1. Basic Product Profile

• Full IUPAC Name: (E)-6,6'-(ethene-1,2-diyl)bis[3-({4-[bis(2-hydroxyethyl)amino]-6-(phenylamino)-1,3,5-triazin-2-yl}amino)benzenesulfonic acid]
• Aliases: Calcofluor White M2R, Tinopal UNPA-GX, C.I. Fluorescent Brightener 28, Optical Brightener 28
• CAS Number: 4404-43-7
• EINECS: 224-548-7
• Molecular Formula: C40H44N12O10S2
• Molecular Weight: 916.98
• Chemical Classification: Anionic bistriazinyl stilbene fluorescent whitening agent, biological fluorescent stain, textile & paper whitening auxiliary
• Core Advantages
  Water-soluble stilbene-type fluorescent brightener with dual triazine functional groups. Absorbs UV light (365 nm excitation) and emits blue fluorescence (435 nm emission) to offset yellow tint of cellulose substrates. Strong affinity for cotton, linen, paper, polyamide; stable in wide pH range. Dual-grade supply: Industrial Grade for textile/paper/detergent; Research Grade for microbiology chitin/fungi fluorescent staining.

2. Physical & Chemical Properties

2.1 Physical Index

1. Appearance: Light yellow to pale yellow crystalline powder
2. Odor: Odorless
3. Solubility: Water-soluble (80 g/L at 25℃); soluble in DMSO, hot ethanol; slightly soluble in methanol; insoluble in aliphatic hydrocarbons
4. Melting Point: 290–300 °C (decomposition)
5. Density: 1.598 g/cm3 (calculated)
6. Fluorescence Spectrum: Excitation λmax=365 nm, Emission λmax=435 nm (bright blue fluorescence)
7. Hygroscopy: Slightly hygroscopic under high humidity air
8. pH (1% aqueous solution): Neutral to weak alkaline

2.2 Chemical Properties

1. Conjugated stilbene central skeleton + two triazine sulfonic acid side chains: Anionic structure enables strong adsorption on cellulose fiber hydroxyl groups
2. Whitening mechanism: Converts invisible ultraviolet radiation into visible blue light, neutralizes inherent yellow hue of natural fibers
3. Acid & Alkali Stability: Stable in pH 5–10; precipitates under strong acidic conditions; compatible with weak alkaline washing systems
4. Thermal Stability: Stable below 180 °C; high temperature above 280 °C destroys conjugated fluorescent skeleton
5. Photostability: Moderate light fastness; long-term strong UV irradiation weakens fluorescence intensity
6. Compatibility: Compatible with anionic surfactants, paper sizing agents, textile softeners; incompatible with cationic dyes, heavy metal salts, strong mineral acids

3. Main Application Fields

3.1 Textile Industry (Core Industrial Usage)

3.2 Paper & Pulp Manufacturing

3.3 Detergent & Daily Chemical Additive

3.4 Biological & Laboratory Research (Research Grade)

1. Specific fluorescent stain for fungal cell wall chitin; stains Candida albicans, mold and yeast for microscopic observation;
2. Biomarker reagent for chitin biosynthesis and plant cell wall structure research;
3. Histology & hematology diagnostic assay auxiliary dye.

4. Quality Specification Table