Like all glymes from n=1 to n=4, Tetraglyme (n=4) is used as inert special solvent for grignard-, reduction- and alkylation-reactions, organo metallic reactions in general, reactions involving alkali metals such as lithium, sodium and potassium. Alkali metal dispersions used for etching of Teflon and Fluoroplymers can be prepared in Tetraglyme. Na/K alloy has a high solubility in Tetraglyme. K is slightly soluble.
Tetraglyme has a high solubility for sodium borohydride (SBH) of 150 g/l (25°C). Reactions involving NaBH4 and other metal hydrides like NaH proceed with higher yields than in standard solvents like caustic water or methanol. A mixture of LiCl, SBH and Tetraglyme significantly increases the reduction potential of sodium borohydride . Even amides can be reduced to amines with this mixture. Handling of more expensive and more dangerous reducing agents like lithium aluminium hydride (LiAlH4) can be avoided. It also offers a versatile route for the in situ generation of diborane.
Diborane is conveniently prepared from NaBH4 and BF3 in Tetraglyme.
Due to the high solubility of inorganic salts having covalent bonding properties in tetraglyme, it is used for the preparation of trimethylsilyl cyanide from trimethylchlorosilane and lithium cyanide (LiCN)
Tetraethylene glycol dimethyl ether acts as chelate ligand for cations. This leaves anions active. Reaction rates of anionic polymerizations, nucleophilic substitutions and metal hydride are significantly enhanced.
Its outstanding stability even at high pH values makes it an excellent solvent for reactions with strong bases.
Production of binders for paints (acrylic paints) are prepared in Tetraglyme. It is also used as coalescing agent in paint formulations.
The boiling point of 275°C and the outstandig stability of Tetraglyme allow for high temperature reactions like hydrogenations, depolymerizations and many more. |