Description

C.I. Basic Yellow 21 is a synthetic cationic dye belonging to the azo class, widely recognized for its bright and stable yellow hue. This product is valued for its excellent substantivity to polyacrylonitrile and modified acrylic fibers, delivering consistent and vibrant coloration. It serves as a critical component for dye houses, textile manufacturers, and industrial ink formulators requiring high-performance colorants for synthetic materials.

Application

• Primary dyeing and printing of acrylic fibers and modacrylics.
• Coloration of paper and specialty paper products.
• Manufacturing of leather and synthetic leather goods.
• Production of inks for various printing applications.
• As a colorant for plastics and certain polymers.
• Staining applications in biological and histological contexts (specific grades).

Basic Information

Product Name	C.I. Basic Yellow 21
CAS No.	12270-31-4
Molecular Formula	C21H25ClN3O3S
Molecular Weight	434.96 g/mol
Synonyms	Basic Yellow 21; Aizen Cathilon Yellow 5GLH; Astrazon Yellow 5GL; Maxilon Yellow 5GL; Cationic Yellow 5GL; 1-Methyl-2-[(1,3-dihydro-1,3,3-trimethyl-2H-indol-2-ylidene)ethylidene]-3,3-dimethyl-3H-indolium p-toluenesulfonate; 2-[(1E)-2-(1,3-Dihydro-1,3,3-trimethyl-2H-indol-2-ylidene)ethylidene]-1,3,3-trimethyl-3H-indolium 4-methylbenzenesulfonate
EINECS	235-543-6

Quality Control

Our C.I. Basic Yellow 21 is manufactured under a strict quality management system. Every batch is tested to ensure it meets precise specifications for color strength, shade, solubility, and impurity profiles. A comprehensive Certificate of Analysis (COA) detailing purity, physical properties, and performance characteristics is provided to guarantee consistency and suitability for your application.

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-brown powder
Identification (IR)	Conforms to standard
Color Strength	100 ± 3% (vs. Standard)
Shade	Within agreed tolerance
Moisture Content	≤ 5.0%
Water Solubility	Clear solution at specified concentration
Ash Content	≤ 1.0%
Particle Size	≥ 95% passes through 80 mesh

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