Kinetic description of ascorbic acid decomposition in redox initiator systems for polymerization processes

Enthalten in
Industrial & engineering chemistry research 
Volume
58
Issue
29
Start Page
12939
End Page
12952
Citation
Industrial and Engineering Chemistry Research 58 (29): 12939-12952 (2019)
Publisher DOI
10.1021/acs.iecr.9b00710
Scopus ID
2-s2.0-85070493401
Publisher
American Chemical Society
Peer Reviewed
true
The temperature dependent redox decomposition rate constants of ascorbic acid (AsAc) in aqueous solutions were quantified in the presence of ammonium iron(III) sulfate dodecahydrate (Fe-cat) and tert-butylhydroperoxide (TBHP). Decomposition rates were determined in a temperature range from 35-75 °C with respect to the component ratios. First-order kinetics were observed up to specific conversions (∼20-80%) for AsAc decomposition. The application of a flexible Weibull model provided a good and comparable description (R2 ≥ 0.992) of decomposition processes up to high AsAc conversions (96%) at all studied reaction conditions. The activation energy was determined as a function of AsAc and Fe-cat ratios (38-79 kJ mol-1). Statistical modeling facilitated the prediction of rate constants. Thus, it was possible to adjust the reaction rate of emulsion copolymerizations of vinyl acetate and Versa10 in a broad temperature range (10-70 °C) by variation of the Fe-cat content.
DDC Class
540: Chemie