Title: Sodium-Lead Alloy
CAS Registry Number: 12740-44-2
Synonyms: Lead-sodium alloy; sodium-lead
Trademarks: Drynap (Wako); Dri-Na
Literature References: Usually contains a minimum of 9.5% active sodium. For tetraethyllead manufacture the sodium-lead alloy is produced in large quantities by making a melt of 90 parts of lead with 10.5 parts of sodium (w/w). The reaction is strongly exothermic and starts at 225°. Prepn of the alloy on a laboratory scale: Soroos,
Ind. Eng. Chem. Anal. Ed. 11, 657 (1939).
Properties: Obtained in brittle lumps which can be stored in an air-tight container. It reacts only slowly with air or water, yet dries ether as completely as sodium wire. Residues of ether or other liquids still containing some active alloy can be destroyed safely by the addition of water, as the reaction never reaches the violence observed with pure sodium metal. The alloy may be ground to a very fine powder under the surface of a non-polar solvent such as kerosine or ether.
CAUTION: Finely ground powder, if not protected by a suitable liquid, may react with excess moisture from the air sufficiently to catch fire.
Use: In manuf of tetraethyllead by reaction of alloy with ethyl chloride; for drying ether and for reductions: Tabei
et al., Bull. Chem. Soc. Jpn. 40, 1538 (1967); as a sodium substitute in many chemical reactions where the presence of lead is not objectionable.
