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Experiment 5, page 3

DIETHYL ETHER:
HARMFUL BY INHALATION, AND INGESTION
MAY FORM EXPLOSIVE PEROXIDES
EXTREMELY FLAMMABLE
Colourless highly volatile liquid with characteristic odour; b.p. 34ºC; immiscible with water. Liable to form explosive peroxides on exposure to light/air. Peroxides removed by treatment with aqueous sodium metabisulfite. Avoid breathing vapour. OEL 1200 mgm^-3.

Toxic effects:Inhalation of the vapour may cause drowsiness, dizziness, mental confusion, faintness
and, in high concentrations, unconsciousness. Ingestion may also produce these effects.
Continued inhalation of low concentrations may cause loss of appetite, dizziness,
fatigue and nausea.
Hazardous reactionsPeroxide formation can result in subsequent explosion. Powerful oxidants can cause
explosion. Reacts vigorously with sulfuryl chloride.
Fire HazardFlash point -45ºC, ignition temp. 180ºC; extinguish fire with CO₂. Spillage & disposalClear area, shut off all sources of ignition. Organise effective ventilation and allow to
evaporate. Diethyl ether should be placed in thenon-chlorinated waste container for
central disposal

WARNING ON THE USE OF LITHIUM ALUMINIUM HYDRIDE (LAH) Powdered lithium aluminium hydride must never be allowed to come into contact with water. 1.All apparatus and reactants should be perfectly dry, and reactions should be run
rigorously under nitrogen, with the reaction temperature below 70ºC at all times. 2.Order of addition is important. Alwaysfirst add the hydride to the solvent in the
nitrogen purged apparatus before mixing with any reactant.
3.The hydride should never be allowed to form a crust above the level of the liquid or to
settle to the bottom of a heated flask, so gentle efficient stirring is essential. 4.To prevent local overheating of the reaction vessel, heating mantles should never be
used. Use an intermediate medium such as oil or graphite bath.
5.After reaction, destroy excess LAH by slow careful addition of ethyl acetate (diluted
with an inert solvent such as dry THF), under nitrogen, keeping the temperature below
50ºC. All LAH reactions should be carried out behind protective screens. 6.Any spillages should of LAH should be reported to the demonstrators who will advise
on procedures for clearing up the spillage.

EXPERIMENTAL PROCEDURES
Note that only one of these experimentsis to be carried out. You will have been allocated one (see the master-plan of the experimental assignements).

1._{Reduction of Cinnamaldehyde to Hydrocinnamyl Alcohol: Normal Addition.}2

^LiAlH
normal add⁴
ition

Dry, in an oven, a 250 ml three-necked flask, a 100 ml tap-funnel and a double surface condenser. In a dry fume cupboardweigh out lithium aluminium hydride (2.9 g) and introduce it into a 3-necked flask viaa powder funnel. Rinse in any residues with dryTHF ([!]20 ml) and at once fit a