Solubility of carbohydrates in heavy water

The solubility of several mono-(glucose and xylose), di-(sucrose and maltose), tri-(raffinose) and cyclic (α-cyclodextrin) saccharides in H2O and in D2O were measured over a range of temperatures. The solution enthalpies for the different carbohydrates in the two solvents were determined using the vant’ Hoff equation and the values in D2O are presented here for the first time. Our findings indicate that the replacement of H2O by D2O remarkably decreases the solubilities of the less soluble carbohydrates, such as maltose, raffinose and α-cyclodextrin. On the other hand, the more soluble saccharides, glucose, xylose, and sucrose, are practically insensitive to the H/D replacement in water.

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► The replacement of H2O by D2O remarkably decreases the solubilities of the less soluble carbohydrates.
► The more soluble carbohydrates are practically insensitive to the H/D replacement.
► This is due to higher cohesive energy of D2O.