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The rate constants and the activation energies of the reaction between carbon dioxide and 1,1,3,3-tetramethylguanidine (TMG) in 1-propanol solution were measured by a stopped-flow technique at a temperature range of 288-308 K and at a TMG concentration range of 2.5-10.0 wt %. Based on the pseudo-first-order reaction for CO 2 , the reaction was modeled by a termolecular reaction mechanism, which resulted in a rate constant of 199.30 m 3 kmol −1 s −1 at 298 K. The activation energies were 5.19 kJ/mol and 5.26 kJ/mol at 2.5 and 5.0 wt % TMG, respectively. In addition, carbon dioxide absorption capacity was investigated using a gas-liquid contact system. Absorption capacity of the 10.0 wt % TMG/1-propanol system was found to be 0.035 mol CO 2 /0.035 mol TMG, indicating a favorable loading ratio of 1:1.Repeatability and potential performance losses of this system were analyzed by Fourier transform infrared spectrometry (FTIR) in the range of 400-4000 cm −1 . It was found that the FTIR spectra of the rich solvent became virtually identical to the spectra of the lean solvent upon thermal desorption, promising efficient regeneration. It is therefore concluded that the TMG/1-propanol/CO 2 system is easily switchable and can be used both for carbon dioxide capture and for other applications that require rapid change of medium from nonionic to ionic liquid.

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The reaction kinetics of CO 2 absorption into new carbon dioxide binding organic liquids (CO 2 BOLs) was comprehensively studied to evaluate their potential for CO 2 removal. A stopped-flow apparatus with conductivity detection was used to determine the CO 2 absorption kinetics of novel CO 2 BOLs composed of DBN (1,.0]non-5ene)/1-propanol and TBD (1,5,7-triazabicyclo[4.4.0]dec-5-ene)/1-butanol. A modified termolecular reaction mechanism for the reaction of CO 2 with CO 2 BOLs was used to calculate the observed pseudo-first-order rate constant k 0 (s −1 ) and second-order reaction rate constant k 2 (m 3 /kmol.s). Experiments were performed by varying organic base (DBN or TBD) weight percentage in alcohol medium for a temperature range of 288-308 K. It was found that k 0 increased with increasing amine concentration and temperature. By comparing using two different CO 2 BOL systems, it was observed that the TBD/1-butanol system has faster reaction kinetics than the DBN/1-propanol system. Finally, experimental and theoretical activation energies of these CO 2 BOL systems were obtained and compared. Quantum chemical calculations using spin restricted B3LYP and MP2 methods were utilized to reveal the structural and energetic details of the single-step termolecular reaction mechanism.

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The reaction rates of CO 2 with an innovative CO 2 -capturing organic solvent (CO 2 COS), consisting of blends of 2-tert-butyl-1,1,3,3-tetramethylguanidine (BTMG) and 1-propanol, were obtained as function of BTMG concentration and temperature. A stopped-flow apparatus with conductivity detection was used. The reaction was modeled by means of a modified termolecular reaction mechanism which resulted in a second-order rate constant, and activation energies were calculated for a defined temperature range. Quantum chemical calculations at the B3LYP/6-31G(d) level also produced the activation energy of this reaction system which strongly supports the experimental findings.

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