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Homework Help: Azeotropic distillation Please help final coming up!

  1. Mar 28, 2009 #1
    1. The problem statement, all variables and given/known data


    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?

    2. Relevant equations


    3. The attempt at a solution

    I think the process is related to pressure-boiling points. I know both are directly proportional, when temperature increases, pressure increases. But I am not sure how I can relate to what I learnt in general chemistry 2 semesters ago.

    Thank you
  2. jcsd
  3. Mar 30, 2009 #2
    Please help. I posted this question yesterday and I don't know what I am missing. Can someone if my trial is incomplete?

    I am new to the forum.

  4. Mar 31, 2009 #3


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    The pump you refer to was actually a vacuum pump. You pulled a vacuum on your distillation rig and did a vacuum distillation. Did you collect anything?

    When the vapor pressure of your compound (yes, it it temperature dependent!) equals the ambient pressure, your compound will boil. If you cool the sulcatol vapors, they will condense. If you direct the vapors to a different part of the apparatus and cool/collect them there, you have performed a distillation.
  5. Apr 1, 2009 #4
    Yes, I collected the distillate in Hickman's head which is attached to the air condenser. Thanks for the response. I did the exam today and it was a practical exam. I was assigned to do Aldol condensation and by chance I didn't have to do Sulcatol distillation.
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