D-甘露醇与D-山梨醇在氯化钠水溶液中的稀释焓

应用等温流动微量热法测定了298.15 K时互为旋光异构体的D-甘露醇与D-山梨醇在不同浓度的氯化钠水溶液中的稀释焓, 利用 McMillan-Mayer 理论计算了D-甘露醇与D-山梨醇在不同浓度的氯化钠水溶液中的焓对相互作用系数. 结果表明, D-甘露醇和D-山梨醇在氯化钠水溶液中的焓对相互作用系数h2均为正值, h2的值随着氯化钠浓度的增加皆逐渐增大, 但D-山梨醇的焓对相互作用系数h2增大的速率[dh2 /dm(NaCl)]比 D-甘露醇的要大. 根据两多元醇分子构象结构的差异， 溶质-溶质相互作用和溶质-溶剂相互作用对结果进行了解释.

Dilution Enthalpies of D-mannitol and D-sorbitol in Aqueous Sodium Chloride Solution

The dilution enthalpies of D-mannitol and D-sorbitol in aqueous sodium chloride solution have been determined by using flow-mix-isothermal microcalorimetry at 298.15 K. The enthalpic pairwise interaction coefficients(h2) in the range of sodium chloride concentration (0～1.2 mol•kg-1) have been calculated according to the McMillan-Mayer theory. It is found that h2 of coefficients D-mannitol and D-sorbitol are all positive in aqueous sodium chloride solution and become more positive with increase of the concentration of sodium chloride. Further analysis indicates that the increasing rate of the h2 coefficient [dh2/dm(NaCl)] for D-sorbitol is larger than that of D-mannitol. The results are discussed in terms of the different conformations of the two polylols, interactions of solute with solute and solute with solvent.