Typical Use Process and Basic Precautions for Rotary Evaporator

Typical use process (distillation process) of rotary evaporator

Check whether the power supply is properly connected and the cooling medium pipe is properly connected before starting. Turn on the power of cold source equipment, vacuum equipment, heating bath, and rotovap for sale. Start the cold source equipment, let the cooling medium passing through the condenser, and check whether the cooling medium pipe is leaking; start the vacuum equipment, and check whether the vacuum connection pipe is leaking.

Set the temperature of the cold source equipment, set the vacuum degree (if equipped with a vacuum controller for rotary evaporator); set the heating bath temperature, and wait for the heating medium to reach its working temperature. Put the distilled solution into the evaporation flask, make sure the volume of the added solution does not exceed 2/3 of the evaporation flask; install the evaporation flask on the rotary evaporator; set the rotation speed and start distillation.

After the cooling medium temperature, vacuum degree, and heating bath temperature reach the preset value for a period of time, the distillation conditions can be re-optimized according to the nature of the solvent, distillation speed, and condensation recovery rate.

After the distillation is completed, the rotation stops, the distillation flask is lifted away from the heating liquid surface of the bath, the power of the bath is turned off, air or inert gas is introduced to relieve the pressure according to the process requirements, the diaphragm vacuum pump and cold source equipment are turned off, and the evaporation flask is removed and collected The bottle is processed in the next step.

Clean the rotary evaporator and set it aside. Common faults of temperature control instruments: The indicated value of the temperature instrument system suddenly changes to the maximum or minimum, which is generally a failure of the instrument system. Because the measurement lag of the temperature instrument system is large, no sudden changes will occur.

RE200-2L-W-D2 laboratory rotary evaporator

At this time, the fault causes are mostly caused by thermocouples, thermal resistance, compensating wire disconnection, or transmitter amplifier failure. The temperature control instrument system indicates rapid oscillation, which is mostly caused by improper adjustment of the control parameter PID. The temperature control instrument system indicates large and slow fluctuations, which may be caused by changes in operation.

If there is no change in operation at that time, it is likely to be a malfunction of the instrument control system itself. The temperature controller of the rotary evaporator has been inspected before leaving the factory, and the customer does not need to adjust it arbitrarily. If it needs to be adjusted, it must be adjusted according to the controller manual.

Precautions for rotary evaporator:

The most important point is that the glass parts should be handled gently, and washed and dried after use; secondly, the heating tank should be filled with water and then energized. Dry burning without water is strictly prohibited; a small amount of vacuum grease should be applied even before the installation of the grinding instrument; Do a simulation test first to ensure the safety of the experiment; when the work is over, turn off the switch and unplug the power supply.

Under higher vacuum conditions, the transpiration temperature of the material can be reduced to a very low level. In addition, because the liquid film in the turbulent state is very thin and the heat transfer coefficient is large, the temperature difference between the temperature of the material inside and outside the transpiration cylinder and the temperature of the jacketed medium

Therefore, compared with conventional distillation, the heating temperature of the rotary evaporator will be lower under equal vacuum conditions, and the temperature of the material near the inside and outside of the transpiration is also correspondingly lower, and then reduce the thermal differentiation and thermal polymerization of heat-sensitive substances.

High transpiration power because the rotating film scraping equipment scrapes the material into a uniform film on the inside and outside of the transpiration cylinder, which effectively reduces the thermal resistance and makes the light component, very simple to distill and separate from the material; because the simplified inside and outside The liquid film between the membrane devices is in a violent turbulent state, and the transfer of different components and the heat transfer with the heating medium in the heating jacket are very good.

In addition, because of the high smoothness of the inside and outside of the cylinder and the wiper The continuous movement of the heating surface makes the heating surface not simply coking and scaling, but also helps to increase the total heat transfer coefficient and improve the transpiration power.