Heat of absorption of carbon dioxide (CO₂) into aqueous N-methyldiethanolamine (MDEA) and N,N-dimethylmonoethanolamine (DMMEA)

In this work the heat of absorption of CO₂ into aqueous solutions of N-methyldiethanolamine (MDEA) and N,N- dimethylmonoethanolamine (DMMEA) has been investigated in a reaction calorimeter. The experiments were conducted at the concentrations 2 M and 4.2 M, and the temperatures 313 K, 353 K and 393 K. The resulting differential heats of absorption were plotted as a function of liquid CO₂ loading. An effect of temperature on the heat of absorption was observed for MDEA. This effect was larger at low loadings and the lower amine concentration. This was also observed for DMMEA but here the effect of temperature was larger. The heat of absorption of CO₂ into aqueous DMMEA is slightly larger than for MDEA.