In this video we give a how to guide on drying a jacketed jab and associated glassware in situ, prior to use.

All wetted apparatus including glassware should be clean and dry before starting any chemical process. On a small scale, glassware like round bottom flasks, pressure equalised feed funnels, condensers etc are often dried in a vacuum oven. This applies a gentle heat and a vacuum for an appropriate time, to remove any moisture which might affect the chemistry.

The exact procedure detailing what the temperature should be, what level of vacuum and for how long, is usually described in a standard operating procedure (SOP) which can be supplied by the lab supervisor.

As the processes scale up, it becomes more cumbersome to dry glassware in the same way. The apparatus gets larger and heavier, manual handling becomes more difficult and vacuum ovens would also need to be bigger, taking up more space in the lab.

Therefore, it is common practice with larger glass reaction systems, to dry and purge all apparatus in situ.

This has many practical benefits, saving time and adopting safer working practices.

By NOT having to remove a vessel and its overhead accessories such as condensers, reflux dividers, feed vessels from the framework, the risk of damage to the glass is significantly reduced.

Once the entire system is clean and dry, it is often a good idea to purge with a dry gas like Nitrogen or Argon, having a slight positive pressure to minimises the risk water contamination before the system is used.

Typically, a vacuum manifold assembly or Schlenk manifold is available in the fumehood to connect both vacuum and Nitrogen, switching between the two using valves integrated in the manifold. The manifold is often connected to the top of the condenser, or a port on the lid of the reactor. The slight overpressure safely vents via a bubbler or pressure relief valve in the system.

Drying and purging chemical reaction systems is a requirement in most scale up chemistry processes. Contamination and cleanability of chemical reaction systems is a subject for consideration when choosing which apparatus is most appropriate for a given application.