Unit 4c: Laboratory Techniques and their Application - BTEC Applied Science

Unit 4c: Laboratory Techniques & their Application

Issue date: 08/06/2022

Deadline: 22/06/2022



Introduction:

For this assignment I will be covering the drug known as aspirin, the techniques used in preparation
& testing of aspirin, the method used in our experiment as well as my calculations & conclusions &
observations for these experiments.

I will be covering the industrial manufacturing & testing of aspirin & identifying different factors that
affect the purity & yield of the aspirin.



Equipment:

 Round bottom flask
 Ethanoic anhydride
 Phosphoric acid
 Ice bath
 Water
 Buchner funnel
 Distilled water
 Scale
 Stirring rod
 Condenser



Method:

Stage 1

 Our apparatus was assembled in order for heating under reflux.
 About 1g of 2-hydroxybenzoic acid was weighed into a round bottom flask fitted with a
stopper. The mass was recorded.
 2cm³ of ethanoic anhydride was added, followed by 8 drops of concentrated phosphoric
acid. We used reflux heating to warm up the apparatus while swirling with a stirring rod until
all of the solids were completely was dissolved.
 We allowed the solution to cool. 5cm³ of cold water was added to the solution by decanting
it down the condenser.

Stage 2

 We put the round bottom flask into a bath of ice water until precipitation appears to be
complete.
 The product was then filtered using a Buchner funnel & was washed with some cold distilled
water & then transferred to a weighted watch glass.
 The mass of the dry product was recorded & the melting point was determined.

, Calculation & Results:

The melting point of Aspirin: 130.8°C

Starting mass of 2-hydroybenzoic acid weighed out=1.00 g

Actual mass of aspirin compound made=0.91 g

Theoretical yield calculation

formula mass of 2-hydroxybenzoic acid=138.12g

formula mass of aspirin=180.1 g

Theoretical yield

No of moles of 2-hydroxybenzoic acid=mass/Mr=1.00/138.12=7.24x10-3mol

No of Aspirin moles=7.24x10-3mol

Mass of aspirin = 7.24 x 10-3 mol x 180.1 = 1.303 g

Theoretical yield = 1.303 g

%Yield=(Actual yield/Theoretical yield)x100=(Actual yield/theoretical yield)x100

0..303 = 69.83883346 % = 70 %



Atom economy calculation

Atom economy=(mass of atoms in the desired product/mass of atoms in reactants)x100

= (180.1 /378.2) x 100 = 47.6 %



Conclusion:

Explaining & comparing the melting point of our sample of aspirin with the recorded value.

The melting point of our sample of aspirin that we got is 130. 8 ℃. However, the recorded pure
value of the melting point of aspirin is 135℃ (online sources). This shows that our sample was
impure, as it is 5 degrees lower that the pure melting point of aspirin. Furthermore, the percentage
difference is : -3.11% (130.8 − 135 ÷ 135 × 100). This demonstrates that there was a difference in the
boiling point of our solution, as this impacted the purity of the solution & minimal impurities was
present & this can be due to human error.



Researching & describing the industrial testing & manufacturing of aspirin.

Within the industry, to produce aspirin, water & corn starch will be added to acetylsalicylic
acid(which is the active ingredient) & during mixing, lubricants portions will be added before & after
the tablets have been compressed, which includes; vegetable oil that is hydrogenated, aluminium
stearate & stearic acid. Aspirin tablets are manufactured in big batches. Different batches of aspirin