The 20/40/60 Rule for Solvent Removal

The use of rotary evaporators for solvent removal has become very ubiquitous. However, to achieve optimal distillation conditions and avoid bumping, users should follow the 20/40/60 Rule, which is a general guideline recommended for the operating conditions of rotary evaporators.

The water bath temperature is Set at twenty degrees higher than the desired vapor temperature and the condenser temperature is Set at twenty degrees lower than the vapor temperature. For example, with an operating bath temperature of 600C, the vacuum should be adjusted properly for each solvent to yield a solvent vapor temperature of 400C which is subsequently condensed at 200C.

To avoid bumping:

  • Always fill your sample flasks with less than 50% full.
  • Faster spin rates could help preventing bumping.
  • Moderate bath temperature is recommended because high bath temperature may lead to excessively fast evaporation and bumping.
  • Best to consider a vacuum controller system that allows accurate adjustment of system pressures at optimal conditions to eliminate bumping.

Good evaporation practices:

  • Once the majority of a solvent has been removed, empty the collection flask. Reattach and continue with the evaporation. This helps drying the samples thoroughly.
  • Empty the collection flask when evaporation is done. Leaving organic solvents in the collection flasks may cause degradation of components in rotary evaporators over the time. Also, the solvents left in collection flask may be unknown to the next user, so it is not safe for the next user to handle the solvents.
  • Use only clean water in the water bath, and immediately change water and if the water bath has become scummy.

Other Safety Precautions:

  • Inspect all your glasswares prior to usage to avoid implosion.
  • Don’t use sample and flasks with visible or star cracks to avoid breakage and loss of samples.
  • Reagents are dangerous if inhaled. Not all 100% highly volatile solvents could be condensed in the traps, therefore the rotary evaporator should be kept in the fumehood if dealing with dangerous solvents and reagents.

EYELA is a reliable brand name for rotary evaporators. We are supplying State-of-the-art models with different sizes that could match a wide variety of applications. EYELA is made to last with very durable body, easy operation and attractive functions.

 

Our basic model EYELA N-1300 has the following key features:

Contact us @enquiry.sg@thermofisher.com if you are looking for a rotary evaporator.




 

 

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