T. Rosenau, A. Pothast, R. Buchner, H. Bruglachner, T. Röder, G. Ebner, and P. Kosma, The cellulose solvent system N,N-dimethylacetamide / lithium chloride revisited: The effect of water, physicochemical properties and chemical stability, Cellulose, 9 (2002) 41-53.
The water content in the binary system N,N-dimethylacetamide/lithium chloride (DMAc/LiCl), a common cellulose solvent, has been proven to be a crucial parameter. A quick determination of water content in DMAc based on the solvatochromism of a UV-active betain probe dye has been developed and validated. An analogous method, based on the solvatochromic fluorescence shift of Zelinskij’s dye, which strongly depends on the solvent polarity, was established for water determination in DMAc containing LiCl. Precise physicochemical data of the system DMAc/LiCl, such as density, viscosity, and conductivity, have been obtained. The limiting solubility for LiCl in absolute DMAc is 8.46 wt%. As shown by light scattering experiments, water in DMAc/LiCl induces aggregation upon standing for longer periods of time, which is even more prominent for diluted solutions and those having a poor state of dissolution.