Entwicklung einer leistungsstarken Mikrorektifikationsapparatur für analytische und präparative Anwendungen

Es wird über die Realisierung einer leistungsfhigen Mikrorektifikationsapparatur (MRA) berichtet, die diskontinuierlich oder kontinuierlich betrieben und sowohl für die analytische wie auch für die prparative Trennung von flüssigen Stoffgemischen eingesetzt werden kann. Mit der MRA wurden verschiedene binre Systeme erfolgreich getrennt und eine theoretische Trennstufenzahl von 12¿und einen Trennstufenhöhe von 1,08¿cm erzielt. Dies ist im Vergleich zum aktuellen Stand der Mikrotechnik (mind. 1,27¿cm) als großer Fortschritt anzusehen. In this contribution it is reported about the realization of efficient micro rectification equipment (MRA), which can be operated intermittently or continuously and be used both for analytical as well as for preparative separations of mixtures of liquid substances. Different binary systems were separated. A theoretical separation stage number of 12¿was obtained together with a height equivalent to one theoretical plate of 1.08¿cm. Compared to the state of microtechnology this can be regarded as an excellent progress

Continuous-flow synthesis of fluorine-containing fine chemicals with integrated benchtop NMR analysis

A compact lab plant was designed for the continuous-flow synthesis of fluorine-containing compounds and was combined with an NMR analysis platform based on a benchtop NMR spectrometer. The approach of a unified synthesis and analysis strategy for fine chemicals was applied to three different reactions, all employing fluorine as a chemical probe for online-19F NMR analysis. A high temperature synthesis for the deprotection of a CF2H group was done as well as Ruppert–Prakash reactions for the perfluoroalkylation of benzaldehyde as a model substrate. The C–H arylation of furan with a trifluoromethylated aryldiazonium salt was performed as an example of a photochemically catalyzed reaction. All three reaction classes challenge the synthesis and analysis setup differently according to sample preparation (premagnetization of bubble-free sample) and spectrometer sensitivity (signal to noise ratio, spectral resolution, scan number, substrate concentration and flow rate), but nonetheless prove the successful application of the continuous-flow synthesis of fluorinated fine chemicals with integrated online NMR analysis

Chemoselective three-phase hydrogenation of an Ombrabulin nitro-stilbene intermediate in a continuous-flow mobile platform

The chemoselective three-phase hydrogenation of an Ombrabulin intermediate based on a nitro-stilbene framework was used as a case study for the formation of the primary amine without affecting the Cdouble bond; length as m-dashC double bond. Two catalysts were tested: Pt nanoparticles supported on ZnO (Pt/ZnO) and agglomerated nitrogen-doped carbon nanotubes (NCNTs). Both materials show a high selectivity at close to full conversion in terms of amine formation (>99%) without changing the configuration of the central stilbene Cdouble bond; length as m-dashC double bond. The continuous hydrogenation process was first tested in lab scale reactors (2 mL and 6 mL) combined with a high pressure interdigital micromixer to ensure efficient three-phase contact. While the specific reactor performance (defined as productivity per unit of reactor volume) was 1.5-fold higher for the Pt/ZnO, the NCNT catalyst was found to be more suitable for flow operation due to a lower pressure drop over the catalytic packed bed. The catalytic reactor was then scaled up to 50 mL and operated in the EcoTrainer mobile modular platform for the hydrogenation of the Ombrabulin intermediate demonstrating a safe, flexible and sustainable fine chemical synthesis