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Experiment 7, page 5

ETHYL ACETATE:
HIGHLY FLAMMABLE
IRRITATING TO EYES AND RESPIRATORY SYSTEM Colourless liquid with fragrant odour; b.p. 77ºC; slightly soluble in water. Avoid breathing vapour. Avoid eye contact. OEL1400 mgm^-3.

Toxic effects:The vapour may irritate the eyes and respiratory system. The liquid irritates the eyes and
mucous surfaces. Prolonged inhalation may cause kidney and liver damage. Fire hazard:Flash point -4.4ºC; ignition temp. 427ºC; extinguish fire with CO₂. Spillage & disposal:Clear area, shut off all sources of ignition. Wear face shield goggles and gloves.
Absorb bulk quantities on sand, shovel into buckets. Wash site of spillage with water
and detergent. Ethyl acetate should be placed in the non-chlorinated waste container for
central disposal.

Experimental Procedure

Note: Osmium salts and especially osmium (VIII) tetroxideare extremely harmful by inhalation, ingestion or contact. Osmium (VIII) tetroxide is a volatile compound, and care must be taken not to liberate this outside of the fume hood. NEVER MIX OSMIUM SALTS WITH ACID AS THIS GENERATES OsO₄.
Carry out ALL of the procedures up to and including the short silica pad filtration in the fixed fume hood provided for the experiment only. Gloves (nitrile) as well as lab coat and safety glasses are to be worn at all times. Notify a demonstrator of any spillages. Place the aqueous osmium waste from this reaction in the labelled bottle. AD-mixes also contain K₃Fe(CN)₆which liberates cyanide anion in solution. Do not ingest AD-mix, and NEVER add acid to the salts, your reaction mixture or glassware (this would liberate lethal HCN).

In a 100ml round-bottomed flask equipped with a reflux condenser and magnetic stirring bar was place tert-butyl alcohol (15 ml), water (15 ml) and AD-mix-a orbas assigned to you (weighed out in a fume cupboard). Stir the mixture at room temperature until two clear phases are produced, the lower (aqueous) phase should be bright yellow. Vigorous stirring is required to dissolve all the AD-mix. Cool the mixture was to 0^oC (some of the dissolved salts may precipitate). Add 3 mmol of the alkene you have been allocated and continue to stir the mixture vigorously at 0^oC (temperature is important!!!), following the progress of the reaction by TLC.
Upon completion of the reaction, or 1 hour before the end of the lab session (whichever is sooner), add solid sodium sulfite (4.5g) whilst stirring at 0^oC and then allow the mixture to warm to room temperature and stir for a further 45 mins. Add 30 ml ethyl acetate to the mixture and separate the two layers were separated. Further extract the aqueous layer with ethyl acetate (3 x 15ml). The aqueous layer should be placed in the bottle marked "Aqueous Osmium Waste" in the fume hood where you have done the reaction.Dry the combined organic extracts were then dried (MgSO₄) and then remove the solvent on the rotary evaporator in a fume hood - not to be done on the bench! The product diol can be separated from the ligand by running the crude product through a short pad of silica gel using EtOAc as the solvent. Evaporate the ethyl acetate to obtain your 1,2-diol, and dry over silica gel in a dessicator.