Diethylethanolamine

Abstract: The dissociation constants of the conjugate acids of 14 amines (diethylethanolamine, monoethanolamine, n-butyldiethanolamine, t-butyldiethanolamine, n,n-dimethylpropanolamine, methyl-diethanolamine, ethyldiethanolamine, monoethylethanolamine, n,n-dimethylisopropanolamine, triethanolamine, 4-methylpiperazine-1-amine, 3-morpholino propylamine, 4,2-hydroxylethylmorpholine, and triethylamine) were measured over a temperature range between 293.15 and 333.15 K using the potentiometric titration method. The change in standard state thermodynamic properties was derived from the van’t Hoff equation. The influence of the steric hindrance, number of −OH groups, and length of alkyl chain on the dissociation constants was identified. Of the studied amines, few sterically hindered derivatives of piperazine, a secondary amine monoethylethanolamine, and a tertiary amine n,n-dimethylpropanolamine have high pKa values but lower standard enthalpy than those of the benchmark amine, monoethanolamine (MEA), and thus were deeme...

Abstract: The molar heat capacities of 14 alkanolamine compounds have been measured at five separate temperatures in the range 299.1 to 397.8 K. These compounds were monoethanolamine (MEA), monomethylethanolamine (MMEA), dimethylethanolamine (DMEA), monoethylethanolamine (MEEA), diethylethanolamine (DEEA), n-propylethanolamine (n-PEA), diisopropylethanolamine (di-PEA), diethanolamine (DEA), methyldiethanolamine (MDEA), ethyldiethanolamine (EDEA), n-butyldiethanolamine(n-BDEA), tert-butyldiethanolamine (tert-BDEA), triethanolamine (TEA) and 2-amino-2-methylpropan-1-ol (AMP). Molar heat capacities of these compounds show a structural dependence, where the molar heat capacity of one molecule may be considered as the sum of various group contributions. Hence, the reported molar heat capacity data have been used as input to a group additivity analysis that yields estimates of CH 2 , OH, NH and N group contributions to molar heat capacities at each investigated temperature. The additivity principle has been explored in more detail by using molecular connectivity indexes to obtain a simple five-term equation that models the molar heat capacities of the investigated alkanolamines over the entire experimental temperature range.

Abstract: N,N-Diethylethanolamine (DEEA), which can be prepared from renewable resources, represents a candidate alkanolamine for CO2 removal from gaseous streams. In this work, the reaction of CO2 with aqueous solutions containing N,N-diethylethanolamine (DEEA) was studied in a stirred cell reactor with a plane, horizontal gas−liquid interface, in the range of temperatures 298−308 K. The DEEA concentration in the aqueous solutions was varied in the range 2−3 kmol/m3. The liquid-side mass transfer coefficient and a combined parameter comprising the reaction rate constant and the diffusivity and solubility of CO2 in DEEA solutions were evaluated. The effect of the addition of piperazine (PIP) as a possible absorption activator was studied, and it was found that even with a small amount of PIP (0.1 kmol/m3) added, the CO2 absorption rate increased.