Ethers

Ether (diethyl ether, ethyl ether) is an extremely common solvent that is routinely used in varying quantity in laboratory procedures through out the University.

It is, however, a substance that has extreme physical hazards cognisance of which must always be a priority when planning even the simplest of procedures and the use of best laboratory practice at all times is paramount in ensuring its safe use.

Explosion and fire hazard

Owing to its volatility and extremely low flashpoint temperature of - 40oC , diethyl ether is one of the greatest fire hazards commonly encountered in the laboratory; it is classed under the UK Chemicals (Hazard Information and Packaging for Supply) Regulations 2002 (CHIP) as extremely flammable (F+) and has been assigned the following EU Safety Phrases:

• S9 Keep container in a well ventilated place
• S16 Keep away from sources of ignition
• S29 Do not empty into drains
• S33 Take precautionary measures against static discharges

and the following EU Risk Phrases:

• R12 Extremely flammable
• R19 May form explosive oxides
• R22 Harmful if swallowed
• R66 Repeated exposure may cause skin dryness or cracking
• R67 Vapours may cause drowsiness and dizziness

Ether does not require a source of ignition such as a naked flame, or spark to initiate combustion.

Ether vapour may be ignited by hot surfaces such as hot plates, steam pipes, electric lamps and static electricity discharges, and since the vapour is heavier than air, it may travel a considerable distance to an ignition source and flash back. Sufficient static electricity to initiate flash ignition can build up when large quantities of ether is being poured from one vessel into another. Ether vapour forms explosive mixtures with air at concentrations of 1.9% to 36% (by volume). Carbon dioxide or dry powder extinguishers should be used for ether fires. Ethers absorb and react with oxygen from the air, in the presence of light, forming unstable peroxides that can detonate with extreme violence when they become concentrated through evaporation or distillation and disturbed by heat, shock or friction.

Toxicity

Acute: harmful by inhalation in high concentrations which can cause inebriation, sedation, unconsciousness and respiratory paralysis. Diethyl ether is irritating to the eyes, respiratory system and skin but these effects are usually reversible on removal of exposure. Due, probably in part, to its high volatility the liquid is not easily absorbed through the skin, however repeated contact can remove the skins natural oils and cause dryness, cracking of the skin and other dermal complaints.

Chronic: there is no evidence of carcinogenic or teratogenic effects attributable to the use of diethyl ether. However it is known that chronic exposure to vapour can lead to exhaustion, drowsiness, dizziness and other central nervous system disorders, along with a loss of appetite.

Handling and control of exposure

Diethyl ether (ethyl ether, ether) must be handled in the laboratory using only best practice methodology, these supplemented by additional precautions for the use of extremely flammable substances.

Storage

Ethers should be stored in tightly closed containers within properly labelled fire resistant metal cabinets, or bins, and on drip trays. They must be stored separate from oxidizers. Containers of solvents such as ethers should be returned to the storage facility as soon as possible after use and you are reminded of the requirement of Part 5 (3.9) of the University Health and Safety Policy 'In order to minimise the risk of a serious laboratory fire, the maximum amount of flammable reagents and solvents etc., stored in any one laboratory should not exceed fifty litres'. Amounts above fifty litres must be stored in a properly constructed and bunded flammables store.

Spillage

Because of its extremely flammable nature a spillage of ether must be dealt with using extreme caution. All ignition sources should be removed and the up as quickly as possible using a proprietary spill pillow, absorbent matt, or an inert material such as sand (never use sawdust). The material containing the absorbed ether should be placed in a suitable sealed container and disposed of via the authorised disposal routes. Spillage of large quantities, or in a small room, may result in an inhalation hazard; in this case your School's Spill Response Team should be contacted in order that the spill can be dealt with using full-face respirators fitted with organic vapour filters.

Disposal

Ethers must never be poured to drain.

Follow the disposal guidance on the Waste and Recycling Office website.

Storage and the detection and removal of peroxides

Further guidance on the storage and the detection and removal of peroxides is available as a PDF document.