摘要 |
A process for producing a solvent mixture comprising (A) at least one compound of formula (I) (B) at least one compound of formula (II a) or (II b) (C) optionally at least one additive selected from aromatic compounds, sultones and exo- methylene ethylene carbonates, melamine, urea, organic phosphates and halogenated organic carbonates, (D) optionally at least one lithium salt, and from 3 to 30 weight ppm of water, which process comprises (a) components (A), (B) and, if used, (C) being mixed with one another, (b) dried over at least one ion exchanger or molecular sieve, (c) separated from ion exchanger or, respectively, molecular sieve, and (d) at least one lithium salt, if used, being added, where the variables are defined as follows: R1, R2 are each the same or different and selected from C1-C4-alkyl, R3 is selected from hydrogen and C1-C4-alkyl. |