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.

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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

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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.

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Etymology

Origin of naphthol

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

Example Sentences

When this compound is combined with naphthol diazo-azo dyes are produced.

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

The most important of the naphthol colours is undoubtedly paranitroaniline red, produced by the combination of paranitroaniline and beta-naphthol.

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

Or, with naphthylamine and naphthol, thus:— C10H7N:NCl + C10H7OH + NaOH = NaCl    +    C10H7N:NC10H6OH    +  H2O Naphthalene azo-naphthol.

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

Such dyes as aniline black, alizarin blue, anthracene brown, tartrazine, some of the azo-reds and naphthol green resist the influence of light as well as, if not better than, any natural colouring-matter.

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