Recovery method of light stabilizer 944 intermediate tert-octylamine sulfuric acid wastewater

Abstract

The invention discloses a light stabilizer 944 intermediate tert-octylamine sulfuric acid wastewater recovery method, which comprises: carrying out gradient cooling on tert-octylamine sulfuric acid wastewater to a temperature of-10 to-5 DEG C, standing for 4-6 h, and separating a high-viscosity oil layer; double-layer functional resin (outer-layer sulfonic group modified macroporous resin and inner-layer copper ion chelating resin) is adopted to adsorb and treat wastewater; after concentration, high-purity sulfuric acid (65-85%) is recovered; resin regeneration adopts methanol-ultrasonic leaching, dilute sulphuric acid backwashing and supercritical CO2 drying processes. According to the method, 99.5% of COD and 80% of ammonia nitrogen can be removed, the recovered sulfuric acid can be directly reused, the resin regeneration efficiency is improved by 50%, and the production cost is reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of wastewater treatment, and in particular relates to a method for recovering tert-octylamine sulfuric acid wastewater, an intermediate of a light stabilizer 944. Background Art

[0002] Tert-octylamine is widely used in chemical, pharmaceutical and other industries. It is mainly used as pharmaceutical synthesis solvent and synthetic light stabilizer 944. It is also used in the fields of medicine, pesticides, emulsifiers, dispersants, etc. Its market prospects are very broad.

[0003] At present, the mainstream production method of light stabilizer tert-octylamine in China and internationally is to first amidate and then hydrolyze to obtain tert-octylamine. Diisobutylene, acetonitrile, concentrated sulfuric acid, water and glacial acetic acid are amidated to obtain the intermediate N-tert-octylacetamide, which is then hydrolyzed and separated in liquid alkali to obtain the target product tert-octylamine. In the post-processing process of the product, a large amount of low-concentration, high-COD, high-ammonia nitrogen sulfuric acid wastewater is generated, which is difficult to apply. After direct concentration, the sulfuric acid water is easy to carbonize and turn black. After application, the product deteriorates, affecting the product performance. There are related reports that sulfuric acid wastewater containing COD is adsorbed by some ordinary macroporous resins and or acidic resins, and there is no resin for tert-octylamine sulfuric acid wastewater. If ordinary resin adsorption method is used, there are the following problems:

[0004] (1) Incomplete separation of the oil layer: The wastewater contains highly viscous organic matter, the sedimentation time at room temperature is long (>10h), the oil-water interface is blurred, and the resin is easily blocked;

[0005] (2) Low resin adsorption efficiency: A single resin cannot remove COD, sulfate and ammonia nitrogen simultaneously, requiring multi-stage treatment, which is costly;

[0006] (3) Complex regeneration process: Conventional acid / base regeneration results in a short resin life (<20 times) and produces secondary pollution.

[0007] Chinese patent CN112759161A discloses a method for recovering tert-butylamine from rubber accelerator TBBS wastewater. Although it uses cooling sedimentation combined with resin adsorption, it is not optimized for the characteristics of tert-octylamine wastewater, and there are problems such as residual oil phase and single resin function. Therefore, an efficient and low-cost integrated treatment solution is urgently needed. Summary of the invention

[0008] In order to solve the above problems, the present invention discloses a method for recovering tert-octylamine sulfuric acid wastewater which is an intermediate of light stabilizer 944.

[0009] To achieve the above object, the technical solution of the present invention is as follows:

[0010] A method for recovering tert-octylamine sulfuric acid wastewater, an intermediate of light stabilizer 944, comprises the following steps:

[0011] (1) The tert-octylamine sulfuric acid wastewater with low concentration, high COD and high ammonia nitrogen in the production of tert-octylamine is placed under stirring conditions, cooled to a low temperature, and then allowed to stand for sufficient sedimentation to separate a high-viscosity oil layer;

[0012] (2) Fill the resin adsorption tower with resin and fill the tower with water to make it moist and tight;

[0013] (3) Slowly pumping the sulfuric acid wastewater from the oil layer after sedimentation into the resin adsorption tower, maintaining a uniform rate of effluent collection;

[0014] (4) Concentrate the collected sulfuric acid wastewater after adsorption to obtain a high-concentration, low-COD, and low-ammonia nitrogen recovery solution.

[0015] As an improvement of the present invention, in step (1), the low-temperature sedimentation temperature is first cooled to 0°C and then further cooled to -10 to -5°C. The gradient cooling can reduce ice crystal formation and improve oil layer separation efficiency.

[0016] As an improvement of the present invention, the standing time in step (1) is 4 to 6 hours.

[0017] As an improvement of the present invention, the resin in step (2) is an organic heterocyclic waste acid macroporous adsorption modified resin, the outer layer of the resin is a sulfonic acid group-modified macroporous resin, and the inner layer of the resin is an aminocarboxylic acid chelating resin loaded with copper ions. The sulfonic acid group resin in the double-layer resin preferentially adsorbs sulfate to reduce the acidity of the wastewater; the copper ion chelating resin selectively binds ammonia nitrogen and organic amines.

[0018] As an improvement of the present invention, the resin pore diameter is 2 to 5 mm.

[0019] As an improvement of the present invention, the amount of the resin used is 0.2 to 0.5 times the amount of tert-octylamine sulfuric acid waste water used.

[0020] As an improvement of the present invention, the step (4) further includes a step (5) of a resin repeated regeneration method, wherein the specific steps of the resin repeated regeneration method are as follows:

[0021] S1. Use methanol-ultrasonic assisted elution at 40-50°C to dissolve the adsorbed organic matter and enhance desorption by ultrasonic cavitation;

[0022] S2. Use 5% dilute sulfuric acid to backwash, replace residual metal ions, and restore the resin acid sites;

[0023] S3. Using supercritical CO 2 The recovered resin is obtained by drying, which replaces the water washing to avoid the resin agglomeration caused by residual water.

[0024] As an improvement of the present invention, in the step (1), the sulfuric acid concentration of the tert-octylamine sulfuric acid wastewater is 10-15%, the COD is 35000-40000 ppm, and the ammonia nitrogen concentration is 7000-8000 ppm.

[0025] As an improvement of the present invention, in the step (4), the sulfuric acid concentration of the recovered solution is 65-85%, the COD is 100-300 ppm, and the ammonia nitrogen concentration is 250-350 ppm.

[0026] The beneficial effects of the present invention are:

[0027] (1) The present invention shortens the oil layer separation time to 4 to 6 hours (the traditional method requires 10 hours) through gradient cooling (-10 to -5°C) and double-layer resin synergistic effect, and the oil phase purity is ≥95%; the sulfonic acid resin adsorbs sulfate, the wastewater acidity is reduced by 30%, and the subsequent concentration energy consumption is reduced; the copper ion chelate resin has an ammonia nitrogen adsorption capacity of 120 mg / g, and the effluent ammonia nitrogen is ≤350ppm, and COD is ≤300ppm. The modified resin used in the present invention has a COD removal rate of 99.5% and an ammonia nitrogen removal rate of 95%.

[0028] (2) The present invention can obtain high-concentration, low-COD, low-ammonia-nitrogen colorless and transparent sulfuric acid by re-concentrating the sulfuric acid wastewater with low concentration, high COD and high ammonia nitrogen after the sulfuric acid wastewater is adsorbed by resin. The recovered sulfuric acid concentration reaches 85% and the purity is ≥98%, which can be directly used in the production of tert-octylamine, reducing the consumption of raw materials. After the tert-octylamine sulfuric acid wastewater treated by the present invention is used in the preparation of tert-octylamine, tert-octylamine with a qualified content can be prepared, and the cost of treating sulfuric acid wastewater as waste liquid is reduced.

[0029] (3) The modified resin of the present invention has a regeneration cycle of more than 50 times (conventional acid regeneration is only 20 times), and the regeneration energy consumption is reduced by 40%. Methanol-ultrasonic elution is used to achieve efficient desorption of organic matter, and supercritical CO 2 The regeneration process does not discharge wastewater, reducing production costs.

[0030] (4) The tert-octylamine sulfuric acid wastewater of the present invention is first subjected to low temperature to remove highly viscous oily substances, which can effectively reduce the amount of oily substances that adhere to the resin in the next step, and the amount of oily substances that need to be regenerated after use is increased from once the wastewater is used up to once every 8-10 times. The present invention integrates low-temperature sedimentation, resin adsorption, and concentration and reuse, reduces the equipment footprint, and is suitable for industrial continuous production. DETAILED DESCRIPTION

[0031] The present invention will be further explained below in conjunction with specific implementation modes. It should be understood that the following specific implementation modes are only used to illustrate the present invention and are not used to limit the scope of the present invention.

[0032] Unless otherwise specified, the experimental methods used in the following examples are conventional methods.

[0033] Unless otherwise specified, the materials and reagents used in the following examples can be obtained from commercial sources.

[0034] Example 1

[0035] 1800g of tert-octylamine sulfuric acid wastewater was added to a 3000mL glass reactor. The sulfuric acid concentration of the tert-octylamine wastewater was 13%, the COD was 38500ppm, and the ammonia nitrogen concentration was 8500ppm, as shown in Table 1. Stirring was started, and the cooling circulation system was turned on to cool down. When the temperature in the reactor dropped to -10°C, it was allowed to stand for 5 hours, and about 1790g of the lower water layer was separated.

[0036] Table 1: Test results of tert-octylamine wastewater raw water

[0037] Raw water COD(ppm) 38500 <![CDATA[N-NH 3 (ppm)]]> 8500 Sulfuric acid concentration (%) 13

[0038] 500g of resin was used to fill the glass adsorption tower. After adding water to moisten it, a peristaltic pump was used to slowly pump the separated tert-octylamine sulfuric acid wastewater into the adsorption tower for uniform adsorption. After the water was discharged, the COD was detected to be 120ppm and the ammonia nitrogen concentration was 330ppm. The test results of the recovered solution are shown in Table 2.

[0039] Table 2: Test results of tert-octylamine wastewater after treatment in Example 1

[0040] Sample 1 COD(ppm) 120 <![CDATA[N-NH 3 (ppm)]]> 330 Sulfuric acid concentration (%) 72

[0041] The concentrated water is distilled under negative pressure to remove water. When the concentration of sulfuric acid reaches 65-85%, the concentration is stopped. The test shows that the concentration of sulfuric acid water is 72% and the appearance is a colorless transparent liquid.

[0042] Example 2

[0043] 1500g of tert-octylamine sulfuric acid wastewater was added to a 3000mL glass reactor. The sulfuric acid concentration of the tert-octylamine wastewater was 13%, the COD was 38500ppm, and the ammonia nitrogen concentration was 8500ppm, as shown in Table 1. Start stirring and turn on the cooling circulation system to cool down. When the temperature in the reactor drops to -8°C, let it stand for 5 hours and separate about 1491g of the lower water layer.

[0044] Use 450g of resin to fill the glass adsorption tower, add water to moisten it, and use a peristaltic pump to slowly pump the separated tert-octylamine sulfuric acid wastewater into the adsorption tower for uniform adsorption. After the water is discharged, the COD is detected to be 111ppm, the ammonia nitrogen concentration is 275ppm, and the recovery solution test results are shown in Table 3.

[0045] Table 3: Test results of raw water for tert-octylamine wastewater after treatment in Example 2

[0046] Sample 2 COD(ppm) 111 <![CDATA[N-NH 3 (ppm)]]> 275 Sulfuric acid concentration (%) 77

[0047] The concentrated effluent is dewatered by negative pressure distillation. When the concentration is concentrated to a sulfuric acid concentration of 65-85%, the concentration is stopped. After testing, the concentration of this batch of sulfuric acid water is 77%, and the appearance is a colorless transparent liquid.

[0048] Example 3

[0049] Put 2000 g of tert-octylamine sulfuric acid wastewater into a 3000 mL glass reaction kettle. The sulfuric acid concentration of the tert-octylamine wastewater is 13%, the COD is 38500 ppm, and the ammonia nitrogen concentration is 8500 ppm. As shown in Table 1, start stirring, turn on the cooling circulation system to cool down. When the temperature in the kettle drops to -6 °C, let it stand for 7 hours, and separate out about 1988 g of the lower water layer.

[0050] Put 1300 g of the resin used 6 times into a flask, add 1500 mL of methanol, place it in an ultrasonic device, heat it to 40 °C, ultrasonicate for 2 hours, filter, and collect and concentrate the filtrate to recover methanol for repeated use.

[0051] Use 600 g of the filtered resin to fill the glass adsorption tower, backwash with 5% sulfuric acid, purge with supercritical carbon dioxide, then wet and compact it with water. Use a peristaltic pump to slowly pump the separated tert-octylamine sulfuric acid wastewater into the adsorption tower for uniform adsorption. After the water outlet is completed, the COD is detected to be 186 ppm, and the ammonia nitrogen concentration is 305 ppm. The detection results of the recovered solution are shown in Table 4.

[0052] Table 4: Detection results of the raw water of tert-octylamine wastewater after treatment in Example 3

[0053] Sample 3 COD(ppm) 186 <![CDATA[N-NH 3 (ppm)]]> 305 Sulfuric acid concentration (%) 82

[0054] The concentrated effluent is dewatered by negative pressure distillation. When the concentration is concentrated to a sulfuric acid concentration of 65-85%, the concentration is stopped. After testing, the concentration of this batch of sulfuric acid water is 82%, and the appearance is a colorless transparent liquid.

[0055] Example 4

[0056] Put 900 g of tert-octylamine sulfuric acid wastewater into a 3000 mL glass reaction kettle. The sulfuric acid concentration of the tert-octylamine wastewater is 13%, the COD is 38500 ppm, and the ammonia nitrogen concentration is 8500 ppm. As shown in Table 1, start stirring, turn on the cooling circulation system to cool down. When the temperature in the kettle drops to -8 °C, let it stand for 7 hours, and separate out about 892 g of the lower water layer.

[0057] Use 300g of recovered resin to fill the glass adsorption tower, add an appropriate amount to rinse once, and then moisten with water. Use a peristaltic pump to slowly pump the separated tert-octylamine sulfuric acid wastewater into the adsorption tower for uniform adsorption. After the water is discharged, the COD is detected to be 179ppm, the ammonia nitrogen concentration is 311ppm, and the recovery solution test results are shown in Table 5.

[0058] Table 5: Test results of tert-octylamine wastewater after treatment in Example 4

[0059]

[0060]

[0061] The concentrated water is distilled under negative pressure to remove water. When the concentration of sulfuric acid reaches 65-85%, the concentration is stopped. The test shows that the concentration of sulfuric acid water is 79.5% and the appearance is colorless transparent liquid.

[0062] It should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. For ordinary technicians in this technical field, several improvements and modifications can be made on the basis of the above embodiments without departing from the principles of the present invention. These improvements and modifications all fall within the scope of protection of the claims of the present invention.

Claims

1. A method for recovering tert-octylamine sulfuric acid wastewater from light stabilizer 944 intermediate, characterized in that: The steps include: (1) The tert-octylamine sulfuric acid wastewater produced by the production of tert-octylamine is stirred to a low temperature, and then allowed to stand for sufficient sedimentation to separate the highly viscous oil layer; (2) Use resin to fill the resin adsorption tower, and fill the tower with water to make it moist and tight; (3) Slowly pump the sulfuric acid wastewater from which the oil layer is separated after sedimentation into the resin adsorption tower, and collect the effluent at a uniform rate; (4) Concentrating the collected sulfuric acid wastewater after adsorption to obtain a recovery solution.

2. The method for recovering tert-octylamine sulfuric acid wastewater of light stabilizer 944 intermediate according to claim 1, characterized in that: In the step (1), the low temperature precipitation temperature is first cooled to 0°C and then further cooled to -10~-5°C.

3. The method for recovering tert-octylamine sulfuric acid wastewater of light stabilizer 944 intermediate according to claim 1, characterized in that: The standing time in step (1) is 4 to 6 hours.

4. The method for recovering tert-octylamine sulfuric acid wastewater of light stabilizer 944 intermediate according to claim 1, characterized in that: The resin in step (2) is an organic heterocyclic waste acid macroporous adsorption modified resin, the outer layer of the resin is a sulfonic acid group-modified macroporous resin, and the inner layer of the resin is an aminocarboxylic acid chelating resin loaded with copper ions.

5. The method for recovering tert-octylamine sulfuric acid wastewater of light stabilizer 944 intermediate according to claim 4, characterized in that: The resin pore size is 2-5 mm.

6. The method for recovering tert-octylamine sulfuric acid wastewater of light stabilizer 944 intermediate according to claim 4, characterized in that: The amount of the resin used is 0.2 to 0.5 times the amount of tert-octylamine sulfuric acid wastewater used.

7. The method for recovering tert-octylamine sulfuric acid wastewater, an intermediate of light stabilizer 944, according to claim 1, is characterized in that: After step (4), the method further includes step (5) of a resin repeated regeneration method, wherein the specific steps of the resin repeated regeneration method are as follows: The resin was recovered by methanol-ultrasonic assisted elution at 40-50°C, followed by backwashing with 5% dilute sulfuric acid, and finally drying with supercritical CO2.

8. The method for recovering tert-octylamine sulfuric acid wastewater, an intermediate of light stabilizer 944, according to claim 1, is characterized in that: In the step (1), the sulfuric acid concentration of the tert-octylamine sulfuric acid wastewater is 10-15%, the COD is 35000-40000 ppm, and the ammonia nitrogen concentration is 7000-8000 ppm.

9. The method for recovering tert-octylamine sulfuric acid wastewater of light stabilizer 944 intermediate according to claim 1, characterized in that: In the step (4), the sulfuric acid concentration of the recovered solution is 65-85%, the COD is 100-300 ppm, and the ammonia nitrogen concentration is 250-350 ppm.

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