Apparatus, for reactions in liquid ammonia

Fig. 69. Apparatus for reactions in liquid ammonia I) reaction tube II) condensation equipment 2 and 6) pressure release valves 3) condensation, drying and storage of NHa 4) protection against spray and fog—fritted glass or glass wool.

Apparatus 2-1 flask (Fig. 1) for the addition of bromine and the coupling with propargylmagnesium bromide 6-1 flask (Fig. 4) for the reaction in liquid ammonia. 

Fig. 1. Apparatus for studying hydrogen exchange reactions in liquid ammonia.

Apparatus For the reactions in liquid ammonia a 1-1 round-bottomed, threenecked flask, equipped with a dropping funnel, a mechanical stirrer, and a gas-outlet for the reaction in THF-hexane mixtures see p. 24, Fig. 1 500 ml. 

Sodium Pbenylethynetellurolate5 An apparatus suitable for work with liquid ammonia under a nitrogen atmosphere is set up. A 500-m/flask is charged with 250 ml of liquid ammonia freshly distilled from sodium. In the liquid ammonia are dissolved 1.15 g (0.05 mol) of sodium, a catalytic amount of iron(III) nitrate is added, and 5.1 g (0,05 mol) of phenylacetylenc are added dropwise over 0.5 h to the sodium amide solution. The mixture is allowed to stand for 40 min and then 6.4 g (0.05 mol) of finely powdered tellurium arc added to the sodium acetylide solution. The ammonia is evaporated and the residue of sodium phenylethyne-tellurolate can be dissolved in an appropriate solvent for further reactions. 

Sodium Benzcnetellurolate This reaction must be carried out under nitrogen or argon in an apparatus suitable for work with liquid ammonia. A filtered suspension of 0.35 g (15 mmol) of sodium in 25 ml of liquid ammonia is added to a suspension of 3.1 g (7.5 mmol) of diphenyl ditellurium in 75 ml of liquid ammonia. The blue color of the sodium/ammonia solution changes rapidly to yellow. The reaction is complete when the solid ditellurium compound has disappeared. The reaction mixture is then filtered, the ammonia is evaporated, and the grey residue is washed with petroleum ether yield 3.1 g (95%). 

Note. (1) In general the apparatus used in these metal-liquid ammonia reductions is essentially that shown in Fig. 2.69 (d), but without the dropping funnel tube extension. The dropping funnel is replaced with the soda-lime guard-tube, which may then be removed at appropriate intervals for the periodic addition of metal fragments. After the flask has been charged with liquid ammonia, the inlet tube is replaced with a suitable thermometer, the bulb of which should be immersed in the reaction solution. A dry ice-acetone cooling bath should be used. 

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