Ethylenediaminetetraacetic acid
CAS No:60-00-4
EINECS No:200-449-4
Ethylenediamine can be obtained by cyclizing ethylenediaminetetraacetic acid with formamide. This is a drug primarily used to treat psoriasis, also known as psoriasis. But as an organic synthesis intermediate, it is not the main use of EDTA. EDTA and its salts can undergo complex reactions with a variety of metal ions to form a stable cyclic structure, which can effectively reduce or inhibit side reactions or harmful effects caused by metal ions. It is the most widely used metal chelating agent and is generally used for Chelates calcium ions at 14>pH>5, copper ions at 14>pH>2, iron ions at 6>pH>1, magnesium ions at 12>pH>6, and manganese ions at 14>pH>3. Due to its excellent chelating properties, domestic EDTA and its salts are mainly used in photographic chemicals, water treatment agents, chemical (cystine) refining, detergents, textile auxiliaries, leather chemicals, paper chemicals, medicine , synthetic rubber, micro-fertilizer production and other fields. EDTA can generate EDTA salt products, mainly including EDTA disodium salt, EDTA tetrasodium salt, and EDTA trisodium salt. Using them as raw materials, EDTA calcium sodium salt, EDTA copper sodium salt, EDTA iron sodium salt, and EDTA iron ammonium salt can also be generated. Salt etc. In addition, in addition to sodium salts, there are also ammonium salts and various salts such as iron, magnesium, calcium, copper, manganese, zinc, cobalt, and aluminum. Each of these salts has different uses.
Ethylenediaminetetraacetic acid (EDTA, molecular weight 292) and its salts are aminopolycarboxylic acids that can effectively chelate calcium ions in blood specimens. Chelating calcium or removing calcium from the site of reaction will block and terminate the intrinsic or extrinsic coagulation process, thereby preventing the blood specimen from coagulating. Suitable for general hematology tests (Usually routine hematology tests use potassium salt EDTA-K2 or EDTA-K3), not suitable for coagulation tests and platelet function tests, nor suitable for calcium ions, potassium ions, sodium ions, iron Determination of ions, alkaline phosphatase, creatine kinase and leucine aminopeptidase and PCR test. EDTA-Li2 can also be used as an anticoagulant and can be used in most biochemical tests.
1.Ethylenediaminetetraacetic acid (EDTA) is an important complexing agent. EDTA is widely used and can be used as bleaching fixative in the processing of color photosensitive materials, dyeing auxiliaries, fiber processing auxiliaries, cosmetic additives, blood anticoagulants, detergents, stabilizers, synthetic rubber polymerization initiators, EDTA is a chelate Representative substances of mixtures. It can form stable water-soluble complexes with alkali metals, rare earth elements and transition metals. In addition to sodium salts, there are also ammonium salts and various salts such as iron, magnesium, calcium, copper, manganese, zinc, cobalt, and aluminum. Each of these salts has different uses. In addition, EDTA can also be used to quickly excrete harmful radioactive metals from the human body and play a detoxifying role. It is also a water treatment agent. EDTA is also an important indicator, but it is used to titrate metals such as nickel and copper. When used, it must be used together with ammonia water so that can function as an indicator.
2. Ethylenediaminetetraacetic acid is an excellent chelating agent for calcium and magnesium ions. It is used as a chelating agent for water used in emulsion polymerization to remove Ca2+, Mg2+, Fe2+, Fe3+ and other metal ions. It is also used as a complexing agent for anaerobic adhesives, that is, treating methacrylic acid diester with EDTA to remove transition metal ions and eliminate the influence that can promote the decomposition of peroxide, which is very effective in improving the stability of anaerobic adhesives. EDTA sodium salt chelates metal ions to improve the speed of modified acrylic acid. Storage stability of solid structural adhesive (SGA), dosage -3×10-4～6.0×10-4. The dosage is 1.5%, and the storage stability at 50°C is more than 360h (storage at 50°C for 4 days is equivalent to 1 year of SGA storage at 20°C). Often used to soften boiler water. Prevent scaling.
3.The production of EDTA and its sodium salt is divided into three production processes based on the different raw materials used, namely the chloroacetic acid method, the hydrocyanic acid method and the sodium cyanide method. At present, most domestic manufacturers use the chloroacetic acid method, and only factories with larger capabilities use the sodium cyanide method. This is different from the situation abroad where the sodium cyanide method is basically used. The chloroacetic acid method is a reaction between chloroacetic acid and sodium carbonate (or 30% NaOH) to form sodium chloroacetate. In an alkaline solution, sodium chloroacetate and ethylenediamine are condensed at low temperature to form sodium ethylenediaminetetraacetate, which is then acidified with sulfuric acid. EDTA is decolorized by activated carbon, filtered, washed with water, crystallized by adding concentrated hydrochloric acid, and then filtered, washed, and dried to obtain the finished EDTA product. This method is an intermittent method. When it encounters water, it decomposes to form glycol acid, which results in low product yield and unstable product quality (containing chloride ions). Chloroplast acid, the main raw material used, seriously corrodes the equipment and the service life of the equipment is very short. This production method has been basically eliminated abroad. However, domestic food-grade EDTA still needs to use this method because customers are worried that cyanide is toxic and harmful to the human body. The hydroponic acid method is a two-step production process. The first step of the reaction is that methamphetamine reacts with hydroponic acid and formaldehyde under weakly acidic conditions to form a water-insoluble nitrile. This product is easily separated from the system. The pure cyanide obtained by is then hydrated under alkaline conditions. , generating purer EDTA. This method has a long process flow and requires the treatment of gaseous and liquid hydrocyanic acid. Therefore, sodium cyanide can be used instead of hydrocyanic acid, so that the reaction can be carried out under strong alkaline conditions. The one-step reaction directly obtains EDTA tetrasodium salt. This is At present, the most widely used EDTA production method in industry is the sodium cyanide method. The sodium cyanide method uses ethylenediamine, sodium cyanide and formaldehyde as raw materials, reacts in one step under alkaline conditions to generate EDTA tetrasodium salt, and then acidifies the EDTA tetrasodium salt mother liquor with sulfuric acid to control the pH value of the solution to obtain EDTA dihydrogen salt. Sodium salt or EDTA products are further reacted by EDTA disodium salt and sodium hydroxide to obtain EDTA tetrasodium salt products. Due to EDTA, DTPA (diethylene triamine pentaacetic acid or diethylene triamine pentaacetic acid), HEDTA (hydroxyethylenediamine triacetic acid), IDA (iminodiacetic acid), PDTA (propylene o-diamine tetraacetic acid) The production processes of chelating agents such as ADA (aminopropionic acid diacetic acid) and NTA (nitrotriacetic acid) are basically the same, so manufacturers generally switch to produce several products (specifications include solid and liquid) in multi-functional devices. Sales and production.
