Nitrilotriacetic acid

Nitrilotriacetic acid
Preferred IUPAC name 2,2′,2′′-Nitrilotriacetic acid[citation needed]
Systematic name 2-[Bis(carboxymethyl)amino]acetic acid[1]
Other names Triglycine[2]
Identifiers
CAS number	139-13-9 Y
PubChem	8758
ChemSpider	8428 Y
EC number	205-355-7
UN number	2811
DrugBank	DB03040
KEGG	C14695 N
MeSH	Nitrilotriacetic+Acid
ChEBI	CHEBI:44557 Y
RTECS number	AJ0175000
Beilstein Reference	1710776
Gmelin Reference	3726
Jmol-3D images	{{#if:[o]:c(:[oH])CN(Cc(:[o]):[oH])Cc(:[o]):[oH]OC(=O)CN(CC(O)=O)CC(O)=O|Image 1 Image 2
SMILES [o]:c(:[oH])CN(Cc(:[o]):[oH])Cc(:[o]):[oH] OC(=O)CN(CC(O)=O)CC(O)=O
InChI InChI=1S/C6H9NO6/c8-4(9)1-7(2-5(10)11)3-6(12)13/h1-3H2,(H,8,9)(H,10,11)(H,12,13) Y Key: MGFYIUFZLHCRTH-UHFFFAOYSA-N Y
Properties
Molecular formula	C6H9NO6
Molar mass	191.14 g mol−1
Appearance	White crystals
Thermochemistry
Std enthalpy of formation ΔfHo298	−1.3130–−1.3108 MJ mol−1
Hazards
GHS pictograms
GHS signal word	WARNING
GHS hazard statements	H302, H319, H351
GHS precautionary statements	P281, P305+351+338
EU classification	Xn
R-phrases	R22, R36, R40
S-phrases	S26, S36/37
Flash point	100 °C; 212 °F; 373 K
LD50	1.1 g kg−1 (oral, rat)
Related compounds
Related alkanoic acids	EDTA Iminodiacetic acid EDDS
Related compounds	Triethanolamine Tris(2-aminoethyl)amine
N (verify) (what is: Y/N?) Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
Infobox references

Nitrilotriacetic acid (NTA) is the aminopolycarboxylic acid with the formula N(CH₂CO₂H)₃. It is a colourless solid that is used as a chelating agent, which forms coordination compounds with metal ions (chelates) such as Ca²⁺, Cu²⁺, and Fe³⁺.^[3]

Production and use

This compound is commercially available as the free acid and as the sodium salt. It is produced from ammonia, formaldehyde, and sodium cyanide or hydrogen cyanide. Worldwide capacity is estimated at 100 thousand tonnes per year.^[4]

Coordination chemistry and applications

The uses of NTA are similar to that of EDTA, both being chelating agents. In contrast to EDTA, NTA is easily biodegradable and is almost completely removed during wastewater treatment. It is used for water softening and as a replacement to sodium and potassium triphosphate in detergents, and cleansers.^[4] NTA is a tripodal tetradentate trianionic ligand.^[5] In the laboratory, this compound is used in complexometric titrations. A variant of NTA is used for protein isolation and purification in the His-tag method. The modified NTA is used to immobilize nickel to a solid support. This allows separation of proteins containing "tag" containing six histidine residues at either terminus.^[6]

• NTA complexes
• 

  Three views of the structure of [Ni(NTA)(H₂O)₂]^-.

• 

  Structure of the [Ca(NTA)(H₂O)₃]^-.

References