Absorption rates of carbon dioxide in amines in hydrophilic and hydrophobic solvents

Additionally, activators such as water, piperazine (PZ), and 4-hydroxy piperidinol (HPIP) were added to the ethereal hydrophobic non-aqueous solvent to determine the effect on the reaction rate. It was found that the water- and amine-based activators lead to an increase in the observed reaction rates as the concentration of the activators increased. The reaction of NMBA with CO2 and PZ exhibited a higher reaction rate but the PZ was insoluble in the non-aqueous NMBZA system, whereas HPIP remained soluble and offered a similar reaction rate. The activation energy of ethereal hydrophobic non-aqueous solvent to react with CO2 increased from 27.98 to 32.83 kJ.mol−1 by adding PZ and 33.51 kJ.mol−1 by HPIP and remained by adding H2O (26.78 kJ.mol−1). From this work, it was found that the non-aqueous solvent plays an important role in the reaction rate of CO2 with amines. Activators and solvents can be selected to increase the reaction rate with CO2.