Photochemistry

Microstructured flow reactors are perfectly suited for performing photochemical synthesis. The formation of very thin liquid films in microchannels or capillaries allows full irradiation of the reaction solution and thus an optimum utilization of the incident light. A precise control over the irradiation period results from the exactly defined volume in the channels and capillaries. Therewith we can prevent both the by-product formation and the decomposition of the reaction components caused by excessive radiation.

"We reduce by-product formation as well as the decomposition of the educts in your synthesis"

Concerning the light input we count on energy-efficient LEDs. The small size of the LEDs and their relatively low waste heat allow for a targeted adaption of the lighting units to the particular microreactor class. A further special advantage of these light sources is their quasi-monochromatic light emission, which allows a very selective excitation of the photocatalyst or of the reaction substrate. Besides the efficient light irradiation into the reaction solution, efficient contacting of the liquid or gas phase with heterogeneous photocatalysts in the microchannels is realized.

The combination of efficient light input and material bonding forms an excellent basis for the reactor and process development for complex photochemical applications. The following reactor classes are available to us:

• Falling film microreactors
  • Laboratory version with max. f_l = 1 ml / min and variable channel dimensions
  • Scale-up version with tenfold flow rate
  • Each equipped with magnetically fixable LED lighting units with different emission wavelengths: e.g. 365 nm, 410 nm, 455 nm, 525 nm, 620 nm, cold white 6500 K
• Capillary photoreactors
  • Capillary reactor with FEP capillaries (ID = 0.8 mm) and integrated, water-cooled LED radial beam with fixed emission wavelengths: 450 nm, 530 nm, 620 nm
  • Capillary reactor comprising two parallel wired FEP capillaries (ID = 0.8 mm), integrated capillary cooling and replaceable, water-cooled LED radial beams with different emission wavelengths: 410 nm, 455 nm, 520 nm, cold white 6500 K
    

For our photocatalysts we use organic sensitizers (such as bengal rose, perylene and porphyrin dye, riboflavin), organometallic complexes, heterogeneous metal oxides (e.g. TiO₂, Bi₂O₃, ZnO) and immobilized inorganic photocatalysts that are modified or doped with organic sensitizers. The photochemical applications include the in-situ generation of singlet oxygen for photo-oxygenations, photo-oxidations, photo-hydrogenations, cis-trans isomerizations, fluorinations and nanoparticle manufacturing.

Whether you are interested in optimizing your photochemical processes or you are thinking about using photochemistry in your processes for the first time, we are the right partner.