https://doi.org/10.1016/j.egypro.2017.03.1211
“Table 2 shows the results of the CO2 loading in the aqueous amine solution at 30wt% at 40 oC. Comparing MEA
with 2MAE where one hydrogen that is attached to nitrogen has been replaced by methyl group to form a secondary
amine. The CO2 has not changed much. However by replacing two hydrogens that are attached to the nitrogen with
two methyl group to form 2DMAE the loading increased from 0.58 to 0.73. Compering 2DMAE with 1DMA2P where
one hydrogen of the carbon closest to the alcohol group has been replaced with methyl group. The change on the CO2
loading is insignificant. The CO2 loading for 2DMAE is 0.73 and for 1DMA 2P is 0.72. The results indicate that
attaching methyl grope to nitrogen to form tertiary amine result on a significant enhancement of the CO2 loading.
Alkyl group has electron donating effect that i ncrease the polarity of the nitrogen which is the reason of the
enchantment of the CO2 loading. These results are in accordance with the studies of Singh et al. where the impact of
the alkyl and number of amino groups in the amine molecule enhance the absorption capacity of the amine based
solvents [6].
TMDAP is tertiary amine with two methyl group attached to the nitrogen like 2DMAE. The difference is that
alcohol group in 2DMAE has been replaced with a tertiary amino group with two methyl group attached to the
nitrogen. The CO2 loading has been significantly increased from 0.73 to 1.16. The reason for this enhancement is
because of the extra amino group that acts as another site for CO2 capture.
MDEA is also tertiary amine with a methyl group attached to the nitrogen similar to 2DMAE and two carbon chain
with alcohol functional group attached to the nitrogen. Alcohol group has an electron attracting effect that results in
reducing the polarity on the nitrogen resulting in reducing the absorption capacity. The absorption capacity of MDEA
decreased from 0.73 to 0.52.”
