EDTA Full Form

EDTA stands for ethylenediaminetetraacetate. It is a common chemical compound that is widely used in medicine, cosmetics, and industrial applications and is known by multiple names. Ethylenediaminetetraacetate, that is, EDTA full form in chemistry is an amino carboxylic acid with the molecular formula [CH2N(CH2CO2H2)2]2. This chemical was synthesized in 1935 for the first time by a scientist named Ferdinand Munz and later this chemical was named by its nomenclature as ethylenediaminetetraacetate which is known as EDTA full form in chemistry. 

It is in the form of white, water-soluble solids that is known for binding calcium and iron ions as hexadentate, which is six teeth chelating agent. Its preferred IUPAC name is given as 2,2l,2ll,2lll-(ethane-1,2-diyl nitrilo)tetraacetic acid. The other common names for EDTA are ethylene diamine tetraacetic acid, N,Nl-ethane-1,2diylbis[N-(carboxymethyl)glycine], diaminoethane tetraacetic acid. The reason behind so many names of EDTA is because it produces several salts, the most commonly used are sodium EDTA, tetrasodium EDTA, and sodium calcium edetate. The molecular structure of EDTA consists of two amino groups with four carboxyl groups that are called lewis base. EDTA forms a hexadentate legend because of its capacity to donate six pairs of lone electrons with the formation of covalent bonds. The structure of EDTA is illustrated below for a clear understanding. 

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As the structure illustrates, the two nitrogen atoms and the four oxygen atoms with lone pair of electrons make covalent bonds.

Nomenclature of EDTA

To describe the various protonated forms of ethylenediaminetetraacetic acid, that is the chemical EDTA full name, it has been divided into two parts. There are primarily two distinctions between two forms of EDTA, one is EDTA4- which is a conjugate base and a ligand. The other one is H4EDTA which acts as a precursor to the ligand. At very low pH or in other words at very high acidic conditions, H6EDTA2+ which is fully protonated is in predomination. But during high pH or in other words low acidic and high alkaline conditions, EDTA4- which is fully deprotonated is in a state of predomination. Thus EDTA actually represents H4-xEDTAx-, whereas the complexes of EDTA (EDTA4-) represent tetra anion ligands. According to the coordinate geometry, EDTA belongs to the ligands of the amino polycarboxylic acid family. A fully deprotonated EDTA (EDTA4-) binds itself to metal cations through lone pairs of electrons of two amines and four carboxylates. Thus the coordinate compound form takes octahedral geometry and these octahedral complexes are chiral in nature. Many complexes with deprotonated EDTA (EDTA4-) form more complex compounds when bonding with water, that is, seven coordinate complexes or one carboxylate arm formed by water molecules. For example, the iron (lll) complex of EDTA forms a seven coordinate compound. EDTA forms strong complexes with Mn (ll), Fe (lll), Co (ll), Pb (ll), and Cu (ll). ethylenediaminetetraacetic acid, which is the EDTA full name in chemistry, because of its high denticity shows a higher affinity for the cations. 

For example,

[Fe(H2O)6]3+ + H4EDTA → [FeEDTA]- + 6H2O + 4H

The above equation has an equilibrium quotient, Keq= 1025.1. This indicates that the metal ions compete with the proton to form a bond with EDTA.

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The above illustration displays the metal EDTA chelates that are found mostly in cobalt [Co(lll)] complexes. 

Properties of EDTA

Some of the physical properties of EDTA are tabulated below:

 Some chemical properties of EDTA are tabulated below.

Synthesis of EDTA

The compound was first synthesized by Ferdinand Munz in 1935 with the compounds ethylene diamine and chloroacetic acid, and the compound formed was named ethylenediaminetetraacetic acid and is popularly known as EDTA full name. These days EDTA is manufactured with compounds, namely, ethylenediamine or (1,2-diaminoethane, formaldehyde, and sodium cyanide. The initial reactions between these compounds yield tetrasodium EDTA, which is then converted in the following reactions into acid forms.

 The reactions for the synthesis of EDTA is as follows.

H2NCH2CH2NH2 + 4CH2O + 4NaCN + 4H2O → (NaO2CCH2)2NCH2CH2N(CH2CO2Na)2 + 4NH3

(NaO2CCH2)2NCH2CH2N(CH2CO2Na)2 + 4HCl → (HO2CCH2)2NCH2N(CH2CO2H)2 + 4NaCl

This process is the most effective method to yield 80000 tons of EDTA each year.

Uses and Application

Food items

In food industries, it has been approved by the USFDA as a safe agent to be used as additives for the canned food items. It helps in retaining the colour, texture, and flavour of canned mushrooms, shrimps, white potato, clams, etc. as it has a property to bind with the enzymes that otherwise spoil the food thus it is used as preservatives in mayonnaise, salad dressings, etc. it also retains the flavour of sodas, pickled cucumber, pickled cabbages, etc. In various food items, it is also used as a stabilizer in order to prevent decolorization due to catalytic oxidation that is catalyzed by the presence of metal ions. As soft drinks contain ascorbic acid as well as sodium benzoate, therefore EDTA is added in order to mitigate the formation of benzene which is a carcinogen.  

Industries

In industries, EDTA is mostly applied to sequester metal ions present in the aqueous solution. In textile industries as the presence of metal ions in the dyes can alter the colour, thus, EDTA is used to prevent metal ions from modifying the colours of the dyes. In pulp and paper industries, EDTA is specifically used in chlorine-free bleaching in order to prevent catalyzing the disproportionation of hydrogen peroxide due to the presence of metal ions, especially Mn2+ ions.in cement industries, in order to detect free lime and free magnesia in cement and clinkers, EDTA is mixed in them.

Laundry detergents

EDTA helps in bringing down the hardness of the water and dissolution scale in the boilers as EDTA and its other complexants bind the metal ions like Mg2+  and Ca2+ ions. Once the binding of these metal ions is accomplished with EDTA or its complementary complexants then the ions are less likely to precipitate or interfere with the action of detergents and soaps. That's why most of the high-end detergents and cleansing soaps these days contain EDTA to a permissible limit. 

Agriculture

As ethylenediaminetetraacetic acid (EDTA long form) is capable of solubilizing Fe3+ ions at neutral pH or below the neutral pH, thus it is also helpful in agriculture including hydroponics.

However as the ligands of EDTA are pH-dependent, therefore, EDTA fails to improve the quality of the soil that has a pH range above neutral. At near pH or above pH iron (lll) forms insoluble salt and is not available for the susceptible plant species biologically. Aqueous [Fe(EDTA)]- is used for scrubbing hydrogen sulfide from the gas stream. 

Medicine

Sodium calcium edetate which is an important derivative EDTA full form in medical application binds the metal ions in the chelation therapy practice that is highly useful in treating mercury and lead poisoning. A similar process is used to remove any extra ion from the body. If any complication arises during the repeated blood transfusion process, this chelation therapy with EDTA is used to treat such complications and it also applies to the treatment of thalassemia. Many dentists around the globe use EDTA solutions in order to lubricate the root canals in endodontics as well as to remove the inorganic debris from the smear layer. This process helps in the preparation of the root canal process for obturation. In eyedrops and during ocular preparation, EDTA serves as a preservative. In the evaluation of any kidney malfunctioning or in case of kidney failure, EDTA complex with cobalt (lll), that is, [Cr(EDTA)]- is intravenously monitored at a certain interval and its filtration in urine is also monitored. This helps in evaluating the glomerular rate (GFR) in nuclear medicine. One of the most extensive uses of EDTA in the medical process is in blood testing for the presence of lead or metal ion traces in the blood. It has an anticoagulant property as it chelates with the calcium ion present in the blood and arrests the coagulation process, thus preserving blood cell morphology. It is mostly used in the blood samples of CBCs and FBCs. EDTA is also a very effective slime dispersant and thus during implantation of the intraocular lens, it prevents any kind of bacterial growth in the area.

Cosmetics

In shampoos, cleansers, and other similar skincare products, EDTA salts are often used as a sequestering agent in order to provide stability of these chemical compounds in the air when they are exposed to the atmosphere.

Laboratory applications

In biochemistry and molecular biology, ion depletion is commonly used in order to deactivate enzymes that are metal-dependent. EDTA is used in such processes for scavenging metal ions. Ion depletion is mostly done either to support their reactivity or to deduce the damage to DNA, proteins, or polysaccharides.  EDTA independent of metal ions acts as selective inhibitors against liver arginase, horseradish peroxidase, and dNTP hydrolyzing peroxides. In analytical chemistry, EDTA is mainly used as a masking agent in order to sequester the metal ions that often interfere in the quantitative analysis. It is also used for complexometric titrations and to detect the hardness of the water. EDTA also prevents the worsening of corneal ulcer in animals and hence have found a place in many biomedical labs such as in veterinary ophthalmology as an anti collagenase reagent. In tissue culture, EDTA is often used as a chelating agent that binds the calcium ion to prevent the joining of cadherins of cells or clumping of cells that are grown in liquid suspensions or detecting adherent cells that can be used for passage. 

Side effects

Though the toxicity of EDTA is found to be very less, still there are some side effects of this compound in medical practices. Some of them are listed below.

1. In animal laboratories, it is found that EDTA is both cytotoxic as well as genotoxic in nature.

2. Oral exposure to EDTA can cause effects to the reproductive system as well as the development of the human body.

3. The dermal exposure of EDTA due to its presence in various cosmetics can cause red skin rashes, blistering as well as peeling of the skin.

4. Overdosing of EDTA in medication can cause nausea, vomiting, and diarrhea.

5. EDTA when injected can cause swelling as well as redness in the area it is being injected.

6. After taking an injection of EDTA repetitively can cause a certain drop in blood pressure. 

Degradation of EDTA

Abiotic Degradation

Though there is a huge functionality of EDTA in various fields like industry, laboratory, medicine, healthcare, and many more, the longevity of EDTA poses some serious environmental and health concerns. EDTA has a very slow degradation process and often degrades very slowly abiotically in the presence of sunlight. In order to remove EDTA from the water surface, it is photolyzed at a wavelength that is below 400 nm. Thus depending on the light intensity the half-life of iron (lll) EDTA can range from 11.3 minutes to as long as 100 hours. Degradation of FeEDTA produces complexes like triacetate, diacetate, and monoacetate in which about 92% of EDDA and EDMA can biodegrade in 20 hours but the other complexes show higher resistance to degradation.

Biodegradation

In many industries, during wastewater treatment, about 80% of EDTA in the liquor can be eliminated by the action of microorganisms that results in the formation of ED3A and iminodiacetic acid that shows that the acetyl group and the backbone of EDTA have been attacked by the microorganisms. It has been observed that some of the microorganisms can produce nitrate through degradation of EDTA but they are functional at a moderate alkaline condition of 9.0-9.9 pH. Some of the bacteria strains that are isolated during the filtration process of wastewater can degrade EDTA efficiently.