Disodium 4,4'-dinitrostilbene-2,2'-disulfonate explained

Disodium 4,4′-dinitrostilbene-2,2′-disulfonate is an organic compound with the formula (O₂NC₆H₃(SO₃Na)CH)₂. This salt is a common precursor to a variety of textile dyes and optical brighteners.

Preparation and reactions

The synthesis of disodium 4,4′-dinitrostilbene-2,2′-disulfonate begins with sulfonation of 4-nitrotoluene. This reaction affords 4-nitrotoluene-2-sulfonic acid. Oxidation of this species with sodium hypochlorite yields the disodium salt of 4,4′-dinitrostilbene-2,2′-disulfonic acid.^[1] The product is useful as its reaction with aniline derivatives results in the formation of azo dyes. Commercially important dyes derived from this compound include Direct Red 76, Direct Brown 78, and Direct Orange 40.^[2] Reduction gives 4,4′-diamino-2,2′-stilbenedisulfonic acid, which is a common optical brightener.

History

Arthur Green and André Wahl first reported the formation of disodium 4,4'-dinitrostilbene-2,2'-disulfonate using sodium hypochlorite.^{[3] [4]}

References

1. Book: Systematic Organic Chemistry: Modern Methods of Preparation and Estimation. 1926. William M.. Cumming. I. Vance. Hopper. T. Sherlock. Wheeler. 314. D. Van Nostrand Company. New York. Preparation 294. - Dinitro-Stilbene-Disulphonic Acid (Na salt).
2. Encyclopedia: Klaus. Hunger. Peter. Mischke. Wolfgang. Rieper. Roderich. Raue. Klaus. Kunde. Aloys. Engel. Azo Dyes. Ullmann's Encyclopedia of Industrial Chemistry. 2005. Wiley-VCH. Weinheim. 10.1002/14356007.a03_245. 3527306730 .
3. Ueber die Oxydation von Paranitrotoluolsulfosäure. German. On the oxidation of para-nitrotoluenesulfonic acid. Arthur G.. Green. Arthur George Green. André R.. Wahl. Ber. Dtsch. Chem. Ges.. 1897. 30. 3. 3097–3101. 10.1002/cber.189703003128.
4. Ueber die Oxydation der Paranitrotoluolsulfosäure. German. On the oxidation of para-nitrotoluenesulfonic acid. Arthur G.. Green. Arthur George Green. André R.. Wahl. Ber. Dtsch. Chem. Ges.. 1898. 31. 1. 1078–1080. 10.1002/cber.189803101195.