Stopped-flow determination of carbon dioxide–diethanolamine reaction mechanism: Kinetics of carbamate formation

✍ Scribed by D. Barth; C. Tondre; J. J. Delpuech

• Book ID: 102927872
• Publisher: John Wiley and Sons
• Year: 1983
• Tongue: English
• Weight: 648 KB
• Volume: 15
• Category: Article
• ISSN: 0538-8066
• DOI: 10.1002/kin.550151104

✦ Synopsis

The reaction mechanism of carbon dioxide with diethanolamine (DEA) is investigated using the stopped-flow method with optical detection in the ranges of concentration [DEA] = 0.111-8.4 X 10-2M and [CO,] = 2.94-5.6 X lOW3M. The comparison of the fast time-dependent light transmission change of a pH indicator with theoretical simulations of integrated rate equations requires a kinetic model in which a simple carbamate formation takes place simultaneously with hydration reactions, whose contributions are far from being negligible. A first-order reaction relative to DEA is thus found with a rate constant for carbamate formation smaller than usually predicted (110 f 15M-1-s-1 at 25°C). The equilibrium constant for the same reaction is also determined giving PKR = 5.3 at 25"C, in satisfactory agreement with values assumed so far.