Rotary evaporators are common laboratory equipment mainly composed of a motor, a rotating flask, a water or oil bath and a condenser tube and other components. It is an essential equipment for concentration, crystallization, drying, separation and solvent recovery in pharmaceutical, chemical and bio-pharmaceutical fields and other fields. As for the distillation, it refers to a purification method for liquids, which can separate components or substances with different boiling points in a mixture, mainly used in industry and laboratory research. Next, the advantages of a rotary evaporator over the distillation will be further discussed.

Evaporation VS. Distillation

Many people consider that evaporation is the same as distillation, but actually there are some differences between them. It can be said that evaporation is preferable comparing to the distillation in most cases. The advantages of a rotary evaporator over the later are as follows: higher efficiency, better accuracy and convenience. Besides, a rotary evaporator is capable of avoiding local overheating due to the special rotating bottle, while the distillation has the disadvantage of local overheating, Hence, the evaporation is used more often than the distillation in many fields.

re501 rotary evaporaator — RE501 Rotary Evaporaator

Primary Use of a Rotary Evaporator

A rotary evaporator (rotovap or rotatvap) refers to a kind of equipment for solvent evaporation under reduced pressure. It can be used for the process of evaporation, concentration, crystallization, drying, separation, and solvent recovery. And the primary use is to continuously distill large amounts of volatile solvents under reduced pressure.

Primary Advantage of a Rotary Evaporator over Distillation

Higher efficiency, together with better accuracy, is the primary advantage of using a rotary evaporator over distillation.

A rotary evaporator is electronically controlled so that the rotation of the flask can be kept at a constant speed, and the mixture can form a film on the inner surface of the flask, creating a larger surface for heating. All of these factors contribute to the faster evaporation speed of solvent, which means higher efficiency and better accuracy.

But the distillation is less efficient and accurate than a rotary evaporator. When adopting the distillation, a mixture is heated to the temperature at which one component will boil. Then the vapor from the hot mixture is collected and recondensed into liquid, which is fast. But actually many kinds of mixtures cannot be separated this way.

Therefore, comparing to the distillation, a rotary evaporator is more widely used in the chemical laboratories, industrial, bio-pharmaceutical and food-making fields.

Can a Rotary Evaporator Remove Water?

A Rotary evaporator is widely used to remove water from materials so that substances can be concentrated. It is commonly seen in kitchens, such as the concentration of the fruit juice. There are other examples of removing water from substances as well.