The rotary evaporator (rotovap) was invented back in the 1950. Perhaps slightly distrustful of the instrument at first, but soon hooked on its speed and ability to remove large amounts of solvent with little manual work involved.
Just like dishwashers have become a staple in nearly every kitchen, rotary evaporators(rotovap) are found in nearly any chemical laboratory. But did you know you could wash your hairbrush, shin guards and flip flops in your dishwasher? Then are you sure you know all the applications of a rotary evaporator?
Typically, users rely on laboratory evaporation to perform:
- Drying of products
- Extractions under flux
- Freeze-drying sample preparation
- Cannabis applications
- Gin applications
Rotary Evaporators are a vital instrument to research and chemical laboratories. They are very valuable in applications that require efficient solvent removal and distillation. They are based on the principle that solvents have a wide range of boiling points that decrease as pressure is reduced and that materials with lower boiling points evaporate more rapidly which is a critical aspect in its different applications. Due to the distillation efficiency, rotary evaporators are preferred over standard distillation system.
What is rotary evaporation?
A rotary evaporator is a device used in chemical labs that efficiently removes solvents from samples by an evaporation process. These devices consist of the following parts.
- Condensate tube : The condensate tube consists of a double serpentine condenser that uses acetone and dry ice to condense the sample.
- Evaporation flask: The flask evaporates the sample by rotating at a constant speed and temperature.
- Receiving flask : The receiving flask recycles the condensed sample.
- Evaporation tube: The evaporation tube is a rotating support shaft for the sample and the sample is cycled through the vacuum system in the evaporation tube.
- Rotary motor : The rotation of the motor is the force that rotates the evaporation bottle with the sample.
- Vacuum system.The vacuum system lowers the pressure of the rotary evaporator system.
- Bath kettle. The bath kettle heats the sample with oil or water.
How are solvents evaporated in a rotary evaporator?
Solvent evaporation occurs routinely in nature when water gains energy, often as heat, and transitions from a liquid state into a gaseous one. Thermal molecular agitation is what underlies this change, hence you apply heat to water and molecules with energy in excess of the thermodynamic potential escape from the water surface as water vapour. The same principles apply to laboratory and process-based solvent evaporation, but it isn’t always expedient practical? or possible to simply heat solvents to the point of evaporation.
The Importance of Proper Vacuum for Rotary Evaporation
Using a vacuum source with your rotary evaporators comes with a significant set of advantages, like making your processes safer, more efficient, cleaner, and overall, easier. In this blog post, we’re going through all the reasons why owning a rotary evaporator is typically paired with using a vacuum source (either built-in or a vacuum pump).
Depending on the rotary evaporator you’re using, you might already have a built-in vacuum controller and you’ll only need to add a vacuum pump.
Controllable vacuum sources allow you to adjust the pressure with surgical precision, providing you with the desired evaporation rate.
An increase in evaporation rate can therefore be achieved without having to upscale your bath’s temperature, which will allow you to achieve evaporation rates previously unattainable using a bath alone. Using a vacuum source also leads to improved solvent-product separation thanks to the controlled and even evaporation rate. It also decreases the risk of bumping (the formation of bubbles due to hasty boiling of samples; This can lead to your sample splashing out of the flask.).
Setting the Right Rotational Speed for your Rotary Evaporator
When operating a rotary evaporators in your lab, you want to make sure that you’re being as efficient as possible. One of the main factors to be considered is the rotational speed of your rotary evaporator, and while it might seem like maxing it out is your best option, it might not always be the case. You wouldn’t want things to spin out of control now, would you?
Some of the factors that you need to keep in mind when operating your rotary evaporator at its upper rotational speed is mechanical damage to your equipment caused by high speeds, and the decrease in evaporation rates beyond said speeds.
Looking to buy?
If you are looking to purchase a new rotovap evaporator for your lab, we have a wide range of scientific instruments available. Call us for more details and get correct product for your Lab needs.