Sodium ethoxide by the cascade method

When sodium ethoxide is made from ethanol, dried by distillation from sodium in vacuum, and vacuum-distilled sodium, the product is always yellow. The author believes that he heard the method of obtaining the pure, colourless product in M. Szwarc s laboratory and that it is unpublished the following description is adapted from a Keele thesis. 

Sodium was purified in the apparatus shown in Fig. 5.1(a), thus Ca. 12 g of sodium, cleaned as described in Section 4.4.3.1, was introduced into a tube A, which was then sealed to the apparatus at a this was evacuated for 8 h without heating the sodium, and then sealed off from the vacuum line at e. Tube A was then heated gently and the molten sodium poured swiftly into B, leaving its skin stuck to the tube, which was sealed off at b. This process was repeated by pouring the sodium successively into C and D and finally collecting the silvery metal in E, the sections being sealed off successively at c, d, and /. It is not known why this method of purification is more effective than distillation. The flask E was reattached to the vacuum line via the break-seal g (Fig. 5.1(i)) and then 300 ml of purified ethanol was distilled into E from the container F. 

---