Radiolytic and hydrolytic degradation of the hydrophilic diglycolamides |
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| Authors: | Andreas Wilden Bruce J. Mincher Stephen P. Mezyk Liam Twight Kristyn M. Rosciolo-Johnson Christopher A. Zarzana |
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| Affiliation: | 1. Forschungszentrum Jülich GmbH, Institut für Energie- und Klimaforschung – Nukleare Entsorgung und Reaktorsicherheit (IEK-6), Jülich, Germany;2. Aqueous Separations and Radiochemistry Department, Idaho National Laboratory, Idaho Falls, ID, USA;3. Department of Chemistry and Biochemistry, California State University at Long Beach, Long Beach, CA, USA |
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| Abstract: | The stability of different hydrophilic diglycolamides against acid degradation and radiolysis was studied. Tetraethyldiglycolamide (TEDGA) was found to undergo degradation in nitric acid at high reaction rates at elevated temperatures with a maximum of a ~8% decrease per hour at 65°C in 4 mol L–1 HNO3. The radiolysis was studied for tetramethyldiglycolamide (TMDGA), TEDGA, methyl-tetraethyldiglycolamide (Me-TEDGA), and dimethyl-tetraethyldiglycolamide (Me2-TEDGA). The degradation rates decreased with increasing molecular weight, following the trend TMDGA > TEDGA > Me-TEDGA ≥ Me2-TEDGA. Degradation products were identified by mass spectrometric techniques and were found to be comparable to those previously reported for the radiolysis of lipophilic diglycolamides in dodecane. Significant insight into the degradation mechanism in water was gained using pulse radiolysis experiments. The ?OH radical was identified as the most important reactive species and predominant mechanism of radical reaction is one of electron transfer rather than H-atom abstraction. |
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| Keywords: | Hydrolysis radiolysis pulse radiolysis diglycolamides TEDGA radical reaction |
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