甘氨酸从水到酰胺衍生物水溶液中的迁移焓

用RD496-Ⅱ型微量热量计测定了298.15 K甘氨酸在N-甲基甲酰胺（NMF），N, N-二甲基甲酰胺（DMF），N-甲基乙酰胺（NMA），N, N-二甲基乙酰胺（DMA）水溶液中的溶解焓，计算了甘氨酸从水到四种酰胺衍生物水溶液中的迁移焓（ΔtrH）。根据结构水合作用模型讨论了酰胺的结构对甘氨酸迁移焓的影响。实验结果表明：甘氨酸在酰胺衍生物水溶液中的迁移焓均为正值，并且随着溶液浓度增大而增大。比较甘氨酸在甲酰胺（FA）和乙酰胺（AD）水溶液中的迁移焓，发现在不同酰胺水溶液中迁移焓大小为：DMA>NMA>DMF>NMF>AD>FA。甘氨酸与甲酰胺之间以亲水-亲水相互作用为主，与其它酰胺之间以亲水-疏水作用为主。

Transfer Enthalpies of glycine in aqueous Amide Derivatives solutions

Enthalpies of solution of glycine in aqueous solutions of N-methylformamide (NMF), N,N-dimethylformamide (DMF), N-methylacetamide (NMA) and N,N-dimethylacetamide (DMA) have been determined at T= 298.15 K by an RD496-II microcalorimeter. The enthalpies of transfer of glycine from water to the aqueous solutions of amide derivatives were derived and discussed in terms of a structural hy-dration interaction model. The values of Δ_(tr)H are positive and increase overall with increasing the concentration of amides. The relative order of Δ_(tr)H from water to the aqueous solutions of formamide (FA), acetamide (AD) and the four derivatives is DMA>NMA>DMF>NMF>AD>FA. The results suggest that in formamide solutions hydrophilic-hydrophilic interaction is responsible for the trends, while in other amide solutions hydrophilic-hydrophobic interaction is predominant.