N-Methyl-2-pyrrolidone (CAS 872-50-4): storage and disposal
N-Methyl-2-pyrrolidone, usually shortened to NMP, is a slow evaporating polar solvent held as a neat liquid in university stores. It causes skin, eye and respiratory irritation and may damage the unborn child. Because it evaporates slowly, a spill or leaking bottle stays on a shelf for a long time, and several different names appear on labels, which complicates the record.
- CAS number
- 872-50-4
- Form
- Liquid
- Storage class
- Toxic
- Signal word
- Danger
- Usual EWC code, laboratory stock
- 16 05 06*
Harmful or irritant
Serious health hazard
What to do this week
- Without moving anything that looks damaged, check the label is readable and write down the opened date if it is not already there.
- Check it is stored as toxic stock, and apart from anything listed under "Do not store with" on this page. If nothing is listed, that does not prove it is safe with everything.
- If you no longer need it, add it to your disposal list so it can be included in a collection.
Safe storage in a school or lab
University stores usually keep NMP in a research group's own cabinet, and the first step in a stock check is to find which group owns each bottle. Keep it in a locked cabinet with a stock record, away from food and drink areas and from acids and oxidisers. A reaction with an oxidiser could release hazardous vapours. Because it may damage the unborn child, staff who may be pregnant should know where it is kept and avoid handling it. Keep the cap tight, since the liquid slowly takes up water from air, and put each bottle on a tray to catch a leak.
How to tell it has deteriorated
Fresh NMP is a clear, colourless liquid, so a bottle that has turned yellow or darker has changed with age. Because it evaporates slowly, it rarely loses visible level, and a leak shows as a sticky or damp ring at the neck or on the tray. Check labels for fading, since the many names for it, including methyl pyrrolidone and N-methyl pyrrolidinone, vary from bottle to bottle. Look for a stuck cap, a swollen liner and cracks in glass or plastic, and for a missing stock record. A bottle that is coloured or unlabelled is listed as aged stock.
How it is disposed of
We arrange this by specialist collection. We do not publish a drain or general waste route for any chemical. It is normally packed in a toxic laboratory pack with compatible chemicals.
Collection takes it from the research group's store, as a lab pack with compatible organic liquids. Waste code 16 05 06* is the usual description, and 16 05 08* applies for a discarded organic chemical outside a pack. Record every name printed on the label, the bottle size, the fill and the owner of the stock, because university bottles often change hands. It is never poured into a sink or drain, never put in the bin and never left to evaporate, and nobody should try to treat it first.
| Usual EWC code, laboratory stock | 16 05 06* |
|---|---|
| Discarded organic chemical, not a laboratory pack | 16 05 08* |
| Usually classed as hazardous waste | Yes |
The code depends on where the waste came from and what it contains, and classifying it is the producer's duty. Use the waste code finder to see why.
Do not store with
- OxidiserToxic and oxidising stock are stored apart. A reaction could release toxic vapours.
- AcidToxic stock is stored apart from acids. Several toxic salts release toxic gas in contact with acid.
Named chemicals to keep apart
- Acetic acidToxic stock is stored apart from acids. Several toxic salts release toxic gas in contact with acid.
- Calcium hypochloriteToxic and oxidising stock are stored apart. A reaction could release toxic vapours.
- Hydrochloric acidToxic stock is stored apart from acids. Several toxic salts release toxic gas in contact with acid.
- Hydrogen peroxideToxic and oxidising stock are stored apart. A reaction could release toxic vapours.
- Nitric acidToxic stock is stored apart from acids. Several toxic salts release toxic gas in contact with acid.
- Potassium nitrateToxic and oxidising stock are stored apart. A reaction could release toxic vapours.
- Potassium permanganateToxic and oxidising stock are stored apart. A reaction could release toxic vapours.
- Sulfuric acidToxic stock is stored apart from acids. Several toxic salts release toxic gas in contact with acid.
Common quantities
Usually held as: neat.
Tell us the container size and how many you hold. An estimate is enough to start with, and some items cannot be priced until someone has looked at them.
Where it is commonly held
Hazard statements
- H315 Causes skin irritation.
- H319 Causes serious eye irritation.
- H335 May cause respiratory irritation.
- H360D May damage the unborn child.
Precautionary statements
- P203 Obtain, read and follow all safety instructions before use.
- P261 Avoid breathing dust, fume, gas, mist, vapours or spray.
- P264 Wash hands and exposed skin thoroughly after handling.
- P264+P265 Wash hands and exposed skin thoroughly after handling. Do not touch eyes.
- P271 Use only outdoors or in a well-ventilated area.
- P280 Wear protective gloves, protective clothing, eye protection and face protection.
- P302+P352 IF ON SKIN: Wash with plenty of water.
- P304+P340 IF INHALED: Remove person to fresh air and keep comfortable for breathing.
- P305+P351+P338 IF IN EYES: Rinse cautiously with water for several minutes. Remove contact lenses, if present and easy to do. Continue rinsing.
- P318 If exposed or concerned, get medical advice.
- P319 Get medical help if you feel unwell.
- P321 Specific treatment (see supplemental first aid instruction on this label).
- P332+P317 If skin irritation occurs: Get medical help.
- P337+P317 If eye irritation persists: Get medical help.
- P362+P364 Take off contaminated clothing. And wash it before reuse.
- P403+P233 Store in a well-ventilated place. Keep container tightly closed.
- P405 Store locked up.
- P501 Dispose of contents and container in accordance with local, regional, national and international regulations.
Substance as classified, dilutions may differ.
Questions
Our NMP bottle is yellow. Does that matter?
A colour change means the liquid has aged, although we cannot say what has formed. List it as aged stock, keep it capped in a tray in the locked cabinet and declare the colour when it is collected.
Why is a slow evaporating solvent a problem when it leaks?
Because it does not disappear. A wet ring or sticky tray stays in place, which means skin contact is more likely. Wear gloves, stand the bottle in a tray and tell the collector about the leak.
What names might be printed on an NMP bottle?
Methyl pyrrolidone, N-methyl pyrrolidinone and n-methyl-pyrrolidone all appear. Record each name on the label together with the CAS number if printed, so the description matches the container.
Who needs to know where NMP is kept?
Anyone who might handle it, especially staff who are pregnant or may become pregnant, because it may damage the unborn child. Keep it in the locked cabinet with the stock record and follow your risk assessment.
