4-nitrophenol
| Chemical formula | OH(C6H4)NO2 |
|---|---|
| OTP appearance | yellow solid |
| Molar Mass(g/mol) | 139.11 |
| Melting Point(°C) | 113-114 |
| Boiling Point(°C) | 279 |
| Solubility in water(g/L) | 11.6 |
| NFPA 704 |  0
0
|
Uses
Other
- Feedstock for 4-aminophenol
- Feedstock for picric acid
- pH indicator (colorless below pH 6, bright yellow above 6)
Natural occurrence
Hazards
- Toxic, irritant
Production
A mixture of 94 grams of phenol and 20 ml. water is added dropwise to a obtained solution containing of 150 grams of sodium nitrate dissolved in 400 ml. water and 250 grams of concentrated sulfuric acid. Good stirring is maintained during the addition, and the temperature is kept below 20°C. Stirring is continued for 2 hours. The mother liquor is poured off from the tarry mixture of nitrophenols, and the tar is melted with 500 ml. water with the addition of enough chalk to make the mixture neutral to litmus. The wash water is poured off and the washing repeated. The crude ortho and para nitrophenols, freed from nitric acid, are subjected to steam distillation, using a condenser with a wide tube. About 40 grams of pure o-nitrophenol distills over. The residue in the distillation flask is cooled and filtered after standing for 24 hours. The precipitate is boiled with 1 liter of 2% hydrochloric acid and filtered through a fluted filter. The pure p-nitrophenol crystallizes from the filtrate in nearly white, long needles. The extraction can be repeated if necessary. The yield is about 40 grams each of the ortho-nitrophenol and para-nitrophenol isomers. It is bad practice to treat the crude nitrophenols with sodium hydroxide, as called for in some procedures, because the sodium hydroxide has an immediate resinifying action.[1]
Synthesis
Synthesis produces a mixture of 2- and 4-nitrophenol, which must then be separated.
nitric acid
- Combine 8g of phenol with 2ml distilled water
- Combine 10ml of concentrated nitric acid with 35ml of distilled water
- Place the nitric acid solution in an ice bath
- Slowly add the phenol solution to the nitric acid solution
- Rinse the phenol container with another 1ml of distilled water, and add this to the nitric acid as well.
- Allow the mixture to stand for 10 minutes.
- NB: The solution should separate with a clear aqueous phase and a dark oily phase
- Decant and retain the oily phase
sulfuric acid and nitrates
- Combine phenol with sodium nitrate and sulfuric acid giving nitrophenol isomers
- 2 C6H5OH + H2SO4 + 2 NaNO3 → 2 C6H4OHNO2 + Na2SO4 + 2 H2O
Purification
- NB 2-nitrophenol, which can produce 2-nitrobenzoic acid, is useful in the production of other compounds, including anthranilic acid and fenamic acid
distillation
Para-nitrophenol (4-nitrophenol) has less affinity for water than 2-nitrophenol. A mixture of the two isomers with water, gently distilled, will carry the 2-nitrophenol to the receiver with the water, leaving just the 4-nitrophenol in the alembic.
steam distillation
- Produce steam
- Bubble the steam through, or pass it over, the mixture of nitrophenols
- Condense the steam (and the associated 2-nitrophenol)
- Retain the 4-nitrophenol which was not carried off by the steam
Testing
Storage
Disposal
See Also
References
- ↑ Fierz-David, H. E. (1949) "The fundamental processes of dye chemistry" (local copy); pp106-107.
link courtesy prepchem.com.