568-63-8

Basic information

• Product Name: Acid Red 51
• Synonyms: PYROSIN B;TETRAIODOFLUORESCEIN;TETRAIODOFLUORESCEIN SODIUM SALT;Benzoic acid, 2-(6-hydroxy-2,4,5,7-tetraiodo-3-oxo-3H-xanthen-J9-yl)-, disodium salt;Fluorescein, 2',4',5',7'-tetraiodo-, disodium salt;Fluorescein, 2',4',5',7'-tetraiodo-, disodium salt (benzoic acid tautomeric form);Nsc 36685;Tif na
• CAS NO: 568-63-8
• Molecular Formula: C₂₀H₆I₄O₅*2Na
• Molecular Weight: 879.86
• EINECS: 240-474-8
• Mol File: 568-63-8.mol
• Article Data: 1

Chemical Properties

• Boiling Point: 693.2oC at 760 mmHg
• Flash Point: 373oC
• Appearance: Dark maroon/Powder
• Water Solubility: Soluble in water, glycerin and methanol.
• Sensitive: Light Sensitive & Hygroscopic
• CAS DataBase Reference: Acid Red 51(CAS DataBase Reference)
• NIST Chemistry Reference: Acid Red 51(568-63-8)
• EPA Substance Registry System: Acid Red 51(568-63-8)

Safety Data

• Hazard Codes: Xn
• Statements: 22
• Safety Statements: 36-24/25-22
• WGK Germany: 3
• RTECS: LM5950000
• TSCA: Yes
• Hazardous Substances Data: 568-63-8(Hazardous Substances Data)

Usage

General Description

Acid Red 51, also known as New Coccine, is a synthetic azo dye commonly used in the food and textile industries. It is a red to orange powder with a potential for skin and eye irritation. In the food industry, Acid Red 51 is often used to dye products such as jams, jellies, and baked goods. It is also used in the textile industry to dye various fabrics and materials. However, there have been concerns raised about its safety, as it has been linked to potential health risks, including allergic reactions and potential carcinogenic properties. Due to these concerns, there are strict regulations and limits on its use in various industries.

InChI:InChI=1/C20H8I4O5.2Na/c21-11-5-9-13(7-3-1-2-4-8(7)20(27)28)10-6-12(22)17(26)15(24)19(10)29-18(9)14(23)16(11)25;;/h1-6,25H,(H,27,28);;/q;2*+1/p-2

Synthetic route

silver (I) ion (14701-21-4) + erythrosin (568-63-8) → 2Ag(1+)*C20H6I4O5(2-)=Ag2C20H6I4O5

Conditions	Yield
In water 25°C, constant ionic strength (KNO3), various concns. of dye; no isolation, identification by potentiometric titration of dye soln. by AgNO3;

erythrosin (568-63-8) + silver nitrate → 2Ag(1+)*C20H6I4O5(2-)=Ag2C20H6I4O5

Conditions	Yield
In water excess of AgNO3; ppt. washed, dried;

Upstream product

• 568-63-8 erythrosin 

Downstream Products

• 69254-43-9 C₂₀H₇I₄O₅^(2-)*2Na⁽¹⁺⁾ 

Relevant articles and documents

A Nanosecond Laser Flash Photolysis Study of Intramicellar Reactions in the Erythrosin B/CTAB Aqueous System

Both "fast", occurring within 1 μs after excitation, and "slow" reactions, occurring in the hundreds of microseconds time scale, were observed following erythrosin B triplet formation in the cationic micellar system cetyltrimethylammonium bromide (CTAB).The "fast" events are shown to occur in multiply occupied micelles and are assigned to bimolecular reactions.The "slow" ones, which have not been studied in detail, are due to first-order deactivation processes of the triplet occurring in singly occupied micelles.The effects of the excitation intensity and occupancy on the fast triplet decay, radical formation, and subsequent geminate recombination have been studied.The triplet disappears with observed rate constants ranging from 5.5 * 1E6 to 3.6 * 1E6 s-1 while the formation of radicals has rate constants varying from 3.3 * 1E7 to 9.1 * 1E6 s-1.Both in triplet decay and in radical formation the increase in rates occurs by increasing the excitation energy and occupancy.The identification of the precursor(s) of radicals is discussed.The geminal radical recombination has a rate constant of 2.1 * 1E6 s-1.