Premium
Nitroxyl Radical‐Mediated Oxidation of Alcohols in Continuous Microreactors
Author(s) -
Deckers Christoph,
Linden Martin,
Löwe Holger
Publication year - 2019
Publication title -
chemical engineering and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.403
H-Index - 81
eISSN - 1521-4125
pISSN - 0930-7516
DOI - 10.1002/ceat.201800427
Subject(s) - chemistry , microreactor , electrolysis , nitroxyl , alcohol oxidation , electrochemistry , cyclic voltammetry , alcohol , radical , primary alcohol , organic chemistry , electrode , catalysis , electrolyte
Primary and secondary alcohols are oxidized to corresponding aldehydes and ketones, respectively, with nitroxyl radicals. The stable radical 2,2,6,6‐tetramethylpiperidine‐1‐oxyl (TEMPO) is used as a mediator for selective oxidation of anisyl alcohol to anisaldehyde. This reaction is operated in different continuous microreactors either in single‐phase or in multiphase applications like double emulsions. The latter are used for a simple separation of the hydrophilic coproduct 1‐hydroxy‐2,2,6,6‐tetramethylpiperidine (TEMPO‐H) and the lipophilic product anisaldehyde. In addition, cyclic voltammetry is applied to determine conditions and parameters for electrochemical recycling of TEMPO‐H. TEMPO‐H is reactivated in a continuous electrolysis cell by anodic oxidation for reuse as mediator.