Rhein
CAS 478-43-3
EC 207-521-4
Formula C15H8O6
MW 284.22 g/mol
Pigments & Colorants Personal Care & CosmeticsTextile, Leather & PaperPrinting & Packaging UV Protection & StabilizationAntioxidant & StabilizerSurface Modification & Wetting
Description
Rhein (CAS 478-43-3), also known as rheic acid, cassic acid, or monorhein, is a naturally derived anthraquinone compound with the molecular formula C15H8O6. It carries no assigned E-code and is classified under HS code 29189900. It occurs naturally in rhubarb and related plant species.
In textile and leather dyeing, rhein functions as an organic pigment and colorant, binding to substrate surfaces through chelation with metal mordants to produce stable yellowish-brown hues. In personal care formulations, it acts as a UV absorber and antioxidant, intercepting free radicals and attenuating UV radiation to protect both the product matrix and skin.
Rhein is supplied as a yellowish-brown solid and is subject to REACH registration requirements for commercial quantities within the EU. Procurement teams should confirm supplier documentation including safety data sheets and certificates of analysis. Buyers should verify grade specifications directly with the supplier for their intended application.
In textile and leather dyeing, rhein functions as an organic pigment and colorant, binding to substrate surfaces through chelation with metal mordants to produce stable yellowish-brown hues. In personal care formulations, it acts as a UV absorber and antioxidant, intercepting free radicals and attenuating UV radiation to protect both the product matrix and skin.
Rhein is supplied as a yellowish-brown solid and is subject to REACH registration requirements for commercial quantities within the EU. Procurement teams should confirm supplier documentation including safety data sheets and certificates of analysis. Buyers should verify grade specifications directly with the supplier for their intended application.
Physical Properties
| Melting Point | 334.8 °C |
| Boiling Point | 346.72°C (rough estimate) |
| Density | 1.3269 (rough estimate) |
| Appearance | Yellowish Brown Solid |
| Color | Yellow to Dark Orange |
| Form | neat |
| Water Solubility | <0.1 g/100 mL at 17 ºC |
| Refractive Index | 1.4413 (estimate) |
| Log P | 4.290 (est) |
Safety & Handling (Learn More)
Warning GHS07
H
H315H319H335
P
P261P264P271P280P319P321P405P501P264+P265P302+P352P304+P340P332+P317P337+P317P362+P364P403+P233P305+P351+P338
Trade & Regulatory
| HS Code | 29189900 |
| Storage Class | 11 - Combustible Solids |
| WGK (Germany) | 2 |
Other Names
Rhein (Molecule)4,5-dihydroxy-9,10-dioxoanthracene-2-carboxylic acidmonorheinrheic acidCassic acid
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