Naphtol AS

chemical compound

Also known as: 2-hydroxy-3-naphthanilide

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July 1, 2026

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Naphtol AS is a chemical compound used in the creation of azoic dyes. It is an anilide of 3-hydroxy-2-naphthoic acid, or more broadly, an arylide of hydroxy aromatic carboxylic acids or acyl derivatives of acetic acid.1

Naphtol AS plays a crucial role in ingrain dyeing, a process where the dye is synthesized directly within the fabric. When Naphtol AS reacts with unsulfonated azoic diazo components on the fabric, it produces insoluble dyes with good resistance to washing. This method was a significant advancement in developing dyes with superior wetfastness.2

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dye
Azo dyes
…was found that 2-hydroxy-3-naphthanilide (Naphtol AS, from the German Naphtol Anilid Säure) forms a water-soluble anion with affinity for cotton, a major step in the development of the ingrain dyes. Its reaction with unsulfonated azoic diazo components on the fabric gives insoluble dyes with good wetfastness; with Diazo Component…
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…was found that 2-hydroxy-3-naphthanilide (Naphtol AS, from the German Naphtol Anilid Säure) forms a water-soluble anion with affinity for cotton, a major step in the development of the ingrain dyes. Its reaction with unsulfonated azoic diazo components on the fabric gives insoluble dyes with good wetfastness; with Diazo Component…
Read More