Thermal Conductivity of Aqueous Solutions with 1,3-Propanediol, 2-Methyl-1,3-Propanediol, 1,2-Butanediol, 1,3-Butanediol, and 1,4-Butanediol from 293 to 373 K

1,3-Propanediol (1,3PD), 2-methyl-1,3-propanediol (2M1,3PD), 1,2-butanediol (1,2BD), 1,3-butanediol (1,3BD), and 1,4-butanediol (1,4BD), and their aqueous solutions, are commonly used as heat transfer fluids. The thermal conductivity (λ) of these substances is a critical physical property. However, limited data are available in the literature, particularly for their aqueous solutions. In this study, λ of the aforementioned aqueous solutions was measured using a transient hot-wire apparatus over the temperature (T) range of 293 to 373 K at ambient pressure close to 0.1 MPa, with an estimated expanded uncertainty of 1.7% (k = 2). The reliability of the experimental setup was validated by using pure water prior to measurements. Empirical correlations were developed to represent λ of both the pure alcohols and their aqueous solutions. For the pure alcohols, the deviation between experimental and correlated values was within 0.5%, while for the aqueous solutions, the deviation was within 3.9%. A brief analysis of structure–property relationships was conducted, suggesting that the nonideality observed in aqueous solutions may be attributed to changes in hydrogen bonding and dipole–dipole interactions caused by structural rearrangement in the solution. The results presented in this work provide valuable data for industrial applications and thermal design involving these aqueous solutions.