Mutual diffusion coefficients of 3–methyl–1–butanol + n–heptane and 2–methyl–1–butanol + n–heptane from 288.15 K to 318.15 K

Highlights: • New mutual diffusion coefficients of 3–methyl–1–butanol + n–heptane and 2–methyl–1–butanol + n–heptane were proposed. • The measurement was conducted over the whole concentration range and at 288.15 to 318.15 K. • Correlations as functions of mass fraction and temperature were presented. -- Abstract: The mutual diffusion coefficients of binary mixtures, 3–methyl–1–butanol + n–heptane and 2–methyl–1–butanol + n–heptane, were measured over the mass fraction from 0.05 to 0.95 at temperatures T = 288.15 K, 298.15 K, 308.15 K and 318.15 K under atmospheric pressure. A digital holographic interferometry system was employed for the measurements and its expanded relative uncertainty of mutual diffusion coefficients was estimated to be less than 2.4%. The influences of temperature and composition on the mutual diffusion coefficients were investigated. Furthermore, the correlations of the mutual diffusion coefficients were fitted to the experimental data as functions of the mass fraction and temperature. The correlations represent the data with the absolute average of relative deviations (AARDs) of 0.88% for 3–methyl–1–butanol + n–heptane and 0.89% for 2–methyl–1–butanol + n–heptane, respectively.