Description

C.I. Acid Yellow 221 is a synthetic organic dye belonging to the acid dye class, identified by CAS NO 61814-59-3. This high-performance colorant is valued for its bright, vivid yellow hue and strong affinity for protein-based and polyamide fibers. It is essential for manufacturers in the textile, leather, and paper industries seeking consistent, wash-fast coloration. Its properties also make it suitable for specialized applications in inks and biological staining.

Application

• Textile Dyeing: Primary application for dyeing wool, silk, and nylon fibers to achieve bright, lightfast yellow shades.
• Leather Finishing: Used for coloring leather goods, providing uniform and penetrating coloration.
• Paper Coloring: Imparts a stable yellow color to specialty papers, including decorative and packaging grades.
• Ink Formulation: A key component in the manufacture of inks for writing, printing, and stamping.
• Biological Staining: Employed in laboratory settings as a histological stain for microscopic analysis.
• Polymer Coloring: Used to color synthetic polymers and plastics where acid dye compatibility is required.

Basic Information

Product Name	C.I. Acid Yellow 221
CAS No.	61814-59-3
Molecular Formula	C16H14N4Na2O7S2
Molecular Weight	492.41 g/mol
Synonyms	Acid Yellow 221; C.I. 14166; Acid Leather Yellow G; Nylosan Yellow E-2G; Telon Yellow G; Acid Fast Yellow E-2G; Aminyl Yellow E-2GL; Supranol Yellow GW
EINECS	Contact for details

Quality Control

Our production of C.I. Acid Yellow 221 adheres to stringent quality management protocols to ensure batch-to-batch consistency and performance. Every lot is tested for critical parameters including color strength, shade, solubility, and impurity profile. Certificates of Analysis (COA) documenting purity, physical properties, and conformance to agreed specifications are provided with each shipment.

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). Keep away from strong oxidizing agents. The product is light-sensitive (store away from light).

Specification

Item	Specification
Appearance	Yellow to orange powder
Identification (IR)	Conforms to standard
Color Strength	100 ± 3% (vs. Standard)
Moisture Content	≤ 5.0%
Water Solubility	Conforms
Ash Content	≤ 1.0%
pH (1% Solution)	6.0 - 8.0
Heavy Metals (as Pb)	≤ 20 ppm

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