A Rotary Evaporator is a device used in Extraction laboratories for efficient and gentle distillation of solvents from samples by evaporation. Rotary evaporation is most often and conveniently applied to separate “low boiling” solvents such a butane or ethyl alcohol from compounds which are solid at room temperature and pressure. However, careful application of reduced pressure allows for removal of a solvent from a sample without degrading the product. Reducing the pressure speeds up the process by lowering the boiling point of the components in the boiling flask allowing the lowest temperature distillation possible. The rotating 10,000 ml boiling flask throws liquid up the sides forcing more of the liquid to be exposed to the surface area and transferring more heat efficiently. The combination of reduced pressure and efficient heat transfer make this distillation apparatus perfect for quick industrial separation.
Working principle of rotary evaporator
The distillation flask of the rotary evaporator can be a pear-shaped or round-bottomed flask with a standard ground port, connected to a pressure reducing pump via a highly refluxing serpentine condenser, and another opening of the reflux condenser with a receiving flask with a grinding port. Connected to receive the evaporated organic solvent. There is a three-way piston between the condensing tube and the decompression pump.
When the system is connected to the atmosphere, the distillation flask and the liquid-receiving flask can be removed and the solvent is transferred. When the system is connected with the decompression pump, the system should be reduced. Pressure state. When using, depressurize first, then start the motor to rotate the distillation flask. At the end, stop the machine first, then pass the atmosphere to prevent the distillation flask from falling off during rotation. As a heat source for distillation, the rotary evaporator can be combined with a circulating water type multi-purpose vacuum pump, a diaphragm vacuum pump, a low temperature circulation (vacuum) pump, a circulation cooler, a constant temperature circulator, a low temperature coolant circulating pump, and the like to form a system device.
You may often meet the below problems when operate rotary evaporator:
1. Low receiving rate while evaporating is good.
2. Vacuum pump being corroded.
3. Harmful gas escaping.
4. Sudden solvent bumping.
Rotary evaporator system vacuum degree is higher than normal is the possible reason. If vacuum degree is too high, will cause solvent steam temperature is too low so couldn’t be collected efficiently. Release vacuum is need, but other problems will happen if vacuum degree is too low.
How to avoid these problems?
Choose one suitable rotary evaporator is most important, the below professional advice for how to choose right rotary evaporator, you need to know:
1. What’s the most important performance of rotary evaporator?
Air impermeability is the first important performance of rotary evaporator, which directly affect rotavapor normal
operating and service life. Air impermeability is good or not is decided by suppliers’ design standard, manufacture
standard and material choice, etc. “Actual vacuum degree” and “vacuum pressure maintaining time” are the measuring standard.
2. What’s the difference of glass lifting and bath lifting?
Bath lifting is more safe, the glass parts matched with rotary evaporator are not easy to be damaged, don’t need to
lock after lifting finished. Glass lifting is mainly suitable for the rotating flask which has fixed size, lifting height is fixed, after finish lifting, need to lock.
3. #29 and #24 Evaporation bottle grinding mouth, choice which type is better?
ISO #29 and ISO #24 both are the standard mouth for laboratory. ISO #29 has high strength and convenient to clean, is more suitable for imported rotary evaporator, and also benefit you to choice flask move device.
4. Which type vacuum pump is most suitable for rotary evaporator?
Vacuum pump is the prerequisite device for rotary evaporator, TOPTION provide SHB-III vacuum pump for 1L ~ 10L
laboratory rotary evaporator, SHB-B95 vacuum pump for industrial roatry evaporator, and 2XZ also supplied for
rotavapor, etc. But using cold trap or other methods provide corrosion protection is more better.
5. In which situation, condensation effect is best?
Tap water temperature changes as different season, its temp. is higher in summer, so solvent recovery efficiency is low, and tap water will make condenser change color and scale formation.
You could choice the below two lab solutions:
1) The best solution: equip appropriate low temperature cooling circulating pump, when you choice, please pay attention to “refrigerating capacity”, “lowest temperature”, “circulating joint”, “circulation capacity” and “circulating pressure”,.We supply low temperature equipment professional for rotary evaporator.
2) For laboratory rotary evaporator, cold trap could be cooling by ice.
6. How to improve rotary evaporator service life?
1) Please operating based on well-known rotary evaporator operation instruction.
2) After finish research, please clean rotary evaporator in time.
3) The surface of rotary evaporator should be keep clean.
4) Please contact our specialist for any problems during rotary evaporator operating.
When using the rotary evaporator, pay attention to the glass parts should be handled gently, washed, dried or dried before loading. A vacuum grease is applied to each grinding port, seal face seal and joint before installation. Water must be added before the heating tank of the rotary evaporator is energized, and dry burning is not allowed. Each connector, the interface is sealed. Sealing ring, whether the sealing surface is effective. Whether the vacuum grease is applied between the main shaft and the seal. Whether the vacuum pump and its hose are leaking. Whether the glass parts are cracked, broken or damaged.