When talking about flow chemistry, this is a chemical reaction that runs in continuous flow stream rather than batch production. For you to understand things a lot easier, the pumps move the fluid in the tube and by the time that the tubes are connected, the fluid forms into one. In case that the fluids are reactive, there will be a spike in reaction.
Flow chemistry is a known and proven technique to use for big scale projects especially when manufacturing big quantities of given material. However, it was just recently when the term is coined after the application on laboratory scale. More often than not, micro-reactors are put into used.
Continuous reactors are also manufactured by using non reactive material such as glass, stainless steel and polymer and also, mostly tube-like. As for the mixing methods, this can be through diffusion or static mixers. The continuous flow reactors create good control on the reaction condition which include time, mixing and heat transfer.
Residence time of the reagents in reactor or simply the amount of time that the reaction needed to cool or heat is observed from the reactor’s volume and at the same time, by checking the flow rate through it. For this reason, in an effort to attain longer residence time, the reagents may be pumped slowly and /or bigger volume reactor is put into used.
The production rates are going to vary from liters per minute to nano-liters per minute.
Few examples of the flow reactors are spinning tube reactors, spinning disk reactors or otherwise called as Colin Ramshaw, oscillatory flow reactors, multi cell flow reactors, microreactors, aspirator reactors and hex reactors. Now for the aspirator reactor, there’s a pump that’s used in order to propel the reagent that is going to suck the reactant in.
Smaller scale of micro-flow reactor or the micro reactors may just be perfect on process development experiments. Although, it is possible to operate flow chemistry at bigger scale, synthetic efficiency benefits from mass transfer as well as improved thermal and also, mass transport.
Process development changes from using serial approach to parallel. In regards to batch, the chemist will be working on it first and then, a chemical engineer will follow once they’re done. Now for flow chemistry, this changes to parallel approach to which both the chemical engineer and the chemist are working side by side. In addition to that, there is a plant setup in which there is a tool designed for it. This particular set up may be used either for non commercial or commercial setting.
It is also possible to make experiments in flow chemistry that utilizes more complex techniques similar to solid phase chemistries while solid phase reagents, scavengers or catalysts might be integrated in the solution and then, pump it on glass columns.