Aurin

Aurin
IUPAC name 4-[bis(p-hydroxyphenyl)methylene]- -2,5-cyclohexadien-1-one
Other names Aurin, corallin, p-rosolic acid, C.I. 43800
Identifiers
CAS number	603-45-2
PubChem	5100
ChemSpider	4921 Y
EC number	210-041-8
ChEMBL	CHEMBL210868 Y
Beilstein Reference	2055205
Jmol-3D images	Image 1
SMILES C1=CC(=O)C=CC1=C(C2=CC=C(C=C2)O)C3=CC=C(C=C3)O
InChI InChI=1S/C19H14O3/c20-16-7-1-13(2-8-16)19(14-3-9-17(21)10-4-14)15-5-11-18(22)12-6-15/h1-12,20-21H Y Key: FYEHYMARPSSOBO-UHFFFAOYSA-N Y InChI=1/C19H14O3/c20-16-7-1-13(2-8-16)19(14-3-9-17(21)10-4-14)15-5-11-18(22)12-6-15/h1-12,20-21H Key: FYEHYMARPSSOBO-UHFFFAOYAG
Properties
Molecular formula	C19H14O3
Molar mass	290.313 g/mol
Density	1.283 g cm-3
Melting point	308 °C (decomp.)
Solubility in water	insoluble
Hazards
R-phrases	R36 R37 R38
NFPA 704	1 1 0
Flash point	308 °C
Y (verify) (what is: Y/N?) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

For the French commune, see Aurin, Haute-Garonne.

For the Aragonese village, see Aurin, Sabiñánigo, Huesca, España.

Aurin (C.I. 43800), sometimes named rosolic acid or corallin is an organic compound, forming yellowish or deep-red crystals with greenish metallic luster. It is practically insoluble in water, freely soluble in alcohol. It is soluble in strong acids to form yellow solution, or in aqueous alkalis to form carmine red solutions. Due to this behaviour it can be used as pH indicator with pH transition range 5.0 - 6.8. It used as intermediate in manufacturing of dyes.

Synthesis

Aurin is formed by heating of phenol and oxalic acid in concentrated sulfuric acid.

References

External links

• MSDS at Oxford University
• History of aurin in Heinrich Caro and the creation of modern chemical industry