DEME - Diethylene Glycol Methyl Ethyl Ether — Frequently Asked Questions

Because a blend is not a substitute for a compound. A mixture of diglyme and the diethyl ether distils over a range rather than at one temperature, and the two components partition differently between phases, which is a problem where consistency matters. DEME gives the intermediate properties as a single pure substance with one boiling point and one behaviour.

Boiling point, water miscibility and cation-solvating strength all fall between those of diglyme and diethylene glycol diethyl ether, which is exactly what the asymmetric methyl and ethyl capping produces. It retains the aprotic character common to all the fully capped glymes.

It is used in electrochemical applications where its cation-solvating ability and aprotic character are useful, including lithium and sodium electrolyte research. Suitability for a specific cell chemistry depends on electrochemical stability window and purity, which should be assessed rather than assumed from the solvent class.

Yes. As an ether it forms peroxides on exposure to air and light, and those concentrate on distillation. It should be supplied inhibited, stored sealed and dark, dated on receipt, and tested before distillation or evaporation to dryness.