Finely divided particles of alkali metals are produced by combining alkali metals with certain aromatic compounds in selected solvents to form low-temperature soluble complexes from which the pure alkali metals precipitate quantitatively when the solutions are warmed. All operations must be carried out in an inert gas atmosphere

Landel, R. F.

Rembaum, A.

English

NASA Technical Reports Server

December 1966	 Brief 66-10639 
NASA TECH BRIEF 
NASA Tech Briefs are issued to summarize specific innovations derived from the U.S. space program, 
to encourage their commercial application. Copies are available to the public at 15 cents each 
from the Clearinghouse for Federal Scientific and Technical Information, Springfield, Virginia 22151. 
Process for Preparing Dispersions of Alkali Metals 
The problem: 
To devise a convenient method of producing highly 
pure, finely divided particles of alkali metals (e.g., 
sodium and potassium). 
The solution: 
A method based on the fact that the alkali metals 
readily combine with certain aromatic compounds in 
selected solvents to form low-temperature soluble 
complexes from which the pure alkali metals precipi-
tate quantitatively when the solutions are warmed. 
How it's done: 
The lower alkyl biphenyls (e.g., 4-ethyl biphenyl) 
and certain tertiary aromatic amines (e.g., N-ethyl 
carbazole) are effective quantitative complexing 
agents. Effective low-temperature solvents for the 
alkali metal complexes formed are certain hydro 
carbon ethers (e.g., tetrahydrofuran and dimeth-
oxyethane). 
The alkali metal is dissolved directly from the solid 
at a relatively low temperature in a solution of the 
complexing agent and the preferred solvent. For 
example, N-ethyl carbazole, when dissolved in tetra-
hydrofuran, dissolves sodium in essentially equimolar 
quantity at approximately —70°C, and the pure metal 
is quantitatively precipitated as the solution ap-
proaches room temperature. The size and uniformity 
of the particles of the precipitated sodium are con-
trollable over an appreciable range by variation of 
the rate of temperature change and the amount of 
agitation during precipitation. The precipitate can be 
removed by filtration, and the filtrate can be reused to 
dissolve more metal in a continuous process. The 
finely divided metal may be redispersed in a conven-
tional manner in a suitable nonreactive liquid (e.g., 
petroleum ether).
During solution of the alkali metal, commonly 
occurring solid impurities remain behind and are 
readily removed by filtration in a preliminary step 
before precipitation of the alkali metal. If the original 
metal should contain an impurity that is soluble at 
the low temperature of the alkali metal reaction, such 
impurity is retained in solution during precipitation of 
the alkali metal. 
Notes: 
1. All operations involving the alkali metals musi 
carried out in an inert gas atmosphere. 
2. Dispersions of alkali metals prepared by 
method contained particles ranging from I to 
microns in diameter. 
3. Lithium was the only alkali metal tested wi 
failed to precipitate quantitatively by this meti 
4. This method may offer advantages for the p 
aration of pure alkali metals (e.g., sodium—po 
sium alloys) used in heat transfer loops, and 
means of coating the metals on temperature se 
tive substrates. The alkali metal solutions or 
persions may also find use in organic syntht 
5. Inquiries concerning this invention may be 
rected to:
Technology Utilization Officer 
Jet Propulsion Laboratory 
4800 Oak Grove Drive 
Pasadena, California 91103 
Reference: B66-10639
se 
Patent status: 
Inquiries about obtaining rights for the commercial 
use of this invention may be made to NASA, Code 
GP, Washington, D.C. 20546. 
Source: Alan Rembaum and Robert F. Landel 
(J PL-734) 
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Category 03 
This document was prepared under the sponsorship of the National 
Aeronautics and Space Administration. Neither the United States 
Government nor any person acting on behalf of the United States
Government assumes any liability resulting from the use of the 
information contained in this document, or warrants that such use 
will be free from privately owned rights.
https://ntrs.nasa.gov/search.jsp?R=19660000637 2020-03-11T17:42:06+00:00Z


Process for preparing dispersions of alkali metals

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