CN111393280A - Decanedioic acid decoloring method - Google Patents
Decanedioic acid decoloring method Download PDFInfo
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- CN111393280A CN111393280A CN202010356883.5A CN202010356883A CN111393280A CN 111393280 A CN111393280 A CN 111393280A CN 202010356883 A CN202010356883 A CN 202010356883A CN 111393280 A CN111393280 A CN 111393280A
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- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C51/00—Preparation of carboxylic acids or their salts, halides or anhydrides
- C07C51/02—Preparation of carboxylic acids or their salts, halides or anhydrides from salts of carboxylic acids
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01D—COMPOUNDS OF ALKALI METALS, i.e. LITHIUM, SODIUM, POTASSIUM, RUBIDIUM, CAESIUM, OR FRANCIUM
- C01D5/00—Sulfates or sulfites of sodium, potassium or alkali metals in general
- C01D5/02—Preparation of sulfates from alkali metal salts and sulfuric acid or bisulfates; Preparation of bisulfates
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C51/00—Preparation of carboxylic acids or their salts, halides or anhydrides
- C07C51/42—Separation; Purification; Stabilisation; Use of additives
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Abstract
The invention provides a method for decoloring sebacic acid, and relates to the technical field of sebacic acid purification. Adding a castor oil microwave pyrolysis product into boiling water, and mixing to obtain an aqueous solution; neutralizing the water solution with sulfuric acid at the temperature of 90-95 ℃ until the pH value is 6.2-5.8, and separating the obtained reaction solution containing the sodium sebacate to obtain an oil phase and a first water phase containing the sodium sebacate; and carrying out liquid separation on the first water phase for multiple times at the temperature of 90-95 ℃ until no layering phenomenon is generated, washing the combined oil phase of the liquid separation by using boiling water, and acidifying the water phase obtained by liquid separation and washing by using sulfuric acid at the temperature of 90-95 ℃ until the pH value is 2.0-2.2 to obtain a reaction liquid containing sebacic acid. The method provided by the invention is simple and convenient to operate, can effectively decolorize the sebacic acid, greatly reduces the color value of a sebacic acid product, does not use decolorizing agents such as activated carbon, macroporous resin and the like, is low in cost and is more environment-friendly.
Description
Technical Field
The invention relates to the technical field of sebacic acid purification, and particularly relates to a method for decoloring sebacic acid.
Background
Sebacic acid is an important organic chemical raw material, and is widely applied to the production of chemical products due to the low toxicity and high temperature resistance of the sebacic acid. The castor oil microwave cracking technology has high production efficiency, does not need to be diluted by phenol, reduces environmental pollution, avoids equipment corrosion, and becomes a new way for producing the sebacic acid. However, natural castor oil is used as a raw material, and the natural pigments of castor oil, including natural pigments generated by fat-soluble substances such as lutein, chlorophyll, carotene and the like, cause color carrying of sebacic acid, so that the color value of a sebacic acid product is high, and thus, the sebacic acid needs to be decolored. In the prior art, sebacic acid is decolorized mainly by decolorizing agents with adsorption capacity such as activated carbon and macroporous resin, and the decolorizing mode usually requires a huge filter pressing device, and has the advantages of high cost, high labor intensity, limited adsorption capacity, difficult adsorbent regeneration and environmental pollution caused by improper treatment.
Disclosure of Invention
In view of the above, the present invention aims to provide a method for decolorizing sebacic acid, which can effectively decolorize sebacic acid, does not use decolorizing agents such as activated carbon and macroporous resin, and is low in cost and environment-friendly.
In order to achieve the above object, the present invention provides the following technical solutions:
the invention provides a method for decoloring sebacic acid, which does not use a decoloring agent and comprises the following steps:
(1) adding the castor oil microwave pyrolysis product into boiling water, and mixing to obtain an aqueous solution;
(2) neutralizing the water solution with sulfuric acid at the temperature of 90-95 ℃ until the pH value is 5.8-6.2 to obtain a neutralization reaction solution, wherein the neutralization reaction solution contains sodium sebacate; then, carrying out liquid separation on the neutralization reaction liquid, wherein the upper layer is a first oil phase, and the lower layer is a first water phase containing sodium sebacate;
(3) carrying out multiple times of liquid separation on the first water phase at the temperature of 90-95 ℃ until no layering phenomenon is generated, obtaining a second water phase, and combining the oil phase separated by the multiple times of liquid separation with the first oil phase in the step (2) to obtain a second oil phase; washing the second oil phase by using boiling water to obtain a third water phase; combining the second aqueous phase and the third aqueous phase to obtain a combined aqueous phase;
(4) and acidifying the combined water phase by using sulfuric acid at the temperature of 90-95 ℃ until the pH value is 2.0-2.2 to obtain an acid reaction solution, wherein the acid reaction solution contains sebacic acid.
Preferably, the ratio of the mass of the boiling water to the mass of the castor oil microwave cracking product in the step (1) is more than or equal to 8: 1.
preferably, the mixing in step (1) is performed under stirring; the stirring speed is 300-500 rpm.
Preferably, the molar concentration of the sulfuric acid in the step (2) and the step (4) is independently 1-3 mol/L.
Preferably, the step (3) is to stir the water phase to be subjected to liquid separation before each liquid separation; the stirring speed is 300-500 rpm, and the stirring time is 25-30 min.
Preferably, the number of times of the multiple liquid separation in the step (3) is 1-5.
Preferably, the volume ratio of the boiling water to the second oil phase in the step (3) is (8: 1) - (10: 1).
Preferably, after the acid reaction solution is obtained in the step (4), the method further comprises cooling the acid reaction solution to room temperature, sequentially filtering and drying a filter cake to obtain sebacic acid.
Preferably, after filtration, the method further comprises cooling and crystallizing the obtained filtrate to obtain sodium sulfate.
The invention provides a method for decoloring sebacic acid, which does not use a decoloring agent and comprises the following steps: (1) adding the castor oil microwave pyrolysis product into boiling water, and mixing to obtain an aqueous solution; (2) neutralizing the water solution with sulfuric acid at the temperature of 90-95 ℃ until the pH value is 5.8-6.2 to obtain a neutralization reaction solution containing sodium sebacate; then, carrying out liquid separation on the neutralization reaction liquid, wherein the upper layer is a first oil phase, and the lower layer is a first water phase containing sodium sebacate; (3) carrying out multiple times of liquid separation on the first water phase at the temperature of 90-95 ℃ until no layering phenomenon is generated, obtaining a second water phase, and combining the oil phase separated by the multiple times of liquid separation with the first oil phase in the step (2) to obtain a second oil phase; washing the second oil phase by using boiling water to obtain a third water phase; combining the second aqueous phase and the third aqueous phase to obtain a combined aqueous phase; (4) and acidifying the combined water phase by using sulfuric acid at the temperature of 90-95 ℃ until the pH value is 2.0-2.2 to obtain an acid reaction solution containing sebacic acid. The main component of castor oil microwave pyrolysis product is decanedioic acid disodium salt, the castor oil microwave pyrolysis product is dissolved in boiling water, then the water solution is neutralized into neutralization reaction liquid containing sodium decanedioic acid disodium salt by adopting sulfuric acid, the neutralization reaction liquid is subjected to oil-water separation for many times at high temperature by utilizing the characteristic that the sodium decanedioic acid is easy to dissolve in the boiling water, fat-soluble natural pigment is effectively removed, and then the sodium decanedioic acid disodium salt is acidified to obtain the decolored decanedioic acid product. The method provided by the invention is simple and convenient to operate, can effectively decolorize the sebacic acid, greatly reduces the color value of a sebacic acid product, does not use decolorizing agents such as activated carbon, macroporous resin and the like, is low in cost and is more environment-friendly.
Drawings
FIG. 1 is an appearance diagram of a sebacic acid product obtained in example 1;
FIG. 2 is an appearance of a sebacic acid product without decolorization treatment.
Detailed Description
The invention provides a method for decoloring sebacic acid, which does not use a decoloring agent and comprises the following steps:
(1) adding the castor oil microwave pyrolysis product into boiling water, and mixing to obtain an aqueous solution;
(2) neutralizing the water solution with sulfuric acid at the temperature of 90-95 ℃ until the pH value is 5.8-6.2 to obtain a neutralization reaction solution, wherein the neutralization reaction solution contains sodium sebacate; then, carrying out liquid separation on the neutralization reaction liquid, wherein the upper layer is a first oil phase, and the lower layer is a first water phase containing sodium sebacate;
(3) carrying out multiple times of liquid separation on the first water phase at the temperature of 90-95 ℃ until no layering phenomenon is generated, obtaining a second water phase, and combining the oil phase separated by the multiple times of liquid separation with the first oil phase in the step (2) to obtain a second oil phase; washing the second oil phase by using boiling water to obtain a third water phase; combining the second aqueous phase and the third aqueous phase to obtain a combined aqueous phase;
(4) and acidifying the combined water phase by using sulfuric acid at the temperature of 90-95 ℃ until the pH value is 2.0-2.2 to obtain an acid reaction solution, wherein the acid reaction solution contains sebacic acid.
According to the invention, the castor oil microwave pyrolysis product is added into boiling water and mixed to obtain an aqueous solution. In the present invention, the castor oil microwave pyrolysis product is preferably a dry castor oil microwave pyrolysis product; the main component of the castor oil microwave pyrolysis product is sebacic acid disodium salt, and the by-product is mainly fatty acid. In the present invention, the ratio of the mass of the boiling water to the mass of the castor oil microwave cleavage product is preferably greater than or equal to 8: under the condition of the mass ratio, the castor oil microwave cracking product can be more completely dissolved in boiling water. According to the invention, the castor oil microwave pyrolysis product is preferably slowly added into boiling water, and the invention has no special requirement on the specific adding speed, so that the castor oil microwave pyrolysis product is ensured not to generate a large amount of bubbles in the process of adding into the boiling water. In the present invention, the mixing is preferably performed under stirring; the stirring speed is preferably 300-500 rpm, and more preferably 400 rpm.
After an aqueous solution is obtained, the aqueous solution is neutralized by sulfuric acid to a pH value of 5.8-6.2 at 90-95 ℃ to obtain a neutralization reaction solution, the neutralization reaction solution contains sodium sebacate, then the neutralization reaction solution is subjected to liquid separation, the upper layer is a first oil phase, and the lower layer is a first water phase containing sodium sebacate, in the invention, the temperature condition of 90-95 ℃ is preferably realized by placing the aqueous solution in a water bath, the molar concentration of the sulfuric acid is preferably 1-3 mol/L, more preferably 2 mol/L, in the invention, the sulfuric acid is preferably dripped into the aqueous solution for neutralization, under the condition of the pH value of 5.8-6.2, the disodium sebacate in the aqueous solution is neutralized into sodium sebacate to obtain the neutralization reaction solution containing sodium sebacate, in the process of neutralization, meanwhile, a layering phenomenon occurs in the solution, the pH condition of the aqueous solution is strictly controlled, if the pH value is less than 5.8, the aqueous solution is converted into the disodium sebacate, the aqueous solution is not beneficial to be directly separated into a fat-soluble sodium sebacate aqueous phase, and the aqueous solution is not beneficial to separation of the fat-soluble sodium sebacate, and the aqueous solution is not beneficial to the separation of the fat-soluble sodium sebacate.
After the first water phase is obtained, the first water phase is subjected to liquid separation for multiple times at the temperature of 90-95 ℃ until no layering phenomenon is generated, a second water phase is obtained, and oil phases separated by the multiple liquid separation are combined with the first oil phase in the scheme to obtain a second oil phase. In the invention, the water phase to be subjected to liquid separation is preferably stirred before each liquid separation; the stirring speed is preferably 300-500 rpm, more preferably 400rpm, and the stirring time is preferably 25-30 min, more preferably 30 min. In the invention, the number of times of the multiple times of liquid separation is preferably 1-5, specifically, when the pH value of the neutralization reaction liquid is 6.2, the number of times of the multiple times of liquid separation is preferably 3-5, namely, the total number of times of liquid separation is 4-6; when the pH value of the neutralization reaction liquid is 5.8, the number of times of multiple times of liquid separation is preferably 1-2, namely the total number of times of liquid separation is 2-3. According to the invention, oil-water separation is carried out on the neutralization reaction liquid for multiple times at high temperature, fat-soluble natural pigments can be effectively removed, liquid separation is carried out for multiple times until no layering phenomenon occurs, and organic substances influencing the chromaticity of sebacic acid do not exist in the obtained second water phase.
After the second oil phase is obtained, the second oil phase is washed by boiling water to obtain a third water phase. In the present invention, the volume ratio of the boiling water to the second oil phase is preferably (8: 1) to (10: 1), and more preferably 9: 1. The oil phase is washed by boiling water, and the sodium sebacate in the oil phase enters the water phase, so that more sodium sebacate can be recovered. After obtaining the second aqueous phase and the third aqueous phase, the present invention combines the second aqueous phase and the third aqueous phase to obtain a combined aqueous phase.
After the water phases are combined, the combined water phase is acidified to a pH value of 2.0-2.2 by using sulfuric acid at 90-95 ℃ to obtain an acid reaction liquid, wherein the acid reaction liquid contains sebacic acid, the molar concentration of the sulfuric acid is preferably 1-3 mol/L, more preferably 2 mol/L, the sulfuric acid is preferably dripped into the combined water phase for acidification, white sebacic acid is continuously generated in the solution during acidification, and when the pH value is 2.0-2.2, the solution is in a white emulsion state, namely the acid reaction liquid containing sebacic acid.
After the acid reaction is obtained, the invention also preferably cools the acid reaction liquid to room temperature, and sequentially performs filtration and filter cake drying to obtain sebacic acid. The method of cooling is not particularly critical to the present invention and cooling methods known to those skilled in the art, such as natural cooling, may be used. The method of filtration is not particularly critical in the present invention, and filtration methods known to those skilled in the art, such as suction filtration, may be used. The invention has no special requirements on the drying temperature and time, and can remove the water in the filter cake fully, and the filter cake is dried to obtain the decolored sebacic acid.
After filtration, the invention also preferably cools and crystallizes the obtained filtrate to obtain sodium sulfate; the cooling crystallization conditions are not particularly required in the present invention, and those known to those skilled in the art can be used.
The method provided by the invention is simple and convenient to operate, can effectively decolorize the sebacic acid, greatly reduces the color value of a sebacic acid product, does not use decolorizing agents such as activated carbon, macroporous resin and the like, is low in cost and is more environment-friendly.
The method for decolorizing sebacic acid according to the present invention is described in detail with reference to the following examples, which should not be construed as limiting the scope of the present invention.
Example 1
(1) Taking 150 g of dry castor oil microwave pyrolysis product, slowly adding 1200m L boiled purified water for dissolving, stirring at the stirring speed of 300rpm, and preventing the generation of foam in the dissolving process to obtain an aqueous solution;
(2) dropwise adding 3 mol/L sulfuric acid into the aqueous solution under the condition of a high-temperature water bath at 90 ℃ until the pH value of the solution is 6.2, carrying out oil-water stratification in the solution during neutralization, carrying out first oil-water separation on the liquid through a separating funnel, collecting a lower-layer water phase as a first water phase, and collecting an upper-layer oil phase as a first oil phase;
(3) stirring the collected first water phase at the stirring speed of 300rpm for 30min at the temperature, allowing oil-water separation of the water phase again, performing oil-water separation for the second time through a separating funnel, and collecting the water phase and the oil phase respectively;
(4) continuing performing third and fourth oil-water separation on the collected water phase under the same temperature condition in the step (3), wherein the oil-water stratification phenomenon does not occur in the obtained water phase, and the collected water phase is marked as a second water phase which is light caramel color; combining the oil phases separated by the first oil-water separation to the fourth oil-water separation, marking as a second oil phase, and washing the second oil phase by using boiling water, wherein the volume ratio of the boiling water to the second oil phase is 8: washing to obtain a third water phase, and combining the second water phase and the third water phase to obtain a combined water phase;
(5) acidifying the combined aqueous phase obtained in step (4) with sulfuric acid of the above concentration at the above high temperature, wherein white sebacic acid is continuously generated in the solution, and the solution is in a white opaque state until the pH of the solution is 2.0; filtering the emulsion, drying the filter cake to obtain a sebacic acid product (shown in figure 1), and cooling and crystallizing the filtrate to obtain sodium sulfate.
The appearance of the sebacic acid product obtained in this example is shown in fig. 1, while the appearance of the sebacic acid product without decolorization is shown in fig. 2, and as can be seen from fig. 1 and fig. 2, the method provided by the present invention can effectively decolorize sebacic acid, and greatly reduce the color value of the sebacic acid product.
Example 2
(1) Taking 150 g of dry cracking products, slowly adding 1200m L boiled purified water for dissolving, stirring at the stirring speed of 300rmp, and preventing the generation of foam in the dissolving process to obtain an aqueous solution;
(2) under the condition of a high-temperature water bath at 95 ℃, 1 mol/L of sulfuric acid is dropwise added into the aqueous solution until the pH value of the solution is 5.8, oil-water stratification occurs in the solution during neutralization, the liquid is subjected to first oil-water separation through a separating funnel, the lower-layer water phase is collected and marked as a first water phase, and the upper-layer oil phase is marked as a first oil phase;
(3) stirring the collected first water phase at the stirring speed of 300rpm for 30min at the temperature, carrying out oil-water separation on the water phase again, carrying out oil-water separation for the second time through a separating funnel, and recording the collected water phase as a second water phase, wherein the water phase is light caramel; combining the oil phases separated from the first liquid separation to the second liquid separation, marking as a second oil phase, and washing the second oil phase by using boiling water, wherein the volume ratio of the boiling water to the second oil phase is 8: 1, washing to obtain a third water phase, and combining the second water phase and the third water phase to obtain a combined water phase;
(4) acidifying the combined aqueous phase obtained in step (3) at the high temperature by using sulfuric acid with the concentration, wherein white sebacic acid is continuously generated in the solution, and the solution is in a white opaque state until the pH value of the solution is 2.0; filtering the emulsion, drying the filter cake to obtain a sebacic acid product, and cooling and crystallizing the filtrate to obtain sodium sulfate.
The appearance of the sebacic acid product obtained in this example is similar to that of figure 1.
The embodiment shows that the method provided by the invention is simple and convenient to operate, can effectively decolorize the sebacic acid, greatly reduces the color value of the sebacic acid product, does not use decolorizing agents such as activated carbon, macroporous resin and the like, is low in cost and is more environment-friendly.
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 (9)
1. A method for decoloring sebacic acid is characterized by not using a decoloring agent and comprising the following steps:
(1) adding the castor oil microwave pyrolysis product into boiling water, and mixing to obtain an aqueous solution;
(2) neutralizing the water solution with sulfuric acid at the temperature of 90-95 ℃ until the pH value is 5.8-6.2 to obtain a neutralization reaction solution, wherein the neutralization reaction solution contains sodium sebacate; then, carrying out liquid separation on the neutralization reaction liquid, wherein the upper layer is a first oil phase, and the lower layer is a first water phase containing sodium sebacate;
(3) carrying out multiple times of liquid separation on the first water phase at the temperature of 90-95 ℃ until no layering phenomenon is generated, obtaining a second water phase, and combining the oil phase separated by the multiple times of liquid separation with the first oil phase in the step (2) to obtain a second oil phase; washing the second oil phase by using boiling water to obtain a third water phase; combining the second aqueous phase and the third aqueous phase to obtain a combined aqueous phase;
(4) and acidifying the combined water phase by using sulfuric acid at the temperature of 90-95 ℃ until the pH value is 2.0-2.2 to obtain an acid reaction solution, wherein the acid reaction solution contains sebacic acid.
2. The method according to claim 1, wherein the ratio of the mass of boiling water to the mass of castor oil microwave cleavage product in step (1) is greater than or equal to 8: 1.
3. the method according to claim 1 or 2, wherein the mixing in step (1) is performed under stirring; the stirring speed is 300-500 rpm.
4. The method according to claim 1, wherein the molar concentration of the sulfuric acid in the step (2) and the step (4) is independently 1-3 mol/L.
5. The method according to claim 1, wherein the step (3) is carried out by stirring the aqueous phase to be subjected to liquid separation before each liquid separation; the stirring speed is 300-500 rpm, and the stirring time is 25-30 min.
6. The method according to claim 1 or 5, wherein the number of times of the multiple times of liquid separation in the step (3) is 1-5 times.
7. The method according to claim 1, wherein the volume ratio of the boiling water to the second oil phase in step (3) is (8: 1) - (10: 1).
8. The method according to claim 1, wherein after the acid reaction solution is obtained in the step (4), the method further comprises cooling the acid reaction solution to room temperature, and sequentially filtering and drying a filter cake to obtain sebacic acid.
9. The method of claim 8, further comprising cooling and crystallizing the filtrate to obtain sodium sulfate.
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| CN202010356883.5A CN111393280A (en) | 2020-04-29 | 2020-04-29 | Decanedioic acid decoloring method |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113264823A (en) * | 2021-05-31 | 2021-08-17 | 丰益高分子材料（连云港）有限公司 | Method for improving stability of sebacic acid |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113264823A (en) * | 2021-05-31 | 2021-08-17 | 丰益高分子材料（连云港）有限公司 | Method for improving stability of sebacic acid |
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