Nomenclature
CAS number: 12740-44-2
Lead-sodium alloy; sodium-lead; Drynap (Wako); Dri-Na.
Description and 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.