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Rhein

CAS Number
478-43-3
EC Number
207-521-4
Chemical Formula
C15H8O6
Molecular Weight
284.22 g/mol

Description

Rhein (CAS 478-43-3 ), also known as Cassic acid and Rhubarb Yellow, is an anthraquinone compound derived from rhubarb root and related botanical sources. It functions as a natural colorant, antioxidant, and UV-stabilizing agent across pharmaceutical, cosmetic, and industrial applications. In personal care formulations, it is incorporated as a natural yellow pigment and antioxidant active, particularly in products targeting skin tone evenness and photoprotection. The textile and leather industries use it as a natural dye capable of imparting yellow to orange hues. This compound is applied to protein-based and cellulosic fibers, often in combination with mordants to improve wash fastness. Pharmaceutical manufacturers source it as a reference standard and active ingredient in preparations derived from traditional botanical extracts. It contributes to the documented bioactivity of rhubarb-based formulations in various medicinal contexts. In paper processing, it is evaluated as a surface-modifying agent that influences substrate wettability and coating adhesion for specialized industrial uses. The material is supplied as a yellow to orange crystalline powder for ease of handling. It is available in research-grade and pharmaceutical-grade specifications, with purity levels typically ranging from 95% to 98%+ by HPLC analysis. Botanical extract standardized forms are also commercially available for buyers sourcing at scale for cosmetic or nutraceutical applications. Our supply chain ensures consistent quality and compliance with international chemical distribution protocols. Contact us for supply of Rhein Request Quote

Other Names (Synonyms)

Monorhein | Cassic acid | Rhubarb Yellow | Rheic acid | 4,5-Dihydroxyanthraquinone-2-carboxylic acid | Chrysazin-3-carboxylic acid | 1,8-Dihydroxyanthraquinone-3-carboxylic acid | 4,5-dihydroxy-9,10-dioxoanthracene-2-carboxylic acid

Key Technical Features

  • High Purity Grade standard
  • Consistent Batch Quality
  • Full Regulatory & REACH Support
  • Global Logistics Network enabled

Physical Properties

Melting Point334.8 °C
Boiling Point346.72°C (rough estimate)
Density1.3269 (rough estimate)
AppearanceYellowish Brown Solid
ColorYellow to Dark Orange
Formneat
Water Solubility<0.1 g/100 mL at 17 ºC
Refractive Index1.4413 (estimate)
Log P4.290 (est)

Safety & Handling

Warning
GHS07· Irritant

Hazard Statements

H315Causes skin irritation
H319Causes serious eye irritation
H335May cause respiratory irritation

Precautionary Statements

P261Avoid breathing dust/fume/gas/mist/vapours/spray.
P264Wash … thoroughly after handling.
P271Use only outdoors or in a well-ventilated area.
P280Wear protective gloves/protective clothing/eye protection/face protection.
P319Get medical advice/attention if you feel unwell.
P321Specific treatment (see … on this label).
P405Store locked up.
P501Dispose of contents/container in accordance with local regulations.
P265Wash … thoroughly after handling.
P352IF ON SKIN: Wash with plenty of water.
P340IF INHALED: Remove person to fresh air and keep comfortable for breathing.
P317Get emergency medical help.
P317If eye irritation persists: Get medical advice/attention. Get emergency medical help.
P364Take off contaminated clothing and wash it before reuse.
P233Store in a well-ventilated place. Keep container tightly closed.
P338IF IN EYES: Rinse cautiously with water for several minutes. Remove contact lenses, if present and easy to do. Continue rinsing.

Trade & Regulatory

HS Code29189900
Storage Class11 - Combustible Solids
WGK (Germany)2