The world of color is deeply rooted in chemical synthesis, and at the heart of many vibrant hues lies Naphthol-4-sulfonic acid (CAS 84-87-7), also known as Winther's acid. This organic compound is a cornerstone intermediate for the production of a vast array of azo dyes, essential for the textile and other color-dependent industries. For R&D chemists and formulators, understanding its chemical behavior and application scope is key to unlocking new possibilities in dye development. As a dedicated manufacturer, we offer insights into why this intermediate is so vital.

Chemical Properties Enabling Dye Synthesis

Naphthol-4-sulfonic acid is characterized by its naphthalene ring structure, featuring a hydroxyl group (-OH) and a sulfonic acid group (-SO3H) at specific positions. This arrangement is crucial for its reactivity as a coupling component in azo dye synthesis. The presence of the hydroxyl group activates the naphthalene ring, particularly at the ortho position (position 2), making it highly susceptible to electrophilic attack by diazonium salts. The sulfonic acid group enhances water solubility, which is a critical property for dyes used in aqueous dyeing processes. Typically appearing as a grayish-white powder, its stability under normal conditions and its solubility in water make it a practical choice for industrial-scale synthesis.

Key Applications in Dye Production

The primary utility of Naphthol-4-sulfonic acid lies in its role as a precursor to various classes of dyes:

  • Direct Dyes: It is instrumental in manufacturing direct dyes such as Direct Copper Blue BR and 2R, and Direct Purple RB. These dyes are known for their affinity to cellulose fibers like cotton and rayon, requiring no mordant for dyeing.
  • Acid Dyes: Naphthol-4-sulfonic acid is also a vital intermediate for acid dyes, including Acid Red B and Acid Medium Bordeaux B. These dyes are primarily used for coloring protein fibers such as wool and silk, as well as synthetic fibers like nylon, owing to their acidic nature and ability to form ionic bonds with basic sites in the fiber.
  • Other Azo Compounds: Beyond direct and acid dyes, it can be employed in the synthesis of pigments and other specialty organic compounds requiring its specific structural attributes.

Why Choose Our Naphthol-4-sulfonic Acid?

As a leading manufacturer and supplier, we provide Naphthol-4-sulfonic acid that meets high-purity standards, ensuring optimal coupling reactions and vibrant, consistent colors. Our commitment extends to offering this essential intermediate at competitive prices, making it accessible for both large-scale dye manufacturers and smaller specialty chemical producers. We understand the demands of the industry and strive to be a reliable partner for your raw material needs. When you decide to buy Naphthol-4-sulfonic acid, consider partnering with us for guaranteed quality and efficient delivery.

The chemical versatility of Naphthol-4-sulfonic acid makes it a non-negotiable component for many dye formulations. By understanding its chemical properties and applications, formulators can effectively leverage this intermediate to create a spectrum of brilliant colors. We are here to support your endeavors by supplying high-quality Naphthol-4-sulfonic acid.