C.I. direct red 28

  • Atlantic congo red
  • Disodium 3,3’-[[1,1’-biphenyl]-4,4’-diybis(azo)]bis(4-aminonaphthalene-1-sulfonate)
  • Azocard red congo
  • Benzo congo red
  • Brasilamina congo 4b
  • Congo red
Formula
C32H22N6Na2O6S2
Structure
Description
Brownish-red powder. Odorless.
Uses
As indicator, usually in 0.1% Aq soln for est free mineral acids, particularly in presence of organic acids, ph: 3.0 Blue-violet, 5.0 Red, detecting & est free hcl in gastric contents, detecting acidity of papers, as addition to culture media, also as reagent for bitter-almond water, dye, biological stain.

Registry Numbers and Inventories.
CAS
573-58-0
EC (EINECS/ELINCS)
209-358-4
EC Index Number
611-027-00-8
EC Class
Carcinogenic Category 2; Toxic for reproduction Category 3
R 45 63
RTECS
QK1400000
RTECS class
Drug; Mutagen; Reproductive Effector; Human Data; Primary Irritant
Merck
12,2562
Beilstein/Gmelin
3894858
Beilstein Reference
4-16-00-00600
Canada DSL/NDSL
DSL
US TSCA
Listed
Austrailia AICS
Listed
New Zealand
Listed
Korea ECL
Listed

Properties.
Formula
C32H22N6Na2O6S2
Formula mass
696.68
Melting point, °C
>360
Vapor density (air=1)
26.1
Solubility in water
33 g/L

Hazards and Protection.
Storage
Keep away from heat and flame. Store in a cool, dry place. Keep containers tightly closed.
Handling
Wash thoroughly after handling. Remove contaminated clothing and wash before reuse. Use with adequate ventilation. May form flammable dust-air mixtures. Keep container tightly closed. Do not get on skin or in eyes. Do not ingest or inhale. Wash clothing before reuse.
Protection
Eyes: Wear appropriate protective eyeglasses or chemical safety goggles as described by OSHA's eye and face protection regulations in 29 CFR 1910.133 or European Standard EN166. Skin: Wear appropriate protective gloves to prevent skin exposure. Clothing: Wear appropriate protective clothing to prevent skin exposure.
Respirators
A respiratory protection program that meets OSHA's 29 CFR 1910.134 and ANSI Z88.2 requirements or European Standard EN 149 must be followed whenever workplace conditions warrant a respirator's use.
Small spills/leaks
Clean up spills immediately, using the appropriate protective equipment. Sweep up or absorb material, then place into a suitable clean, dry, closed container for disposal. Avoid generating dusty conditions. Provide ventilation.
Disposal code
3
Stability
Stable at room temperature in closed containers under normal storage and handling conditions. Materials containing similar functional groups can decompose at elevated temperatures.
Incompatibilities
Strong oxidizing agents can cause fire or explosion on contact. Incompatible with strong reducing agents, strong acids.
Decomposition
Carbon monoxide, oxides of sulfur, carbon dioxide, nitric oxide (NOx) and ammonia (NH3) fumes, nitrogen.

Fire.
Fire fighting
Wear a self-contained breathing apparatus in pressure-demand, MSHA/NIOSH (approved or equivalent), and full protective gear. During a fire, irritating and highly toxic gases may be generated by thermal decomposition or combustion. This material in sufficient quantity and reduced particle size is capable of creating a dust explosion. Extinguishing media: Use extinguishing media most appropriate for the surrounding fire. In case of fire use water spray, dry chemical, carbon dioxide, or appropriate foam.
Health
2
 
Flammability
0
 
 
Reactivity
0
 

Health.
Exposure effects
May cause reproductive and fetal effects.
   Ingestion
May cause gastrointestinal irritation with nausea, vomiting and diarrhea. Low hazard for usual industrial handling.
   Inhalation
May cause respiratory tract irritation. Low hazard for usual industrial handling.
   Skin
May cause skin irritation. May cause skin sensitization, an allergic reaction, which becomes evident upon re-exposure to this material.
   Eyes
May cause eye irritation.

First aid
 
   Ingestion
If victim is conscious and alert, give 2-4 cupfuls of milk or water. Never give anything by mouth to an unconscious person. Get medical aid.
   Inhalation
Remove from exposure to fresh air immediately. If not breathing, give artificial respiration. If breathing is difficult, give oxygen. Get medical aid.
   Skin
Get medical aid. Wash clothing before reuse. Flush skin with plenty of soap and water. Destroy contaminated shoes.
   Eyes
Flush eyes with plenty of water for at least 15 minutes, occasionally lifting the upper and lower eyelids. Get medical aid.

Transport.
HS Code
3204 14 00