When vacuum distillation is selected – Purpose of vacuum distillation

There are different type of distillation process is used for the separation process. The types of distillation is defined below

  1. Simple distillation
  2. Vacuum distillation
  3. Flash distillation
  4. Azeotropic distillation
  5. Extractive distillation

Today in this article we will try to understand what is vacuum distillation and when we use vacuum distillation.

Introduction – What is vacuum distillation?

Distillation is a process of separating compounds based on the difference of boiling point. The distillation is carried out at the pressure less than the atmospheric pressure is known as vacuum distillation.

When vacuum distillation is selected

  1. Vacuum distillation is select when the product is heat sensitive and get decompose at temperature below boling point. In such situation vacuum distillation is used to separate/ remove selected solvent or compound from the product

E.g. Let us understand this purpose of vacuum distillation using and example.

Suppose you have a product whose wet cake (after centrifugation) you need to dry it to remove traces of methylene chloride. The boling point of MDC is 39.6 °C. But you know that the product is heat sensitive and it get degrade at 30 °C. So in this case, you will use vacuum tray dryer in place of tray dryer as the temperature required for the removal of traces of MDC in vacuum tray dryer will be less the the product degrade temperature i.e. 30 °C.

2. If the temperature require for the distillation system is very high then in this case you can go for the use of vacuum distillation which will help you to use economical utility like steam.

e.g. The boiling point of toluene is 110 °C hence if from the binary mixture, you need to distill out toluene then you need steam than can heat the compound upto 110 °C, but if you apply vacuum then toluene can recover at lower temperature.

3. It reduces undesirable side reactions, if taking place.

4. System requires fewer stages or lower reflux ratio, as relative volatility increases with decrease in operating pressure.

5. It increases product recovery when dealing with maximum temperature constraints.

Wrapping Up

This was the article on when vacuum distillation is used and application of vacuum distillation. Hope you had now a clear idea on When vacuum distillation is selected. If you have any problem then feel free to use comment section and if you have some addition to the article then share with everyone by explaining in the comment section.

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