How big is a reactor?
Peschke: The size of our current prototypes here at the Institute of Professor Niemeyer is about 7.5 cm x 2.5 cm with a volume of 150 microliters. They are very tiny but you can essential apply this to other dimensions.
What dimensions would you need to facilitate industrial use?
Peschke: It depends on how much product you have to generate. Some methods have shown that you can easily batch several of these reactors in parallel. In other words, instead of entirely new complex process calculations with a larger reactor, you just increase the number of microreactors. This is called parallelization. You use linear extrapolation of the process and subsequently obtain the needed dimension.
Rabe: In the industrial sector, parallelization of reaction units in pure chemical syntheses is quite common. However, it was previously impossible to do this with biological catalysts because you could not get them into a form that allows them to be continuously active in the flow reactor. Our method shows that you can operate the reactor with enzymes for weeks.
Does this mean that the technology to use your procedure is already available?
Rabe: Yes, the technology is available and there is also interest in using enzymes.
Peschke: We take several industry developments like microreactor technology into account in this setting. Several processes have shown that it is better to take a small reactor and connect several of them in parallel. This facilitates more controlled reaction conditions because microreactors enable more effective heat transfer and better mass transport. That’s also why some industrial processes are now conducted with microreactors. Another thought was that large-scale factories are not necessary to produce specialty chemicals that don’t require mass production. Portable factories are a conceivable option in the form of containers for example. In this case, you could connect multiple reactors, allowing you to set up the container where the material is needed. This facilitates on-site production and eliminates large-scale facilities in one place that supply the global market.
Rabe: Chemicals that are produced on a mass scale will not be produced in these types of reactors anytime soon. That’s because crude oil is unfortunately still unrivaled in this setting. Having said that, the process is suitable for plastic building blocks, medication or cosmetics that involve multiple reactions or a fairly complex synthesis. In a manner of speaking, you front-load the basic materials, processes subsequently take place inside the successively connected reactors and out comes the desired product.