Description

4-[(4-Chloro-3-Sulphophenyl)Azo]-3-Hydroxy-2-Naphthoic Acid is a high-purity azo dye intermediate, also known as C.I. Mordant Brown 33. This compound is valued for its ability to form stable, complexed colors with metal ions, making it a critical component in the production of high-performance mordant and pre-metallized dyes. It is primarily sought after by manufacturers in the textile, leather, and specialty ink industries who require consistent chroma and excellent fastness properties in their final products.

Application

• Textile Dyeing: As a key intermediate for producing mordant dyes used on wool, silk, and nylon, offering good wash and light fastness.
• Leather Coloring: Employed in the formulation of dyes for leather goods, providing rich, durable brown shades.
• Pre-metallized Dye Synthesis: Used in the manufacture of 1:1 or 2:1 metal-complex dyes for industrial applications.
• Specialty Inks: A component in the production of pigments for inks requiring specific color stability and chemical resistance.
• Research & Development: Serves as a chemical building block in organic synthesis and colorant research laboratories.
• Paper Staining: Used in limited applications for specialty paper products requiring specific, stable coloration.

Basic Information

Product Name	4-[(4-Chloro-3-Sulphophenyl)Azo]-3-Hydroxy-2-Naphthoic Acid
CAS No.	25310-97-8
Molecular Formula	C17H11ClN2O6S
Molecular Weight	406.80 g/mol
Synonyms	C.I. Mordant Brown 33; 3-Hydroxy-4-[(2-hydroxy-1-naphthyl)azo]-5-chlorobenzenesulfonic Acid; Acid Mordant Brown MR; Benzenesulfonic acid, 4-[(4-chloro-3-sulfophenyl)azo]-3-hydroxy-2-naphthoic acid; Mordant Brown 33; 4-[(4-Chloro-3-sulfophenyl)azo]-3-hydroxy-2-naphthalenecarboxylic acid; 5-Chloro-2-hydroxy-3-[(2-hydroxy-1-naphthyl)azo]benzenesulfonic Acid
EINECS	Contact for details

Quality Control

Our 4-[(4-Chloro-3-Sulphophenyl)Azo]-3-Hydroxy-2-Naphthoic Acid is manufactured under a strict quality management system. Every batch undergoes rigorous analytical testing to ensure it meets precise specifications for purity, color strength, and impurity profiles. A comprehensive Certificate of Analysis (COA) detailing assay, identification, and related substances is provided with each shipment to guarantee traceability and compliance with your quality standards.

Storage

Preserve in a tightly closed container, protected from light. Store in a cool, dry, and well-ventilated area at room temperature (15-25°C). This product is hygroscopic (moisture-sensitive); keep the container tightly sealed when not in use to prevent absorption of atmospheric moisture, which may affect product performance.

Specification

Item	Specification
Appearance	Brown to dark brown powder
Identification (IR)	Conforms to structure
Assay (HPLC)	≥ 95.0%
Loss on Drying	≤ 2.0%
Sulfated Ash	≤ 1.0%
Heavy Metals (as Pb)	≤ 20 ppm
Water Solubility	Sparingly soluble

Note: Specifications can be tailored. Please contact us for the detailed technical data sheet of a specific grade.