Method for producing amino water reducer by using triclosan etherification wastewater extract

Abstract

The invention relates to the technical field of industrial wastewater, in particular to a method for producing an amino water reducing agent by using triclosan etherification wastewater extract, which comprises the following steps: (1) taking collected triclosan etherification wastewater, adjusting the pH value to be acidic, layering, and collecting upper-layer extract and lower-layer wastewater; (2) taking lower-layer wastewater, adding an extracting agent, stirring, and concentrating and crystallizing the collected lower-layer potassium chloride solution to obtain a potassium chloride product; an upper-layer extract and condensate water are reserved for use; and (3) taking condensate water, adding phenol, sodium sulfanilate, the upper-layer extract and the upper-layer extract, stirring, adjusting the pH value to be alkaline, heating, dropwise adding formaldehyde, continuously heating for reaction, cooling, adjusting the pH value, and adding water to adjust the solid content, thereby obtaining the amino water reducer. According to the method, zero discharge of the triclosan etherification waste liquid is realized, the current pollution situation of the phenol-containing waste water is effectively improved, the environment is protected, the triclosan etherification waste water is comprehensively utilized, and the method has good economic benefits and environmental protection benefits.

Description

Technical Field

[0001] This invention relates to the field of industrial wastewater technology, and in particular to a method for producing amino water-reducing agents using triclosan etherification wastewater extract. Background Technology

[0002] Triclosan is a safe, highly effective, and broad-spectrum antibacterial agent. In existing mature industrial production processes, the main domestic and international processes involve using 2,5-dichloronitrobenzene and 2,4-dichlorophenol as raw materials, reacting them via the Williamson reaction to form ethers, followed by nitro reduction, diazotization, hydrolysis, and purification to obtain the target product, triclosan. However, the etherification reaction requires harsh conditions, involves numerous side reactions, and generates highly concentrated phenol-containing wastewater with complex components. The main components include the raw materials 2,4-dichlorophenol and 2,5-dichloronitrobenzene, and byproducts such as 4-chloro-2-nitrophenol and 2,2',4-trichloro-2'-nitrodiphenyl ether. This wastewater is characterized by high COD concentration, difficulty in degradation, high toxicity, severe environmental pollution, and complex and difficult treatment processes.

[0003] Existing technologies disclose methods for treating triclosan etherification wastewater. In this method, a mixed extractant is added to the etherification wastewater, the pH is adjusted, and the mixture is stirred for extraction. The wastewater is further treated before discharge. The organic phase is back-extracted, the extractant is recycled, and the extract is reused in the etherification reaction. However, the organic matter recovered through extraction has a high impurity content, complex composition, and is difficult to separate. Therefore, the recovered material is not suitable for reuse as a raw material for triclosan etherification. Even with complex distillation processes, only the effective components can be utilized in the production process, while other impurities still need to be discharged. Reusing it in the triclosan etherification production process will significantly impact the quality of subsequent products, resulting in high costs for etherification wastewater recycling. Therefore, to address these issues, it is necessary to develop a method for producing amino water-reducing agents using extracts from triclosan etherification wastewater. Summary of the Invention

[0004] The technical problem to be solved by this invention is to provide a method for producing amino water-reducing agents using triclosan etherification wastewater extract, which effectively recycles and utilizes etherification wastewater and increases the economic benefits of enterprises by obtaining amino water-reducing agents.

[0005] To solve the above-mentioned technical problems, the technical solution of the present invention is as follows:

[0006] A method for producing an amino water-reducing agent using triclosan etherification wastewater extract, the method comprising the following steps:

[0007] (1) Take the collected triclosan etherification wastewater, adjust the pH to acidic, stir, let it stand and separate into layers, and collect the upper layer extract and the lower layer wastewater for later use.

[0008] (2) Take the lower layer wastewater mentioned in step (1), add extractant, stir, let stand and separate into layers, collect the lower layer potassium chloride solution, concentrate and crystallize to obtain potassium chloride product, and collect the condensate collected during the concentration of the potassium chloride solution for later use; add sodium hydroxide solution to the collected upper layer extract to adjust the pH, collect the back extract for later use, and collect the extractant for recycling.

[0009] (3) Take the condensate from step (2), add tap water, phenol, sodium p-aminobenzenesulfonate, the upper extract from step (1) and the back extract from step (2), stir, adjust the pH to alkaline, heat to the reaction temperature and add formaldehyde dropwise, continue to raise the temperature after the formaldehyde dropwise addition is completed, keep the temperature for a period of time and then lower the temperature, adjust the pH to no more than 8.5, add water to adjust the solid content, and you can get an amino water-reducing agent with a water reduction rate of not less than 25%.

[0010] As an improved technical solution, in step (1), hydrochloric acid is used to adjust the pH to 2-3, the stirring time is 20-40 min, and the standing time is 1-2 h.

[0011] As an improved technical solution, the extractant in step (2) is a non-polar solvent that is insoluble in water. The extractant includes benzene, toluene or xylene, and the extractant is mixed with the lower wastewater in a volume ratio of 1:3-4.

[0012] As an improved technical solution, the upper extract collected in step (2) is added to sodium hydroxide solution to adjust the pH to 14.

[0013] As an improved technical solution, in step (3), 32wt% liquid alkali is used to adjust the pH to 9-11 and the mixture is heated to a reaction temperature of 80-85℃.

[0014] As an improved technical solution, after the formaldehyde is added in step (3), the temperature is raised to 90-98℃, kept warm for 5-7 hours, and then cooled to 50-60℃, and the pH is adjusted to 7-8.5.

[0015] As an improved technical solution, water is added in step (3) to adjust the solid content to 35%-40%.

[0016] After adopting the above technical solution, the beneficial effects of the present invention are:

[0017] This invention provides a method for the resource utilization of triclosan etherification wastewater. In practice, the triclosan etherification wastewater is pretreated by acidification, causing most of the phenolic substances in the water to precipitate out and most of the organic matter to be separated, reducing the extraction pressure. The wastewater containing trace amounts of organic matter is further extracted with an extractant—back-extraction separation. The organic matter is used in the production of aminosulfonate water-reducing agents. Subsequently, the aqueous phase is adjusted to neutral with potassium hydroxide, concentrated, and crystallized to recover high-quality potassium chloride. The condensate is reused in the process water for triclosan etherification production or amino water-reducing agent preparation. This invention opens up a new way for the treatment and neutralization of triclosan etherification wastewater. Through this method, zero discharge of triclosan etherification wastewater is achieved, effectively improving the current pollution status of this type of phenol-containing wastewater. It not only protects the environment but also enables the comprehensive utilization of triclosan etherification wastewater, resulting in good economic and environmental benefits.

[0018] The method of this invention achieves a good integration of organic matter and the production process of amino water-reducing agents. The performance indicators of the amino water-reducing agent prepared using this invention all meet the performance and quality requirements of products produced using conventional processes. Furthermore, this method not only fully utilizes the organic matter in the waste liquid but also completely recovers and reuses the inorganic salt potassium chloride, aligning with the development requirements and trends of green chemistry. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0020] Example 1

[0021] A method for producing an amino water-reducing agent using triclosan etherification wastewater extract includes the following steps:

[0022] (1) Pump 3000L of wastewater (pH=14, COD=108192mg / L, salt content 35g / L) generated from the triclosan etherification process into the acidification kettle, add 220L of 35% hydrochloric acid under stirring, adjust the pH value to 2, continue stirring for 20min, let stand for 1h and then separate into layers, and obtain 2980L of lower layer wastewater and 260kg of upper layer extract for later use.

[0023] (2) Transfer the 2980L of lower layer wastewater (pH=2.5, COD=8035mg / L, salt content 35.2g / L) from step (1) into the extraction reactor. Add the extractant (benzene) at a volume ratio of 1:3 with the lower layer wastewater, stir for 0.5h, let stand for 1h to separate the layers, neutralize the collected lower layer aqueous phase with potassium hydroxide to pH 7, and obtain 1050kg of potassium chloride product by concentration and crystallization. Also, 2070L of condensate collected during the concentration of potassium chloride solution is reserved for use. Add 15% sodium hydroxide solution to the collected upper layer extract to adjust the pH to 14 for back-extraction. The extractant is recycled and 13.5kg of back-extraction liquid is collected for use.

[0024] (3) Take 150g of the condensate from step (2), and add 50g of tap water, 60g of phenol, and 165g of [unclear text - possibly a typo].

[0025] Sodium p-aminobenzenesulfonate, 23g of the upper extract from step (1) and 1g of the back-extraction liquid from step (2) were stirred, and the pH was adjusted to 9 with 6g of 32wt% liquid alkali. When the reaction temperature was heated to 80℃, 170g of formaldehyde was added dropwise. After the formaldehyde was added, the temperature was raised to 90℃. After the reaction was kept at this temperature for 5 hours, the temperature was lowered to 50℃, and the pH was adjusted to 7. Water was added to adjust the solid content to 35%, and the amino water-reducing agent was obtained.

[0026] Example 2

[0027] A method for producing an amino water-reducing agent using triclosan etherification wastewater extract includes the following steps:

[0028] (1) 3000L of wastewater (pH=14, COD=108192mg / L, salt content 35.1g / L) generated from the triclosan etherification process was pumped into the acidification reactor. 214L of 35% hydrochloric acid was added under stirring to adjust the pH value to 2.5. Stirring was continued for 30min. After standing for 1.5h, the layers were separated. 3050L of the lower layer wastewater and 263kg of the upper layer extract were obtained for later use.

[0029] (2) Transfer the 3050L of lower layer wastewater (pH=2.5, COD=8005mg / L, salt content 35.0g / L) from step (1) into the extraction reactor. Add the extractant (toluene) at a volume ratio of 1:3.5 with the lower layer wastewater, stir for 0.6h, let stand for 1.5h to separate the layers, neutralize the collected lower layer aqueous phase with potassium hydroxide to pH 7.3, and obtain 1065kg of potassium chloride product by concentration and crystallization. Also, 2005L of condensate collected during the concentration of potassium chloride solution is reserved for use. Add 15% sodium hydroxide solution to the collected upper layer extract to adjust the pH to 14 for back-extraction. The extractant is recycled, and 15.5kg of back-extraction liquid is collected for use.

[0030] (3) Take 150 mL of the condensate from step (2), add 50 mL of tap water, 40 g of phenol, 165 g of sodium p-aminobenzenesulfonate, 40 g of the upper extract from step (1) and 8 g of the back extract from step (2), stir, adjust the pH to 10 with 2.5 g of 32 wt% liquid alkali, heat to the reaction temperature of 83°C and add 170 g of formaldehyde dropwise. After the formaldehyde dropwise addition is completed, continue to raise the temperature to 95°C, keep the reaction temperature for 6 hours and then lower the temperature to 55°C, adjust the pH to 8, add water to adjust the solid content to 35%, and the amino water-reducing agent can be obtained.

[0031] Example 3

[0032] A method for producing an amino water-reducing agent using triclosan etherification wastewater extract includes the following steps:

[0033] (1) Pump 3000L of wastewater (pH=14, COD=108192mg / L, salt content 35g / L) generated from the triclosan etherification process into the acidification kettle, add 215L of 35% hydrochloric acid under stirring, adjust the pH value to 3, continue stirring for 40min, let stand for 2h and then separate into layers, and obtain 2985L of lower layer wastewater and 262kg of upper layer extract for later use.

[0034] (2) Transfer the 2985L of lower layer wastewater (pH=2.5, COD=8023mg / L, salt content 35.2g / L) from step (1) into the extraction reactor. Add the extractant (xylene) at a volume ratio of 1:4 with the lower layer wastewater, stir for 0.7h, let stand for 2h to separate the layers, neutralize the collected lower layer aqueous phase with potassium hydroxide to pH 7.5, and obtain 1063kg of potassium chloride product by concentration and crystallization. Also, 2013L of condensate collected during the concentration of potassium chloride solution is reserved for use. Add 15% sodium hydroxide solution to the collected upper layer extract to adjust the pH to 14 for back-extraction. The extractant is recycled and 17.0kg of back-extraction liquid is collected for use.

[0035] (3) Take 100 mL of the condensate from step (2), add 100 mL of tap water, 40 g of phenol, 165 g of sodium p-aminobenzenesulfonate, 38 g of the upper extract from step (1) and 10 g of the back extract from step (2), stir, adjust the pH to 10 with 2.2 g of 32 wt% liquid alkali, heat to the reaction temperature of 85 ℃ and add 170 g of formaldehyde dropwise. After the formaldehyde dropwise addition is completed, continue to raise the temperature to 98 ℃, keep the reaction temperature for 7 h and then lower the temperature to 60 ℃, adjust the pH to 8.5, add water to adjust the solid content to 35%, and the amino water-reducing agent can be obtained.

[0036] To better demonstrate that the amino water-reducing agent obtained by the process method of the present invention has better performance indicators, the following comparative examples are given. The concrete performance indicators were tested according to the requirements of GB8076-2008 "Concrete Admixtures", and the test results are shown in Table 1 below.

[0037] Comparative Example 1

[0038] Add 200g of tap water to a 500ml four-necked flask, along with 80g of phenol and 165g of sodium p-aminobenzenesulfonate, and stir until well combined. Stir the flask while stirring, then add approximately 6.5g of 32% alkali solution dropwise to adjust the pH to 10. Slowly raise the temperature to 80℃, then begin adding 170g of formaldehyde solution dropwise, completing the addition in about 1 hour. Raise the temperature to 95℃ and maintain this temperature for 6 hours. Cool the flask to 55℃, adjust the pH to 8, and add water to adjust the solid content to 35%. This is the standard commercial amino water-reducing agent.

[0039]

[0040] The data in Table 1 show that the amino water-reducing agents obtained in Examples 1-3 have similar product indicators to the comparative examples.

[0041] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for producing an amino water-reducing agent using triclosan etherification wastewater extract, characterized in that, The method includes the following steps: (1) Take the collected triclosan etherification wastewater, adjust the pH to acidic, stir, let it stand and separate into layers, and collect the upper layer extract and the lower layer wastewater for later use. (2) Take the lower layer wastewater mentioned in step (1), add extractant, stir, let stand and separate into layers, collect the lower layer potassium chloride solution, concentrate and crystallize to obtain potassium chloride product; add sodium hydroxide solution to the collected upper layer extract to adjust pH, collect the back extract for later use, and collect the extractant for recycling. (3) Take the condensate from step (2), add tap water, phenol, sodium p-aminobenzenesulfonate, the upper extract from step (1) and the back extract from step (2), stir, adjust the pH to alkaline, heat to the reaction temperature and add formaldehyde dropwise, continue to raise the temperature after the formaldehyde dropwise addition is completed, keep the temperature for a period of time and then lower the temperature, adjust the pH to no more than 8.5, add water to adjust the solid content, and you can get an amino water-reducing agent with a water reduction rate of not less than 25%.

2. The method for producing an amino water-reducing agent using triclosan etherification wastewater extract according to claim 1, characterized in that, In step (1), hydrochloric acid is used to adjust the pH to 2-3, the stirring time is 20-40 min, and the standing time is 1-2 h.

3. The method for producing amino water-reducing agent from triclosan etherification wastewater extract according to claim 1, characterized in that, The extractant in step (2) is a non-polar solvent that is insoluble in water. The extractant includes benzene, toluene or xylene, and the extractant is mixed with the lower wastewater in a volume ratio of 1:3-4.

4. The method for producing an amino water-reducing agent using triclosan etherification wastewater extract according to claim 1, characterized in that, The upper extract collected in step (2) was added to sodium hydroxide solution to adjust the pH to 14.

5. The method for producing an amino water-reducing agent using triclosan etherification wastewater extract according to claim 1, characterized in that, In step (3), 32wt% liquid alkali is used to adjust the pH to 9-11, and the mixture is heated to a reaction temperature of 80-85℃.

6. The method for producing an amino water-reducing agent using triclosan etherification wastewater extract according to claim 1, characterized in that, After the formaldehyde is added in step (3), continue to raise the temperature to 90-98℃, keep the temperature for 5-7 hours, then lower the temperature to 50-60℃, and then adjust the pH to 7-8.

5.

7. The method for producing an amino water-reducing agent using triclosan etherification wastewater extract according to claim 1, characterized in that, In step (3), water is added to adjust the solid content to 35%-40%.

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