Naphthalenedisulfonic acid

Naphthalenedisulfonic acid refers to organic compounds with the formula C₁₀H₆(SO₃H)₂. They are derivatives of naphthalene. Twelve isomers are possible, but only a few have been examined in some depth, often as precursors to azo dyes or to various drugs. ^[1] They are colorless solids with high solubility in water. Some derivatives are prepared by sulfonation of naphthalene or its monosulfonic acids. A few are produced by indirect routes.

Hydroxynaphthalenesulfonic acids

name	Registry number	m.p., °C	prep	Precursor to
1,3-Naphthalenedisulfonic acid	6094-26-4	250	deamination 2-aminonaphthalene-6,8-disulfonic acid	obscure
1,5-Naphthalenedisulfonic acid, Armstrong acid	81-04-9	240-245	sulfonation of naphthalene with oleum (together with 1,6-isomer)	1-hydroxynaphthalene-5-sulfonic acid, 1,5-dihydroxynaphthalene, 1,3,5-naphthalenetrisulfonic acid
1,6-Naphthalenedisulfonic acid	525-37-1	125	sulfonation of naphthalene with oleum (together with 1,5-isomer)	1,6-dihydroxynaphthalene, 1,3,6-naphthalenetrisulfonic acid
1,7-Naphthalenedisulfonic acid	5724-16-3	?	low T sulfonation of naphthalene-2-sulfonic acid in low yields	obscure
2,6-Naphthalenedisulfonic acid	581-75-9	?	high T sulfonation of naphthalene	2-hydroxynaphthalene-6-sulfonic acid and 2,6-dihydroxynaphthalene
2,7-Naphthalenedisulfonic acid	92-41-12	?	high T sulfonation of naphthalene	2-hydroxynaphthalene-7-sulfonic acid, 2,7-dihydroxynaphthalene

In addition to these compounds, several naphthalenetrisulfonic acids are known as well as several hydroxy derivatives.

References

1. Booth, Gerald (2000). "Naphthalene Derivatives". Ullmann's Encyclopedia of Industrial Chemistry. doi:10.1002/14356007.a17_009. ISBN   978-3-527-30385-4.