Monoalkylcarbonate formation in the system monoethanolamine–water–carbon dioxide

Abstract

In a recent study, we have shown by NMR spectrocopy that monoalkylcarbonates are formed in substantial amounts in aqueous solutions of the tertiary alkanolamine methyldiethanolamine (MDEA) upon loading with carbon dioxide (CO 2 ). These species had been overlooked by most authors previously. In the present work, this study was extended to the primary alkanolamine monoethanolamine (MEA). Also here monoalkylcarbonates were found, but only at CO 2 loadings above 0.5 mol CO 2 per mol MEA. Both the amine and its carbamate form monoalkylcarbonates. The concentration of the monoalkylcarbonates was determined with 13 C NMR spectroscopy in a wide range of CO 2 loadings, MEA concentrations, and temperatures. Based on this comprehensive data the chemical equilibirium constants of the formation of the monoalkylcarbonates were determined.

A comparison of non‐uniform sampling and model‐based analysis of NMR spectra for reaction monitoring

“…where Á k k denotes the Euclidean norm and the model spectrum s model implicitly depends on the set of parameters as per Equation (4). The challenge then is to determine the set of parameters θ k that best matches the data.…”

“…In recent years, NMR spectroscopy has attracted growing interest for reaction monitoring as it can provide direct, quantitative information about the chemical composition with high chemical specificity. [3][4][5] Furthermore, in the last decade, benchtop NMR instruments have become available, which provide the functionality of a conventional superconducting NMR instrument in a much more compact and affordable package. This new generation of benchtop equipment makes online monitoring of chemical reactions possible in a conventional chemical lab or even in operating production processes.…”

Speciation in CO2-loaded aqueous solutions of sixteen triacetoneamine-derivates (EvAs) and elucidation of structure-property relationships

“…Determining the speciation of CO 2 -loaded aqueous solutions of amines means quantifying the amounts of protonated/unprotonated amine, bicarbonate and carbonate, carbamates, alkylcarbonates, molecular CO 2 , and eventually other compounds. The state of the art method for determining the speciation of CO 2 -loaded aqueous amine solutions is 1 H and 13 C NMR spectroscopy [17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34]. Other spectroscopic methods, such as Infra-red or Raman spectroscopy, have also been applied [35,36,37,38].…”

Online process monitoring of a batch distillation by medium field NMR spectroscopy

“…A variety of applications of high field NMR spectroscopy for online process monitoring have been described in the literature [3][4][5][6], but they are limited to laboratory conditions. The advent of commercially available medium field NMR spectrometers opened up new possibilities.…”