DULCIN SYNTHESIS
- Assemble glassware and apparatus reflux with a 50mL RB flask (with 2.4 g of urea
inside)
- Add 5mL of distilled water and 1.4mL of paraphenidine (measure it directly with the
dispenser, not with a graduated cylinder) - remember to take initial reading of the
dispenser (miniscus) then again after dispensing 1.4mL into flask
- Mix thoroughly via a gentle swirl, then add 1.0 mL of concentrate HCl (measure directly
out the other buret with the HCl, taking initial and final volume reading after dispensing)
- You will start to see fumes, make sure to keep flask in fumehood and don’t stick your
face in
- Add 6 drops of acetic acid, swirl, then clamp it the neck with a 3-finger clamp on a sand
bath over a hot plate
- Place condenser into flask, turn water on, turn on stir and heat (full heat first, then half
when reflux, aka boiling, starts happening) – when it starts boiling, start timer and adjust
heat to keep it a minimal boil
- Make sure the condenser to cool, increase amount of cold water via tap in order to see
water leaking out of the thin hose and prevent reflux line from reaching too high
- Iced a couple mL of water (test tube with water placed in a beaker of ice)
- 30 minutes later, turn off heat (but leave stir on) and let it slowly cool – bring the flask off
the hot plate (still in the clamp though)
- When cooled, take flask and, using a stir rod, pull the solid from the bottom by adding a
bit of cold water to create a slurry
- Set up a buckner flask with a funnel with a filter paper with a bit of distilled water, pour
the slurry (make sure suction is on) – this allows the water to separate from solid
- Pour iced water into solid, we now have our dulce
- Take a large filter paper, take buckner funnel and scrap the dulce onto said paper
- Get the stir bar and wash it and put it away
- Wrap the dulcin, label and leave it for next week
DULCIN RECRYSTALLIZATION
- Dissolve our solid dulcin in just enough boiled water to do so, add another 20-30mL of
hot water
- Have another flask prepared with a funnel and filter paper prepared for our filtration
- Pour the hot mix down a glass rod tilted inside filter paper, by a few mL at a time
- Place back on hot plate to keep boiling, then add another few mL, repeat until the solid is
no longer present in the brown liquid
- Place the filtration set up on a hot plate and keep pouring, make sure it’s not boiling too
much!
- Let the dulcin cool off to the side, you will see needle shaped dulcin, and when cooled
set it on top of ice (~10 minutes), then bury the flask further for another 10-15 mins
MELTING POINT ANALYSIS
- Take weight of our recrystallized dulcin
