rotary evaporator system

• Rotary evaporators are used for fast and gentle distillation of most samples.

  Due to the centripetal force and friction between the liquid sample and the evaporating flask, the liquid sample can form a liquid film on the inner surface of the evaporating flask, increasing the heating area.

  The force generated by the sample rotation effectively suppresses the boiling of the sample.

A complete rotovap setup comprises of:

Rotary Evaporator (Solvent Evaporator): Substances can be evaporated from a mixture using the rotary evaporator with little chance of wastage.

Vacuum Pump: It lowers the temperature of the liquids in order to accelerate the process of evaporation.

Temperature Control (Chiller/Heater): Controls and keeps the process at the required temperature. Chillers are used to cool the condenser while warm baths are usually bath heaters.

Cold Trap: This prevents the solvents from reaching the vacuum pump by trapping the leftover solvents.

These components form a complete laboratory evaporators system from a rotary vacuum evaporator factory.

As you procure components for a rotary evaporator distillation system, it is essential to ensure that the parts used are well understood in terms of functionality as well as the specific laboratory evaporators and vacuum distillation system needs. Some of the pertinent factors include the following:

Evaporation flask size: Choose an evaporation flask with a volume that is related to the sample size that is being used, usually, 2 to 3 times the sample volume, to avoid spillage. The common sizes include 1L, 2L, 5L and 10L.

Condenser type: Select a condenser that meets your cooling needs and the nature of the solvents that you will be having. Design options for laboratory evaporators that are common include coil condensers (good for high boiling solvents), cold finger condensers (good for low boiling solvents) and vertical condensers (good for various types of solvents).

Receiving flask volume: Make sure that the receiving flask will capture enough of the distilled solvent that you do not have to keep emptying it too often. Such flasks should likewise, fit within the rotary evaporator distillation setup and be easy to remove for use.

Vacuum pump compatibility: Vacuums pumps that are acceptable to use with the rotavapor which can pump down the desired vacuum for use in the vacuum distillation system should be selected. Things like pumping rate, ultimate vacuum and what the pump is made off as far as chemicals is concerned.

Chiller or circulator: Choose a chiller or circulation device that has enough cooling capacity to maintain the condensation temperature during your rotary evaporator distillation process. Make sure that the lab chiller which you get is compatible with your condenser and has the necessary fittings and pipes.

• University laboratory, commonly used for separation of solvents, concentration and drying of composites, distillation of water, etc.
• Biomedicine, separation and purification, concentration and drying of pharmaceutical liquids, etc., can be used with recirculating chillers and vacuum pumps.
• Petrochemical industry, solvent recycling, vacuum distillation of high boiling point substances, etc.
• Cosmetics, essential oil extraction, low temperature separation, emulsification under reduced pressure, etc.

There are various devices which are regarded as vacuum pumps and used in labs with the rotary evaporator such as diaphragm vacuum pumps, which are free from oil and can be used with corrosive liquids, and water pumps which are cheaper and more versatile. A number of factors must be taken into consideration when choosing a pump:

Degree of vacuum: Give a suitable pressure for the solvents you have.

Corrosion resistance: Non-Corrosive – ensure that pump materials are resistant to rust.

Volume flow rate/vacuum pump capacity: Get one that will accommodate a reasonable size of your lab’s evaporators.

Rotary evaporator uses in the laboratory: Connect the pump to the rotary evaporator for optimal performance.

One of the typical problems while operating the rotary evaporator is cross contamination, particularly during lab evaporation ends which involves the use of solvents. In order to reduce the cross-contamination risks between the different distillations, use the following measures:

Thorough cleaning: Ensure that all parts, such as the evaporation flask, receiver and condenser, that had contact with the sample or solvent from rotary evaporator are cleaned every time after using it. Scrub the surfaces with appropriate detergent and cleaning solvents and thoroughly wash with distilled or deionized water.

Dedicated glassware: Whenever possible, limit the use of certain types of glassware (evaporation flasks, coarse filters, and receiving flasks) to a set of specific solvents or samples in order to avoid possible contamination. This is critical when solvent evaporates from sensitive high purity samples in your solvent evaporation process.

Solvent recovery system: To reduce the need of using fresh distilled solvents, convert the available receiving flask into a solvent recovery system for collecting the distilled solvents in your rotary evaporator machine setup which can be reused. This reduces cross contamination due to any solvent residues that are likely to be present in the vacuum system and the receiving flask.

Cold traps: Insert cold traps in-between the condenser and the vacuum pump in order to ensure that any evaporated solvent vapor does not reach the vacuum pump. As a result, this will help to avoid contamination of the vacuum system and also extend the service period of your vacuum pump.

Vacuum pump maintenance: Always service and clean your vacuum pump so that it doesn’t have traces of previous solvent. Employ a cold trap or solvent recovery system to reduce the volume of solvent that goes into the pump during the laboratory evaporation processes.

Proper ventilation: Make sure that the rotary evaporator machine is sited in a sufficient area with proper ventilation, to avoid building-up of the solvent vapour which may result to cross-contamination. To avoid vapours generated during solvent evaporation processes from spreading, there triggers a necessity to employ gas-phase management devices like fume hoods or local exhaust ventilation systems.

Quality control checks: Check every single solvent that you distill to ascertain if appropriate purification levels have been attained on a regular basis. This will depend on cross-contamination issues at a later stage where corrective measures will be implemented.