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Method for treating wastewater in process for synthesizing N-phenylmaleimide by one-step method

A technology of maleimide and treatment method is applied in the field of treatment of wastewater from one-step synthesis of N-phenylmaleimide process, and can solve the problems of large amount of production, limited COD removal rate and high treatment cost

Pending Publication Date: 2021-09-10
SINOPEC NANJING RES INST OF CHEM IND CO LTD +2
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

For wastewater with high COD value, if the Fenton oxidation method is used for pretreatment directly, on the one hand, the COD removal rate is limited, the treatment cost is high, and a large amount of iron sludge will be generated, and additional treatment units will be added later. On the other hand, Fenton oxidation Reagents and catalysts must be added step by step for many times, otherwise a large amount of foam will be generated, making the reaction impossible, and the reaction time may be as long as more than 10 days
Therefore, wastewater with a high COD value is not suitable for direct pretreatment by Fenton oxidation.

Method used

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  • Method for treating wastewater in process for synthesizing N-phenylmaleimide by one-step method

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Experimental program
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Effect test

Embodiment 1

[0034] N-PMI wastewater (COD value 210115 mg / L) was neutralized to pH = 4 by adding lye, stirred evenly and suction filtered to obtain a clarified filtrate. Fill the catalytic oxidation reactor with activated carbon catalyst, the filling volume is 1 / 2 of the volume of the reactor, and add water until the liquid level is flush with the catalyst level. The filtrate and air were passed through the top and bottom of the catalytic oxidation reactor respectively, and the volume flow rate of the catalyst was 20 h -1 , The ratio of filtrate to air flow rate is 1:150. Under the action of the catalyst, the gas-liquid contacts in countercurrent, and an oxidation reaction occurs at room temperature to generate catalytic oxidation wastewater with a COD value of 14560 mg / L. Add the catalytic oxidation wastewater to the Fenton reactor, add acid to pH = 4, and then add Fenton’s reagent (30% H 2 o 2 solution) and catalyst (FeSO 4 ), H in the reaction system 2 O, H 2 o 2 , FeSO 4 The ma...

Embodiment 2

[0036] N-PMI wastewater (COD value 210115 mg / L) was neutralized to pH = 4 by adding lye, stirred evenly and suction filtered to obtain a clarified filtrate. Fill the catalytic oxidation reactor with activated carbon catalyst, the filling volume is 1 / 2 of the volume of the reactor, and add water until the liquid level is flush with the catalyst level. The filtrate and air were passed through the top and bottom of the catalytic oxidation reactor respectively, and the volume flow rate of the catalyst was 30 h -1 , The ratio of filtrate to air flow rate is 1:180. Under the action of the catalyst, the gas-liquid contacts in countercurrent, and an oxidation reaction occurs at room temperature to generate catalytic oxidation wastewater with a COD value of 13970 mg / L. Add the catalytic oxidation wastewater to the Fenton reactor, add acid to pH = 4, and then add Fenton’s reagent (30% H 2 o 2 solution) and catalyst (FeSO 4 ), H in the reaction system 2 O, H 2 o 2 , FeSO4 The mass...

Embodiment 3

[0038] N-PMI wastewater (COD value 210115 mg / L) was neutralized to pH = 4 by adding lye, stirred evenly and suction filtered to obtain a clarified filtrate. Fill the catalytic oxidation reactor with activated carbon catalyst, the filling volume is 1 / 2 of the volume of the reactor, and add water until the liquid level is flush with the catalyst level. The filtrate and air were passed through the top and bottom of the catalytic oxidation reactor respectively, and the volume flow rate of the catalyst was 25 h -1 , The ratio of filtrate to air flow rate is 1:200. Under the action of the catalyst, the gas-liquid contacts in countercurrent, and an oxidation reaction occurs at room temperature to generate catalytic oxidation wastewater with a COD value of 11430 mg / L. Add the catalytic oxidation wastewater to the Fenton reactor, add acid to pH = 4, and then add Fenton’s reagent (30% H 2 o 2 solution) and catalyst (FeSO 4 ), H in the reaction system 2 O, H 2 o 2 , FeSO 4 The ma...

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Abstract

The invention relates to a method for treating wastewater in a process for synthesizing N-PMI by a one-step method. The method comprises the following steps: (1) catalytic oxidation; and (2) Fenton oxidation. The wastewater can be directly subjected to biochemical treatment. Compared with a direct Fenton oxidation method, the method has the advantages that the treatment process is simplified, and the treatment cost is obviously reduced. Compared with an existing method for treating the N-PMI wastewater in patent literature, the process is suitable for treating the wastewater with higher acid content, secondary pollution such as solid waste cannot be generated in the treatment process, and the process is more economical and environmentally friendly, so that the process has better application prospects.

Description

technical field [0001] The invention relates to a treatment method for one-step synthesis of N-phenylmaleimide process wastewater, and belongs to the fields of chemical treatment and chemical technology. Background technique [0002] N-phenylmaleimide (N-PMI for short) is a polymer heat-resistant modifier that has emerged in recent years, mainly used in pesticides, medicines, ship antifouling agents and ABS, PVC, PMMA resins and photosensitive Heat-resistant modification of materials. With the rapid development of the global automobile industry and electrical appliance industry in recent years, the output of high heat-resistant plastics is also increasing, and the demand for N-PMI is also increasing year by year. [0003] At present, the industrial production of N-PMI mainly adopts the azeotropic method, that is, a two-step method, including two-step reactions of amination and dehydration cyclization. However, domestically produced N-PMI products often have disadvantages s...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C02F9/04C02F1/72C02F1/74C02F103/36
CPCC02F9/00C02F1/001C02F1/66C02F1/725C02F1/74C02F1/722C02F2103/36C02F2305/026
Inventor 史乐萌吴钊姚卫舟付春高留冕韦志强
Owner SINOPEC NANJING RES INST OF CHEM IND CO LTD
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