naphthol

American  

[naf-thawl, -thol, nap-] / ˈnæf θɔl, -θɒl, ˈnæp- /

noun

Chemistry.

1. either of two isomeric hydroxyl derivatives, C 1 0 H 7 OH, of naphthalene alpha-naphthol, or 1-naphthol, and beta-naphthol, or 2-naphthol, white or yellowish crystals, with a phenolic odor, that darken on exposure to light: used chiefly in dyes, drugs, perfumes, and insecticides.

---

naphthol British  

/ ˈnæfθɒl, ˈnæp- /

noun

1. a white crystalline solid having two isomeric forms, alpha-naphthol, used in dyes, and beta-naphthol, used in dyes and as an antioxidant. Formula: C 10 H 7 OH

---

naphthol Scientific  

/ năf′thôl′,-thōl′,năp′- /

1. A poisonous organic compound occurring in two isomeric forms. Both isomers are important in the manufacture of dyes, and also in making antiseptics, insecticides, and tanning agents. Naphthol consists of a hydroxyl group (OH) attached to naphthalene. Chemical formula: C ₁₀ H ₈ O.

---

Etymology

Origin of naphthol

First recorded in 1840–50; naphth- + -ol ¹

Example Sentences

This was discovered in 1879 by Caro, and introduced as “acid naphthol yellow.”

From Coal and What We Get from It by Meldola, Raphael

It is a remarkable fact that non-condensed methane derivatives of naphthol, e.g., b-naphthol-a-methanesulphonic acid, dissolved in water and partly neutralised, are devoid of tanning character when allowed to act upon pelt.

From Synthetic Tannins by Grasser, Georg

When a good method for making the naphthol was discovered in 1869, the dye was made from this.

From Coal and What We Get from It by Meldola, Raphael

They are also called naphthol colours from the use of beta-and alpha-naphthol in their production.

From The Dyeing of Cotton Fabrics A Practical Handbook for the Dyer and Student by Beech, Franklin

The azo-blacks are obtained by combining diazotised sulpho-acids of amidoazo-compounds of the benzene or naphthalene series with naphthol sulpho-acids or other naphthalene derivatives.

From Coal and What We Get from It by Meldola, Raphael