Description

4,4'-Diamino-2,2'-stilbenedisulfonic acid is a high-purity, synthetic organic intermediate of significant industrial importance. Its core value lies in its role as a key building block for the production of optical brighteners and fluorescent whitening agents (FWAs). This compound is essential for manufacturers in the textile, paper, detergent, and plastics industries seeking to enhance the brightness and perceived whiteness of their products. Its disulfonic acid groups provide excellent water solubility, making it particularly suitable for aqueous application systems.

Application

• Primary raw material for Fluorescent Whitening Agents (FWAs): Serves as the central chromophore in the synthesis of stilbene-type optical brighteners, such as DSBP and DAS1.
• Textile Industry: Used in brighteners applied to cotton, nylon, and other fibers to achieve high whiteness and brilliance.
• Paper Manufacturing: Incorporated into coatings and pulps to improve the optical brightness and quality of high-grade papers.
• Detergent Formulations: A key precursor for brighteners added to laundry detergents and fabric softeners to make white fabrics appear cleaner and brighter.
• Plastics and Polymers: Employed in the production of brighteners for synthetic fibers (e.g., polyester) and plastic materials.
• Analytical Chemistry: Can be used as a fluorescent probe or tracer in certain research and diagnostic applications due to its inherent fluorescence.

Basic Information

Product Name	4,4'-Diamino-2,2'-stilbenedisulfonic Acid
CAS No.	81-11-8
Molecular Formula	C14H14N2O6S2
Molecular Weight	370.40 g/mol
Synonyms	DAS; 4,4'-Diaminostilbene-2,2'-disulfonic Acid; trans-4,4'-Diaminostilbene-2,2'-disulfonic Acid; DSD Acid; 2,2'-(1,2-Ethenediyl)bis[5-aminobenzenesulfonic Acid]; Benzenesulfonic acid, 2,2'-(1,2-ethenediyl)bis[5-amino-; Fluorescent Brightener DAS; Tinopal DAS
EINECS	201-327-3

Quality Control

Our production of 4,4'-Diamino-2,2'-stilbenedisulfonic acid adheres to stringent quality management protocols. Every batch undergoes comprehensive analytical testing, including HPLC for purity and identity confirmation, to ensure it meets exacting specifications for use in high-performance optical brightener synthesis. Certificates of Analysis (COA) detailing purity, assay, and impurity profiles are provided with each shipment to guarantee traceability and consistency for our B2B partners.

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 acids and incompatible organic solvents. Due to its light-sensitive nature, prolonged exposure to direct light should be avoided to maintain product integrity.

Specification

Item	Specification
Appearance	Yellow to light brown crystalline powder
Identification (IR)	Conforms to structure
Assay (HPLC)	≥ 98.0%
Water Content (KF)	≤ 1.0%
Residue on Ignition	≤ 0.5%
Trans-isomer Content (HPLC)	≥ 95.0%

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