Benchtop rotary evaporators are used for the efficient and gentle removal of solvents from samples in R&D and QC-scale applications. They are frequently referred to as ‘rotavaps’ and are used to remove solvents from reaction mixtures and can accommodate volumes as big as three liters. As benchtop rotary evaporators perform this task so quickly, they can be found in most organic laboratories across the world.
How do Benchtop Rotary Evaporators Work?
Rotary benchtop evaporators work on the principle that the boiling point of a solvent in question is significantly lower than the liquid it is surrounded by. When pressure of liquids is decreased, their boiling point slowly reduces and means that the solvent can be vaporized at a lower temperature than their standard boiling point. A vacuum space is created in the rotary glass flask as the vacuum system is critical to the evaporation process.
The condenser at the other end aids conversion of the gas back to a liquid form that needs lower temperatures. In order for this cooling effect to work, traditional condensers use either dry ice, glycol, water, or liquid nitrogen. This represents an additional resource cost plus ecological issues and potential safety hazards. At Ecodyst, we recognized these pain points and embarked on a mission to disrupt conventional condenser technology using our own proprietary direct cooling technology.
How are Benchtop Rotary Evaporators Used?
Usually, rotary evaporators have a water bath which can be heated in a metal container or crystallization dish, preventing the solvent from freezing during the evaporation process. The solvent is then removed under vacuum, trapped by a condenser and then collected for reuse or disposal.
The majority of laboratories use a simple water aspirator vacuum on their benchtop rotary evaporators, so these rotary evaporators should not be used for air and water-sensitive materials. In the laboratory vacuum line, a circulation bath or membrane pump is employed as a source for the vacuum, meaning that boiling points of solvents will be substantially lower than ambient pressure.
The flask is rotated throughout the evaporation process, meaning the surface area is larger than normal, substantially increasing the evaporation rate. The solvent is collected in a flask and can be appropriately disposed of afterwards. Using benchtop rotary evaporators also means that overheating of the target is avoided because lower temperatures are used.
EcoChyll rotary evaporators work on a different principle altogether. You can learn more about the working principles of our industry-leading systems in our recent article Rotary Evaporators from Ecodyst.
Uses for Benchtop Rotary Evaporators
The benchtop rotary evaporator is used to concentrate non-volatile components in a mixture. An example of this would be removing water from fruit to concentrate the purest, freshest flavors. They are also used to extract the volatile aroma and flavor molecules gently, without needing to heat the mixture up.
The key difference between benchtop rotary evaporators for distillation when compared with standard distillation is that it can separate food compounds from one another without altering them. This is because the solvent is removed under vacuum, lowering its boiling point and eliminating the need for high-temperature distillation. Additionally, the rotation of the evaporating flask, immersed in a heated water bath increases the surface area of the product which greatly speeds up distillation and keeps the mixture as evenly heated as possible to support even evaporation.
Benchtop rotary evaporators are also used for educational purposes such as research, as well as the production of chemical, biological, and pharmaceutical products. Recently, benchtop rotary evaporators have also been used in the cooking industry for molecular cooking, combining cooking skills with advanced technology. Their use preserves volatile aromatics in food, meaning they are not lost during the process of heating.
Benchtop Rotary Evaporators at Ecodyst
At Ecodyst we produce safe, easy-to-use, eco-friendly benchtop rotary evaporators that have a small footprint and very low operational costs. Contact us today for more information on how our products could enhance your work, or for RFQs on particular configurations.