MUTUAL-DIFFUSION COEFFICIENTS AND VISCOSITIES FOR THE WATER-2-METHYLPROPAN-2-OL SYSTEM AT 15 AND 25-DEGREES-C

Mutual-diffusion coefficients have been measured by the Taylor dispersion technique and viscosities by capillary viscometry at 15 and 25 degrees C for dilute aqueous solutions of 2-methylpropan-2-ol (tert-butyl alcohol or TBA). Comparison is made with other water-alcohol systems and water-2-butoxyethanol. Ornstein-Zernicke correlation lengths, xi, for this system are compared with those for mixtures of water with methanol, ethanol, propan-1-ol and butan-1-ol and contrasted with those of systems representative of other classes of non-electrolyte mixtures. xi for water-propan-1-ol rises to a maximum at a mole fraction (x) of 0.15, suggestive of the long-range correlation of molecular motion in this solution or pseudo-critical behaviour; water-TEA appears to behave similarly with a rapid increase in xi above x = 0.05.