10 things you may not know about continuous flow chemistry

To continue the “10” theme in celebration of Syrris India’s 10-year anniversary this month (April 2019), this post covers 10 things you may not know about continuous flow chemistry!

1. Do you know what flow chemistry actually is?

Flow chemistry is the process of performing chemical reactions in a tube, capillary, or microstructured device (a flow reactor).

Compared to a traditional batch chemistry reactor where reagents are mixed together in a vessel, flow chemistry systems use a pump to push reagents through tubes and into a flow reactor where they are mixed and instantly heated or cooled using a temperature control module.

Various flow reactor types are available, including glass microreactor chips, tube reactors, and solid-phase column reactors or packed bed reactors.

Read our “What is flow chemistry? How do flow chemistry systems work?” blog post for a detailed breakdown, or watch our “Introduction to Flow Chemistry and its First Principles” on-demand webinar

2. Do you know why you should perform your chemistry on continuous flow?

Chemists in all industries are introducing continuous flow techniques into their labs, but are you aware of the benefits your lab will see by performing chemistry in continuous flow? There are 9 main benefits that continuous flow chemistry offers; click links below to discover more.

• Faster reactions
• Safer reactions
• Faster reaction optimization
• Fast serial library synthesis
• Reaction conditions not possible in batch
• Reactions are usually more selective
• Scale up is easier in flow than batch
• Easy integration of reaction analysis
• Reactions are easier to work-up in flow

3. Continuous flow polymerization is possible!

Though the idea of performing polymerizations in tubes may sound counter-intuitive, chemists are successfully doing just that.

The key aims of polystyrene production methods are high molecular weight, narrow molecular weight distribution, good productivity, and high conversion rates of the styrene monomer to polymer. Using a Syrris Asia Flow Chemistry System, Professor Ardson dos Santos Vianna (Department of Chemical Engineering, São Paulo State University) enabled a new polystyrene production technique that offers good conversion of the styrene monomer into a high molecular weight polymer, a narrow and reproducible molecular weight distribution, and improved productivity compared to traditional batch methods. This technique produces high-quality polystyrene in a more efficient and reproducible way than other techniques.

Read the full article on Speciality Chemicals Magazine here, and read our “Improving polystyrene production with continuous flow chemistry” blog post here.

4. Flow chemistry makes electrochemistry and photochemistry easily accessible

Reagentless chemistries – such as electrochemistry and photochemistry – are notoriously difficult for chemists to perform accurately. The high levels of control that continuous flow chemistry systems offer make these chemistries easily accessible.

Electrochemistry techniques in the past have relied on electrolysis in glass reactors that lead to poor reaction control, low selectivity, and reproducibility and slow reaction rates. These systems can be easily set-up but because of the reasons stated above, there has been a reluctance to adopt them.

Electrochemistry is a surface phenomenon, meaning large surface area to volume ratios are required; this lends itself to continuous flow chemistry systems as flow chemistry reactors have a large surface area to volume ratio compared to equivalent volume batch reactors. Read our “Electrochemistry made easy with continuous flow chemistry techniques” blog post for a detailed breakdown of performing continuous flow electrochemistry.

5. Continuous flow biocatalysis is on the rise – for good reason!

The area of continuous flow biocatalysis is fast becoming a key area of focus for chemists with applications in the production of fine chemicals, drugs, biotherapeutics, and biofuels to name a few.

The graph below shows the total number of patents and publications in continuous flow biocatalysis since 2000. 

In traditional biocatalysis systems batch stirred tank reactors are the most common method and rightly so as this is the most widely available type of reactor. This method, however, has relatively low volumetric productivity and the collision of the enzyme with stirrers and impellers causes degradation and attrition of the enzyme.

Flow chemistry, however, offers several advantages over traditional methods, including;

• Increased rates of biotransformations: due to its increased mass transfer, flow chemistry makes biocatalysis more economical by decreasing reaction times and increasing throughput of material
• Immobilization of enzymes allows for better stability, reduces product purification, allows better control of substrate contact time and its recyclability reduces costs and extends their applicability for production

Read “The rise of biocatalysis in continuous flow” blog post here.

6. Continuous flow nanoparticle synthesis offers multiple benefits over traditional methods

Nanoparticles are used in a wide range of fields because of their physical and chemical properties, resulting in a growing demand that challenges chemists to provide a reliable supply of large amounts of good quality nanoparticles

Various chemical methods have been applied to produce nanoparticles in batch, but these all present problems: non-homogeneity in mixing, the importance of aging, the difficulty of accurate temperature control and questionable reproducibility from batch to batch. Often a batch process relies as much on the skill of the chemist as on the chemistry itself.

All of these issues become even more difficult to address when scaling up the manufacturing. Flow chemistry offers a number of advantages that help to overcome these challenges;

• Fast and reproducible mixing
• Accurate reaction control
• Excellent temperature control
• The ability to carry out pressurized reactions
• System modularity
• Easy scale-up

Read our “Continuous flow microreactors in nanoparticle synthesis” blog post for a full run-down of the benefits continuous flow chemistry techniques provide nanoparticle chemists with.

7. Chemists are drastically improving old chemistries through continuous flow

There are plenty of examples we could use here, but one that really stands out is the work by researchers at the Kappe Lab who have developed a continuous flow procedure for synthesizing Ciprofibrate – a drug used for the treatment of various blood diseases – which replaced hours of vigorous batch stirring with a 4-minute residence time. The conversion of batch to flow improved safety, speed, yield, and scalability of an existing process. Read more in this open access paper.

8. Solid phase catalysis is possible in continuous flow

Contrary to some chemist’s beliefs, it’s possible to perform solid phase catalysis in continuous flow thanks to packed bed or column reactors that allow the chemist to flow the liquid phase through a column reactor packed with solid phase catalyst. This blog post by Syrris Support Technician, Neal, explains how.

9. Converting your batch processes to flow – or introducing continuous flow in your existing setup – doesn’t have to be a difficult task

Sometimes the biggest hurdle for chemists adopting flow chemistry is the time it takes to convert a batch process into a seamless flow set-up – but it doesn’t have to be! Whether you want gradual or immediate adoption, this blog post covers the 7 main things you should consider when you are looking to convert your batch process into continuous flow.

10. Continuous flow will continuously grow

With the FDA’s recent approval of continuous flow production processes, the need for lab’s to investigate and introduce continuous flow processes is ever-increasing to keep up with the competition thanks to the accelerated production, reduced energy needs, reduced waste, and minimized risk of human error that continuous flow provides.