Excess enthalpies and excess volumes of N,N-dimethylethanolamine plus 1,4-dioxane, plus DMF, plus DMA or plus DMSO

The excess molar enthalpies of N,N-dimethylethanolamine (DMEA) + 1,4-dioxane, + DMF, + DMA or + DMSO at 298.15 K have been measured with a Picker microcalorimeter. Excess enthalpies for DMEA with DMF, DMA or DMSO are negative over the entire composition range except for 1,4-dioxane. Density measurements were made with an Anton Paar DMA 602 densimeter. Excess volumes of the title mixtures and apparent molar volumes of the components are reported. Excess volumes are all positive. Excess enthalpies and volumes of these systems decrease in the same sequence: 1,4-dioxane > DMA > DMSO > DMF. The observations are discussed in terms of hydrogen bonding interactions. (C) 1997 Elsevier Science B.V.