Dielectric relaxation of LiCl solutions in methylpyrrolidone on addition of a second solvent component

Dielectric loss spectra up to 72 GHz have been measured at 20 degrees C for binary liquid mixtures of N-methyl-2-pyrrolidone with eight other substanc es as additives and for LiCl solutions in those binary solvents. After subt raction of the conductivity contribution, the spectra can be described by a superposition of up to four Debye type components. The discussion is focus ed on the two lower frequency components, which are related to ionic relaxa tion processes. The systems studied fall into two groups: The first compris es various cyclic and acyclic ethers and some chloro compounds as additives and is characterized by a comparably long 'ionic' relaxation time. The sec ond group comprises pyrrolidone derivatives, disubstituted amides and aceto nitrile as additives and is characterized by a 'ionic' relaxation time clea rly shorter than for the first group.