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Process for preparing EDTA disodium salt

A technology of ethylenediaminetetraacetic acid disodium salt and ethylenediamine, applied in the field of preparation of ethylenediaminetetraacetic acid disodium salt, can solve the problem of high production cost

Inactive Publication Date: 2007-04-11
四川省天然气化工研究院
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] This method has the disadvantage that the production cost is higher due to the need to first synthesize EDTA, and then synthesize EDTA disodium salt through EDTA tetrasodium salt.

Method used

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  • Process for preparing EDTA disodium salt

Examples

Experimental program
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Effect test

Embodiment 1

[0019] Mix 15.1 g of ethylenediamine 99.4% by mass and 173.3 g of sodium hydroxide 30% by mass in a 250ml three-flask of 250 ml with a thermometer, condenser, and stirrer, and heat up at 85°C Within 5 hours, 163 g of hydroxyacetonitrile with a mass percent content of 35% was added dropwise. After the drop was completed, the temperature was raised to 110° C. to react for 30 minutes, and 130 g of water and 0.2 g of hydrogen peroxide were added. Add 75g of EDTA to adjust the pH value of the reaction solution to 5-6. Add activated carbon to the reaction solution for decolorization, add 42g of EDTA to the decolorized reaction solution to adjust the pH value to 3.5-4.5, concentrate, crystallize, separate and dry the reaction solution to obtain 147.5g of white crystalline product of EDTA disodium salt, content 99.3% , Yield 60.5% (calculated as sodium hydroxide). After separating the disodium salt of EDTA, the mother liquor can be acidified with sulfuric acid to obtain EDTA, which i...

Embodiment 2

[0021] Carry out feeding operation by embodiment 1, difference is that the hydroxyacetonitrile charging amount among the example 1 becomes 187.5g, finally obtains the white crystalline product 151g of EDTA disodium salt, content 99.4%, yield 62% (with sodium hydroxide count).

Embodiment 3

[0023] The feeding operation is carried out as in Example 1, the difference is that hydroxyacetonitrile is added dropwise at 85°C, and the temperature is raised slowly at the same time. After the drop is completed within 5 hours, the temperature rises to 110°C, and finally the white crystalline product 152.3 of EDTA disodium salt is obtained. g, content 99.5%, yield 62.6% (calculated as sodium hydroxide).

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Abstract

The present invention provides process of preparing EDTA disodium salt. The process includes the following steps: 1. mixing ethylene diamine and sodium hydroxide and heating, dropping hydroxyl acetonitrile within 5 hr, reaction after finishing dropping for at least 30 min until releasing ammonia completely; 2. adding EDTA to regulate pH value to 5-6; 3. adding active carbon into the reacted liquid to decolorize; 4. adding EDTA to regulate pH value to 3.5-4.5; and 5. concentrating the reacted liquid to crystallize, separating and drying to obtain EDTA disodium salt product. The present invention has low production cost and high product quality.

Description

Technical field: [0001] The invention relates to a preparation method of ethylenediaminetetraacetic acid disodium salt (EDTA disodium salt). Background technique: [0002] The existing method for preparing EDTA disodium salt is mainly ethylenediaminetetraacetic acid (EDTA) method. [0003] This method is to synthesize EDTA by sodium cyanide method, hydrocyanic acid method, chloroacetic acid method and hydroxyacetonitrile method, then dissolve EDTA in alkali solution to generate EDTA tetrasodium salt, and then add EDTA to adjust the pH of the reaction solution to 5~ 6. After adding activated carbon to the reaction solution for decolorization, then add EDTA to adjust the pH of the reaction solution to 3.5-4.5, and finally concentrate, crystallize, separate and dry the reaction solution to obtain the EDTA disodium salt product. [0004] The method has the disadvantage of high production cost because EDTA must first be synthesized, and then EDTA disodium salt is synthesized thr...

Claims

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Application Information

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IPC IPC(8): C07C213/00C07C229/16
Inventor 周伟罗克俊高含张娟
Owner 四川省天然气化工研究院
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