CN109593037B - Method for recovering perfume-grade benzyl benzoate from benzoic acid rectification residual liquid - Google Patents
Method for recovering perfume-grade benzyl benzoate from benzoic acid rectification residual liquid Download PDFInfo
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- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C67/00—Preparation of carboxylic acid esters
- C07C67/48—Separation; Purification; Stabilisation; Use of additives
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C67/00—Preparation of carboxylic acid esters
- C07C67/48—Separation; Purification; Stabilisation; Use of additives
- C07C67/52—Separation; Purification; Stabilisation; Use of additives by change in the physical state, e.g. crystallisation
- C07C67/54—Separation; Purification; Stabilisation; Use of additives by change in the physical state, e.g. crystallisation by distillation
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C67/00—Preparation of carboxylic acid esters
- C07C67/48—Separation; Purification; Stabilisation; Use of additives
- C07C67/56—Separation; Purification; Stabilisation; Use of additives by solid-liquid treatment; by chemisorption
Abstract
The invention discloses a method for recovering perfume-grade benzyl benzoate from benzoic acid rectification residual liquid, which comprises the steps of taking the benzoic acid rectification residual liquid as a raw material, extracting a benzyl benzoate crude product by a reduced pressure rectification mode, then removing benzoic acid and most other impurities by alkali washing, refining the benzyl benzoate crude product into colorless high-purity perfume-grade benzyl benzoate by using a suspension crystallization technology through the steps of cooling, crystallizing, centrifuging, washing and the like. The raw materials used in the invention are benzoic acid rectification raffinate treated as hazardous waste before, other raw materials are not needed in the whole recovery process, the used energy sources are only water, electricity, steam and purified benzyl benzoate, and the energy consumption of falling film heating rectification and suspension crystallization of the benzyl benzoate is relatively low. The content of the benzyl benzoate purified and refined by the method reaches 99.50-99.99%, the color number is 5-15 HZ, the benzyl benzoate has slight aromatic odor, and the use standard of perfume-grade benzyl benzoate is met.
Description
Technical Field
The invention relates to the field of pharmaceutical and chemical waste recovery, in particular to a method for recovering perfume-grade benzyl benzoate from benzoic acid rectification residual liquid.
Background
Benzyl benzoate is transparent, colorless crystal or oily liquid, has weak fragrance, and is mainly used as solvent for artificial Moschus, vanillin and other perfumes, fragrance fixative for floral essence and blending perfume for ylang essence and other essences. At present, benzyl benzoate industrial products are mainly synthesized by reacting sodium benzoate and benzyl chloride, but the benzyl chloride has pungent smell and contains chlorine elements, so that the production requirements of spice-grade benzyl benzoate cannot be met. The by-product produced in the process of producing benzoic acid by oxidizing toluene contains a certain amount of benzyl benzoate, and the benzyl benzoate has a high boiling point and can exist in benzoic acid rectification residual liquid produced in the production process. The rectification residual liquid amount of the benzoic acid accounts for 5-7% of the total benzoic acid yield, and the rectification residual liquid amount of the benzoic acid mainly comprises the following components: benzoic acid, benzyl benzoate, catalyst cobalt salt manganese salt, fluorenone, etc.; wherein the content of benzyl benzoate accounts for 50-70% of the total amount of the rectification residual liquid. Because the benzoic acid is produced by adopting a toluene oxidation process, the byproduct benzyl benzoate does not contain chlorine, and if the benzyl benzoate can be purified, the benzyl benzoate has the natural advantage of perfume-grade application. However, the benzoic acid rectification residual liquid contains complex components and contains a plurality of substances with similar structures and physical properties to benzyl benzoate, and because the catalyst for toluene oxidation also exists in the rectification residual liquid, substances in the benzoic acid rectification residual liquid can continuously decompose low boiling point substances such as benzoic acid and the like when being heated. Thus, it is difficult to directly extract high-purity benzyl benzoate from the rectified benzoic acid residue.
At present, benzoic acid manufacturers treat benzoic acid rectification residual liquid as solid waste, or only rectify part of low-purity benzyl benzoate, the content and color and smell of the benzyl benzoate are poor, the general content is less than 50%, the color number is more than 300HZ, the benzyl benzoate rectification residual liquid has pungent smell, cannot meet the perfume grade application of the benzyl benzoate, can only be used as a low-end solvent, and the resource utilization rate and the economic value are low.
Disclosure of Invention
The invention provides a method for recovering perfume-grade benzyl benzoate from benzoic acid rectification residual liquid, which is used for solving the problems of low purity, dark color and pungent smell of the existing method for extracting benzyl benzoate from benzoic acid rectification residual liquid and the current situation that the perfume-grade benzyl benzoate is mainly produced by adopting a high-cost alcohol exchange method, so that the resource utilization rate of the benzoic acid rectification residual liquid is greatly improved, and the economic value is obviously improved.
In order to achieve the aim, the invention provides a method for recovering perfume-grade benzyl benzoate from benzoic acid rectification residual liquid, which comprises the following steps:
(1) introducing benzoic acid rectification residual liquid into a rectification tower, heating a tower kettle of the rectification tower through a falling film reboiler, and rectifying a benzyl benzoate crude product A in a reduced pressure rectification mode, wherein the pressure during reduced pressure rectification is 30-200 pa, the temperature of the tower kettle is 130-180 ℃, and the temperature of the tower top is 110-150 ℃;
(2) mixing and stirring the obtained benzyl benzoate crude product A and a sodium carbonate solution with the mass fraction of 10-30%, standing and layering to obtain a benzyl benzoate crude product B, and removing benzoic acid and most other impurities;
(3) feeding the obtained benzyl benzoate crude product B into a suspension crystallizer for crystallization treatment, wherein the temperature of the suspension crystallizer is-15-0 ℃, and growing crystals at constant temperature for 3-8 hours to obtain a large amount of fine crystals, wherein the crystals are benzyl benzoate crude product C;
(4) feeding the obtained benzyl benzoate crude product C into a centrifuge for centrifugal treatment, wherein the temperature of the centrifugal treatment is 20-30 ℃, the rotating speed is 1100-2800 rpm, and removing the mother liquor to obtain a benzyl benzoate crystal D;
(5) and leaching the obtained benzyl benzoate crystal D with pure benzyl benzoate at 25-50 ℃, centrifuging again, and repeatedly leaching and centrifuging for 3-5 times to obtain benzyl benzoate E.
Preferably, after the step (5), a step of completely melting the benzyl benzoate E at 40-60 ℃ is further provided. Because the solid material is inconvenient to transport, the benzyl benzoate which is discharged from the bin of the centrifuge and is convenient to transport is obtained after the solid material is melted.
Further, in the step (1), the pressure during the vacuum rectification is 50-130 pa, the temperature of a tower kettle is 150-175 ℃, and the temperature of a tower top is 120-140 ℃.
Further, in the step (2), the mass ratio of the benzyl benzoate crude product A to the sodium carbonate solution is 5-10: 1; the mass fraction of the sodium carbonate solution is preferably 15-25%; the temperature of the benzyl benzoate and the sodium carbonate solution during reaction is 30-60 ℃. The benzoic acid content of the treated crude product A of benzyl benzoate is about 3-5%, and the benzoic acid is mixed with a sodium carbonate solution and stirred for reaction, wherein the sodium carbonate solution is mainly used for neutralizing benzoic acid in benzyl benzoate. To ensure complete neutralization of benzoic acid, the lye needs to be slightly in excess, but excess lye will decompose benzyl benzoate, so the lye usage should be controlled well.
And further, in the step (3), the temperature of the suspension crystallizer during crystallization treatment is-12 to-9 ℃, and the crystals are grown for 4 to 5 hours at constant temperature.
And (4) further, in the step (4), the temperature of the centrifugal treatment is 24-27 ℃, and the rotating speed of the centrifugal machine is 1400-1800 rpm.
Further, in the step (5), leaching with pure benzyl benzoate at 30-40 ℃ during leaching treatment; and when the centrifugal treatment is carried out again, the temperature is 20-30 ℃.
The invention takes benzoic acid rectification raffinate generated in the production of benzoic acid by toluene oxidation as a raw material, firstly extracts a benzyl benzoate crude product by a reduced pressure rectification mode, then removes benzoic acid and most other impurities by alkali washing, and refines the benzyl benzoate crude product into colorless high-purity perfume-grade benzyl benzoate by steps of centrifugation, washing and the like after suspension crystallization treatment. During the vacuum rectification, if the high-boiling-point substance reaches 180 ℃, the low-boiling-point substance can be decomposed, and the higher the temperature, the higher the decomposition rate is, so the invention controls the proper pressure range and temperature range, thereby reducing the decomposition of the high-boiling-point substance in the benzoic acid rectification residual liquid, and controlling the impurity content in the benzyl benzoate from the source. Meanwhile, due to the low rectification temperature, the falling film reboiler is adopted, so that the energy consumption is reduced. By adopting the benzyl benzoate bulk suspension crystallization, the lower crystallization temperature and the longer crystal growing time are controlled during the suspension crystallization, so that the crystallization rate of the benzyl benzoate is higher and the crystals are purer. The solidifying point of the pure benzyl benzoate is 21 ℃, the solidifying point of the impurity-containing benzyl benzoate is lower, most of benzyl benzoate can be solidified when the temperature is controlled to be-15-0 ℃ and is preferably-11-9 ℃ during suspension crystallization, the main impurity is liquid and is remained in the mother liquor, and only a small amount of the impurity is attached to the solid surface of benzyl benzoate. Meanwhile, during centrifugal treatment, a higher centrifugal temperature is limited, so that the surface layer of the benzyl benzoate crystal can be melted, mother liquor and washing liquid attached to the benzyl benzoate are taken away, and impurity residues in the crystal are reduced; if the temperature is too high, the benzyl benzoate will melt in a large amount, and the yield and productivity will be reduced. After centrifugally separating the crystals and the mother liquor, the produced pure benzyl benzoate is directly used for washing the crystals, so that most impurities can be washed away without cooling or heating, the crystallized benzyl benzoate is not excessively melted, and other impurities are not introduced. The washed washing liquid directly returns to the suspension crystallizer for recrystallization, and the mother liquid can return to the suspension crystallizer or the rectifying tower according to actual conditions, thereby not only ensuring the purity of the product, but also ensuring the yield. The washed washing liquid is directly returned to the suspension crystallizer for recrystallization. The whole process does not need the participation of foreign matters, does not have additional discharge and pollution, and can improve the content of benzyl ester to 99.99 percent by controlling the washing times. Compared with the traditional alcohol exchange method, the method has the advantages of simpler operation and lower cost, and simultaneously, the content, color and smell of the benzyl benzoate produced by the method reach the standard of perfume grade use, so the economic benefit is improved. Practice proves that the content of the benzyl benzoate purified and refined by the method reaches 99.50-99.99%, the color number is 5-15 HZ, the benzyl benzoate has slight aromatic odor, and the use standard of perfume-grade benzyl benzoate is met. In addition, because the raw materials used in the invention are benzoic acid rectification residual liquid which is treated as hazardous waste before, other raw materials are not needed in the whole recovery process, the used energy sources are only water, electricity, steam and purified benzyl benzoate, and the energy consumption of the benzyl benzoate for heating rectification and suspension crystallization through a falling film reboiler is relatively low. Therefore, the recovery method of the invention also has the advantages of energy conservation, emission reduction, environmental protection and the like.
Drawings
FIG. 1 is a process flow diagram of the present invention for recovering fragrance-grade benzyl benzoate from benzoic acid rectification raffinate.
Detailed Description
The process of the present invention for recovering perfume-grade benzyl benzoate from benzoic acid rectification raffinate is described in further detail below with reference to the accompanying drawings and specific examples.
Example 1
Taking benzoic acid rectification raffinate generated in the process of oxidizing toluene in a factory A for producing benzoic acid to produce benzoic acid as a raw material, and treating the benzoic acid rectification raffinate according to the steps as shown in a process flow shown in figure 1:
(1) and (3) rectification under reduced pressure: introducing the benzoic acid rectification residual liquid into a rectification tower, heating a tower kettle of the rectification tower through a falling film reboiler, and simultaneously rectifying a benzyl benzoate crude product A in a reduced pressure rectification mode, wherein the reduced pressure rectification conditions are that the pressure is 50pa, the temperature of the tower kettle is 135 ℃, and the temperature of the tower top is 123 ℃, so that the content of the obtained benzyl benzoate crude product A is 96.41 percent (mass fraction), the color number is 140HZ, and the product has pungent smell;
(2) alkali washing: mixing the crude benzyl benzoate A and a sodium carbonate solution with the mass fraction of 20%, stirring and reacting, controlling the reaction temperature to be 40 ℃, standing and layering, and obtaining a crude benzyl benzoate B on the upper layer to remove benzoic acid and other impurities; the mass ratio of the benzyl benzoate crude product A to the sodium carbonate solution is 8: 1;
(3) and (3) crystallization treatment: the crude product B of the benzyl benzoate enters a suspension crystallizer, the temperature is reduced to-9 ℃, a large number of fine crystals are obtained through crystallization, then crystals are grown for 4 hours at constant temperature until the material is thick and the crystals are good, and a crude product C of the benzyl benzoate is obtained;
(4) and (3) centrifugal treatment: feeding the crude product C of benzyl benzoate into a centrifuge for centrifugal treatment, controlling the temperature at 27 ℃ and the rotating speed at 1800rpm during the centrifugal treatment, removing mother liquor to obtain a benzyl benzoate crystal D, and returning the mother liquor to a rectifying tower for rectification again;
(5) washing: and uniformly leaching the benzyl benzoate crystal D by using pure benzyl benzoate at 42 ℃, centrifuging again at 25 ℃, repeatedly leaching and centrifuging for 3 times, completely whitening the mother liquor at a material throwing port, operating the centrifuge at the rotating speed of 150rpm, and starting a scraper to scrape off the materials in the centrifuge. The mother liquor and the washed washing liquid are directly returned to the suspension crystallizer for recrystallization. Finally heating the materials to 56 ℃ and completely melting the materials to obtain a finished product E of benzyl benzoate.
Through detection, the content of E of the obtained benzyl benzoate finished product is 99.94% (mass fraction), the color number is 10HZ, and the fragrance is slight. The yield of benzyl benzoate in this example was 78%.
Example 2
Taking benzoic acid rectification raffinate generated in the process of oxidizing toluene to produce benzoic acid from a manufacturer B for producing benzoic acid as a raw material, and treating the benzoic acid rectification raffinate according to the steps as shown in a process flow shown in figure 1:
(1) and (3) rectification under reduced pressure: introducing the benzoic acid rectification residual liquid into a rectification tower, heating a tower kettle of the rectification tower through a falling film reboiler, and simultaneously rectifying a benzyl benzoate crude product A in a reduced pressure rectification mode, wherein the reduced pressure rectification conditions comprise the pressure of 70pa, the temperature of the tower kettle of 150 ℃ and the temperature of the tower top of 131 ℃, the content of the obtained benzyl benzoate crude product A is 95.50 percent (mass fraction), the color number is 180HZ, and the benzoic acid rectification residual liquid has pungent smell;
(2) alkali washing: mixing the crude benzyl benzoate A and a sodium carbonate solution with the mass fraction of 15%, stirring and reacting, controlling the reaction temperature to be 40 ℃, standing and layering, and obtaining a crude benzyl benzoate B on the upper layer to remove benzoic acid and other impurities; the mass ratio of the benzyl benzoate crude product A to the sodium carbonate solution is 10: 1;
(3) and (3) crystallization treatment: the crude product B of the benzyl benzoate enters a suspension crystallizer, the temperature is reduced to-11 ℃, a large number of fine crystals are obtained through crystallization, then the crystals are grown at constant temperature for 5 hours until the material is thicker and the crystals are better, and then a crude product C of the benzyl benzoate is obtained;
(4) and (3) centrifugal treatment: feeding the crude product C of benzyl benzoate into a centrifuge, centrifuging at the temperature of 24 ℃ and the rotating speed of 1400rpm, removing mother liquor to obtain a benzyl benzoate crystal D, and returning the mother liquor to the suspension crystallizer for recrystallization;
(5) washing: uniformly leaching the benzyl benzoate crystal D by using pure benzyl benzoate at 48 ℃, centrifuging again at 20 ℃ until no obvious mother liquor flows out of a discharge port, repeatedly leaching and centrifuging for 5 times, and completely whitening the mother liquor at the discharge port; the mother liquor returns to the rectifying tower for rectification again, and the washed washing liquid directly returns to the suspension crystallizer for recrystallization; and then, operating the centrifuge at the rotating speed of 300rpm, starting a scraper to scrape off materials in the centrifuge, and finally heating the materials to 48 ℃ to completely melt the materials to obtain a finished product E of benzyl benzoate.
Through detection, the content of the obtained benzyl benzoate finished product is 99.97% (mass fraction), the color number is 5HZ, the aromatic odor is slight, and the yield of benzyl benzoate is 73%.
Example 3
Taking benzoic acid rectification raffinate generated in the process of producing benzoic acid by oxidizing toluene in a certain benzoic acid production C factory as a raw material, and treating the benzoic acid rectification raffinate according to the steps as shown in a process flow shown in figure 1:
(1) and (3) rectification under reduced pressure: introducing the benzoic acid rectification residual liquid into a rectification tower, heating a tower kettle of the rectification tower through a falling film reboiler, and simultaneously rectifying a benzyl benzoate crude product A in a reduced pressure rectification mode, wherein the reduced pressure rectification conditions are that the pressure is 130pa, the temperature of the tower kettle is 170 ℃, and the temperature of the tower top is 138 ℃, so that the obtained benzyl benzoate crude product A has the content of 94.87% (mass fraction), the color number is 190HZ, and the product has pungent smell;
(2) alkali washing: mixing the crude benzyl benzoate A and a sodium carbonate solution with the mass fraction of 28% for reaction under stirring, controlling the reaction temperature to be 40 ℃, standing for layering, and obtaining a crude benzyl benzoate B on the upper layer to remove benzoic acid and other impurities; the mass ratio of the benzyl benzoate crude product A to the sodium carbonate solution is 6: 1;
(3) and (3) crystallization treatment: the crude product B of the benzyl benzoate enters a suspension crystallizer, the temperature is reduced to-12 ℃, a large number of fine crystals are obtained by crystallization, then the crystals are grown at constant temperature for 4 hours until the material is thicker and the crystals are better, and then the crude product C of the benzyl benzoate is obtained;
(4) and (3) centrifugal treatment: feeding the crude product C of benzyl benzoate into a centrifuge, centrifuging at the temperature of 26 ℃ and the rotating speed of 1400rpm, removing mother liquor to obtain a benzyl benzoate crystal D, and returning the mother liquor to the suspension crystallizer for recrystallization;
(5) washing: uniformly leaching the benzyl benzoate crystal D by using pure benzyl benzoate at 40 ℃, centrifuging again at 24 ℃ until no obvious mother liquor flows out of a discharge port, repeatedly leaching and centrifuging for 4 times, and completely whitening the mother liquor at the discharge port; the mother liquor returns to the rectifying tower for rectification again, and the washed washing liquid directly returns to the suspension crystallizer for recrystallization; and then, operating the centrifuge at the rotating speed of 300rpm, starting a scraper to scrape off materials in the centrifuge, and finally heating the materials to 50 ℃ to completely melt the materials to obtain a finished product E of benzyl benzoate.
Through detection, the content of the obtained benzyl benzoate finished product is 99.89% (mass fraction), the color number is 15HZ, the aromatic odor is slight, and the yield of benzyl benzoate is 85%.
Example 4
Taking benzoic acid rectification raffinate generated in the process of producing benzoic acid by oxidizing toluene from a certain benzoic acid production D factory as a raw material, and treating the benzoic acid rectification raffinate according to the steps as shown in a process flow shown in figure 1:
(1) and (3) rectification under reduced pressure: introducing the benzoic acid rectification residual liquid into a rectification tower, heating a tower kettle of the rectification tower through a falling film reboiler, and simultaneously rectifying a benzyl benzoate crude product A in a reduced pressure rectification mode, wherein the reduced pressure rectification conditions are that the pressure is 200pa, the temperature of the tower kettle is 175 ℃, and the temperature of the tower top is 132 ℃, so that the obtained benzyl benzoate crude product A has the content of 94.33% (mass fraction), the color number is 220HZ, and the obtained benzyl benzoate crude product A has pungent smell;
(2) alkali washing: mixing the crude benzyl benzoate A and a sodium carbonate solution with the mass fraction of 20%, stirring and reacting, controlling the reaction temperature to be 40 ℃, standing and layering, and obtaining a crude benzyl benzoate B on the upper layer to remove benzoic acid and other impurities; the mass ratio of the benzyl benzoate crude product A to the sodium carbonate solution is 8: 1;
(3) and (3) crystallization treatment: the crude product B of the benzyl benzoate enters a suspension crystallizer, the temperature is reduced to-14 ℃, a large number of fine crystals are obtained through crystallization, then the crystals are grown at constant temperature for 6 hours until the material is thicker and the crystals are better, and then a crude product C of the benzyl benzoate is obtained;
(4) and (3) centrifugal treatment: feeding the crude product C of benzyl benzoate into a centrifuge, centrifuging at the temperature of 25 ℃ and the rotating speed of 1400rpm, removing mother liquor to obtain a benzyl benzoate crystal D, and returning the mother liquor to the suspension crystallizer for recrystallization;
(5) washing: uniformly leaching the benzyl benzoate crystal D by using pure benzyl benzoate at 45 ℃, centrifuging again at 22 ℃ until no obvious mother liquor flows out of a discharge port, repeatedly leaching and centrifuging for 5 times, and completely whitening the mother liquor at the discharge port; the mother liquor returns to the rectifying tower for rectification again, and the washed washing liquid directly returns to the suspension crystallizer for recrystallization; the centrifuge was then run at 300rpm and the scraper was turned on to scrape the material off the centrifuge. Finally heating the materials to 45 ℃ and completely melting the materials to obtain a finished product E of benzyl benzoate.
Through detection, the content of the obtained benzyl benzoate finished product is 99.92 percent (mass fraction), the color number is 10HZ, the aromatic odor is slight, and the yield of the benzyl benzoate is 70 percent.
Example 5
Taking benzoic acid rectification raffinate generated in the oxidation of toluene in E factory for producing benzoic acid from a certain benzoic acid as a raw material, and treating the benzoic acid rectification raffinate according to the following steps in the process flow shown in figure 1:
(1) and (3) rectification under reduced pressure: introducing the benzoic acid rectification residual liquid into a rectification tower, heating a tower kettle of the rectification tower through a falling film reboiler, and simultaneously rectifying a benzyl benzoate crude product A in a reduced pressure rectification mode, wherein the reduced pressure rectification conditions are that the pressure is 50pa, the temperature of the tower kettle is 150 ℃, and the temperature of the tower top is 138 ℃, so that the obtained benzyl benzoate crude product A has the content of 94.87% (mass fraction), the color number is 190HZ, and the product has pungent smell;
(2) alkali washing: mixing and stirring the crude benzyl benzoate A and a sodium carbonate solution with the mass fraction of 22% for reaction, controlling the reaction temperature to be 40 ℃, standing for layering, and obtaining a crude benzyl benzoate B on the lower layer to remove benzoic acid and other impurities; the mass ratio of the benzyl benzoate crude product A to the sodium carbonate solution is 7: 1;
(3) and (3) crystallization treatment: the crude product B of the benzyl benzoate enters a suspension crystallizer, the temperature is reduced to-12 ℃, a large number of fine crystals are obtained by crystallization, then the crystals are grown at constant temperature for 4 hours until the material is thicker and the crystals are better, and then the crude product C of the benzyl benzoate is obtained;
(4) and (3) centrifugal treatment: feeding the crude product C of benzyl benzoate into a centrifuge, centrifuging at the temperature of 26 ℃ and the rotation speed of 1400rpm, removing mother liquor to obtain a benzyl benzoate crystal D, and returning the mother liquor to the suspension crystallizer for recrystallization;
(5) washing: uniformly leaching the benzyl benzoate crystal D by using pure benzyl benzoate at 40 ℃, centrifuging again at 24 ℃ until no obvious mother liquor flows out of a discharge port, repeatedly leaching and centrifuging for 4 times, and completely whitening the mother liquor at the discharge port; the mother liquor returns to the rectifying tower for rectification again, and the washed washing liquid directly returns to the suspension crystallizer for recrystallization; and then, operating the centrifuge at the rotating speed of 300rpm, and opening a scraper to scrape materials in the centrifuge to obtain a finished product E of the benzyl benzoate.
Through detection, the content of the obtained benzyl benzoate finished product is 99.73 percent (mass fraction), the color number is 15HZ, the aromatic odor is slight, and the yield of the benzyl benzoate is 85 percent.
Claims (10)
1. A method for recovering perfume-grade benzyl benzoate from benzoic acid rectification residual liquid is characterized in that: the method takes benzoic acid rectification residual liquid generated in the production of benzoic acid by toluene oxidation as a raw material, and comprises the following steps:
(1) introducing benzoic acid rectification residual liquid into a rectification tower, heating a tower kettle of the rectification tower through a falling film reboiler, and rectifying a benzyl benzoate crude product A in a reduced pressure rectification mode, wherein the pressure during reduced pressure rectification is 30-200 pa, the temperature of the tower kettle is 130-180 ℃, and the temperature of the tower top is 110-150 ℃;
(2) mixing and stirring the obtained benzyl benzoate crude product A and a sodium carbonate solution with the mass fraction of 10-30%, reacting, and standing for layering to obtain a benzyl benzoate crude product B;
(3) feeding the obtained benzyl benzoate crude product B into a suspension crystallizer for crystallization treatment, wherein the temperature of the suspension crystallizer is-15-0 ℃, and growing crystals at a constant temperature for 3-8 hours to obtain a benzyl benzoate crude product C;
(4) feeding the obtained benzyl benzoate crude product C into a centrifuge for centrifugal treatment, wherein the temperature of the centrifugal treatment is 20-30 ℃, the rotating speed is 1100-2800 rpm, and removing the mother liquor to obtain a benzyl benzoate crystal D;
(5) and leaching the obtained benzyl benzoate crystal D with pure benzyl benzoate at 25-50 ℃, centrifuging again, and repeatedly leaching and centrifuging for 3-5 times to obtain benzyl benzoate E.
2. The process of claim 1 for recovering a fragrance-grade benzyl benzoate from a rectified benzoic acid residue, wherein: after the step (5), the method further comprises the step of carrying out melting treatment on the benzyl benzoate E at the temperature of 40-60 ℃.
3. The process of claim 1 for recovering a fragrance-grade benzyl benzoate from a rectified benzoic acid residue, wherein: in the step (1), the pressure is 50-130 pa, the temperature of a tower kettle is 150-175 ℃, and the temperature of a tower top is 120-140 ℃ during vacuum rectification.
4. The process of claim 1 for recovering a fragrance-grade benzyl benzoate from a rectified benzoic acid residue, wherein: in the step (2), the mass ratio of the benzyl benzoate crude product A to the sodium carbonate solution is 5-10: 1.
5. the process of claim 1 for recovering a fragrance-grade benzyl benzoate from a rectified benzoic acid residue, wherein: in the step (2), the mass fraction of the sodium carbonate solution is 15-25%.
6. The process of claim 1 for recovering a fragrance-grade benzyl benzoate from a rectified benzoic acid residue, wherein: in the step (2), the reaction temperature of the benzyl benzoate and the sodium carbonate solution is 30-60 ℃.
7. The process of claim 1 for recovering a fragrance-grade benzyl benzoate from a rectified benzoic acid residue, wherein: in the step (3), the temperature of the suspension crystallizer during crystallization treatment is-12 to-9 ℃, and the crystals are grown for 4 to 5 hours at constant temperature.
8. The process of claim 1 for recovering a fragrance-grade benzyl benzoate from a rectified benzoic acid residue, wherein: in the step (4), the temperature of the centrifugal treatment is 24-27 ℃, and the rotating speed of the centrifugal machine is 1400-1800 rpm.
9. The process of claim 1 for recovering a fragrance-grade benzyl benzoate from a rectified benzoic acid residue, wherein: in the step (5), the rinsing treatment is carried out by rinsing with pure benzyl benzoate at 30-40 ℃.
10. The process of claim 1 for recovering a fragrance-grade benzyl benzoate from a rectified benzoic acid residue, wherein: in the step (5), the temperature during the second centrifugation treatment is 20-30 ℃.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811338048.8A CN109593037B (en) | 2018-11-12 | 2018-11-12 | Method for recovering perfume-grade benzyl benzoate from benzoic acid rectification residual liquid |
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| CN104030924A (en) * | 2013-12-03 | 2014-09-10 | 湖北微控生物科技有限公司 | Method for recovering and refining benzyl benzoate |
| CN106458827A (en) * | 2014-06-02 | 2017-02-22 | 苏舍化学技术有限公司 | Method for purification of benzoic acid |
| CN107501098A (en) * | 2017-08-28 | 2017-12-22 | 武汉有机实业有限公司 | The discoloration method of benzoic acid heavy byproducts Ergol |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN104030924A (en) * | 2013-12-03 | 2014-09-10 | 湖北微控生物科技有限公司 | Method for recovering and refining benzyl benzoate |
| CN106458827A (en) * | 2014-06-02 | 2017-02-22 | 苏舍化学技术有限公司 | Method for purification of benzoic acid |
| CN107501098A (en) * | 2017-08-28 | 2017-12-22 | 武汉有机实业有限公司 | The discoloration method of benzoic acid heavy byproducts Ergol |
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| Title |
|---|
| 《闪蒸-减压精馏分离苯甲酸废料》;韩檬等;《化学工程》;20070715;第35卷(第7期);第1-3页 * |
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