Proton nuclear magnetic resonance study of water + t-butyl alcohol, water + t--butylamine and water + t-butyl alcohol + t--butylamine mixtures
AbstractHydroxyl-proton chemical shifts for water and t-butyl alcohol in water + t-butyl alcohol mixtures with 8 mol% t-butyl alcohol, and the average hydroxyl and amino proton chemical shift for water + t-butylamine mixtures, have been determined at 200 MHz for four temperatures (263, 278, 298 and 313 K) as a function of composition. Further measurements have been made for water + t-butyl alcohol + t-butylamine ternary mixtures at 310 K over the complete mole fraction range at 60 MHz. Variations in solvent composition have little effect on the resonance for the methyl protons of the cosolvent, but the signal for the hydroxylic protons is substantially influenced. The water proton resonance initially shifts to higher frequencies (low fields) as the cosolvent is added to water, and the shift to higher frequency is strongly temperature dependent, the effect being greatly enhanced at lower temperatures. As the proportion of cosolvent increases the hydroxyl proton signals in the water + t-butyl alcohol system and the average proton signals in water + t-butylamine mixtures shift to lower frequency (high field).
(Received November 22, 2001; revised July 4, 2002)
(Bulletin of The Chemical Society of Ethiopia: 2002 16 (2): 187-198)