Crystalline anhydrous α,α-trehalose (polymorph β) and crystalline dihydrate α,α-trehalose: A calorimetric study

The mean values of the standard massic energy of combustion of crystalline anhydrous α,α-trehalose (C12H22O11, polymorph β) and crystalline dihydrate α,α-trehalose (C12H26O13) measured by static-bomb combustion calorimetry in oxygen, at the temperature T = 298.15 K, are Δcu∘ = −(16434.05 ± 4.50) J · g−1 and Δcu∘ = −(14816.05 ± 3.52) J · g−1, respectively.The standard (p∘ = 0.1 MPa) molar enthalpy of formation of these compounds were derived from the corresponding standard molar enthalpies of combustion, respectively, ΔfHm∘(C12H22O11,cr)=-(2240.9±3.9)kJ·mol-1, and ΔfHm∘(C12H26O13,cr)=-(2832.6±3.6)kJ·mol-1.The values of the standard enthalpies of formation obtained in this work, together with data on enthalpies of solution at infinite dilution (ΔsolH∞) for crystalline dihydrate and amorphous anhydrous trehalose, allow a better insight on the thermodynamic description of the trehalose system which can provide, together with the future research on the subject, a contribution for understanding the metabolism in several organisms, as well as the phase transition between the different polymorphs.