ISSN:
0025-116X
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Physics
Notes:
Alkali metals dissolve not only in liquid ammonia but also in ethers, such as tetrahydrofuran (THF), 1.2-dimethoxyethane (DME), and dimethyl ether of diethylene glycol (diglyme), blue solutions being obtained1,2. “Blue” solutions can be obtained only with rigorously purified reagents in full absence of moisture and oxygen, usually at low temperature. They are not very stable systems, especially at room temp., and discoloration begins shortly after the removal of the metal. The concn. of the metal dissolved is as low as 10-4 to 10-3 mole/1. The electrical conductivity of the “blue” solutions is in the range of 10-5 to 10-6 ohm-1 cm-1 and that of the discolored solution is 10-8 to 10-9 ohm-1 cm-1.Obviously the solvation ability of the solvent plays a very important role in the formation of metal solutions. DAINTON et al.1,3 presented arguments that the predominant species in the “blue” solutions are pairs of electrons (e2) with coupled spins, whereas TUTTLE and WEISSMAN4 observed at -80°C a weak singlet in the ESR spectrum of the potassium solution in DME, and CAFASSO and SUNDHEIM2 revealed a weak ESR signal in a rubidium solution in bis-2-(2-methoxyethoxy) ethyl ether as well as in a frozen potassium solution in DME.“Blue” alkali metal solutions can be easily obtained in hexamethylphosphoramide but it is not still clear whether they are solutions of alkali metals5 or of anion-radicals of the solvent6.It was established that potassium solutions in THF and DME initiated polymerization of acrylonitrile (conversion about 4%) and of styrene (conversion up to 100%), but not of methyl methacrylate and acrylamide3.
Additional Material:
3 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/macp.1970.021340129
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