4-Nitrophenol (CAS 100-02-7): storage and disposal
4-Nitrophenol is a pale yellow solid kept in college and university stores, usually as a reagent or indicator. It is harmful if swallowed, in contact with skin and if inhaled, may damage organs through prolonged or repeated exposure, and is harmful to aquatic life with long lasting effects. Because its storage class is general, it can end up among ordinary reagents without the extra care that repeated exposure deserves.
- CAS number
- 100-02-7
- Form
- Solid
- Storage class
- General
- Signal word
- Warning
- Usual EWC code
- 16 05 06*
Harmful or irritant
Serious health hazard
What to do this week
- Check the label is readable and write down the opened date if it is not already there.
- Check it is stored as general stock and apart from the items listed under "Do not store with".
- If you no longer need it, add it to your disposal list so it goes on the next collection.
Safe storage in a school or lab
Alkalis are the main thing to keep away from it, because they turn it into its yellow salt, so a leaking alkali bottle beside the jar shows up as a bright stain and spoils the stock. Oxidising stock should also be kept apart, as with any organic solid. It sits in a dry, labelled store with a tight lid, a stock record and a tray, and with gloves and a dedicated scoop nearby. Since harm from skin contact and from repeated exposure is on its list, spilled powder on the shelf is something to clear up straight away by the lab's own procedure, not leave.
How to tell it has deteriorated
Colour is a poor guide here, because even fresh stock is pale yellow, and it gives few reliable visible signs of age. What the shelf shows instead is staining and container condition. Look for yellow marks on the outside of the jar, on the label or on the shelf, which show powder or solution has escaped. Caking and damp lumps show moisture has entered, and a crust on the thread or a cap that will not turn shows long exposure. Indicator solutions in dropper bottles can dry at the tip and cap. Record any jar with these features as it stands and leave it closed.
How it must be disposed of
By specialist collection only. It never goes down the drain or into general waste. It is normally packed in a non-regulated or low hazard laboratory pack with compatible chemicals.
Waste code 16 05 06* is the code for laboratory chemicals in a lab pack, and the asterisk marks it as hazardous waste, which fits a substance harmful by three routes and harmful to aquatic life. A discarded organic chemical outside a lab pack takes 16 05 08*. The jar travels as UN 1663, packed with compatible organic solids. Record whether it is the solid or an indicator solution, the amount left and any yellow staining. It must not be put down a drain or in a bin, and no one should try to treat residues first.
| EWC code, laboratory chemicals | 16 05 06* |
|---|---|
| Discarded organic chemical, not a laboratory pack | 16 05 08* |
| Hazardous waste | Yes |
The code depends on where the waste came from and what it is mixed with. Use the waste code finder to see why.
Common quantities we collect
Usually held as: solid, indicator.
Part-used bottles and full containers are both fine. Tell us the size and how many, and an estimate is enough for a first price.
Where it is commonly held
Hazard statements
- H302 Harmful if swallowed.
- H312 Harmful in contact with skin.
- H332 Harmful if inhaled.
- H373 May cause damage to organs through prolonged or repeated exposure.
- H412 Harmful to aquatic life with long lasting effects.
Precautionary statements
- P260 Do not breathe dust, fume, gas, mist, vapours or spray.
- P261 Avoid breathing dust, fume, gas, mist, vapours or spray.
- P264 Wash hands and exposed skin thoroughly after handling.
- P270 Do not eat, drink or smoke when using this product.
- P271 Use only outdoors or in a well-ventilated area.
- P280 Wear protective gloves, protective clothing, eye protection and face protection.
- P301+P317 IF SWALLOWED: Get medical help.
- P302+P352 IF ON SKIN: Wash with plenty of water.
- P304+P340 IF INHALED: Remove person to fresh air and keep comfortable for breathing.
- P317 Get medical help.
- P319 Get medical help if you feel unwell.
- P321 Specific treatment (see supplemental first aid instruction on this label).
- P330 Rinse mouth.
- P362+P364 Take off contaminated clothing. And wash it before reuse.
- P501 Dispose of contents and container in accordance with local, regional, national and international regulations.
- P273 Avoid release to the environment.
- P301+P316 IF SWALLOWED: Get emergency medical help immediately.
- P405 Store locked up.
Substance as classified, dilutions may differ.
Questions
Why is 4-nitrophenol kept away from alkalis?
Alkalis turn it into its yellow salt, which stains the jar and the shelf and spoils the stock. Separating them also stops a leak of one from affecting the other. Store alkalis low and in their own tray.
Is pale yellow colour a sign the jar has gone off?
No. The solid is pale yellow when fresh, so colour alone tells you little. Check the container instead for staining, caking, a crusted thread and a fading label.
How should an indicator solution be described for collection?
By its label. A dropper bottle of indicator is not the pure solid, so copy the wording as printed, give the volume and the container type, and say if the tip has dried or the label is faded.
