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The potentiometric titration method was used to measure pK a values of nine amines [2-(diisopropylamino)­ethanol [2-DIPA], N,N,N′,N′-tetrakis­(2-hydroxypropyl)­ethylenediamine [THPEDA], 2-{[2-(dimethylamino) ethyl]­methyl amino} ethanol [2-DMAEMAE], tris­[2-(2-methoxyethoxy)­ethyl]­amine [TMEEA], N-(2-hydroxyethyl) aniline [2-HEAN], 1-(2-hydroxyethyl)­piperazine [HEP], piperazine [PZ], monoethanolamine [MEA], and N-methyldiethanolamine [MDEA] at (298.15, 303.15, 313.15, 323.15, and 333.15) K. pK a values of the last three amines were compared with published data to validate the procedure and assess the accuracy of the instrument. Thermodynamic quantities, such as standard enthalpy (ΔH°·kJ–1·mol–1) and entropy (ΔS o·kJ–1·mol–1) for the dissociation process, were determined at 298.15 K using the van’t Hoff equation. From the experimental results, the values of the standard state thermodynamic properties were derived and compared to the values of commercially available amines used as absorbents for CO2 capture. Among the studied amines, 2-DMAEMAE was identified as having a high pK a (9.18) and lower heat of dissociation than MEA (27.77 kJ/mol, as compared to 48.59 kJ/mol for MEA) and can therefore be considered a potential candidate for CO2 capture applications.

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In this report, the adsorption of CO 2 on metal organic frameworks (MOFs) is comprehensively reviewed. In Section 1, the problems caused by greenhouse gas emissions are addressed, and different technologies used in CO 2 capture are briefly introduced. The aim of this chapter is to provide a comprehensive overview of CO 2 adsorption on solid materials with special focus on an emerging class of materials called metal organic frameworks owing to their unique characteristics comprising extraordinary surface areas, high porosity, and the readiness for systematic tailoring of their porous structure. Recent literature on CO 2 capture using MOFs is reviewed, and the assessment of CO 2 uptake, selectivity, and heat of adsorption of different MOFs is summarized, particularly the performance at low pressures which is relevant to post-combustion capture applications. Different strategies employed to improve the performance of MOFs are summarized along with major challenges facing the application of MOFs in CO 2 capture. The last part of this chapter is dedicated to current trends and issues, and new technologies needed to be addressed before MOFs can be used in commercial scales.

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