Acid Orange 74 Dye Reagent Grade CAS 10127-27-2 High Purity Chromium Complex Azo Dye for Textile Dyeing, Leather Processing, and Analytical Chemistry

Product Overview

Acid Orange 74 is a chromium complex azo dye with the molecular formula C₁₆H₁₁CrN₅NaO₈S and a molecular weight of 508.34 g/mol. This orange-red to dark brown powder is a member of the acid dye family, characterized by its excellent water solubility and strong affinity for protein fibers such as wool, silk, and nylon. The chromium complex structure imparts superior lightfastness and washfastness compared to simple azo dyes, making it particularly valuable in high-performance textile and leather applications.

The dye is synthesized by complexing a chromium atom with a sulfonated azo ligand derived from the coupling of diazotized aromatic amines with pyrazolone derivatives. Its molecular structure contains both sulfonic acid groups (conferring water solubility) and a chromium coordination center (providing dye-metal complexation properties), enabling strong binding to fiber substrates.

Synthetic Process

Acid Orange 74 is manufactured through a multi-step synthetic process:

• Diazotization: An aromatic amine is diazotized using sodium nitrite and hydrochloric acid at low temperature (0-5°C) to form a diazonium salt.

• Coupling reaction: The diazonium salt is coupled with a pyrazolone derivative in alkaline medium to form the azo dye intermediate.

• Sulfonation: The intermediate is sulfonated to introduce sulfonic acid groups, enhancing water solubility.

• Chromium complexation: The sulfonated azo dye is reacted with a chromium salt (typically chromium(III) chloride or chromium(III) sulfate) under controlled pH and temperature conditions to form the 1:1 chromium complex.

• Salt formation: The complex is converted to the sodium salt form and purified by precipitation or crystallization.

Mechanism of Action / Application Principles

• Protein Fiber Dyeing: Acid Orange 74 binds to wool, silk, and nylon fibers through ionic interactions between the dye's sulfonic acid groups and the protonated amino groups of the fiber. The chromium complex enhances dye-fiber affinity through additional coordination interactions.

• Leather Processing: Used in the dyeing of chrome-tanned leather, where the chromium center in the dye provides excellent compatibility with the chromium-tanned substrate.

• High Fastness Requirements: The chromium complex structure provides superior lightfastness (rating 6-7 on the blue wool scale) and washfastness compared to non-metallized acid dyes.

• Analytical Applications: Used as a colorimetric reagent for the detection of certain metal ions.

Quality Specifications

Each batch is accompanied by a Certificate of Analysis (COA).

Packaging & Storage

• Research quantities: 25g, 100g HDPE bottles

• Bulk quantities: 500g HDPE containers

Storage conditions: Store in a cool, dry place in tightly sealed containers, protected from light. Under recommended conditions, shelf life is 36 months.

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