3189. 4′,5′-Diiodofluorescein

Nomenclature

CAS number: 38577-97-8
3′,6′-Dihydroxy-4′,5′-diiodospiro[isobenzofuran-1(3H),9′-[9H]xanthen]-3-one; hydroxydiiodo-o-carboxyphenylfluorone; D & C Orange No. 10; C.I. Solvent Red 73; C.I. 45425:1.
C20H10I2O5; mol wt 584.10.
C 41.13%, H 1.73%, I 43.45%, O 13.70%.

Description and references

Prepd by reaction of fluorescein with I2 and HIO4 or ICl in alkali: Colour Index vol. 4 (3rd ed., 1971) p 4427.

Chemical structure

Properties

Orange-red powder. Slightly sol in water; sol in alcohol, in alkali hydroxide solns.

Derivative

Sodium salt.

Nomenclature

CAS number: 33239-19-9
Erythrosine Extra Yellowish; D & C Orange No. 11; C.I. Acid Red 95; C.I. 45425.
C20H8I2Na2O5; mol wt 628.06.
C 38.25%, H 1.28%, I 40.41%, Na 7.32%, O 12.74%.

Use

As an adsorption indicator in the determn of iodides in the presence of chlorides and bromides. The salts in dyeing and printing cotton, in printing half-silk, in dyeing jute, straw, etc.