This document includes the steps to form ethyl ethanoate in college laboratory and then conclusion drawn. Overall, I received a distinction in this assignment and the unit 4 overall.
, HAJRAH ALI (40157986)
ASSIGNMENT B UNIT 4 (MANOJ THAKRAR)
INTRODUCTION
B.P3 PREPARE AND TEST THE PURITY OF AN ORGANIC LIQUID AND DRAW CONCLUSIONS.
In conclusion, the Ethyl Ethanoate was formed during the practical, but in the lab, I got 83 degrees showing that it is
impure as pure ester has a boiling point of 77.1oC, my ester was impure because I did not wash it properly and I did not
wait long enough for the two mixtures to settle and separate, we also lost some ester while purifying, filtering and using
the separating funnel and some may of have drained when we drained the eater as we did not let the mixtures settle.
We washed the ester only three times which may have not got rid of all the impurities, there may have still been acid
remaining, So, we used anhydrous calcium chloride which soak’s any impurities that were water soluble from the ester
like water. The physical properties of the ester we produced was a cloudy milk like because it was impure. Pure ester
should be clear, colourless liquid with a pleasant, sweety fruity odour. Our ester smells like nail varnish and is strong.
B.M2 DEMONSTRATE SKILFUL APPLICATION OF TECHNIQUES IN PREPARING AND TESTING THE PURITY OF AN ORGANIC
LIQUID AND DRAW DETAILED CONCLUSIONS.
The liquid (ester) should be at a hot temperature so that the solvent is able to dissolve because if it is cold the product
will not dissolve as it would be impossible and will not be able to recrystilise too. A small amount of solvent is used
which allows the product to re-crystiliilse later on if too much solvent is present it will make it difficult for the ester to
re-crystilise. This is done by a hot water bath rather than a bunsen burner for safety precautions as ethanol is a
flammable product which Is not ideal to use in an open laboratory instead a fume cupboard is used if the solvent is
toxic. So we you a hot water bath and kettle water to help quicken the process. Acid Reflux is when an organic syntheses
often requires heating for a long time to achieve a complete dissolution of stubborn solutes, we condense and re-collect
the solvent vapour in the boiling flask so that we do not lose any volume whilst we boil the liquid. We used a refulx
condenser which was opened from the top to prevent pressuristaion or an explosion which would potentially lead to an
injury. The colling region would allow the sample to re-condensed and fall back into the boiling flask, which is held in
place by a clamp. A water hose should also be attached and water should be flowing through the outer jacket which will
re-condense the vapour and send it back to the location. Its effect in volume should stay the same at 0, and it could be
done for fours, says and significantly long periods without significant loss of volume benefit.
Having done the boiling point in the lab I got 70 degrees as my boiling point. This is impure because we saw that the
liquid was cloudy which meant that there were impurities in the substance, so that is why the boiling point was higher.
The boiling point is used as it determines the purity of ester., you can determine the boiling point using methods such as
spectroscopy, and TLC (thin layer chromatography).We can also carry out thin layer chromatography TLC on the
product. You have a mobile and stationary phase, and the compound will interact between these two phases. For the
stationary phase, a silicon gel is used for this and place the spots on the line and prepare the mobile phase by preparing
a beaker with a small amount of solvent to determine whether the paper is saturated it should begin to become wet,
and then seal it from the top as organic substance are volatile and will evaporate into the air which is dangerous to
inhale. Once it reaches the top pencil will mark the mobile phase and use a UV light to visualise the spots.
2 dots impure
1 dot pure
Determine pure product see which dots line. Silicon is very polar, so carboxylic acid is 1 dot nearer as it is polar
“assuming” Less polar attracted to the mobile phase. The spots that shown on the chromatography paper that are
impure can be a waste product, an acid, or a by-product that is has been completely removed. The End Product will
In conclusion we got a higher boiling point of ester because it was impure, this could of have been because we did not
filter properly so we still had either some water or acid left mixed with the layer of ester during the separating funnel
and draining the water. We washed it three times and rushed, rather than waiting for the two mixtures to separate and
sit and then to drain out the water. We also had a lower yield as we may have taken out some ester when draining the
water as we did not wait for long or whilst draining some of the water ester which had evaporated must have escaped
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