Preparation method of sodium adipate

Abstract

The invention belongs to the field of chemical engineering, and particularly relates to a preparation method of sodium adipate. Comprising the following steps: (1) adding a proper amount of sodium hydroxide into the ammonium adipate formation waste liquid, stirring at 25 + / -5 DEG C, and fully reacting until trivalent aluminum ions are converted into aluminum hydroxide precipitates; (2) drying and calcining aluminum hydroxide precipitate obtained by filtering the material obtained in the step (1) to obtain alumina powder; (3) filtering the filtrate obtained in the step (2) through a nanofiltration membrane to remove chloride ions; (4) heating and evaporating the filtrate obtained in the step (3), condensing steam to obtain ammonia water, and taking the residual filtrate as a sodium adipate solution; and (5) drying the sodium adipate solution obtained in the step (4) to obtain a sodium adipate solid. The invention provides the method for preparing sodium adipate by using the ammonium adipate formation waste liquid for the electrolytic capacitor low-voltage formation industry, aluminum hydroxide, aluminum oxide and ammonia water products are obtained at the same time, and the method is simple, feasible, safe, environment-friendly, low in cost and remarkable in social and economic benefits.

Description

Technical Field

[0001] The invention belongs to the technical field of chemical industry, and particularly relates to a method for preparing sodium adipate. Background Art

[0002] Sodium adipate (i.e. disodium adipate) is widely used in many fields. It is used as a pharmaceutical intermediate and mothproofing agent in the pharmaceutical industry. In plastic production, sodium adipate is an important raw material for the synthesis of polyester plastics. In paint and surface coating production, sodium adipate is widely used as an important component of resin ester polymers. In dyes and pigments, sodium adipate can be used as an intermediate and stabilizer in dyes and pigments. In the field of technical fibers, sodium adipate can be used to produce nylon fibers, polyester, etc. In the field of environmental protection, it can be used as a desulfurization additive. Sodium adipate is an effective metal corrosion inhibitor. It can be used in the formulation of mechanical hydraulic oils. It can be used to prepare water-soluble coatings and adhesives. In the field of fuel and energy, sodium adipate is used as a granular fuel additive to improve combustion efficiency. In leather processing, sodium adipate is used as a reducing agent and ketal agent. Sodium adipate can also be used as a hydrotrope, a buffer in pet feed, etc.

[0003] Due to its wide range of important applications, sodium adipate has become a very important chemical and is produced both at home and abroad. Currently, there are several methods for preparing sodium adipate: 1. Acid-base neutralization method: Adipic acid and sodium hydroxide are neutralized to obtain sodium adipate. The reaction equation is: HOOC(CH 2 ) 4 COOH + 2NaOH → NaOOC(CH 2 ) 4 COONa+2H 2 O.

[0004] 2. Sodium carbonate method: Sodium carbonate is reacted with adipic acid to produce sodium adipate. The reaction equation is: HOOC(CH 2 ) 4 COOH+Na 2 CO 3 →NaOOC(CH 2 ) 4 COONa+CO 2 ↑+H 2 O.

[0005] 3. Reaction of potassium hexanoate and sodium chloride: Sodium chloride and potassium hexanoate are reacted to obtain sodium adipate. The reaction equation is: KOOCC 5 H 11 + NaCl → NaOOC(CH 2 ) 4COONa+KCl.

[0006] 4. Methanol method: Adipic acid is reacted with methanol and sodium hydroxide under heating conditions to obtain methyl adipate, and then the obtained methyl adipate and sodium hydroxide are hydrolyzed to generate sodium adipate. The reaction equation is: HOOC(CH 2 ) 4 COOH+CH 3 OH+NaOH→HOOC(CH 2 ) 4 COOCH 3 +H 2 O HOOC(CH 2 ) 4 COOCH 3 +NaOH+H 2 O→NaOOC(CH 2 ) 4 COONa+CH 3 OH.

[0007] However, when preparing sodium adipate by the above method, the raw material cost is high, the side reaction is serious, the reaction conditions are difficult to control, and the industrial production is relatively dangerous. Due to the high raw material cost and poor safety, the market price of sodium adipate remains high.

[0008] On the other hand, in the electrolytic capacitor industry, the chemical process of low-voltage electronic aluminum foil is to form a dense oxide film (aluminum oxide) on the surface of the low-voltage corroded aluminum foil that has been electrochemically or chemically corroded to expand its surface area. This production process will inevitably produce a large amount of ammonium adipate chemical waste liquid. The ammonium adipate solution commonly used as the chemical electrolyte is prepared by adding high-purity water to capacitor-grade ammonium adipate, with a concentration of 10%. In the chemical production, the chemical electrolyte will be mixed with more impurity ions such as aluminum ions and chloride ions. When the content of impurity ions reaches a certain concentration, the electrical properties of the produced chemical foil products will not meet the expected requirements. If the defective chemical foil products are used to manufacture electrolytic capacitors, explosions will occur. Therefore, low-voltage foil manufacturers must replace the chemical solution after a certain period of use. Ammonium adipate is a high-value chemical raw material. Frequent replacement will increase the production cost of the product. Since ammonium adipate contains a large amount of organic matter and ammonium salts, if it is discharged directly, it will pollute the water body and the environment, fail to meet environmental protection requirements, and cause waste of resources. If the waste liquid is subjected to biochemical treatment, ammonia nitrogen, total nitrogen, COD, etc. in the waste liquid must be removed, and the investment cost and treatment cost are very high.

[0009] At present, the recovery and treatment methods of ammonium adipate are mostly to acidify the waste liquid of ammonium adipate with strong inorganic acid, so that the adipic acid radical combines with the hydrogen ion to form adipic acid, and then cool and crystallize to obtain adipic acid crystals. However, the adipic acid crystals thus obtained are not pure substances, but contain acid radical ions. To obtain pure adipic acid crystals, a large amount of pure water is required to be washed, which will produce a large amount of wastewater containing adipic acid and acid radicals, and the treatment cost of this wastewater is quite high.

[0010] In summary, the market needs a low-cost and highly safe method for preparing sodium adipate, and also needs a simple, easy, solid waste-free, low-wastewater discharge method for treating ammonium adipate waste liquid. Summary of the invention

[0011] In order to solve the deficiencies in the above-mentioned prior art, the present invention provides a method for preparing sodium adipate, and sodium adipate products and byproducts such as ammonia water, aluminum hydroxide, and aluminum oxide can be obtained by harmlessly treating and reusing the waste liquid of ammonium adipate. Among them, sodium adipate (disodium adipate) is an expensive and widely used chemical product; ammonia water is used in many fields such as agricultural fertilizers, pharmaceuticals, leather making, and cleaning; aluminum hydroxide is used in chemical raw materials, flame retardants, ceramics, sewage treatment, catalyst carriers, papermaking industry, etc.; aluminum oxide powder is a fine chemical product, which is widely used in many high-tech and cutting-edge industries such as aerospace, weapons, electrical insulation materials, integrated circuit substrates, high-speed cutting tools, high-strength wear-resistant and corrosion-resistant materials, high-intensity gas discharge lamps, phosphor carriers, single crystal materials, catalyst carriers, laser materials, etc. It is an important basic material for tri-color phosphors for green lighting, automotive sensors, magnetic tape additives, catalyst carrier coatings, semiconductors and liquid crystal displays, transparent high-pressure sodium lamps, precision instruments, and aviation optical devices.

[0012] The technical solution of the present invention is: a method for preparing sodium adipate, which comprises the following steps: (1) Add the waste liquid of ammonium adipate (containing chloride ions and aluminum ions) into a reaction tank, add an appropriate amount of sodium hydroxide therein, control the temperature at 25±5°C, stir, and react fully until the trivalent aluminum ions therein are converted into aluminum hydroxide precipitates, and remove the aluminum ions in the waste liquid of ammonium adipate; (2) filtering all the materials obtained in step (1) to filter out the aluminum hydroxide precipitate therein, and the aluminum hydroxide can be reused as an intermediate product. The obtained aluminum hydroxide precipitate is dried and calcined to obtain aluminum oxide powder; (3) filtering the filtrate obtained in step (2) through a nanofiltration membrane to remove chloride ions therein; (4) The filtrate obtained in step (3) is heated and evaporated, and the obtained steam is condensed to recover the ammonia gas therein to obtain ammonia water, which can be reused as a finished product, and the remaining filtrate is the sodium adipate solution.

[0013] (5) Drying the sodium adipate solution obtained in step (4) to obtain a sodium adipate solid product.

[0014] Further preferred solutions include: The aluminum hydroxide precipitate obtained in step (2) is dried and then calcined to obtain aluminum oxide powder.

[0015] The filtration in step (2) is performed by a plate and frame press.

[0016] The heating evaporation in step (4) is carried out in an evaporation reactor.

[0017] The drying in step (5) is carried out in a drying device.

[0018] Compared with the prior art, the method for preparing sodium adipate of the present invention has the following advantages: (1) The present invention provides a high-value product, sodium adipate, as well as aluminum hydroxide, aluminum oxide, and ammonia water by-products, thereby increasing the source of economic income, achieving a recycling rate of more than 90% of the waste liquid from ammonium adipate formation, and reducing environmental pressure.

[0019] (2) The investment cost of production equipment is low, it has high industrial utilization value and good economic benefits.

[0020] (3) The production process is simple and easy, the equipment used is all conventional equipment, and the maintenance cost is low.

[0021] (4) A new method for recycling and reusing ammonium adipate waste liquid in the low-voltage electrolytic capacitor formation industry is provided. The adipate, aluminum ions and ammonium ions in the waste liquid are effectively utilized. The treatment process is safe, environmentally friendly, has no solid waste, and has low wastewater discharge, with significant social and economic benefits. DETAILED DESCRIPTION

[0022] The present invention is further described in detail below in conjunction with embodiments.

[0023] The present invention is further described in detail below in conjunction with the examples, taking the treatment of 10 tons, 20 tons and 30 tons of ammonium adipate waste liquid (whose original concentration of the waste liquid is 10% ammonium adipate solution) as an example (wherein the aluminum content is 0.8N and the chlorine content is 10 mg / l); the examples provided are only for further elaboration of the characteristics and advantages of the present invention, rather than for limiting the scope of the claims of the present invention. Example

[0024] (1) 10 tons of ammonium adipate waste liquid was transported to the reaction tank, and 0.78 m3 of 30% sodium hydroxide solution was added to it. 3 , the reaction temperature is controlled at 25±5°C, stirred, and fully reacted until the trivalent aluminum ions are converted into aluminum hydroxide precipitates; (2) passing all the materials obtained in step (1) into a plate-and-frame filter press to separate the aluminum hydroxide precipitate, drying the obtained aluminum hydroxide precipitate to obtain an aluminum hydroxide product, and calcining the obtained aluminum hydroxide product to obtain 125 kg of alumina powder; (3) filtering the entire filtrate obtained in step (2) through a nanofiltration membrane. After passing through the nanofiltration membrane system, more than 80% of the chloride ions in the filtrate can be removed to obtain a small amount of chlorine-containing wastewater and sodium-containing ammonium adipate solution, wherein the chlorine content in the chlorine-containing wastewater is about 2 mg / l, which can meet the industrial wastewater discharge standard for discharge; (4) The sodium-containing ammonium adipate solution obtained in step (3) is fed into a reaction kettle, and the temperature is controlled at 80°C-95°C to obtain ammonia gas and sodium adipate solution. The obtained ammonia gas is condensed and recovered to obtain 0.4 tons of aqueous ammonia; (5) The sodium adipate solution obtained in step (4) is recovered into a drying device and the temperature is controlled at above 130° C., and finally 1.1 tons of sodium adipate solid product with a purity of 99% is obtained.

[0025] The recycling rate of the ammonium adipate waste liquid in this embodiment is 95%. Example

[0026] (1) 20 tons of ammonium adipate waste liquid was transported to the reaction tank, and 1.56 m3 of 30% sodium hydroxide solution was added to it. 3 , the reaction temperature is controlled at 25±5°C, stirred, and fully reacted until the trivalent aluminum ions are converted into aluminum hydroxide precipitates; (2) Passing all the materials obtained in step (1) into a plate-and-frame filter press to separate the aluminum hydroxide precipitate, drying the obtained aluminum hydroxide precipitate to obtain an aluminum hydroxide product, and calcining the obtained aluminum hydroxide product to obtain 256 kg of alumina powder; (3) filtering the entire filtrate obtained in step (2) through a nanofiltration membrane. After passing through the nanofiltration membrane system, more than 80% of the chloride ions in the filtrate can be removed to obtain a small amount of chlorine-containing wastewater and sodium-containing ammonium adipate solution, wherein the chlorine content in the chlorine-containing wastewater is about 2 mg / l, which can meet the industrial wastewater discharge standard for discharge; (4) feeding the sodium-containing ammonium adipate solution obtained in step (3) into a reaction kettle, controlling the temperature at 80°C-95°C, obtaining ammonia gas and sodium adipate solution, and condensing and recovering the obtained ammonia gas to obtain 0.8 tons of aqueous ammonia; (5) The sodium adipate solution obtained in step (4) is recovered into a drying device and the temperature is controlled at above 130° C., and finally 2.2 tons of sodium adipate solid product with a purity of 98% is obtained.

[0027] The recycling rate of the ammonium adipate waste liquid in this embodiment is 97%. Example

[0028] (1) 30 tons of ammonium adipate waste liquid was transported to the reaction tank, and 2.34 m3 of 30% sodium hydroxide solution was added to it. 3 , the reaction temperature is controlled at 25±5°C, stirred, and fully reacted until the trivalent aluminum ions are converted into aluminum hydroxide precipitates; (2) passing all the materials obtained in step (1) into a plate-and-frame filter press to separate the aluminum hydroxide precipitate therein, drying the obtained aluminum hydroxide precipitate to obtain an aluminum hydroxide product, and calcining the obtained aluminum hydroxide product to obtain 388 kg of alumina powder; (3) filtering the entire filtrate obtained in step (2) through a nanofiltration membrane. After passing through the nanofiltration membrane system, more than 80% of the chloride ions in the filtrate can be removed to obtain a small amount of chlorine-containing wastewater and sodium-containing ammonium adipate solution, wherein the chlorine content in the chlorine-containing wastewater is about 2 mg / l, which can meet the industrial wastewater discharge standard for discharge; (4) feeding the sodium-containing ammonium adipate solution obtained in step (3) into a reaction kettle, controlling the temperature at 80°C-95°C, obtaining ammonia gas and sodium adipate solution, and condensing and recovering the obtained ammonia gas to obtain 1.2 tons of aqueous ammonia; (5) The sodium adipate solution obtained in step (4) is recovered into a drying device and the temperature is controlled at above 130° C., and finally 3.4 tons of sodium adipate solid product with a purity of 97% is obtained.

[0029] In this embodiment, the recycling rate of the ammonium adipate waste liquid is 98%.

Claims

1. A method for preparing sodium adipate, characterized in that: It consists of the following steps: (1) Add the waste liquid of ammonium adipate into the reaction tank, add an appropriate amount of sodium hydroxide, control the temperature at 25±5°C, stir, and react fully until the trivalent aluminum ions therein are converted into aluminum hydroxide precipitate; (2) filtering all the materials obtained in step (1) to separate the aluminum hydroxide precipitate therein; (3) filtering the filtrate obtained in step (2) through a nanofiltration membrane to remove chloride ions therein; (4) The filtrate obtained in step (3) is heated and evaporated, and the obtained steam is condensed to recover the ammonia gas therein to obtain ammonia water, and the remaining filtrate is the sodium adipate solution.

2. (5) Drying the sodium adipate solution obtained in step (4) to obtain a sodium adipate solid product.

3. The method for preparing sodium adipate according to claim 1, characterized in that: The aluminum hydroxide precipitate obtained in step (2) is dried and then calcined to obtain aluminum oxide powder.

4. The method for preparing sodium adipate according to claim 1, characterized in that: The filtration in step (2) is performed by a plate and frame filter press.

5. The method for preparing sodium adipate according to claim 1, characterized in that: The heating evaporation in step (4) is carried out in an evaporation reactor.

6. The method for preparing sodium adipate according to claim 1, characterized in that: The drying in step (5) is carried out in a drying device.