How to improve distillation efficiency of rotary evaporator?

The distillation efficiency of rotary evaporation apparatus in laboratory is a very important performance On the one hand, the distillation efficiency determines the experimental efficiency, on the other hand, it also reflects the quality of a product The distillation efficiency of laboratory rotary evaporator determines the number of samples that can be distilled every day One obvious reason is that the higher the distillation efficiency is, the more samples can be distilled in the same solvent How to improve the distillation efficiency of the rotary evaporator? 1 In order to ensure the distillation efficiency, the temperature of the cooling medium is generally recommended to maintain a temperature difference of about 40 ° C with the temperature of the heating pot in order to condense the hot steam quickly, so as to reduce the impact of the steam on the system vacuum 2 The temperature of the heating pot the higher the temperature of the rotary evaporator in the laboratory, the faster the distillation effect of the solvent However, considering the safety of operation and the thermal sensitivity of the target component, the common temperature is 60 ℃ and then more than 80 ° C However, it is difficult to clean the silicone oil medium Generally, we suggest that customers reduce the vacuum value to achieve faster distillation efficiency 3 The components of the system vacuum value laboratory rotary evaporator are as follows: evaporation bottle, evaporation tube, sealing ring, condensation tube, vacuum buffer bottle, vacuum pump, vacuum pipeline, among which the factors affecting the system vacuum are vacuum pump, sealing ring and vacuum pipe Generally speaking, the lower the limit of vacuum pump, the lower the vacuum value of the system Therefore, it is necessary to set a reasonable vacuum value through the vacuum controller to ensure the distillation efficiency and avoid boiling The limiting vacuum of the circulating water pump is about 0.095 kPa, and the limiting vacuum of the diaphragm vacuum pump can reach 2 mbar However, if the budget allows adding a vacuum controller or a vacuum valve, it can control the system vacuum value required for distillation As the key seal of the evaporation pipe and the condensation pipe, the wear resistance and corrosion resistance of the seal ring is the key PTFE and rubber are commonly used as sealing ring materials The wear resistance and corrosion resistance of PTFE are better than that of rubber Silicone tube is naturally a vacuum tube because its aging efficiency is slower than ordinary rubber tube 4 Speed of the evaporation bottle laboratory rotary evaporation apparatus the faster the speed of the evaporation bottle, the larger the wetted area of the inner surface of the bottle, the larger the heating area; but at the same time, the thicker the liquid film is, and the greater the temperature difference of heat transfer There is rotation speed for different viscosity materials and the rotation power is provided by the motor 5 System size and power: the distillation speed in a given system is mainly limited by the condenser's ability to condense solvent vapor (rarely by the heater) If you let too much steam rush into the condenser, it will overload and fail to work effectively, which will result in valuable volatiles loss To avoid saturation, you should monitor the system pressure so that 2 / 3 of the condenser is always covered with condensate If the liquid begins to form at the top 1 / 3 of the coil, there is a risk that the incoming steam will be drawn into the vacuum pump and lost forever In practice, we often make the condensate close to 3 / 4 of the condenser Another indicator is the "condensation line", which is usually located above the area on the coil where the actual liquid is seen This is easy to see in water distillation, but hard to see in alcohol distillation You can also consult online customer service to help you select the model.