invention, the reverse osmosis concentrate is preferably subjected to mechanical vapor concentration (MVR) to recover inorganic salts.
In the invention, the reverse osmosis water is directly used for returning to a 3,3', 4' -diphenyl ether tetracarboxylic acid refining section, thereby effectively reducing the refining production cost.
The preparation method provided by the invention is characterized in that 3,3', 4' -diphenyl ether tetracarboxylic acid organic solid alkali in mother liquor is dissolved into 3,3', 4' -diphenyl ether tetracarboxylic acid salt and dissolved in the mother liquor, insoluble impurities are filtered out and then filtered by a nanofiltration membrane to obtain nanofiltration concentrated solution containing 3,3', 4' -diphenyl ether tetracarboxylic acid salt macromolecular organic matters, and the nanofiltration concentrated solution is subjected to acid precipitation to obtain high-purity 3,3', 4' -diphenyl ether tetracarboxylic acid which is used for producing 3,3', 4' -diphenyl ether dianhydride.
According to the invention, the nanofiltration dialysate is preferably subjected to reverse osmosis membrane treatment to obtain a high-salt-content reverse osmosis concentrated solution, salt is treated by an MVR system, and reverse osmosis water can be directly applied to a production refining station. The recovery processing method provided by the invention is efficient and energy-saving, the 3,3', 4' diphenyl ether tetracarboxylic acid in the mother liquor is effectively separated from the inorganic salt, the 3,3', 4' diphenyl ether tetracarboxylic acid is recovered to improve the product yield, the inorganic salt is used as a byproduct, and reverse osmosis dialysis water is mechanically applied to a production post, so that clean production is realized, and the method is suitable for industrial production.
The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. It is to be understood that the described embodiments are merely exemplary of the invention, and not restrictive of the full scope of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Example 1
3000L of refined mother liquor of 3,3', 4' -diphenyl ether tetracarboxylic acid is taken, wherein the content of the 3,3', 4' -diphenyl ether tetracarboxylic acid is 0.1wt%, and the acid content is 1wt%. Adjusting pH of the mother liquor to 8.0 with sodium hydroxide, and filtering the mother liquor with 5 μm bag filter by air pressure filtration to remove insoluble substances and impurities. Pumping the impurity-removed mother liquor into a nanofiltration membrane by using a pipeline pump for filtration, adjusting the cut-off molecular weight of the aromatic polyamide composite nanofiltration membrane to be 200-500, adjusting the membrane inlet pressure to be 20bar by using a pressure pump, allowing inorganic salt small molecules to flow out along with the dialysate, and circularly filtering the concentrated solution in the nanofiltration membrane until the membrane dialysis amount is reduced to 0.7m 3 H, the dialysis amount is 2 to 3m 3 The volume of nanofiltration dialysis liquid is 2700L, and the volume of nanofiltration concentrated liquid is 300L.
Adding 30wt% HCl into the nanofiltration concentrated solution to adjust the pH value to 1.0, heating to 80 ℃, keeping the temperature for 1h, cooling to 5 ℃, and centrifuging to obtain 3,3', 4' -diphenyl ether tetracarboxylic acid 3kg, wherein the recovery rate reaches 100%, and the total yield of 3,3', 4' -diphenyl ether dianhydride is improved by 2%.
And (3) filtering the nanofiltration dialysate by a reverse osmosis membrane, wherein the molecular weight cut-off of the polyamide reverse osmosis membrane is 50-100, regulating the membrane inlet pressure to 25bar by a pressure pump, and circularly filtering inorganic salt in the concentrated solution in the reverse osmosis membrane until the membrane inlet pressure of the system reaches 40bar. The reverse osmosis concentrated liquid volume is 400L, and the reverse osmosis water volume is 2300L.
The reverse osmosis concentrated solution enters an MVR evaporation system, and 20kg of NaCl salt is discharged. The reverse osmosis water is returned to the refining post of 3,3', 4' -diphenyl ether tetracarboxylic acid for reuse.
Example 2
2000L of 3,3', 4' -diphenyl ether tetracarboxylic acid refined mother liquor is taken, wherein the content of the 3,3', 4' -diphenyl ether tetracarboxylic acid is 0.09wt%, and the content of the acid is 0.9wt%. Adding sodium hydroxide to adjust the pH value of the mother liquor to 8.0, and filtering the mother liquor through a 5-micron bag filter by using air to filter out insoluble substances and impurities in the mother liquor. Pumping the impurity-removed mother liquor into a nanofiltration membrane by using a pipeline pump for filtration, adjusting the cut-off molecular weight of the aromatic polyamide composite nanofiltration membrane to be 200-500, adjusting the membrane inlet pressure to be 25bar by using a pressure pump, allowing inorganic salt small molecules to flow out along with the dialysate, and circularly filtering the concentrated solution in the nanofiltration membrane until the membrane dialysis amount is reduced to 0.7m 3 H, the dialysis amount is 2 to 3m 3 The volume of nanofiltration dialysis liquid is 1800L, and the volume of nanofiltration concentrated liquid is 200L.
30wt% of HCl is added into the nanofiltration concentrated solution to adjust the pH value to 1.5, the solution is heated to 80 ℃ and kept for 1h, the temperature is reduced to 5 ℃ and the solution is centrifuged to obtain 1.8kg of 3,3', 4' -diphenyl ether tetracarboxylic acid, the recovery rate reaches 100 percent, and the total yield of 3,3', 4' -diphenyl ether dianhydride is improved by 2 percent.
And (3) filtering the nanofiltration dialysate by using a reverse osmosis membrane, wherein the molecular weight cut-off of the polyamide reverse osmosis membrane is 50-100, adjusting the membrane inlet pressure to 30bar by using a pressure pump, and circularly filtering inorganic salts in the concentrated solution in the reverse osmosis until the membrane inlet pressure of the system reaches 40bar. 250L of reverse osmosis concentrated liquid and 1550L of reverse osmosis water are obtained.
The reverse osmosis concentrated solution enters an MVR evaporation system, and NaCl salt is discharged by 16kg. The reverse osmosis water is returned to the refining post of 3,3', 4' -diphenyl ether tetraformic acid for reuse.
Example 3
3000L of refined mother liquor of 3,3', 4' -diphenyl ether tetracarboxylic acid is taken, wherein the content of the 3,3', 4' -diphenyl ether tetracarboxylic acid is 0.11wt%, and the acid content is 0.1wt%% of the total weight of the composition. Adding sodium hydroxide to adjust the pH value of the mother liquor to 8.5, and filtering the mother liquor through a 5-micron bag filter by using air to filter insoluble substances and impurities in the mother liquor. Pumping the impurity-removed mother liquor into a nanofiltration membrane by using a pipeline pump for filtration, adjusting the cut-off molecular weight of the aromatic polyamide composite nanofiltration membrane to be 200-500, adjusting the membrane inlet pressure to be 20bar by using a pressure pump, allowing inorganic salt small molecules to flow out along with the dialysate, and circularly filtering the concentrated solution in the nanofiltration membrane until the membrane dialysis amount is reduced to 0.7m 3 H, the dialysis amount is 2 to 3m 3 Per hour, the volume of nanofiltration dialysis liquid is 2600L, and the volume of nanofiltration concentrated liquid is 400L.
30wt% HCl is added into nanofiltration concentrated solution to adjust pH value to 2.0, the solution is heated to 80 ℃ and kept for 1h, the temperature is reduced to 5 ℃ and the solution is centrifuged to obtain 3,3', 4' -diphenyl ether tetracarboxylic acid 3.2kg, the recovery rate reaches 97%, and the total yield of 3,3', 4' -diphenyl ether dianhydride is increased by 1.9%.
And (3) filtering the nanofiltration dialysate by a reverse osmosis membrane, wherein the molecular weight cut-off of the polyamide reverse osmosis membrane is 50-100, regulating the membrane inlet pressure to 25bar by a pressure pump, and circularly filtering inorganic salt in the concentrated solution in the reverse osmosis membrane until the membrane inlet pressure of the system reaches 40bar. The reverse osmosis concentrated liquid volume was 400L, and the reverse osmosis water volume was 2200L.
The reverse osmosis concentrated solution enters an MVR evaporation system, and 20kg of NaCl salt is discharged. The reverse osmosis water is returned to the refining post of 3,3', 4' -diphenyl ether tetraformic acid for reuse.
The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.
Claims (7)
1. A recovery processing method of 3,3', 4' -diphenyl ether tetracarboxylic acid refining mother liquor is characterized by comprising the following steps:
mixing 3,3', 4' -diphenyl ether tetracarboxylic acid refined mother liquor with inorganic base to obtain alkali-soluble mother liquor, wherein the pH value of the alkali-soluble mother liquor is more than or equal to 7, and carrying out solid-liquid separation on the alkali-soluble mother liquor to obtain impurity-removed mother liquor; the mass percentage content of the 3,3', 4' -diphenyl ether tetracarboxylic acid in the refined mother liquor of the 3,3', 4' -diphenyl ether tetracarboxylic acid is 0.09-0.11%; the mass percentage content of the total formic acid in the refined mother liquor of the 3,3', 4' -diphenyl ether tetracarboxylic acid is 0.1 to 1 percent;
filtering the impurity-removed mother liquor by using a nanofiltration membrane to obtain nanofiltration concentrated liquor, wherein the molecular weight cut-off of the nanofiltration membrane is more than or equal to 100; the nanofiltration membrane is an aromatic polyamide composite nanofiltration membrane, and the molecular weight cut-off of the nanofiltration membrane is 100-1000; the membrane inlet pressure of the nanofiltration membrane is 2-25 bar, the concentration multiple of the nanofiltration membrane is 5-15 times, and the temperature of the impurity-removing mother liquor is 10-40 ℃ during filtration by the nanofiltration membrane; the nanofiltration membrane filtration is to circularly carry out nanofiltration membrane filtration on the obtained concentrated solution until the dialysis capacity of the nanofiltration membrane is less than or equal to 1.0m3/h to obtain the nanofiltration concentrated solution;
and mixing the nanofiltration concentrated solution with inorganic acid for acid precipitation to obtain the 3,3', 4' -diphenyl ether tetracarboxylic acid.
2. The recycling method according to claim 1, wherein the nanofiltration membrane is used for filtering to obtain nanofiltration dialysate, and the nanofiltration membrane is used for filtering the nanofiltration dialysate through a reverse osmosis membrane to obtain a reverse osmosis concentrate and reverse osmosis water, wherein the reverse osmosis concentrate has a molecular weight cut-off of not less than 50, is an inorganic salt solution, and is used for refining the 3,3', 4' -diphenyl ether tetracarboxylic acid.
3. The recycling method according to claim 1, wherein the pH value of the acid precipitation solution obtained by mixing the nanofiltration concentrated solution and the inorganic acid is less than or equal to 2, the temperature for maintaining the acid precipitation is 70-90 ℃, and the time for maintaining the acid precipitation is 0.5-1 h.
4. The recovery treatment method according to claim 2, wherein the reverse osmosis membrane is a polyamide reverse osmosis membrane, and the reverse osmosis membrane has a molecular weight cut-off of 50 to 200.
5. The recycling method according to claim 2 or 4, wherein the reverse osmosis membrane has a membrane inlet pressure of 20 to 40bar, a concentration multiple of 4 to 10 times, and a temperature of the nanofiltration dialysate of 20 to 40 ℃ during the reverse osmosis membrane filtration.
6. The recycling method according to claim 2 or 4, wherein the reverse osmosis membrane filtration is performed by circulating the obtained concentrated solution to reverse osmosis membrane filtration until the membrane inlet pressure of the reverse osmosis membrane filtration is more than or equal to 40bar to obtain the reverse osmosis concentrated solution, and combining the dialysate filtered by the reverse osmosis membrane each time to obtain reverse osmosis water.
7. The recovery processing method according to claim 2, wherein the reverse osmosis concentrated solution is concentrated by mechanical steam to recover inorganic salts.
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| CN108658757B (en) * | 2018-05-11 | 2020-11-06 | 国药集团威奇达药业有限公司 | Method for recovering phenylacetic acid from 6-aminopenicillanic acid enzymatic aqueous solution |
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