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

Abstract

The mean values of the standard massic energy of combustion of crystalline anhydrous α,α-trehalose (C 12H 22O 11, polymorph β) and crystalline dihydrate α,α-trehalose (C 12H 26O 13) measured by static-bomb combustion calorimetry in oxygen, at the temperature T = 298.15 K, are Δ c u ∘ = −(16434.05 ± 4.50) J · g −1 and Δ c u ∘ = −(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, Δ f H m ∘ ( C 12 H 22 O 11 , cr ) = - ( 2240.9 ± 3.9 ) kJ · mol - 1 , and Δ f H m ∘ ( C 12 H 26 O 13 , 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 (Δ sol H ∞) 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.