A rotary evaporator is widely used in various industries such as in the medical industry, the chemical industry as well as in laboratories for production as well as for scientific research. Any industry that handles a reaction solvents utilizes a rotary evaporator or a rotovap as it is typically known.

What Does a Rotary Evaporator Do?

It is an equipment that is used for reduced pressure distillation. It is used to separate solvents from a sample. A rotary evaporator typically consists of a water bath, a rotary flask, a rotary control panel, a condenser, a vacuum pump, and a collecting flask among others.

The flask that is used for heating the liquid mixture keeps rotating. This rotation process and heating under reduced pressure helps in heating solvents to a temperature at which they will normally decompose. The solvent derived from this process is typically so clean that it can be used many times over. Here is how rotary evaporation works.

A rotary flask is filled with the liquid mix containing the solvent and the sample. It is lowered into the water bath and submerged partially. The water bath is then heated and brought to the desired temperature. This rotary flask is attached to a mechanism that slowly rotates this flask.

A vacuum pump is used to reduce the pressure in this airtight system. This helps in preventing the escape of volatile vapors into the air as that might create a potentially dangerous situation. The motor attached to the rotary flask keeps rotating at a set speed. A heater helps in keeping the water bath at a steady temperature.

The water bath is heated to a temperature which is enough to evaporate the solvent in the rotary flask. The rotary flask is used in this process to make the process more efficient. When it rotates, it creates a thin layer of the liquid mix on the glass surface and when this thin layer comes in contact with the water bath, it results in even distribution of heat which leads to even evaporation of the solvent. In this manner, the solvent keeps vaporizing and moves upwards into the condenser part of the rotary evaporator.

The condenser is made of a self-contained chamber that contains a chiller fluid running through a pipe in a spiral pattern which helps in maximizing the surface area of the chilled surface. When the heated vaporizer comes in contact with this chilled surface, it immediately cools down and gets collected in the connected flask after returning to liquid form. When all the solvent has evaporated from the rotary flask, only the sample remains behind. This process produces a solvent which is so pure that it can be easily reused many times.

The biggest advantage of using rotary evaporation is that it helps in supplying consistent and even heat to the liquid mixture. This process helps in creating smoother and even distribution of heat which helps in maintaining a uniform temperature without any risk of overheating. The evaporation is carried out under vacuum as it helps in bringing down the boiling point of liquids that are to be evaporated.

By bringing down the boiling point, you can extract the liquid solvents without using extreme heat which can have an adverse effect on the sample as well as the condensates. Simply put, it works in reverse the way a pressure cooker works as a pressure cooker helps in increasing the boiling point whereas heating under vacuum helps in decreasing the boiling point.

One of the biggest advantages of rotary evaporation is that it is significantly faster as compared to the open-air evaporation methods. Another big advantage of this method evaporation is that it helps in preventing any unwanted reactions from the atmosphere and keeps the noxious fumes produced during vaporization contained within the setup.

As far as buying a rotary evaporator is concerned, there are many different types of rotary evaporators available in the market. Though you shouldn’t have a problem with any rotary evaporator made by accredited manufacturers, it is essential to make sure the equipment has been thoroughly tested and has received the necessary certifications. The major difference between different products is typically in their volume and output. Another thing that differentiates between different models is the control levels of the rotary motor and the heater. It should allow you precise control.