Methyl red

  • Acid Red 2
  • 4'-Dimethylaminoazobenzene-2-carboxylic acid
  • C.I. 13020
  • p-(Dimethylamino)azobenzene-o-carboxylic acid
  • 4-(2-Carboxyphenylazo)-N,N-dimethylaniline
Formula
C15H15N3O2
Structure
Description
Glistening, violet crystals from toluene.
Uses
As indicator in 0.1% Alcoholic soln, ph: 4.4 Red, 6.2 Yellow, used for titrating nh3, weak organic bases, eg, alkaloids, not suitable for organic acids, except oxalic & picric acid.

Registry Numbers and Inventories.
CAS
493-52-7
EC (EINECS/ELINCS)
207-776-1
S 22 24/25
RTECS
DG8960000
RTECS class
Tumorigen; Mutagen
UN (DOT)
1230
Merck
12,6199
Beilstein/Gmelin
750102
Beilstein Reference
4-16-00-00504
Canada DSL/NDSL
DSL
US TSCA
Listed
Austrailia AICS
Listed
New Zealand
Listed
Japan ENCS (MITI)
Listed
Korea ECL
Listed

Properties.
Formula
C15H15N3O2
Formula mass
269.31
Melting point, °C
178 - 182
Density
1.31 g/cm3
Solubility in water
Insoluble
pKa/pKb
2.5 (pKa)

Hazards and Protection.
Storage
Store in a cool, dry, well-ventilated area away from incompatible substances.
Handling
Wash thoroughly after handling. Use with adequate ventilation. Minimize dust generation and accumulation. Avoid contact with skin and eyes. Avoid ingestion and inhalation.
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 minimize contact with skin.
Respirators
Follow the OSHA respirator regulations found in 29CFR 1910.134 or European Standard EN 149. Always use a NIOSH or European Standard EN 149 approved respirator when necessary.
Small spills/leaks
Clean up spills immediately, using the appropriate protective equipment. Sweep up, then place into a suitable container for disposal. Avoid generating dusty conditions. Provide ventilation.
Disposal code
3
Stability
Stable under normal temperatures and pressures. Materials containing similar functional groups can decompose at elevated temperatures.
Incompatibilities
Strong oxidizing agents.
Decomposition
Nitrogen oxides, carbon monoxide, irritating and toxic fumes and gases, carbon dioxide.

Fire.
Fire fighting
Wear a self-contained breathing apparatus in pressure-demand, MSHA/NIOSH (approved or equivalent), and full protective gear. Combustion generates toxic fumes. Extinguishing media: For small fires, use water spray, dry chemical, carbon dioxide or chemical foam.
Health
1
 
Flammability
0
 
 
Reactivity
0
 

Health.
Poison_Class
4 (Substances and products that must be considered harmful)
Exposure effects
Substance may have carcinogenic potential.
   Ingestion
May cause irritation of the digestive tract. The toxicological properties of this substance have not been fully investigated.
   Inhalation
May cause respiratory tract irritation. The toxicological properties of this substance have not been fully investigated.
   Skin
May cause skin irritation.
   Eyes
Contact may cause transient eye irritation. This product contains an anionic dye. Similar dyes have not caused injury to the cornea or conjunctiva in documented exposure cases with human or rabbit eyes.

First aid
 
   Ingestion
Get medical aid. Do NOT induce vomiting. If conscious and alert, rinse mouth and drink 2-4 cupfuls of milk or water. Wash mouth out with water.
   Inhalation
Remove from exposure to fresh air immediately. If not breathing, give artificial respiration. If breathing is difficult, give oxygen. Get medical aid if cough or other symptoms appear.
   Skin
Flush skin with plenty of soap and water for at least 15 minutes while removing contaminated clothing and shoes. Get medical aid if irritation develops or persists. Wash clothing before reuse.
   Eyes
Flush eyes with plenty of water for at least 15 minutes, occasionally lifting the upper and lower eyelids. Get medical aid.

Transport.
UN number
1230
Response guide
HS Code
2927 00 00