Rotovap evaporator

The rotovap or rotary evaporator is a lab instrument used to remove solvents by evaporation under reduced pressure, essential in chemical synthesis.

About this subject

The rotary evaporator, commonly called rotovap, is a fundamental piece of equipment in chemistry and pharmaceutical laboratories. Invented in the 1950s by Lyman C. Craig, it efficiently removes solvents from liquid samples under reduced pressure and rotation, increasing surface area and lowering boiling points.

Operation combines a vacuum pump with gentle heating of the round-bottom flask immersed in a water bath. As the flask rotates, solvent evaporates, is condensed in a water- or ice-cooled condenser, and collected in a separate flask. This evaporation occurs at lower temperatures, protecting heat-sensitive compounds.

Indispensable for recrystallization, extraction, and sample concentration, the rotovap is used in pharmaceutical, food, and biotechnology labs. Modern models feature digital controls for temperature, rotation, and vacuum, enhancing precision and reproducibility.

A technical curiosity: "Rotavapor" is a trademark of Büchi, the Swiss company that dominated the market for decades, though it became a generic term. Proper glassware and ventilation are critical for safety, especially with flammable solvents and pressure handling.

Frequently Asked Questions

What is a rotovap used for?

A rotovap removes solvents from liquid samples by evaporation under vacuum, used for concentration, purification, and recrystallization.

How is a rotovap different from a simple evaporator?

A rotovap combines vacuum, rotation, and controlled heating for faster, gentler evaporation, ideal for heat-sensitive compounds. A simple evaporator only heats without pressure control.

What safety precautions should be taken?

Use proper glassware, check seals and vacuum connections, never exceed maximum pressure, and operate in a fume hood with flammable solvents to prevent accidents.