What You Need to Know About a Rotary Evaporator

rotary evaporation

Don’t let the sophisticated name intimidate you. A rotary evaporator is simply a machine that is typically found in chemical laboratories. Among its uses is separating the solvent from samples through evaporation. Another application of the rotary evaporator is molecular baking in preparing extractions and distillations.

Craig around the early 1950s produced the prototype of the device. The Swiss company later on came and commercialized it around 1957. Currenty we have brands like WKIE LAB – The reliable rotary evaporator manufacturer on the market. The rotary evaporator comes in different forms, such as the one litre benchtop unit. Another form is the large scale twenty and fifty-litre version that is used in large scale commercial chemical plants.

How Is It Designed?

The device may appear complicated, but when you break it down it is more understandable. A few of the necessary apparatuses are;
• One motor which spins the evaporation jar that features the user’s sample.
• One vapour vent which acts as the center for rotation
• One vacuum system which reduces the amount of pressure in the system.
• One fluid bath (containing water) to warm up the sample
• One condenser containing a coil
• One flask for collection at the bottom to hold the solvent prior to it re-condensing
• One device to quickly lift the evaporation flask from the heat-bath

Why Use Them?


These types of evaporators are commonly used when trying to separate low boiling point solvents. A good example is ethyl acetate and hexane. Such solvents are generally solid at room temperature. Solutions with high boiling points such as water can also be evaporated if the machine is tweaked to perfection.
The advantages that go about using this are;
• The force of centrifuge in the evaporator force a thin film of water to be spread over a large surface
• It allows for smooth and rapid evaporation of solvents from original samples
Disadvantages;
• It can only work one sample at a time
• When sample types crush into each other, they result in loss of substances intended to be retained

Safety Measures

It is advised only trained chemists and lab technicians to handle the rotary evaporator to avoid accidents. Explosions and burns may occur if handled carelessly. It is therefore keen to ensure you wear gloves, laboratory glasses, and a lab coat. One is also encouraged to have a fire extinguisher that is powder-based nearby in case a fire occurs. Also, seek assistance in case you are faced with any challenge.

I hope that this article proves helpful in giving you the necessary information on rotary evaporation.