Cleaning production process of iminodiacetic acid

Abstract

The invention relates to a cleaning production process of preparing iminodiacetic acid with iminodiacetic acid sodium salts as raw materials. The invention is characterized in that iminodiacetic acid sodium salts are used as the raw materials and a membrane integration technique is used to prepare iminodiacetic acid. The particular process comprises the following steps: 1) iminodiacetic acid sodium salts are used as the raw materials, softened water or crystallized mother liquors of diacetate is added, and the weight percentage of the iminodiacetic acid sodium salts is diluted to 5%-30%; 2) the solution in the step 1 passes through a multi-medium filter containing activated carbons at a flow rate of 2-20 m / h for removing mechanical impurities and sticky substances and is filtered through one or more combination of a precision filter, a micropore filter and a ultrafiltration membrane for removing micron, sub-micron and macromolecular impurities; 3) the solution is introduced to an electrodialyzer for electrodialysis to control PH=1-5 at a salt chamber for obtaining the iminodiacetic acid solution and obtain a sodium hydroxide solution at a base chamber; 4) the temperature of the iminodiacetic acid solution obtained in the step 3) is reduced to the temperature of -5 to 20 DEG C or the temperature of 5 DEG C below zero to 20 DEG C following the regulation of PH=1.2 -3 to precipitate the IDA solid, and then the residual mother liquor is concentrated with a membrane to remove water and the concentrated liquid returns to crystallization.

Description

technical field [0001] The invention relates to a clean production process for preparing iminodiacetic acid by using iminodiacetic acid sodium salt as a raw material, and belongs to the field of preparation methods of chemical product intermediate iminodiacetic acid. Background technique [0002] Iminodiacetic acid (IDA) is an important raw material and intermediate for surfactants, complexing agents, synthetic metal surface treatment materials and ion exchange resins. Its largest use is to produce the herbicide glyphosate. At present, the technologies for industrialized production of iminodiacetic acid mainly include chloroacetic acid method, nitrilotriacetic acid method, hydrocyanic acid method and diethanolamine method. These processes are to first produce iminodiacetic acid sodium salt, and then obtain For iminodiacetic acid, the used or reported desalination methods include hydrochloric acid acidification method, sulfuric acid acidification method, hot filtration method...

AI Technical Summary

Problems solved by technology

This method is easy to form calcium salt precipitation because iminodiacetic acid has very strong complexation, and yield is very high, but generates a large amount of calcium chloride waste liquids again while acidifying with hydrochloric acid, is more difficult to handle, causes water pollution

Chinese patent CN101186581A proposes a method of directly using iminodiacetic acid sodium salt to produce glyphosate without going through the process steps of producing iminodiacetic acid, so that a large amount of sodium chloride is produced as a by-product in the process of producing bisaminodiacetic acid. The whole system is viscous, and the mixing equipment is severely corroded, which not only affects the production capacity, but also has a large amount of waste water

Yang Hongquan and others used electrodialysis to prepare IDA in the article "Research on the Preparation of Iminodiacetic Acid" (Chemical Production and Technology. 2007, 14(2). 28-31). The resulting product has good quality, high yield and no waste water discharge , but this method only uses a cation exchange membrane, which leads to low equipment efficiency, complicated operation, and produces a large amount of hydrogen and oxygen, which has potential safety hazards

Xu Liuxing and others proposed a method of acidifying DA with concentrated sulfuric acid in "New Synthesis Process of Glylin Intermediate Iminodiacetic Acid" (Pesticides. 2006, 45(11). 751-753), and the product purity reached 99.3%. , but the yield is only 85%, which cannot meet the needs of industrialization

Zeng Xiaojun proposed a method for preparing iminodiacetic acid with bipolar electrodialysis membrane in the article "Application of bipolar electrodialysis membrane in the preparation of iminodiacetic acid" (Fine Chemical Industry, 2002 No. 4), and the obtained product Good quality and high yield, but the solution after electrodialysis needs to be evaporated and recrystallized, and the mother liquor after crystallization needs to be evaporated again, which causes the problems of high steam consumption and energy waste

[0003] The above methods are either complicated in process, high in cost, and high in energy consumption, or consume a lot of raw materials and wastes, which are difficult to accept in industrial production.

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