Synthesis of Aspirin pt 1 Flashcards
(40 cards)
(1) To a 100 mL round-bottomed flask add water
(50 mL) followed by careful addition of NaOH (10 g). What will happen to the flask
The flask will become warm. Carefully swirl the flask to
allow the NaOH to dissolve.
(2) After we allow the flask to cool briefly and add methyl salicylate (0.030 mol). Record the mass actually
added in the table below. What do we then add
(3) Add 2-3 anti-bumping granules to the flask.
When we clamp the round-bottomed flask to a retort stand above a tripod and ceramic gauze, and then fit a waterless condenser, applying what to the joint?
a VERY SMALL AMOUNT of grease
(4) Turn on the mantle to a medium heat. All of the
solid should have dissolved. It is recommend that you
reflux your solution for at least how long?
5 minutes beyond the point at which everything is in solution.
Allow the solution to reflux for 10-15 minutes.
(5) Once the solution has been cooled for around 5
minute cool the flask with what until it reaches room
temperature.
water
(6) Gently pour the reaction mixture into a 250 mL
conical flask and place the flask into where?
Ensure you leave the anti-bumping
granules in the round bottom flask.
an ice bath.
(7) why do we then slowly add 1 M H2SO4 to the reaction mixture in the conical flask (approx. 100 mL may be required).
Gently swirl the flask during the addition of
the H2SO4.
to neutralise the base in the reaction mixture
Test the pH using what to
determine when the reaction mixture becomes
acidic.
Universal pH paper
Universal indicator paper before adding
sulphuric acid to the solution (basic) colour
blue
Universal indicator paper after adding
sulphuric acid to the solution (acidic) colour
red
(8) what do we cautiously add to
precipitate the crude product?
(8) Keep the reaction mixture at ice temperature and
while slowly swirling the flask, cautiously add
more 1 M H2SO4 (approximately 10-20 mL)
(9) Isolate the crude product - how?
by vacuum filtration on a Büchner funnel.
Allow the filtration to proceed for at least 5 min to remove as much water as possible (you may press the collected crystals down with the base of a clean sample vial to assist this).
last step : what to do with the crude product
Place the crude product onto a watch glass,
spreading it out over a large area to assist drying. After
a MINIMUM of 10-15 min (the longer the better) in the
oven. You can monitor the mass of crude product over
time. Record the mass of your dry crude product.
salicylic acid aka
2-hydroxybenzoic acid
we synthesise salicylic acid (2-hydroxybenzoic acid), by hydrolysis of what?
methyl salicylate
(Oil of Wintergreen).
An ester can be hydrolysed on heating with water and what as a catalyst.
either an acid or a base
The hydrolysis reaction is reversible in the presence of
an acid
The hydrolysis reaction is irreversible in the presence of
a base
what is the saponification of an ester
the irreversible reaction of an ester with an alkali-metal hydroxide (a base) to give the parent alcohol and the metal salt of the parent acid
In this experiment you will hydrolyse methyl salicylate using what
aqueous NaOH
to give salicylic acid, which is the immediate precursor of aspirin.
What is the molecular formula of methyl salicylate?
C8H8O3
ester functional group
-C(=O)O- (or RCOOR’)
reaction ratio
1:1
Sodium hydroxide is caustic and can cause burns
avoid contact of any reactants with the skin and wear gloves
