Separation of Liquids by DISTILLATIONS

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Separation of Liquids byDISTILLATIONS

• Simple distillations
• and
• Fractional distillations

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Start setting up with a suitable ring
stand.Tighten the rod so it will not wobble!
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Start setting up NEAR A WATER OUTLET!Place the
burner on the ring stand next.
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Then, add the iron ring, leaving 2-3 inches for
the flame.
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The wire gauze goes on top of the iron ring.
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The RB flask is clamped directly on top of the
wire gauze. Leave NO air space!
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Put your mixture and boiling stone into the pot
BEFORE you assemble the apparatus
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The 3-way adapter (still head) is added on top
the RB flask.
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A thermometer is fitted through the rubber holder
AND the glass adapter. The assembly is inserted
into the still head.
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The thermo-meter bulb should be just below the
opening to the side-arm of the still head.
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The attached condenser is secured to another
ring stand. Water enters the lower end.
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A graduated cylinder serves as the receiver.
Clamp it in place if necessary.
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Hotplates are now available if you prefer !Heat
transfer??
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• For FRACTIONAL DISTILLATIONS, A PACKED COLUMN
  MUST BE INSERTED BETWEEN THE RB FLASK AND THE
  STILL HEAD.

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The condenser, still head, and thermometer
assembly are removed,leaving theRB flask
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Put your mixture and boiling stone into the pot
BEFORE you assemble the apparatus
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A column, packed with beads and/or rings, is
clamped to the RB flask.
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The still head is added to the top of the packed
column.
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The thermometer assembly is inserted into the
still head, as before.
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The condenser is clamped to the still head. Water
enters the LOWER end.
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A graduated cylinder is clamped to the stand to
serve as a receiver.
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Hotplates are available if you prefer.Heat
transfer??
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• Interpreting the composition boiling point
  diagram.
• Its on page 12 in your laboratory manual and on
  page 322ff. of Zubrick.

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The LOWER curve shows the composition of the
liquid that boils at a given temperature.

• The UPPER curve shows the composition of the
  vapors that occur at that same temperature.

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A mixture of 80 A and 20 B boils at about 85o C.

• But, -- what is the compositon of the vapors??

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The VAPORS have a composition of about 47 A and
53 B.

• Those VAPORS condense back to a LIQUID of 47 A
  and 53 B.

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THAT LIQUID will boil at about 60o C
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Those VAPORS have a composition of about15 A
and 85 B

• When condensed, the LIQUID will have that same
  composition 15 A and 85 B

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THAT LIQUID will boil at 45o C,
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The VAPORS rising will have a composition of
about ummm3 4 A and 96 97 B.

• Note that if the vapors are richer in the LOWER
  boiling component, then the composition of the
  liquid in the pot must be getting richer in the
  HIGHER boiling component

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When the VAPORS condense back to a LIQUID . . .

• . . .well, I believe you can see where this is
  going . . .

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Can you figure it out!?!

• Im sure you can . . .

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O.K.??

• O.K !!

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Check the bulletin board to see if you are on
CLEAN-UP.

• Record your data FIRST, then complete your
  Laboratory Report Forms.
• Trim off the ragged edges and
• Turn them in along with the Recrystallization
  Reports from last week .