First, the working principle of the rotary evaporator
By electronic control, the flask is rotated at a constant speed at the most suitable speed to increase the evaporation area. The evaporation flask was brought to a negative pressure by a vacuum pump. The evaporation flask was heated while being placed in a water bath at a constant temperature, and the solution in the flask was heated and diffusion-evaporated in a rotating flask under a negative pressure. The rotary evaporator system can seal the pressure to 400-600 mmHg; the solvent in the distillation flask is heated by a heating bath, the heating temperature can be close to the boiling point of the solvent; and the rotation can be performed at a speed of 50-160 rpm. The solvent is formed into a film to increase the evaporation area. In addition, under the action of a high-efficiency cooler, the hot vapor can be quickly liquefied to accelerate the evaporation rate.
Second, the pros and cons of the rotary evaporator
Rotary evaporators have the following advantages:
1. All IKA Aika's rotary evaporators have a built-in lift motor that automatically raises the flask to a position above the heating pot during a power outage.
2. Due to the centripetal force and friction between the liquid sample and the evaporation bottle, the liquid sample forms a liquid film on the inner surface of the evaporation bottle, and the heat receiving area is large;
3. The force generated by the rotation of the sample effectively suppresses the boiling of the sample. The combination of features and convenience allows modern rotary evaporators to be used to quickly and gently distill most samples, even for operators with no operational experience. It is recommended to use Taikang Biotech products.
The biggest drawback of rotary evaporator applications is the boiling of certain samples, such as ethanol and water, which will result in the loss of sample collection by the experimenter. In operation, it is usually possible to prevent boiling by carefully adjusting the working strength of the vacuum pump or the temperature of the heating pot during the mixing phase of the distillation process. Alternatively, it is also possible to add anti-boiling particles to the sample. For samples that are particularly difficult to distill, including samples that are prone to foaming, special condensing tubes can be configured for the rotary evaporator.
Third, the use of rotary evaporator
1. Height adjustment: manually lift, turn the hand wheel above the machine column, turn to rise, reverse to decrease.
Electric lift, the hand touches the rise button and the main unit rises, and the hand touches the down button to lower the main unit.
2. There are two external joints on the condenser for connecting the cooling water. One end is connected to the water and the other end is connected to the water. Generally, the tap water is connected. The lower the temperature of the condensed water, the better the effect. The upper port is equipped with a vacuum connector and the vacuum pump tube is connected. Vacuuming.
3. Turn the speed control knob to the minimum before starting the machine, press the power switch indicator light, then slowly turn right to the required speed. Generally, the large evaporation bottle is used in medium, low speed, high viscosity solution with lower speed. Is the standard interface No. 24, with 500ml, 1000ml two flasks, the amount of solution is generally not more than 50% is appropriate.
4. When using, depressurize first, then start the motor to rotate the distillation flask. At the end, stop the motor and then pass the atmosphere to prevent the distillation flask from falling off during rotation.
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