- Monomethyl aniline
Colorless to light viscous liquid with a characteristic odor. Turns brown on exposure to air.
Organic synthesis, solvent, acid acceptor.
Registry Numbers and Inventories.
EC Index Number
Toxic; Danger of cumulative effects; Dangerous for the Environment
R 23/24/25 33 50/53
S 28 36/37 45 60 61
Japan ENCS (MITI)
Melting point, °C
Boiling point, °C
Vapor pressure, mmHg
0.5 (20 C)
Vapor density (air=1)
395 ppm (0.04%) at 20 C (calculated)
0.989 g/cm3 (20 C)
Solubility in water
2.568 cp @ 15C
39.97 g/s2 @ 15 C
1.5702 (20 C)
Partition coefficient, pKow
Heat of vaporization
Heat of combustion
Hazards and Protection.
Keep away from heat, sparks, and flame. Keep away from sources of ignition. Keep container closed when not in use. Store in a tightly closed container. Store in a cool, dry, well-ventilated area away from incompatible substances. Store under an inert atmosphere.
B3 D1B D2A
Wash thoroughly after handling. Use only in a well ventilated area. Avoid contact with eyes, skin, and clothing. Empty containers retain product residue, (liquid and/or vapor), and can be dangerous. Keep container tightly closed. Avoid contact with heat, sparks and flame. Avoid ingestion and inhalation. Do not pressurize, cut, weld, braze, solder, drill, grind, or expose empty containers to heat, sparks or open flames.
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.
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.
Absorb spill with inert material, (e.g., dry sand or earth), then place into a chemical waste container. Avoid runoff into storm sewers and ditches which lead to waterways. Clean up spills immediately, using the appropriate protective equipment. Remove all sources of ignition. Provide ventilation. Do not get water inside containers.
Stable under normal temperatures and pressures. Substance undergoes color change upon exposure to air.
Strong oxidizing agents, acids, acid chlorides, acid anhydrides.
Nitrogen oxides, carbon monoxide, carbon dioxide, nitrogen.
Upper exp. limit, %
Lower exp. limit, %
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. Use water spray to keep fire-exposed containers cool. Combustible Liquid. Contact with metals may evolve flammable hydrogen gas. Containers may explode when heated. Extinguishing media: Do NOT get water inside containers. For small fires, use dry chemical, carbon dioxide, or water spray. For large fires, use dry chemical, carbon dioxide, alcohol-resistant foam, or water spray. Cool containers with flooding quantities of water until well after fire is out.
Combustible material: may burn but does not ignite readily.
When heated, vapors may form explosive mixtures with air: indoors, outdoors, and sewers explosion hazards.
Toxic vapors are generated when heated.
NIOSH REL: TWA 0.5 ppm (2 mg/m3) [skin] OSHA PEL: TWA 2 ppm (9 mg/m3) [skin] IDLH 100 ppm
May cause methemoglobinemia, which is characterized by chocolate-brown colored blood, headache, weakness, dizziness, breath shortness, cyanosis, rapid heart rate, unconsciousness and possible death. Prolonged or repeated exposure may cause nausea, dizziness, and headache. Effects may be delayed.
May cause gastrointestinal irritation with nausea, vomiting and diarrhea. Methemoglobinemia is characterized by dizziness, drowsiness, headache, breath shortness, cyanosis with bluish skin, rapid heart rate and chocolate-brown colored blood. Effects may be delayed.
Effects may be delayed. May cause respiratory tract irritation. May cause methemoglobinemia, cyanosis, convulsions, tachycardia, dyspnea, and death.
May cause skin irritation.
May cause eye irritation.
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.
Remove from exposure to fresh air immediately. If not breathing, give artificial respiration. If breathing is difficult, give oxygen. Get medical aid. DO NOT use mouth-to-mouth respiration.
Get medical aid. Flush skin with plenty of soap and water for at least 15 minutes while removing contaminated clothing and shoes. Wash clothing before reuse.
Flush eyes with plenty of water for at least 15 minutes, occasionally lifting the upper and lower eyelids. Get medical aid immediately.