Experiment D Separation Of Alcohols By Fractional Distillation
Experiment D: Separation of Alcohols by Fractional Distillation
Pre-lab Properties:
Propanol, butanol, methanol
Purpose: To separate two alcohols by distillation and analyze results with GC.
Do not plug mantle directly into electrical outlet, use controller!
Use 40/60 mol percent propanol/butanol (no cyclohexane or toluene are used in this lab because they are more toxic)
Set up fractional distillation
Set heat at highest level to start, then turn back down to 60-80% when vapor starts up column, collect first sample then adjust heat as needed
Not too fast or slow, distillation should take about 30 minutes
Write procedure during distillation not when finished! You may split page with one side procedure and one side a table for volume collected and temperature recorded.
Post-lab Reminders:
Retention times (see chromatograms)
Calculations for C, R, XPV (mole fraction of propanol vapor), XBV (mole fraction of butanol vapor) – fill out the table
Standard (l)
Sample (v)
AP
AB
AP/AB
R
C
XP
XB
Include an example of each calculation
Plot of boiling point versus volume (from recorded table in procedure)
Calculate HETP (include calculation in report)
Copy of chromatograms (from the TA)
Calculations
Background:
Theoretical plate – result of simple distillation
Each distillation (plate) makes vapor more rich in more volatile component
Column can have several theoretical plates n is the total theoretical plates in apparatus n-1 is the total theoretical plates in column (boiling flask is first plate)
Determine n from mole fraction (X) of components
Directions
Introduction:
Distillation has been around since Egyptians distilled wood for embalming fluid. Current uses of this technique include making perfumes, coke, charcoal, and even refining petroleum for fuel and lubricants. During the distillation of liquids, the more volatile component will come off first in the separation. See the videos for more
Pre-lab Properties:
Propanol, butanol, methanol
Purpose: To separate two alcohols by distillation and analyze results with GC.
Do not plug mantle directly into electrical outlet, use controller!
Use 40/60 mol percent propanol/butanol (no cyclohexane or toluene are used in this lab because they are more toxic)
Set up fractional distillation
Set heat at highest level to start, then turn back down to 60-80% when vapor starts up column, collect first sample then adjust heat as needed
Not too fast or slow, distillation should take about 30 minutes
Write procedure during distillation not when finished! You may split page with one side procedure and one side a table for volume collected and temperature recorded.
Post-lab Reminders:
Retention times (see chromatograms)
Calculations for C, R, XPV (mole fraction of propanol vapor), XBV (mole fraction of butanol vapor) – fill out the table
Standard (l)
Sample (v)
AP
AB
AP/AB
R
C
XP
XB
Include an example of each calculation
Plot of boiling point versus volume (from recorded table in procedure)
Calculate HETP (include calculation in report)
Copy of chromatograms (from the TA)
Calculations
Background:
Theoretical plate – result of simple distillation
Each distillation (plate) makes vapor more rich in more volatile component
Column can have several theoretical plates n is the total theoretical plates in apparatus n-1 is the total theoretical plates in column (boiling flask is first plate)
Determine n from mole fraction (X) of components
Directions
Introduction:
Distillation has been around since Egyptians distilled wood for embalming fluid. Current uses of this technique include making perfumes, coke, charcoal, and even refining petroleum for fuel and lubricants. During the distillation of liquids, the more volatile component will come off first in the separation. See the videos for more