All About Flow Chemistry
Instead of batch production, flow chemistry is a type of chemical reaction that is basically running in continuous flow stream. To make it simpler, pumps are moving the fluid into the tube and where the tube joins in one another, fluids get contact to each. 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.
In most instances, continuous reactors are tube-like and at the same time, manufactured from polymers, stainless steel as well as glass because they’re known to be non reactive material. When it comes to the method of mixing, it can be either of the two, static mixers or diffusion. 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, the reagents are pumped slowly and/or it is using bigger volume reactor to be able to attain longer residence time.
When it comes to production rates, this can be 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. When talking about aspirator reactor, pumps are used in propelling one reagent that will then suck the reactant.
Smaller scale of micro-flow reactor or the micro reactors may just be perfect on process development experiments. Even though, it is feasible to operate flow chemistry at ton scale, the synthetic efficiency benefits from the mass transfer and improved thermal as well as mass transport.
Processes development is changing from serial approach to parallel. Now when talking about batch, the chemist is going to work first and then, they’ll be followed by a chemical engineer. In flow chemistry, this changes to parallel approach where chemist and the chemical engineer is working interactively. Typically, there’s plant setup in lab wherein there’s a tool intended for both. Be it non commercial or commercial setting, this set up can be useful.
It’s feasible as well to run experiments in flow chemistry using more complicated techniques like solid phase chemistries while solid phase reagents, scavengers or catalysts may be used in the solution and be pumped through glass columns.