Title: Aurin
CAS Registry Number: 603-45-2
CAS Name: 4-[Bis(4-hydroxyphenyl)methylene]-2,5-cyclohexadien-1-one
Additional Names: 4-(p,p¢-dihydroxybenzhydrylidene)-2,5-cyclohexadien-1-one; p-rosolic acid; corallin; C.I. 43800
Molecular Formula: C19H14O3
Molecular Weight: 290.31
Percent Composition: C 78.61%, H 4.86%, O 16.53%
Literature References: Prepd by heating a mixture of phenol, oxalic and sulfuric acids: Zulkowsky, Ann. 194, 109, 122 (1878); 202, 179 (1880); Monatsh. Chem. 16, 358 (1895); Colour Index vol. 4 (3rd ed., 1971) pp 4407. By heating phenol with formic acid and stannous chloride: Nencki, Schmid, J. Prakt. Chem. [2] 23, 549 (1881). By heating phenol and carbon tetrachloride to 140-160° in presence of AlCl3 or ZnCl2 and treating the reaction product with water: Heumann, DE 68976 (Frdl. 3, 103).
Properties: Deep red (garnet-like) crystals with metallic luster. Orthorhombic bipyramidal. Technical product may occur as yellowish-brown pieces with dark green metallic fracture. Dec 308-310°. Not volatile in vacuo at 180°. Absorption max (KOH): 534.6, 479.5 nm. Practically insol in water (0.12%) and in benzene. Freely sol in alc, giving a golden yellow solution, in aq or alc NaOH and KOH giving a carmine-red solution, in concd or 70% H2SO4, in HCl, in HClO4 giving a yellow to orange soln. Moderately soluble in glacial acetic acid; slightly sol in ether, chloroform.
Absorption maximum: Absorption max (KOH): 534.6, 479.5 nm
Derivative Type: Sodium salt (yellow corallin)
Properties: Yellowish pieces with greenish, metallic luster; sol in water, giving a carmine-red soln.
Use: Dye intermediate. |