5 research outputs found
Continuous Krapcho Dealkoxycarbonylation in API Synthesis
A high pressure and high temperature continuous flow reactor has been used to intensify a Krapcho dealkoxycarbonylation
reaction in the context of API synthesis. The reactor enables operation of the reaction above temperatures
possible in batch and thus significantly increased conversion rates are achieved. Also a broader choice of solvents is
possible by the use of the continuous process. Batch and continuous reaction are compared in terms of operation range
and space-time-yield. Despite lower concentrations of the reactants in the continuous process, space-time-yield exceeds
that of the batch process by more than an order of magnitude due to the higher reaction rates
UVâVis Monitoring of Radical Polymerizations by Spin Trapping with Chromophoric Nitrones
The application of chromophoric radical
spin traps for highly sensitive
UVâvis monitoring of conversion of radical enhanced spin capturing
polymerizations (ESCP) is presented. In ESCP the growing macroradical
is reacting with a nitrone providing the corresponding polymeric nitroxide
radical spin trap which will react irreversibly with a second macroradical
to eventually give a polymeric alkoxyamine. The progress of styrene
and <i>n</i>-butyl acrylate ESC polymerizations in the presence
of Ï-conjugated nitrones is successfully visualized via a significant
change of absorbance of the nitrone chromophore in the 200â500
nm range due to the nitrone transformation into an alkoxyamine moiety
upon incorporation into the polymer. Moreover, related studies on
UVâvis monitoring of photochemical rearrangement of nitrones
to their corresponding oxaziridines are discussed
UVâVis Monitoring of Radical Polymerizations by Spin Trapping with Chromophoric Nitrones
The application of chromophoric radical
spin traps for highly sensitive
UVâvis monitoring of conversion of radical enhanced spin capturing
polymerizations (ESCP) is presented. In ESCP the growing macroradical
is reacting with a nitrone providing the corresponding polymeric nitroxide
radical spin trap which will react irreversibly with a second macroradical
to eventually give a polymeric alkoxyamine. The progress of styrene
and <i>n</i>-butyl acrylate ESC polymerizations in the presence
of Ï-conjugated nitrones is successfully visualized via a significant
change of absorbance of the nitrone chromophore in the 200â500
nm range due to the nitrone transformation into an alkoxyamine moiety
upon incorporation into the polymer. Moreover, related studies on
UVâvis monitoring of photochemical rearrangement of nitrones
to their corresponding oxaziridines are discussed