Views: 9 Author: Rotary evaporator Publish Time: 2021-12-14 Origin: Rotary evaporator manufacturer
Rotary evaporator, referred to as rotary evaporator, is an instrument used in laboratories to continuously distill a large amount of volatile solvents under reduced pressure, and can separate and purify reaction products.
The rotary evaporator is mainly composed of a rotary motor, an evaporation tube, a vacuum system, a fluid heating pot, a condenser tube, and a condensed sample collection bottle. Its working principle is to make the evaporation flask in a negative pressure state through a vacuum pump, and through electronic control, make the flask rotate at a constant speed at a suitable speed to increase the evaporation area. The Suke purchasing steward learned that the rotary evaporator system can seal and reduce pressure to 400-600 mmHg, and the rotation speed can reach 4 to 200 rpm, so that the solvent can form a thin film and increase the evaporation area. The force generated by the rotation can effectively inhibit the boiling of the solution.
To purchase a high-efficiency rotary evaporator, you need to consider the following factors:
1. Choose the size of the rotary evaporator according to the experimental needs
What is the amount of distillation required for one experiment? What is the number of distilled samples? What are the solvents for distillation? What are their boiling points? Through the above questions, determine what temperature range of the rotary evaporator is needed, what level of temperature control accuracy is required, and how large the volume of the evaporating flask and collection flask should be. Generally speaking, a laboratory-grade rotary evaporator with a capacity of less than 5L is enough, and an industrial-grade CNC rotary evaporator can be adapted to a 20L large-capacity evaporating flask.
2. Vacuum is the core indicator
Under the corrosion of various solvents and in the state of motion, whether the system can maintain a high vacuum degree is the most important criterion for measuring the rotary evaporator. Choose a rotary evaporator sealed with Teflon material and glass, which can withstand various solvents, has long-lasting and reliable air tightness, and can maintain a high vacuum degree above -0.098MPa.
3. Selection of heating pot and heating medium
The temperature of the heating pot should be 20 degrees higher than the boiling point of the solvent. Note that the boiling point of the solvent under vacuum may be different from the boiling point under normal conditions. The heating medium is generally tap water or distilled water. If the heating medium is silicone oil, the ignition point is at least 25°C higher than the maximum temperature of the heating pot.
4. Choice of condenser
There are two common condensers on the market, vertical condensers and inclined condensers. The vertical condenser occupies a small space, and the vertical condenser for the large-capacity evaporator is more space-saving.
5. Optional explosion-proof glass components
Distilling flammable and explosive solvents, it is recommended to choose glass components with explosion-proof coating. Choose a rotary evaporator with automatic deflation function to prevent manual deflation from causing an explosion if the speed is not well controlled.
6. Parameters affecting evaporation efficiency
Understanding the factors that affect the distillation efficiency of the rotary evaporator will help you to better choose the right product and obtain the best experimental results through the correct experimental operation. Soke Purchasing Manager has summarized the following factors that have an impact on the efficiency of the rotary evaporator for your reference:
(1) The vacuum value of the system, among which the most critical factors are the materials of the vacuum pump, sealing ring and vacuum tube.
(2) The temperature of the heating pot. The higher the temperature, the faster the distillation effect, but considering the heat sensitivity of the ingredients and the safety of operation, the commonly used temperature is 60 degrees Celsius. It is generally recommended to lower the vacuum value to achieve faster distillation efficiency.
(3) Rotation speed of distillation flask. The faster the speed, the larger the heated area, but at the same time the thicker the thickness of the liquid film will increase the heat transfer temperature difference. Therefore, materials with different viscosities have different applicable optimum speeds.
(4) The temperature of the cooling medium. It is generally recommended to maintain a temperature difference of 40°C between the cooling medium and the heating pot, which can improve the condensation efficiency and reduce the effect of steam on the vacuum of the system.