Aniline

 

Aniline

Chemical formula	C6H5NH2
OTP appearance	clear or yellowish liquid
Molar Mass(g/mol)	93.13
Density(g/cc)	1.0217
Melting Point(°C)	-6.3
Boiling Point(°C)	184.13
Immediate Danger to Life and Health	5ppm (inh)
NFPA 704	2 3 0

Uses

Justification Questioned

Other

• Feedstock for synthetic indigo dye (indigotin)
• Precursor for many organic compounds, including sulfa drugs via N-acetylsulfanilyl chloride

Hazards

• Toxic and flammable
  • Inhalation, ingestion, or skin exposure can all result in aniline toxicity, which can produce cyanosis and cardiopulmonary difficulties leading to hypoxia. Treatments include supplementary oxygen, breathing support, and methylene blue. The standard dose of methylene blue is 1 to 2 mg/kg body weight (0.1 to 0.2 mL/kg of a 1% solution) intravenously over 5 to 10 minutes, repeated in one hour if needed. The total 24 hour dose should not exceed 7 mg/kg

Production

Extraction

from indigotin

Aniline, [...] an oily liquid which distils over when finely pulverized indigo is decomposed by a highly concentrated solution of caustic potash or soda in a retort Its quantity amounts to about 15 or 20 per cent of the indigo employed.

The quote above indicates that dry distillation converts about two molecules of indigotin to one of aniline: 93 / (2 × 262) = 17.7. Either that or the indigotin contained a significant percent by weight of impurities.

1. Combine indigotin and one of sodium, potassium, or calcium hydroxide.
2. Mix thoroughly
3. Grind finely
4. Distill
5. Discard residue
6. Distillate is aniline (yield: 3g per kg of plant?)

Synthesis

• From nitrobenzene via reduction with hydrogen and a catalyst (Zinin)

See Also

• Benzene
• Toluene
• Phenol