How to choose a rotary evaporator when doing distillation purification experiments？
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.
It should be noted that when using the rotary evaporator, it should be noted that there are two external joints on the condenser for connecting the cooling water. One end is connected to the water, the other end is connected to the water, and the tap water is generally connected. The lower the temperature of the condensate, the better the effect. The port is equipped with a vacuum connector, which is connected to the vacuum pump for vacuum pumping. Before turning on the power, turn the speed control knob to Zui small, press the power switch indicator light, then slowly turn right to the required speed. Generally, the large evaporation bottle uses medium, low speed, high viscosity solution with lower speed. The flask is a standard interface No. 24, and is supplied with two flasks of 500 ml and 1000 ml, and the amount of the solution is generally not more than 50%.
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.