Red 2G

Red 2G is a synthetic red azo dye. It is soluble in water and slightly soluble in glycerol. It usually comes as a disodium salt of 8-acetamido-1-hydroxy-2-phenylazonaphthalene-3,6 disulfonate.

Red 2G

Names
Other names Acid Red 1 Food Red 10 Amidonaphthol red G azogeranine azophloxine azofloxin C.I. 18050
Identifiers
CAS Number	3734-67-6 Y
3D model (JSmol)	Interactive image
ChemSpider	21106472 Y
ECHA InfoCard	100.020.999
E number	E128 (colours)
PubChem CID	6507024
UNII	3365R6427R Y
CompTox Dashboard (EPA)	DTXSID9044663
InChI InChI=1S/C18H15N3O8S2/c1-10(22)19-14-9-13(30(24,25)26)7-11-8-15(31(27,28)29)17(18(23)16(11)14)21-20-12-5-3-2-4-6-12/h2-9,23H,1H3,(H,19,22)(H,24,25,26)(H,27,28,29)/p-2/b21-20+ Y Key: RSNSKUBBVCGSND-QZQOTICOSA-L Y InChI=1/C18H15N3O8S2/c1-10(22)19-14-9-13(30(24,25)26)7-11-8-15(31(27,28)29)17(18(23)16(11)14)21-20-12-5-3-2-4-6-12/h2-9,23H,1H3,(H,19,22)(H,24,25,26)(H,27,28,29)/p-2/b21-20+ Key: RSNSKUBBVCGSND-OLKPTRFBBB
SMILES CC(=O)Nc2cc(cc3cc(c(/N=N/c1ccccc1)c(O)c23)S([O-])(=O)=O)S([O-])(=O)=O
Properties
Chemical formula	C18H13N3O8S2
Molar mass	463.44 g·mol−1
Solubility in water	18 g/100 mL (20 °C)
Solubility	1 g/ 100 mL glycerol Negligible in ethanol
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). N verify (what is YN ?) Infobox references

Preparation

Red 2G is produced by azo coupling of Acetyl-H acid and diazonium derivative of Aniline under basic conditions:^[1]

Uses

Food dye

In the European Union, Red 2G was used as a food dye (E number E128). However, it was only permitted for use in breakfast sausages with a minimum cereal content of 6% and burger meat with a minimum vegetable and/or cereal content of 4%.^[2]

Following safety concerns raised by the European Food Safety Authority (EFSA) in its opinion of 5 July 2007,^[3] the European Commission has prepared a draft Regulation to suspend use of E128 as a food colouring. This proposed course of action was unanimously approved by European Union Member States at a meeting of the Standing Committee of the Food Chain and Animal Health (Section Toxicological Safety of the Food Chain) on 20 July 2007.^[4] and Commission Regulation (EC) No 884/2007^[5] on emergency measures suspending the use of E 128 Red 2G as food colour was published in the Official Journal of the European Union on 27 July 2007.

Red 2G is also banned in Australia, Canada, Japan, Norway,^[6] and Malaysia.^[7] It was banned in Israel in July 2007 ^{[citation needed]}.

It is relatively insensitive to the bleaching effect of sulfur dioxide (E220) and sodium metabisulfite (E223). In the intestines, Red 2G can be converted to the toxic compound aniline,^[8] so there are concerns Red 2G may ultimately interfere with blood haemoglobin, as well as cause cancer.

Inks

It is also used as a dye for coatings, inks, paper, crepe paper, and fine tissue.

Histology

Red 2G can be also used for staining in histology, though rarely, e.g. as a component of Masson's trichrome.

Potential health risks

In July 2007, the EFSA established that E128 is potentially carcinogenic because it forms aniline in the body when consumed.^[9] The pressure group, The Food Commission, said there had been concerns about Red 2G going back decades and it was suspected of being a carcinogen in the 1980s.^[10]