6859. Orange B

Nomenclature

CAS number: 15139-76-1
4,5-Dihydro-5-oxo-4-[(4-sulfo-1-naphthalenyl)azo]-1-(4-sulfophenyl)-1H-pyrazole-3-carboxylic acid 3-ethyl ester disodium salt; 5-oxo-4-[(4-sulfo-1-naphthyl)azo]-1-(p-sulfophenyl)-2-pyrazoline-3-carboxylic acid 3-ethyl ester disodium salt; 5-hydroxy-4-[(4-sulfo-1-naphthalenyl)azo]-1-(4-sulfophenyl)-1H-pyrazole-3-carboxylic acid 3-ethyl ester disodium salt; 1-(4-sulfophenyl)-3-ethylcarboxyl-4-(4-sulfonaphthylazo)-5-hydroxypyrazole disodium salt; C.I. Acid Orange 137; C.I. 19235.
C22H16N4Na2O9S2; mol wt 590.49.
C 44.75%, H 2.73%, N 9.49%, Na 7.79%, O 24.39%, S 10.86%.

Description and references

Prepn: W. H. Kretlow et al., US 3285906 (1966 to Stange Co.). Review: Fed. Regist. 43, 45611 (1978). See also Colour Index vol. 4 (3rd ed., 1971) p 4134.

Chemical structure

Properties

Dull orange crystals. Absorption max (0.04N ammonium acetate): 442 nm. Soly in water at 77°: 220 g/l. Violet soln in conc H2SO4, changing to fuchsia then red on dilution. Red soln in conc HCl. Yellowish soln in 10% NaOH, changing to brownish yellow on dilution.

Use

In coloring sausage and frankfurter casings.