Mixed bead resins comprising weakly acidic (carboxylic acid) and weakly basic (tertiary amine) groups were produced with properties similar to the thermally regenerable Sirotherm resin. This resin typically had a capacity of about 0.5 mmol NaCl per gram and the sorption isotherm was found to be consistent with the Langmuir equation. The resin could be partially regenerated by heat (80%) and water washing (40%) as the ion sorption capacity was much reduced on heating to 80°C. However, the resin could be completely regenerated by a combination of heat and pre-washing with concentrated ammonium bicarbonate solution. On heating to 60°C or more the bicarbonate salt completely decomposes and can be removed from the resin as carbon dioxide and ammonia gases. These initial results suggest that this type of ion exchange resin could be used in a continuous process where the regeneration salt (ammonium bicarbonate) is thermally decomposed, collected and re-used to improve the efficiency of regeneration.

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Reaction of substituted 4-aminooxanes with a mixture of formaldehyde and formic acid gave 4-(dimethylamino)oxanes in good yields. The methiodides of these (dimethylamino)oxanes were also prepared. The conformations of these tertiary amines as well as those of the corresponding quaternary ammonium iodides were analyzed via and 13C NMR analysis. The spectral data suggest that the methiodides with an axial C-N bond exist in twist conformations. The rates of methylation of epimeric pairs of (dimethylamino)oxanes with methyl iodide have been measured at 30 ± 0.05 °C in acetonitrile. The kinetic data are used, in part, to evaluate the steric environment of the dimethylamino group in this system. A possible twist conformation for trans-2,6diphenyl-cis-3,5-dimethyl-r-4-(dimethylamino)oxane and its C(4) epimer is suggested from the kinetic results.