11053457
Iman boukjija zamani
Aspirin synthesis
Aim
The purpose of this experiment is to perforate a sample of aspirin (2- hydroxybenzoic acid
(silica acid), 11g), Purified by recrystallisation, measure it's melting point and estimate the
yield.
Introduction
Aspirin is the common name for the compound acetylsalicylic acid, widely used as a fever
reducer and as a painkiller.
to prepare aspirin, silica acid is reacted with an excess of acetic anhydride. a small amount
of a strong acid is reduced as a catalyst which speeds up the reaction.
in this experiment, phosphoric acid values as a catalyst. the excess acetic acid will be
quenched with the addition of water. the aspirin product is not very soluble in water so the
aspirin product will be precipitated when water is added.
Materials:
● Safety spectacles and protective gloves
● Weighing bottle
● Spatula
● Ethanoic anhydride (CH3CO)2o, 4 cm3
● 2- hydroxybenzoic acid (silica acid), 11g
● Phosphoric (V) acid, 85%, a few drops (with teat pipette)
● Access to balance, sensitive 0.01g
● Measuring cylinder, 10 cm3
● Beaker, 250 cm3
● Beaker, 100 cm3
● Reflux apparatus consisting of liebig condenser and 50 cm3 pear-shaped flask
● Conical flask, 100 cm3
● Glass rod
● Suction filtration apparatus
● Ice, about half a 250 cm3 beaker of crushed ice
● Wash-bottle of distilled water
Method
1. Transfer 2.0g of 2-hydroxybenzoic acid into a waiting bottle and weight to the
nearest 0.01g
2. into a 50 cm3 pear shaped flask 4 cm3 of a phonic anhydride and end the bulk of the
two hydro benzoic acid from the waiting room
3. we wait there waiting bottle, with any remaining solid, to the nearest 0.01g
4. to the mixture in the pear-shaped flask at five drops of 85% phosphoric acid, using a
teat pipette, and swirl to mixed.
5. food flask with a reflux condenser and heat the mixture on the steam bath for about
5 minutes. ensure the flask is thrilled at intervals.
6. without calling, add to CM3 of water down the condenser. this will hydrolyse any
excess ethanoic anhydride and in a vigorous reaction.
7. when the reaction from Steps six has finished pour the mixture into for CM3 of cold
water in 100 CM3 Beaker and follow it to cool to room temperature