13C-NMR Study of Acid Dissociation Constant (pKa) Effects on the CO2 Absorption and Regeneration of Aqueous Alkanolpiperidine

Yukio Furukawa*, Hirotaka Koriki, Daiki Shuto, Hiroshi Sato, Yasuro Yamanaka

*Corresponding author for this work

Research output: Contribution to journalConference articlepeer-review

2 Citations (Scopus)


We have studied the formation rates of HCO3-/CO32-, amine/protonated amine, carbamate/protonated carbamate, and carbonate/protonated carbonate in the course of CO2 absorption at room temperature, and composition changes and CO2 release upon heating at 93 °C for 30 min for aqueous solutions of 9 kinds of alkanolpiperidines using 13C-NMR spectroscopy. The pKa values of these alkanolpiperidines were measured. The initial CO2 capture rates of alkanolpiperidines do not depend on their pKa values, which is quite different from general trends of aqueous amine absorbents. The CO2 release amount of each alkanolpiperidine increased with decreasing pKa, as a general trend. The CO2 release amounts of 1-HE-PD, 2-HM-1-M-PD, 3-HM-1-M-PD, and 4-HM-1-M-PD increased with increasing concentrations.

Original languageEnglish
Pages (from-to)1765-1771
Number of pages7
JournalEnergy Procedia
Publication statusPublished - 2017
Event13th International Conference on Greenhouse Gas Control Technologies, GHGT 2016 - Lausanne, Switzerland
Duration: 2016 Nov 142016 Nov 18


  • C-NMR
  • CO capture
  • CO regeneration
  • acid dissociation constant
  • alkanolpiperidine

ASJC Scopus subject areas

  • Energy(all)


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