Experimental Study Of The Kinetics Of The Homogenous Reaction Of CO₂ Into A Novel Aqueous 3-Diethylamino-1,2-Propanediol Solution

With the rapid development of the global economy, the demand for energy has increased since the 20th century. The high energy consumption results in the rapidly increasing of carbon dioxide (CO2) emission. So the study of efficient and viable carbon capture technology has become an indispensable tool to reduce the global CO2 emissions. Amine solvent CO2 capture technology is considered as the most promising technology currently, however, the biggest drawback of this technique is that it reqiures high desorption energy. Therefore, the research and development of new solvents and new processes to obtain efficient, economical and feasible method of amine CO2 capture technology is the most important thing.In this work, the ion specices of amine-CO2-H2O system was determined by both of pH method and NMR method. It was found that the result obtained by NMR method was more accurate than pH method. Stopped-flow technique was used to determine the kinetic parameters in terms of pseudo first-order rate constants (ko) for homogenous reaction of CO2 into aqueous 3-Diethylamino-1,2-Propanediol (DEA-1,2-PD) solutions as temperature ranged from 293K to 313K and amine concentrations ranged from 0.20 kmol/m3 to 1.00 kmol/m3. It was found that ko increased with increasing amine concentration and temperature. Both the base-catalyzed hydration and the termolecular models were applied to interpret the experimental data. The results showed that the predicted CO2 absorption rates exhibited good agreement with experimental data with an absolute average deviation (AAD) of 5.7% and 3.8% with respect to base-catalyzed hydration and the termolecular model, respectively. Furthermore, the pKa of DEA-1,2-PD was experimentally determined over the temperature range from 298 to 318 K. The relationship between experimentally measured second-order reaction rate constants (k2) and pKa was correlated using the Br(?)nsted relationship. The results suggest that the Br(?)nsted relationship for DEA-1,2-PD developed in this work can predict the reaction rate constant very well with an AAD of 0.8%.In this work, the pH potentiometric titration method was used to measured the dissociation constant pKa of DEA-1,2-PD solvent with the temperature ranged from 298-318 K. Br(?)nsted relationship was then used to fit the pKa value and second-order reaction rate constant rate. The relationship obtained in this work can well predict the kinetic constants of aquoues DEA-1,2-PD solutions absorption CO2. DEA-1,2-PD has the faster reaction kinetics and lower regeneration energy than those of 3DMA1P,1DMA2P, DMMEA, and MDEA. It could be a promising novel solvent to be used in absorping CO2.