Our customers frequently ask us "What's a good reaction to work on to convert from batch to flow mode?"
Although the answer may seem simple enough to those readers experienced in flow chemistry, it can be overwhelming for newer chemists. We try to summarise some of our heuristics and thumb rules on this topic:
- Go for the largest tonnage products. Impact is often highest when you can free up max capacity of batch reactors.
- Choose reactions where a reactant, product or intermediate is particularly nasty. Nasty could mean toxic, unstable, flammable or something similar. This rule may seem count intuitive but the goal behind this strategy is to reduce on site inventories of the nastiest chemicals. Ask yourself: would the Bhopal gas tragedy been as bad if they only had a few kilos of MIC?
Image source: NDTV
If you need further heuristics for what counts as a “nasty” chemical (from the acute toxicity viewpoint) see the table below.
- Choose reactions that are heat or mass transfer limited. Those are limitations that can be overcome using high intensity flow reactors.
- Focus on steps that are using very high T or P conditions. A flow reactor will usually be much lighter and cheaper for systems like this.
- Finally, do not blindly use the same T P conditions you are used to using for batch mode. Flow chemistry yields maximum advantages when applied in conjunction with process intensification!
Again, talk to our experts at Amar for more guidance! Do not miss our upcoming flow chemistry workshop!
