GUTMANN ACCEPTOR PROPERTIES OF LICL, NACL, AND KCL BUFFERED AMBIENT-TEMPERATURE CHLOROALUMINATE IONIC LIQUIDS

Gutmann acceptor numbers have been determined using P-31 nuclear magne tic resonance (NMR) for AlCl3/EMIC melts as well as LiCl, NaCl, and KC l neutral buffered melts. In AlCl3/EMIC melts, where EMIC is 1-ethyl-3 -methylimidazolium chloride, the change in Gutmann acceptor number as a function of the AlCl3:EMIC melt ratio is attributed to an equilibriu m between a monoadduct of triethylphosphine oxide . AlCl3 and a diaddu ct of triethylphosphine oxide . 2AlCl(3). Observed acceptor numbers fo r the neutral buffered melts appear linear with respect to the melt's initial mole ratio of AlCl3:EMIC prior to buffering. The lithium catio n appears to be the most Lewis acidic alkali metal cation followed by the sodium and potassium cations. Possible reasons for the change in a cceptor number as a function of changing alkali metal cation concentra tion are presented.