ASSIGNMENT 4C
ASPIRIN IN LAB.
CONCLUSION:
The melting point of pure aspirin is between 138-140 degrees. The
melting temperature of the aspirin I made in the lab, which is
between 135 -136 degrees C, is not the exact same as the melting
point for pure aspirin, thus I believe it is not entirely pure. The
melting points of my sample and pure aspirin differed somewhat,
indicating the sample I made has a few contaminations. When I did
thin-layer chromatography, an extra spot showed up, which shows
that my sample has some contaminations.
INDUSTRIAL PREP OF ASPIRIN:
Since aspirin is manufactured on an enormous scale in industries, it
requires modern equipment to make and test it to achieve maximum
production and less contaminations. Because aspirin produced in
factories is utilised in a range of medicines, the companies ensure to
use the bests and the best equipment possible. Due to the great
demand for this aspirin, industrial manufacturing scales are far larger
than those in laboratories. It is commonly manufactured in batches.
ACIDS:
- Acetic acid, Salicylic acid, Acetic anhydride.
METHOD:
- First, a little of acetic acid, acetic anhydride, and salicylic acid, are
added to the column of rector along with acetic anhydride. The
temperature is then progressively raised to 85° C and kept there till
the reaction is nearly finished.
, -The aspirin product then crystallised from this mixture by stirring it
within a crystalliser or reaction chamber. At 77 degrees
crystallization starts and lasts till 15 degrees Celsius.
-After, aspirin crystals are separated from the acetic anhydride-rich
mother liquid via filtration and then washed twice, once with water
and then with glacial acid (acetic acid).
-The acetic anhydride-rich mother liquor and the acetic acid wash
liquor are then combined and separated in 30–70%. then, the
crystals that are appropriate are separated, and the leftover material
is delivered to a secondary reactor where some salicylic acid is added
to it, and the temperature is raised to 85 degrees C.
- Following the completion of the reaction, the mixture is transferred
to a crystallizer, where the crystallisation process involves cooling
and mixing, and the crystals that are produced are separated by
filtration.
- then crystals are once more washed with glacial acid (acetic acid)
and mixed with second mother liquor. Then,The unsuitable crystals
were sent back to the reactor.
- The acetic acid rinse also second mother liquor are provided for
distillation under less pressure in order to get a residual that can be
turned into salicylic acid as well as eliminate volatile components.
-Sodium hydroxide is then used to hydrolyze the resulting residue,
and the mixture is then cooled. It is then acidified with the help of
sulfuric acid.
-To extract salicylic acid, which then goes to the reactor, the mixture
is once more tested with cooling and filtration.
-Next, the volatile components recovered through distillation are
condensed to produce acetylsalicylic acid, a substance that is suited
for manufacturing tablets.