1,4-Dioxane, basic behavior

Jpor several years, studies regarding the behavior of lignin on acidolysis, —i.e., heating with 0.2M hydrogen chloride in dioxane-water 9 1— have been carried out in our laboratory. Analytical examination of the changes incurred by this treatment, and more recently, the isolation of various degradation products helped to elucidate some basic structural features of the lignin molecule. 

The PC/ABS = 90/10 blends have shown different behavior for different grades of ABS. Thus, solubility of PC-l/ABS-3 in tetrahydrofu-ran, cyclohexanone, 1,4-dioxane was found to be different. This has been attributed to the difference in the degrees of interaction between the two polymers. The basic difference in the weight fractions of A, B and S in the ABS resin was the influencing factor. However, with the increase in ABS content in the blends, the blends showed... 

A second type of very useful behavior occurs in aprotic (or sometimes inert ) solvents, which usually exhibit very weak acid properties. Examples are dimethylformamide, dimethylsulfoxide, dioxane, ether, various nitriles, methyl isobutyl ketone, hydrocarbons, carbon tetrachloride. These solvents often permit differentiation (or stepwise titration) of a series of acidic or basic species which, in water, either titrate together or not at all. For example, perchloric, hydrochloric, salicylic, and acetic acids and phenol can be titrated stepwise in methyl isobutyl ketone solvent to obtain discernible endpoints for each compound, using tetrabutyl ammonium hydroxide in isopropyl alcohol as titrant. 

Solvation of f-element cations in mixed aqueous solvents has been studied using the fluorescence technique. With Eu(III) ion as a probe (Tanaka et al. 1988, Lis and Choppin 1991), in water-acetone, water-acetonitrile and water-1,4-dioxane, the first solvation sphere is occupied exclusively by water molecules even at bulk-phase mole fractions of water as low as 0.1 (fig. 6, curve I). However, in solvents with more basic donors such as DMSO (DMSO is dimethylsulphoxideX the metal ion is preferentially solvated by DMSO even for very low mole fractions of DMSO in the solvent (curve II, fig. 6). Less regular behavior can be expected for systems in which (a) strong interactions exist between the components of the solvent mixture or between the coordinated... 

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