Help with Chem- Azeotropic Distillation

[Aerodynamic20]

Hello,

I am curious on how azeotropic distillation works. I know it has to do with the gas law, PV=nRT but I would like to know in depth analysis how this process works.

I have organic 2 lab final coming up (this Tuesday) and it may happen we might be asked to explain how azeotropic distillation works.

The experiment we did was synthesis of Sulcatol (6-methyl-5-hepeten-2-ol). I transferred the crude prepared Sulcatol to a round bottom flask connect to thermometer and manometer (to measure the pressure). Also, pump was connected to the set-up to generate pressure, and I heated the crude sulcatol till it evaporated. Can someone help me in explaining what is going on in the pressure-boiling process?

Also, I would like to know why the manometer reading is in negative not positive?

Please let me know if my method of submitting the question is incomplete. I am new to the forum.
Thanks,

 

[Nino MMP]

Azeotropic distillation is a process involving the use of a ternary mixture of liquids and/or solids in order to achieve a desired result. It involves the use of a pressure-boiling process, in which the vapor pressure of the mixture is increased to a point that it becomes greater than the atmospheric pressure outside the system. This causes the boiling point of the mixture to increase and the volatile components to escape as vapor. The vapor is then condensed and collected. The gas law, PV=nRT, is used to calculate the pressure-boiling point of a ternary mixture. n is the number of moles of the vapor, R is the universal gas constant, and T is the temperature. This equation allows for the calculation of the pressure at which the boiling point of the mixture will exceed the atmospheric pressure outside the system. In your experiment with the synthesis of Sulcatol, the manometer reading should be negative because the pressure inside the system is higher than the atmospheric pressure outside the system. The pump is used to increase the pressure inside the system, and the manometer is used to measure the difference in pressure between inside and outside the system. I hope this helps to explain azeotropic distillation and the pressure-boiling process. Good luck with your lab final!

 

[Blueshift5]

Hello,

Azeotropic distillation is a process used to separate azeotropic mixtures, which are mixtures of liquids that boil at the same temperature. This can be a challenging task because traditional distillation methods rely on the difference in boiling points between the components of a mixture. However, with azeotropic mixtures, this difference is minimal or non-existent, making it difficult to separate the components.

In azeotropic distillation, an additional substance, known as an entrainer, is added to the mixture to break the azeotrope and allow for separation. This entrainer can be a solvent or another substance that has a different boiling point than the components of the azeotrope. When heated, the entrainer forms a new azeotrope with one of the components of the original mixture, allowing for separation of the other component.

In your experiment, the crude Sulcatol is heated in a round bottom flask, causing it to evaporate. The pressure generated by the pump helps to control the temperature at which the Sulcatol boils. As the Sulcatol evaporates, it forms a vapor that contains both the desired product and other impurities. The entrainer, in this case, is the pump-generated pressure. This pressure increases the boiling point of the Sulcatol, causing it to boil at a higher temperature than the impurities. As a result, the impurities remain in the liquid state while the desired product is vaporized and can be collected.

The negative reading on the manometer is due to the difference in vapor pressure between the Sulcatol and the impurities. The higher pressure generated by the pump increases the vapor pressure of the Sulcatol, causing it to boil at a higher temperature. This difference in vapor pressure is what allows for the separation of the components.

I hope this helps to explain the process of azeotropic distillation. Best of luck on your lab final!