Mechanism of EDTA

General description 

Ethylenediaminetetraacetic acid disodium salt also known as disodium ethylenediamine tetraacetate, commonly known as disodium ethylenedicarboxylate, referred to as EDTA disodium salt, code name m-23. White or yellowish crystalline powder. Soluble in water, insoluble in ethanol and ether. Crystal water starts to lose at 100 ℃ and becomes anhydrous salt at 120 ℃. It can react with calcium ions in hard water to form soluble salts. It can also eliminate the destructive effect of copper and iron ions on the preservation of Caiyi developer and prevent the formation of fog. It is an important complexing agent and water softener. Used in photographic developer, color developer, pre bath, stabilization, fixing and other solutions. The container shall be sealed and stored in a cool, dry and ventilated place.[1]

Application 

Also known as disodium ethylenediamine tetraacetate, commonly known as disodium ethylenedicarboxylate, referred to as EDTA disodium salt, code name m-23. White or yellowish crystalline powder. Soluble in water, insoluble in ethanol and ether. Crystal water starts to lose at 100 ℃ and becomes anhydrous salt at 120 ℃. It can react with calcium ions in hard water to form soluble salts. It can also eliminate the destructive effect of copper and iron ions on the preservation of Caiyi developer and prevent the formation of fog. It is an important complexing agent and water softener. Used in photographic developer, color developer, pre bath, stabilization, fixing and other solutions. The container shall be sealed and stored in a cool, dry and ventilated place.[2]

Mechanism of action  

EDTA has a wide range of coordination properties and can form stable chelates with almost all metal ions. Advantages: it provides the possibility of extensive determination of elements (better than acid-base and precipitation methods). Disadvantages: it is easy to interfere between various components - selectivity. Most of the coordination ratio between EDTA and m-edta is 1:13, and most of the chelates are charged, so they can be dissolved in water and react quickly.[3]

Synthesis 

Sampling and liquid preparation: obtain monochloroacetic acid and put it into a round bottom flask. Add sodium carbonate until the liquid in the round bottom flask begins to bubble. Add ethylenediamine and stand for a moment. Add 50 parts of 35-45% sodium hydroxide. Add distilled water to the round bottom flask until the liquid volume is 300ml; Preliminary reaction: install the round bottom flask and the solution in the round bottom flask in step S1 with a cooling reflux device, conduct graded thermal insulation treatment on the solution in the round bottom flask, and remove the round bottom flask after thermal insulation; Obtaining the crude product of EDTA: remove the round bottom flask in step S2 and cool it for 35-45 minutes, add concentrated hydrochloric acid to the round bottom flask to prepare the pH value of 1.2, and white precipitation appears in the solution to obtain the white precipitation, which is the crude product of EDTA; Crude product purification: obtain the white precipitate in step S3, place the white precipitate in a clean beaker, add deionized aqueous solution to the beaker, stir evenly, stand for 5 minutes, filter with a filter screen and retain the solid filter;

Figure1 the synthesis route of EDTA

Preparation of disodium EDTA: obtain the solid filter in step S4, place the solid filter in a clean beaker, add sodium hydroxide solution, stand for 20 minutes, add sodium carbonate and adjust the pH value to 4-5; Distillation and crystallization: cool the reaction solution in the beaker in the step for 1 hour, and place the cooled solution in the distillation tower for distillation to prepare disodium ethylenediamine tetraacetic acid for crystallization; Removing crystal water: put the crystal of disodium EDTA prepared in step S6 into the de crystallization instrument, remove the crystal water and obtain disodium EDTA solid powder; Quality test: test the disodium EDTA powder obtained in step S7 and store it.[5]

References

1. Zheng Mengke,Wu Zhenguo,Wang Yang,Chen Nannan,Teng Zhaogang,Su Xiaodan,Xu Peng. Synthesis of Ethylenediaminetetraacetic Acid Disodium Salt Functionalized Magnetite/Chitosan Nanospheres for the Highly Efficient Removal of Methylene Blue.[J]. Journal of nanoscience and nanotechnology,2021,21(3).

2. Song XiuShi,Gu KaiXin,Gao Jing,Wang JianXin,Ding ShaoChen,Zhou Mingguo. Ethylenediaminetetraacetic Acid Disodium Salt Acts as an Antifungal Candidate Molecule against Fusarium graminearum by Inhibiting DON Biosynthesis and Chitin Synthase Activity.[J]. Toxins,2020,13(1).

3. Geng Xin,Li Zhaohui,Hu Yalei,Liu Haifang,Sun Yuanqiang,Meng Hongmin,Wang Yingwen,Qu Lingbo,Lin Yuehe. One-Pot Green Synthesis of Ultrabright N-Doped Fluorescent Silicon Nanoparticles for Cellular Imaging by Using Ethylenediaminetetraacetic Acid Disodium Salt as an Effective Reductant.[J]. ACS applied materials & interfaces,2018,10(33).

4. Xing Chen,Kai Huang,Cheng-yan Wang. Facile synthesis of monodispersed copper oxalate flaky particles in the presence of EDTA[J]. International Journal of Minerals, Metallurgy, and Materials,2018,25(7).

5. Pesenti Cristina,Arnone Alberto,Bellosta Stefano,Bravo Pierfrancesco,Canavesi Monica,Corradi Eleonora,Frigerio Massimo,Meille Stefano V,Monetti Mara,Panzeri Walter,Viani Fiorenza,Venturini Romina,Zanda Matteo. Total synthesis of a pepstatin analog incorporating two trifluoromethyl hydroxymethylene isosteres (Tfm-GABOB) and evaluation of Tfm-GABOB containing peptides as inhibitors of HIV-1 protease and MMP-9[J]. Tetrahedron,2001,57(30).

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