ISSN:
1572-8927
Keywords:
Aqueous solutions
;
carbohydrates
;
differential scanning calorimetry
;
enthalpy of fusion
;
enthalpy of solution
;
solution calorimetry
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
Notes:
Abstract A differential scanning calorimeter (DSC) was modified for the determination of enthalpies of solution. The measurements were performed on aqueous solutions of the deoxy- and fluoro-deoxy derivatives of D-glucopyranose (Glu) where the OH group on the C1, C2, C3, and C6 is replaced by H (1HGlu, 2HGlu, 3HGlu, and 6HGlu) and by F (1FGlu, 2FGlu, 3FGlu, and 6FGlu), 4-deoxy 4-fluoro-α-D-glucopyranoside (4FGlu), 1-methoxy-α-D-glucopyranoside (αMeOGlu), 1-phenoxy-α-D-glucopyranoside (αPheOGlu), D-mannopyranose (Man), and 3-methoxy-α-D-glucopyranoside (3MeOGlu), at 15.1, 25.0, 35.0, and 45.1°C. The enthalpies of solution ΔsH0(T) ranged from 1.00±0.25 kJ-mol−1 for 6HGlu at 15.1°C to 20.4±1.4 for αPhOGlu at 45.1°C and were in good agreement with literature values for Man, αGlu, αMeOGlu, and 3MeOGlu at 25.0 and 35.0°C and for αMeOMan and 2HGlu at 35.0°C. ΔsH0(T) for the derivatives were then extrapolated up to the melting temperature Tm and compared with their enthalpies of fusion, ΔfH also determined from DSC measurements. If the agreement between ΔsH0(Tm) and ΔfH was within the 95% confidence level, then it was concluded that intermolecular interactions between the carbohydrate molecules in the liquid phase were the same as between the carbohydrate and water molecules in the solution phase. This agreement was observed for aqueous solutions of Man, αGlu, αMeOGlu, 3HGlu, 3FGlu, and 6FGlu.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00972993
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