Reasons for Suck-back Phenomenon of Rotary Evaporator

Rotary evaporators, as a kind of commonly used equipment in laboratories, are mainly used for continuous distillation of volatile solvents under reduced pressure, and are used in chemistry, chemical engineering, biomedicine and other fields. Why does the rotary evaporator appear to suck back during use? Today, I will list the causes of the suck-back phenomenon of rotary evaporator here.
 
Main reasons for the suck-back phenomenon of rotary evaporator:
1. It may be that the temperature is too high. Too much solution is added, and the vacuum is too high. When conducting suction filtration or rotary evaporation, you must first unplug the tube or open the valve to vent, and then turn off the vacuum pump to prevent the suck-back. During evaporation, if the pump suddenly shuts down, a suck-back  phenomenon will occur.
2. The boiling points of the two are too similar, so they are not easy to separate. Too much concentrated liquid is added, and it will cause high vacuum and high alcohol content.
3. Check whether the heating temperature is too high, and it is necessary to confirm whether the solution to be evaporated in the flask was splashed out due to bumping or real suck-back phenomenon.
4. The solvent bumping will produce bubbles, which will be sucked into the collection bottle. This is generally due to too much concentrated liquid, resulting in too high vacuum and alcohol.
5. Is there any process in the middle? It is impossible for the solvent to be placed in the flask for a while to produce suck-back in the collection bottle. Even if the amount of the concentrate is small, it will produce foam and then bump. High alcohol content will also cause bumping.
6. The high water content of the distillate can also cause bumping, and another reason is that the part of the distilling flask soaked in water is relatively deep.  
 
Rotary evaporator is an evaporation instrument widely used in laboratories. It is suitable for reflux operation, rapid evaporation of large amounts of solvents, concentration of trace components and reaction processes that require stirring. Rotary evaporators are mainly used for concentration, crystallization, drying, separation and solvent recovery in pharmaceutical, chemical and biopharmaceutical industries. The modern rotary evaporator can be used to quickly and gently distill most samples, even by operators with no operating experience.