Reactions feel the pressure in enclosed spaces

The device was designed by researchers at the University of Twente, the Netherlands, and can withstand pressures of up to 600 bar with continuously flowing substances. "Chemical reactions in microreactors is the future of exploratory chemistry as a whole - especially in drug discovery chemistry,"​ said Professor David Reinhoudt, supervisor of the project. He continued by explaining that the need for smaller quantities of reagents were the driving force behind the push for microfluidic chemistry reactors, especially as the technology could allow multiple tandem reactions to be conducted on a single chip. The group initially studied a range of reactions that are accelerated by increased pressure such as substitution reactions. Microfluidic chips allow users to monitor a reaction while it is in progress by sampling the flow as it passes these ports. Reinhoudt did caution that these ports were often a bottleneck especially at such high pressures. Fernando Lopez, the lead author of the work, found that tube-like structures that were coated with fluorocarbon compounds worked best for many applications as they deactivate the surfaces and also eliminate surface effects. Reinhoudt told LabTechnologist.com that the next major goal for the technology is to couple catalysts to the surface of the channels which have very high surface areas, allowing for efficient catalyst / substrate contact. The group are using a supramolecular approach, previously developed in the group, to attach the catalysts to the surface, by first functionalising the surface with a 'host' compound that can attach a 'guest' catalyst. The benefit of this approach is that the attachment is reversible and that the catalyst for one reaction could be specifically attached before it is removed and replaced with the right catalyst for another. Reinhoudt said that if several different 'hosts' are attached along the length of the microfluidic device it may even be possible to conduct multi-step catalytic reactions within one device. He continued by mentioning that reactions in supercritical CO2 (sCO2) were very effective in the device, with sCO2 having the advantage of being a "nice and environmentally friendly solvent." ​ The research team also managed to attach on-line monitoring systems to the device, such as mass spectrometers (MS) and nuclear magnet resonance (NMR) instruments. The group has previously designed a multichannel chip with an integrated NMR detection coil that allowed on-line reaction monitoring of specific reactions.