Melamine_cyanurate

Melamine cyanurate

Melamine cyanurate

Chemical compound

Melamine cyanurate, also known as melamine–cyanuric acid adduct or melamine–cyanuric acid complex, is a crystalline complex formed from a 1:1 mixture of melamine and cyanuric acid. The substance is not a salt despite its non-systematic name melamine cyanurate. The complex is held together by an extensive two-dimensional network of hydrogen bonds between the two compounds, reminiscent of the guanine–cytosine base pairs found in DNA.[2] Melamine cyanurate forms spoke-like crystals from aqueous solutions [3] and has been implicated as a causative agent for toxicity seen in the Chinese protein export contamination and the 2007 pet food recall.[3]

Quick Facts Names, Identifiers ...

Chemistry

The substance is best described as a melamine-cyanuric acid complex, or non-covalent adduct. The two compounds do not form a salt as suggested by its colloquial name melamine cyanurate.

Uses

Melamine cyanurate is used as a flame retardant, most commonly in polybutylene terephthalate (PBT), polyamide 6 (nylon 6) and polyamide 6,6 (nylon 6:6).[4] It is also used to fireproof in polyester fabrics.

Toxicity

It has been considered to be more toxic than either melamine or cyanuric acid alone.[5]

LD50 in rats and mice (ingested):

  • 4.1 g/kg – Melamine cyanurate
  • 6.0 g/kg – Melamine[clarification needed]
  • 7.7 g/kg – Cyanuric acid

A toxicology study conducted after recent pet food recalls concluded that the combination of melamine and cyanuric acid in diet does lead to acute kidney injury in cats.[6] A 2008 study produced similar experimental results in rats and characterized the melamine and cyanuric acid in contaminated pet food from the 2007 outbreak.[7]

Section of the extensive two-dimensional hydrogen bond network (dashed) between melamine (blue) and cyanuric acid (red)

See also

References

  1. [1]
    EPA: Substance : Archived 2008-09-22 at the Wayback Machine
  2. [2]
    Perdigão LM, Champness NR, Beton PH (2006). "Surface self-assembly of the cyanuric acid-melamine hydrogen bonded network". Chem. Commun. (5): 538–540. doi:10.1039/b514389f. PMID 16432575.
  3. [3]
    Lili He; Yang Liu; Mengshi Lin; Joseph Awika; David R Ledoux; Hao Li; Azlin Mustapha (2008). "A new approach to measure melamine, cyanuric acid, and melamine cyanurate using surface enhanced Raman spectroscopy coupled with gold nanosubstrates". Sens. & Instrumen. Food Qual. 2: 66–71. doi:10.1007/s11694-008-9038-0. S2CID 93425738.
  4. [4]
    Gijsman, Pieter; Steenbakkers, Rieky; Fürst, Christian; Kersjes, Joyce (2002). "Differences in the flame retardant mechanism of melamine cyanurate in polyamide 6 and polyamide 66". Polymer Degradation and Stability. 78 (2): 219–224. doi:10.1016/S0141-3910(02)00136-2.
  5. [5]
    A.A. Babayan, A.V.Aleksandryan, "Toxicological characteristics of melamine cyanurate, melamine and cyanuric acid", Zhurnal Eksperimental'noi i Klinicheskoi Meditsiny, Vol.25, 345-9 (1985). Original article in Russian.
  6. [6]
    Puschner et al. (November 2007). Assessment of melamine and cyanuric acid toxicity in cats. Journal of Veterinary Diagnostic Investigation. Retrieved on 2007-11-16.
  7. [7]
    Dobson; et al. (August 2008). "Identification and characterization of toxicity of contaminants in pet food leading to an outbreak of renal toxicity in cats and dogs". Toxicological Sciences. 106 (1): 251–62. doi:10.1093/toxsci/kfn160. PMID 18689873.
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