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Org-Chem 221 Lab
Exp
...
Ghasssan
Student Name: Yazan Bassam Abu Kwerder Partner Name: Ghaida
Student No: 1140426
Partner No: -------------------------
Experiment No: 3
Experiment title: Recrystallization of Acetanilide prepared from Aniline
Submission date: 12/3/2016
Objectives:
1- Learning the technique of purifying organic solids
''Recrstalization''
...
3- Determining the purity of the product
...
Chemicals:
1- Aniline
2- Acetic Anhydride
3- Water
4- Zinc Dust
Glassware:
1- Filter Flask
2- Water Aspirator
3- Filter paper
4- 250 ml Erlenmeyer flask
5- Graduated cylinder
6- Thermometer
7- Buncher Funnel
Reactions:
(Including the name of the synthesis reaction and the reaction equation)
Aniline + Acetic Anhydride Acetanlide + Acetic Acid
Reference : "http://www
...
com/articles/680/preparationrecrystallization-acetanilide"
Mechanisms:
Reference : " http://www
...
edu/~chem216/216%20S11Expt%201
...
C- Add 5ml of acetic
anhydride in several small
portions
...
3- After boiling , cool a bit and
add 0
...
Cooling before addition of
charcoal is important in
order not to pump out
...
dissolve
5- Filter out charcoal using a
fluted filter paper and a
preheated short stem
funnel "Gravity Filtration"
6- Cool the filtrate to room
temperature then cool in
ice ,crystals should appear
...
8- Keep the suction on to
squeeze out all the solvent
9- Remove the filter paper
with the crystals after
drying them , and weigh
them
...
In addition calculate the moles and mass or volume
of the reagents
...
I
...
III
...
V
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VII
...
IX
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66g
Final Weight of filter paper : 0
...
17g
Final Weight of normal paper (Boat) : 9
...
19g
Crystals weight''Acetinlide'' ( III + VI ) : 4
...
13g
The Melting point of acetanlide : 115
...
3C
- Molecular weight : 93
...
3C
-Boiling Point :184C
Acetanilide :-Molecular weight :102
...
219g/cm3
-Boiling Point :138C
Calculation and results:
(Step by step)
To Determine the limiting reagent :
9
...
1mole
5ml analine ??
X= 0
...
055mole
10ml acetic Anhydride 0
...
053
As a result of this , Acetic Anhydride is the limiting reagent !!
Also the stoichiometric of the reaction is 1:1 !
...
053x1mole
= 0
...
053mole x 135g/mole (density) = 7
...
13/7
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68%
Discussion & Comments:
Provide a summary of the experiment including observations, analysis of all data and
results, and methods to correct errors or optimize the experiment
...
It was noticed that the yield was low, this is maybe caused due
to the additional amount of charcoal which stick with the
acetanilide so didn't went down through the filter paper
...
Q1
...
First of all ,
maybe we did not add enough crystal charcoal or we didn’t filtrate it correctly ,
which caused by falling of some fine charcoal with the hot supernatant into the
flask
...
To obtain colorless product e need to repeat the filtration process with adding
enough charcoal
...
9
...
1moles aniline
15ml
????
X= 0
...
106 moles acetanilide
15ml
???
X= 0
...
159moles x 135g/mole(density) = 21
...
The theoretical yield = 21
...
Q5
...
10g of benzoic acid :
a- At 75C
2
...
1g
????
X= 4
...
18g Benzoic acid 100ml
0
...
5ml of water
bAt 60C
32grams benzoic acid 100ml CCl4
0
...
3125 ml CCl4
AT 0C
1
...
1g
???
X= 6
...
Also , As the difference in solubility between hot and cooled
water is greater than the CCl4 , so the crystals obtained will be larger and
better
...
2g Benzoic acid 100ml water
100g
????
X= 4545
...
18g Benzoic acid 100ml
100g
??0
X= 5555
...
5 ml CCl4
AT 0C
1
...
67
CAs we see water is better solvent , because water is easier to measure
the quantity used