Excess enthalpies of binary mixtures of butylamines + propanols at 298.15 K

Low-temperature thermal properties of the aqueous solutions of simple aminoalcohols: Finding of peculiarities in 1-amino-2-propanol solutions

“…Takeda et al disclosed that the binary solutions between two compounds; one with dihydroxy and the other with diamino groups reveal a maximum in the glass-transition temperature (T g ) at an intermediate composition [15,16]. T g is the characteristic temperature at which the relevant molecular rearrangement is frozen in on our experimental time scale and that is ordinarily in proportion to the activation energy against the rearrangement [17].…”

“…For example, the two of 1,2-and 1,3-propanediols give the same T g value of 169 K, and their aqueous solutions even reveal the same smooth molar-fraction dependence of T g values as characteristic features of ordinary liquids [15,16,27,28]. Thus, we assume tentatively here that the pre-exponential factor of τ 0 is given by [15,16] that the T g values of the binary system between two compounds one with dihydroxy and the other diamino groups give, at a certain composition, a similar maximum to the T g -difference curve shown in Figure 5 for the 1A2P aqueous solutions. The ratio between the numbers of protons and lone electronpairs changes with the composition in the system by Takeda et al, resulting in the change of the number density of hydrogen bonds with the composition.…”

Unveiling the Dependence of Glass Transitions on Mixing Thermodynamics in Miscible Systems

“…Fig. 4(a) and (b) show the composition dependences of Δ C p and T g for the system of 12PDA vs. PG over the whole composition, where Δ H mix maximum of 12PDA vs. PG is recorded to be −3876 J/mol 23 . A remarkably positive T g deviation is seen in the system.…”

“…The results in this work allow us to check the presumably quantitative correlation between T g and Δ H mix in binary mixtures. In addition to the experimental measurements reported here, more T g 8 21 25 29 32 and Δ H mix values 21 22 23 33 34 35 36 37 are collected. Fig.…”

Enthalpic discrimination of R‐ and S‐limonenes in nonpolar solvents at 298.15 K

“…The excess enthalpies of mixing and dilution were measured by a microcalorimeter (Thermometric AB, Järfälla, Sweden) with a 0.8 ml mixing vessel at 298.15 K 17, 18. Details of the calorimetric procedure and precision test have been described previously 11, 17, 18. The densities of the samples were measured by a vibrating‐tube densimeter (Anton Paar DMA55) at (298.15 ± 0.001) K. The densitometric procedures were the same as those described previously 19…”