Andrew Mansfield Head of Flow Chemistry, Syrris

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What is flow chemistry? How do flow chemistry systems work?

By on June 22nd, 2018 in Batch chemistry, Flow chemistry {Edit}

This blog post is the first in a series of “flow chemistry learning” posts – simply subscribe to stay updated with the latest!

Famous chemistry professors are doing it. Magazines are writing about it. Students are focusing on it. Research and development chemists are perfecting reactions with it, and scale-up chemists are producing products with it.

You’ve undoubtedly heard about flow chemistry, but unless you’ve used our R&D100 Award-winning Asia Flow Chemistry System, you might still be wondering – what, exactly, is flow chemistry?

The basics of flow chemistry

Though it goes by a number of names – “plug flow chemistry”, “microchemistry”, and “continuous flow chemistry” – the principles of flow chemistry are the same.

Flow chemistry is the process of performing chemical reactions in a tube or pipe

What this means is that reactive components are flowed down temperature-controlled tubes or pipes and mixed together at a mixing junction; a radically different approach from the traditional chemistry method of performing reactions in glass flasks or jacketed reactors.

The differences between plug flow and continuous flow chemistry

Though often used interchangeably, there is a small difference between “plug flow chemistry” and “continuous flow chemistry”.

Continuous flow chemistry is just that – continuous. The reactive materials are continuously pumped with no breaks, resulting in a continuous stream of chemicals, and therefore a continuous stream of end product.

Plug flow chemistry is where alternating “plugs” of reactive materials and solvent are pumped, where each plug is considered as a separate entity. These plugs never meet so the conditions in which they go through the flow chemistry system (i.e. temperature and residence time) can be changed to observe how the reaction changes.

Intelligent systems, such as the Asia Flow Chemistry System, can automatically collect the individual plugs, sending the product into one collector and the solvent into another.

What is a mixing junction?

So what do we mean by a “mixing junction”? Essentially, it’s the equivalent of a round-bottomed flask or a jacketed reactor – it’s where the mixing occurs in a flow chemistry system.

The two (or more) separate tubes of reactive compounds are brought together and flowed through a single, temperature-controlled channel in order to mix them.

What types of mixing junctions are available?

Glass microreactor chips

Glass microreactor chips are the most commonly known type of reactor used in a flow chemistry system. A piece of glass is “etched” with a particular design (depending on the application); the design helps determines how wide the mixing channel is and how the mixing occurs. A longer channel enables a longer residence time than a shorter channel (assuming the pump flow rate is the same).

Glass microreactor chips are inserted into chip climate controllers which maintain a set temperature throughout the entire chip and are the perfect system for chemists just starting out in flow chemistry.

Tube reactors

Tube reactors are effectively long tubes wrapped around a heated or cooled coil. The large length of the coil offers far longer residence times than glass microreactor chips (or much faster pump flow rate) if the application requires it.

Column reactors

Column reactors are glass tubes and allow the use of solid phase chemistry such as catalysts, solid-supported reagents, or scavengers.

So why are chemists adopting flow chemistry into their reactions?

FYI – We’ve put a whole blog post and infographic together to explain the 9 main benefits flow chemistry offers. Read it here.

There are a number of reasons chemists across all industries are introducing, or switching to, continuous flow chemistry.

In short, the main benefits are;

When is continuous flow chemistry not the answer?

Coming soon…

The importance of smooth flow

Coming soon…

About Dr. Andrew Mansfield

Andrew was formerly a Research Chemist at Pfizer and spent much of his career focusing on introducing flow chemistry technologies, meaning Andrew is well placed to lead Syrris’ flow chemistry offering. Read Andrew’s bio here.

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