Critical dynamics at the col point of the ternary system methanol- n-hexane-cyclohexane

Abstract

The ternary system methanol- n-hexane-cyclohexane (MeOH-Hex-CH) has been investigated at the col point in order to look for indications of critical exponent renormalization. Ultrasonic spectroscopy, quasielastic light scattering, and shear viscosity measurement have been performed as a function of temperature and have been evaluated in terms of existing theories for binary critical systems. When compared to the results for the limiting binary mixtures MeOH-Hex and MeOH-CH it is found that, as a function of reduced temperature, both the fluctuation correlation length and the relaxation rate of fluctuations of the ternary mixture display power law behaviour with critical exponents as applying to binary systems near their consolute point. Also the experimental scaling function of the ultrasonic attenuation spectrum agrees well with the Bhattacharjee–Ferrell theory for binary mixtures. Hence with respect to power laws and scaling the MeOH-Hex-CH mixture at col point composition behaves like a quasibinary system. The individual parameters of the ternary system fit to the data for the systems MeOH-Hex and MeOH-CH.