Safe and Fast Continuous-Flow Microfluidic Hydrogenation

A novel microfluidic device for conducting heterogeneous hydrogenation at high temperatures and pressures has been developed by Thales Nanotechnology, an emerging company based in Budapest, Hungary. The new device makes huge advances for hydrogenation in terms of speed, practicality, automation and safety.

Traditionally, heterogeneous catalytic hydrogenation is carried out in batch reactors called autoclaves or reaction bombs. There are however, a number of safety and practical disadvantages associated with batch reactor hydrogenation.
- The interaction between the hydrogen gas, substrate solution, and the solid catalyst is very low and inefficient. ,- Separation of the pyrophoric catalyst and the reaction mixture can be hazardous. ,- The size of the reaction is limited to the capacity of the batch reactor.,- Analysis can only be performed at the end of the experiment.
Thales Nanotechnology has developed a continuous flow reactor to overcome these limitations. The hydrogen is produced by the electrolysis of water. A continuous-flow of substrate mixes with the hydrogen, passes into a small reaction line, and through a catalyst-packed cartridge. The hydrogenated product emerges continously from the other end of the cartridge and into a reaction vial. Temperature and pressure can be controlled between 1-100°C and 1-100 bars respectively.
Using the system with varying catalysts, temperatures, and pressures we have managed to reduce a wide variety of functional groups in high conversion and qunatitative yield. Microchannels formed by the catalyst in the cartridge increase the mass transfer between the three phases leading to a more efficient reduction and therefore high yields and conversion. Reactions may be performed from 10mg-100g using the same reactor, but different size cartridges.
The device offers numerous advantages over batch systems.
- Due to the small channels involved, the amount of substrate reacting at any one time is very small, making the reaction much safer and easier to control in terms of temperature and pressure.,- A filter system placed at either end of the catalyst cartridge separates the pyrophoric catalyst from the substrate removing the need for filtration.,- Analysis can be conducted while the reaction is on-going. Temperature, pressure, and flow-rate can then be changed to react to any analytical result. Optimization is therefore simple and rapid, with up to 60 different sets of conditions analysed in one day.
In addition, the device can also be incorporated into an automated liquid handling system. This allows a large number of small-scale compounds to be automatically injected into the device at timed intervals and the hydrogenated products collected in different fractions. This technology would be highly useful for the pharmaceutical industry, where the reduction of large numbers of compounds as a last synthetic step has not yet been exploited.
It is hoped that with the improved safety, the adaptability to automated technology, and faster reaction optimization, the adoption of this method will make hydrogenation a more accessible and versatile process.

Länder

Hungary