Para Red

Chembox new
ImageFile = Para Red.png ImageSize =
IUPACName = 1- [(E)-(4-Nitrophenyl)diazenyl] -2-naphthol
OtherNames = 1-((4-Nitrophenyl)azo)-2-naphthalenol, 1-((4-nitrophenyl)azo)-2-naphthol, 1-((p-nitrophenyl)azo)-2-naphthalenol, 1-((p-nitrophenyl)azo)-2-naphthol, paranitraniline red, Pigment Red 1, C.I. 12070, Recolite Para Red B, Carnelio Para Red BS
Section1 = Chembox Identifiers
CASNo = 6410-10-2
EINECS = 229-093-8
PubChem =
SMILES = OC1=C(N=NC3=C C=C( [N+] ( [O-] )=O) C=C3)C2=C(C=C C=C2)C=C1
Section2 = Chembox Properties
Formula = C₁₆H₁₁N₃O₃
MolarMass =
Appearance = Red solid
Density =
MeltingPt = 248 - 252 °C
BoilingPt =
Solubility =
Section3 = Chembox Hazards
MainHazards =
RPhrases = R36/37/38
SPhrases = S26, S36
FlashPt =
Autoignition =

Para Red (paranitraniline red, Pigment Red 1, C.I. 12070) is a chemical dye. Chemically, the dye is similar to Sudan I. The dye was discovered in 1880 by von Gallois and Ullrich, and was the first azo dye. It dyes cellulose fabrics a brilliant red, but is not very fast. The dye can be washed away easily from cellulose fabrics if not dyed correctly. Throughout making Para Red, the solution will become acidic and basic. Small amounts of byproducts may be left over after the Para Red dye is made that may be acidic or basic, but if made correctly there are little of these and the byproducts have no effect.

ynthesis

Para Red is prepared by diazotisation of "para"-nitroaniline at ice-cold temperatures, followed by coupling with β-naphthol: [cite book
last = Williamson
first = Kenneth L.
title = Macroscale and Microscale Organic Experiments, Fourth Edition
publisher = Houghton-Mifflin
year = 2002
isbn = 0618197028]

UK food alert

In the United Kingdom, the dye is not permitted in food. The UK's Food Standards Agency (FSA) stated that "the Agency’s independent scientific experts have advised that, although there are very limited data available, it would be prudent to assume that it could be a genotoxic carcinogen". cite news | url = http://www.food.gov.uk/news/newsarchive/2005/apr/oldelpaso | title = Old El Paso Dinner Kits for enchiladas and burritos found with illegal dye | publisher = Food Standards Agency | format = press release | date = 21 April 2005]

On 21 April 2005, the FSA announced that some batches of Old El Paso dinner kits had been contaminated with the dye, and issued an alert. Also, reported on the 5 May 2005, the dye was found in 35 products which have now been taken off supermarket shelves. The products were mainly cooking sauces, though some are also spices. [cite news | url = http://news.bbc.co.uk/1/hi/health/4518139.stm | title = Banned dye found in more products | publisher = BBC News | date = 5 May 2005]

References

External links

* [http://physchem.ox.ac.uk/MSDS/PA/para_red.html MSDS at Oxford University]