Chemical equilibria of absorption of CO2 into nonaqueous solution of amine.

The moles of CO2absorbed into an amine-nonaqueoussolvent mixture were measuredby using the stirred-cell method.The test solutions were the mixtures of amine such as butylamine, terf-butylamine, dibutylamine, diethylamine and dipropylamine, and solvents such as octane, triethylamine and methanol.The equilibria of the reactions between CO2and amine in nonaqueous solvent were studied by examining the pressure dependency of the absorption of CO2at lower temperatures, and could be described by the following reactions:where R is the alkyl group.The equilibrium constants, K19K2 and K3, were estimated simultaneously by the method of least squares with respect to the pressure dependency of the absorption of CO2.The equih'bria of the reactions in a nonpolar solvent were mainly described by Eqs.(1) and ( 2).Those in a polar solvent were described by Eqs.(1) and ( 3).The proposed reactions, Eqs.(1) to ( 3), were supported by enthalpies estimated from the Arrhenius plot of the equilibrium constant.