Temperature-Dependent Diffusion Coefficients from 1D Raman Spectroscopy

A setup for the measurement of temperature-dependent diffusion coefficients has been developed based on 1D Raman spectroscopy. The presented setup was used to measure binary diffusion coefficients for mixtures of monoethanolamine + water, cyclohexane + toluene, and methanol + toluene for temperatures between T = 298.15 and 330.15 K. The experimental diffusion coefficients agree well with available literature data. For the mixture methanol + toluene, literature data was only found for T = 298.15 K. The novel setup was therefore used to determine temperature-dependent diffusion coefficients of methanol + toluene up to T = 328.15 K. The experimental data are also compared to a temperature correlation for diffusion coefficients in concentrated solutions. While the correlation describes the temperature dependence well for simple systems, measurement techniques remain indispensable for diffusion in complex mixtures.