Diglyme

Diglyme, or bis(2-methoxyethyl) ether, is an organic compound with the chemical formula (CH₃OCH₂CH₂)₂O. It is a colorless liquid with a slight ether-like odor. It is a solvent with a high boiling point. It is the dimethyl ether of diethylene glycol. The name diglyme is a portmanteau of diglycol methyl ether. It is miscible with water as well as organic solvents.

It is prepared by a reaction of dimethyl ether and ethylene oxide over an acid catalyst.

Solvent

Because of its resistance to strong bases, diglyme is favored as a solvent for reactions of alkali metal reagents even at high temperatures. Rate enhancements in reactions involving organometallic reagents, such as Grignard reactions or metal hydride reductions, have been observed when using diglyme as a solvent.

Diglyme is also used as a solvent in hydroboration reactions with diborane.

It serves as a chelate for alkali metal cations, leaving anions more active.

Safety

The European Chemicals Agency lists diglyme as a substance of very high concern (SVHC) as a reproductive toxin.

At higher temperatures and in the presence of active metals diglyme is known to decompose, which can produce large amounts of gas and heat. This decomposition led to the T2 Laboratories reactor explosion in 2007.

References

1. Sodium borohydride
2. Potassium bis(trimethylsilyl)amide
3. Triethylene glycol dimethyl ether
4. Dipotassium cyclooctatetraenide
5. Vanadium hexacarbonyl
6. C6H14O3
7. Lithium aluminium hydride
8. Sodium chlorodifluoroacetate
9. DG
10. Nitrilium
11. Diborane
12. Diethylene glycol diethyl ether
13. Sodium cyanoborohydride
14. Perylene
15. Surface treatment of PTFE
16. Metal carbonyl
17. T2 Laboratories explosion and fire
18. Hydrogen storage
19. Cyclopentadienylmolybdenum tricarbonyl dimer
20. Molybdenum hexacarbonyl