Molar heat capacities of solvents used in CO2 capture: A group additivity and molecular connectivity analysis

The molar heat capacities of 38 pure solvents used for CO2 capture studies are reported in the temperature range of 303.15–393.15 K and atmospheric pressure. Existing structural similarities between these compounds were explored using a group additivity analysis (GAA) and molecular connectivity principles in terms of the reported heat capacity data. Group additivity yields the estimates of CH3, CH2, CH, C, CH, NH2, NH, N, N–, OH, O and O group contributions to the molar heat capacities at each investigated temperature. Molecular connectivity approach provides a single equation that models the molar heat capacities of amines over the investigated temperature range. Absolute average deviations for the GAA were found to be <2.5%, and <3% for the molecular connectivity analysis. The developed equations were tested by predicting the molar heat capacities of solvents newly proposed for CO2 capture. Les capacites calorifiques molaires de trente huit (38) solvants purs utilises pour les etudes de capture du CO2 sont rapportees dans la gamme de temperature de (303.15 a 393.15) K et a pression atmospherique. Les similitudes structurelles existantes entre ces composes ont ete explorees a l'aide d'une analyse additivite de groupe et les principes de connectivite moleculaire en termes de capacite thermique. L'analyse fournit les estimations de la contribution des groups CH3, CH2, CH, C, CH, NH2, NH, N, N–OH, O et S = aux capacites calorifiques molaires a chaque temperature etudiee. L'approche de connectivite moleculaire fournit une seule equation qui modelise les capacites calorifiques molaires des amines dans l'intervalle de temperature etudie. Les ecarts absolus moyens pour l'analyse additivite des groupes ont ete de moins de 2.5%, et de moins de 3% pour l'analyse de la connectivite moleculaire. Les equations developpees ont ete testees en predisant les capacites calorifiques molaires des solvants nouvellement proposes pour la capture du CO2. © 2011 Canadian Society for Chemical Engineering