Description

Dipotassium 4,4'-Bis[(4-Methoxyphenyl)Azo]Stilbene-2,2'-Disulphonate is a high-purity, water-soluble anionic dye belonging to the stilbene class, widely recognized for its strong fluorescent whitening properties. This compound is essential for enhancing the brightness and perceived whiteness of materials by absorbing ultraviolet light and re-emitting it as visible blue light. It is a critical raw material for manufacturers in the detergent, paper, textile, and plastics industries seeking to improve product aesthetics and market appeal.

Application

• Optical Brightening Agent (OBA) / Fluorescent Whitening Agent (FWA) in laundry detergents and fabric softeners.
• Paper Brightening for high-quality writing, printing, and tissue papers to achieve superior whiteness.
• Textile Finishing for cotton, nylon, and other fibers to compensate for natural yellowness.
• Plastics and Synthetic Fibers masterbatch formulation to brighten polyamide, polyester, and PVC products.
• Coatings and Inks to impart a bright, clean visual effect to specialty paints and printing inks.
• Soap and Personal Care Products as an additive to enhance the visual brightness of bars and formulations.

Basic Information

Product Name	Dipotassium 4,4'-Bis[(4-Methoxyphenyl)Azo]Stilbene-2,2'-Disulphonate
CAS No.	96846-71-8
Molecular Formula	C30H24K2N4O8S2
Molecular Weight	710.93 g/mol
Synonyms	Dipotassium 4,4'-bis[(4-methoxyphenyl)azo]stilbene-2,2'-disulfonate; Fluorescent Brightener 351; Tinopal CBS-X; Blankophor BSU; FWA 351; 4,4'-Bis[(4-methoxyphenyl)azo]-2,2'-stilbenedisulfonic Acid Dipotassium Salt; CBS-X; Optical Brightener CBS
EINECS	Contact for details

Quality Control

Our production of Dipotassium 4,4'-Bis[(4-Methoxyphenyl)Azo]Stilbene-2,2'-Disulphonate adheres to stringent quality management protocols. Every batch undergoes comprehensive analytical testing, including HPLC for purity and spectrophotometry for strength and hue, to ensure consistent performance as a fluorescent whitening agent. Certificates of Analysis (COA) documenting purity, absorbance, and other critical parameters are available upon request to support your quality assurance and regulatory needs.

Storage

Preserve in a tightly closed container, protected from light. Store in a cool, dry, well-ventilated area at room temperature (15-25°C). This material is hygroscopic (moisture-sensitive); keep the original container tightly sealed to prevent absorption of atmospheric moisture.

Specification

Item	Specification
Appearance	Yellowish powder
Identification (IR)	Conforms to structure
Assay (HPLC)	≥ 98.0%
Moisture (KF)	≤ 2.0%
Absorbance (λ max)	349 - 353 nm
Ash Content	≤ 0.5%
Heavy Metals (as Pb)	≤ 20 ppm

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