Congo red excellent quality manufacturer, exporter and supplier. Congo red is an organic compound, the sodium salt of 3,3′-([1,1′-biphenyl]-4,4′-diyl)bis(4-aminonaphthalene-1-sulfonic acid. It is an azo dye. Congo red is water-soluble, yielding a red colloidal solution; its solubility is greater in organic solvents. However, the use of Congo red has long been abandoned, primarily because of its carcinogenic properties.

Application

Congo red was formerly used to dye cotton but has been superseded by dyes more resistant to light and to washing. It is still used in histology to stain tissues for microscopic examination, and to serve as an acid-base indicator, since it turns red in the presence of alkalies and blue when exposed to acids.

Congo Red is an inverse ph indicator.

Technical Specification

Specifications:

Mol. weight: 696.665 g/mol

Odor: Odorless.

Color: Red. Brownish-red. (Dark.)

pH (1% soln/water): 8.5 - 9.0 [Basic.]

Melting Point: >360°C (680°F) 

Solubility: Soluble in cold water. Very slightly soluble in acetone. Insoluble in diethyl ether. Soluble in Ethanol. Solubility in water: 1g/30 ml water