CHEMISTRY 30132 SPRING 2009
ORGANIC QUALITATIVE ANALYSIS
LABORATORY REPORT FORM
UNKNOWN CODE NUMBER: __X15___
NAME: __John Doe_____
Date: ____02/18/2009____
Identity of Unknown: ___3 – NitroXXXX_____
Physical State: _____Solid______
1. PHYSICAL CONSTANTS (observed and published)
a. List of values measured in the laboratory:
b. List of values from the literature:
M.P. Range: ____xxx-zzz oC __________
Lit. Value (ref): ___ yyy oC (text; pg xxx)
__
2. SOLUBILITY TESTS: soluble (+), insoluble (-)
H2 O
5 % NaOH
5 % NaHCO3
5 % HCl
Conc. H2SO4
Ether
-
+
+
N/A
N/A
N/A
Reaction to litmus (water soluble compounds only): ___N/A____
Solubility Classification: ____A1_______
3. SODIUM FUSION ANALYSIS
X - (halogen) ___(-)ve_____
CN - ___(+)ve____
S 2- ___(-)ve____
4. NEUTRALIZATION EQUIVALENT (NE):
Run #1_____17.9 ml_______
Run #2_____17.8 ml_______
Calculations:
Neutralization equivalent (NE) =
Weight of sample (g) * 1000
Volume of the alkali (ml) * M
NE
=
0.2 g * 1000
17.8 ml * 0.0683 M
NE
=
164.51 (observed / calculated)
Neutralization equivalent (NE) = Molecular weight of the compound
NE
=
167.12 (MDL Beilstein)
Run #3_____17.8 ml_______
5. INFRARED SPECTRUM:
N/A
6. NUCLEAR MAGNETIC RESONANCE SPECTRUM:
N/A
7. MASS SPECTRUM:
N/A
8. CLASSIFICATION AND SUB-CLASSIFICATION TESTS
No.
Name of Test
Specific Observations and conclusion (+ve or –ve)
(1)
Sodium Bicarbonate Test –
Test for carboxylic acids
(Experiment 31)
Gas evolved spontaneously.
(+)ve test – presence of a carboxylic acid
(2)
Bromine Water Test –
Test for phenols or anilines
(Experiment 46)
Bromine color did not discharge; solution remained brown color.
(-)ve test – absence of a phenol or aniline
(3)
Sodium Hydroxide Test –
Test for Aromatic Nitro groups
(Experiment 44)
Initially no observation; after 30 minutes, solution turned pale yellow.
(+)ve test – presence of nitro group (not a very strong conclusion)
(4)
Potassium Permanganate Test –
Test for alkenes or alkynes
(Experiment 38)
Solution remained purple color; no precipitate was formed.
(-)ve test – absence of alkene or alkyne
(5)
Chromic Anhydride Test –
Test for 10 or 20 alcohols
(Experiment 08)
Solution remained orange.
(-)ve test – absence of 10 or 20 alcohol
(6)
2,4-DNP Test –
Test for aldehydes or ketones
(Experiment 12)
No observation; precipitate was not formed.
(-)ve test – absence of aldehyde or ketone
Specific functional groups consistent with parts 2 and 3: __–COOH & –NO2___
(Classification tests were carried out after listing a table of possible compounds within a particular melting point
range. Therefore tests for 30 alcohols, amines, amides, and other functional groups were not required to be
carried out.)
9. TABLE OF POSSIBLE COMPOUNDS
Compound Name & Structure
Melting point
(MP) (oC)
NE
Specific Reason for Ruling Out
52.03
The unknown contains Nitrogen
(Na fusion); but this does not
contain any Nitrogen.
The observed neutralization
equivalent (NE) is 164.51; but
the NE of this molecule is much
lower.
186.21
The unknown contains Nitrogen
(Na fusion); but this does not
contain any Nitrogen.
The observed neutralization
equivalent (NE) is 164.51; but
the NE of this molecule is much
higher.
164.16
The unknown contains Nitrogen
(Na fusion); but this does not
contain any Nitrogen.
The unknown did not contain a
keto-group (2,4-DNP test); but
this molecule contains a ketogroup.
Propanedioic acid (malonic acid)
135d
1-Naphthaleneethanoic acid
135
2-Acetylbenzoic acid (aspirin)
135
1,5,5-Trimethylcyclopentene-2-carboxylic acid
135
154.21
The unknown contains Nitrogen
(Na fusion); but this does not
contain any Nitrogen.
The unknown was saturated;
but this is unsaturated.
2,4-Hexadienoic acid (sorbic acid)
135
112.13
The unknown contains Nitrogen
(Na fusion); but this does not
contain any Nitrogen.
The observed neutralization
equivalent (NE) is 164.5; but
NE of this molecule is lower.
The unknown was saturated;
but this is unsaturated.
3-Phenylpropynoic acid (phenylpropiolic acid)
137
146.15
The unknown contains Nitrogen
(Na fusion); but this does not
contain any Nitrogen.
The observed neutralization
equivalent (NE) is 164.5; but
NE of this molecule is lower.
The unknown was saturated;
but this is unsaturated.
(+/-)-cis-Camphenic acid
137
154.22
The unknown contains Nitrogen
(Na fusion); but this does not
contain any Nitrogen.
The unknown was saturated;
but this is unsaturated.
E-2-chloro-3-phenyl-2-propenoic acid
138
182.61
The unknown contains Nitrogen
(Na fusion); but this does not
contain any Nitrogen.
The unknown does not contains
Cl (Na fusion); but this contains
Chlorine (Cl).
The observed neutralization
equivalent (NE) is 164.5; but
NE of this molecule is higher.
2-Methylpropanedioic acid
138d
59.05
The unknown contains Nitrogen
(Na fusion); but this does not
contain any Nitrogen.
The observed neutralization
equivalent (NE) is 164.5; but
NE of this molecule is lower.
2-Pyridinecarboxylic acid (2-picolinic acid)
138
123.11
The observed neutralization
equivalent (NE) is 164.5; but
NE of this molecule is lower.
(did not ruled out)
5-Chloro-2-nitrobenzoic acid
139
201.57
The unknown does not contains
Cl (Na fusion); but this contains
Chlorine (Cl).
The observed neutralization
equivalent (NE) is 164.5; but
NE of this molecule is much
higher.
75.04
The unknown contains Nitrogen
(Na fusion); but this does not
contain any Nitrogen.
The observed neutralization
equivalent (NE) is 164.5; but
NE of this molecule is lower.
The unknown did not contain a
–OH; but this does contain.
(R,S)-2,3-Dihydroxybutanedioic acid
140
3-Nitrobenzoic acid
141
167.12
This molecule fits all the
classification descriptions as
well as the observed
neutralization equivalent (NE).
(can not be ruled out)
2-Chloro-4-nitrobenzoic acid
142
201.57
The unknown does not contains
Cl (Na fusion); but this contains
Chlorine (Cl).
The observed neutralization
equivalent (NE) is 164.5; but
NE of this molecule is much
higher.
4-Chloro-2-nitrobenzoic acid
142
201.57
The unknown does not contains
Cl (Na fusion); but this contains
Chlorine (Cl).
The observed neutralization
equivalent (NE) is 164.5; but
NE of this molecule is much
higher.
Z-3-Chloro-3-phenyl-2-propenoic acid
142
182.61
The unknown contains Nitrogen
(Na fusion); but this does not
contain any Nitrogen.
The unknown does not contains
Cl (Na fusion); but this contains
Chlorine (Cl).
The observed neutralization
equivalent (NE) is 164.5; but
NE of this molecule is higher.
2-Chlorobenzoic acid
142
156.57
The unknown does not contains
Cl (Na fusion); but this contains
Chlorine (Cl).
The unknown contains Nitrogen
(Na fusion); but this does not
contain any Nitrogen.
Octanedioic acid (Suberic acid)
144
87.10
The unknown contains Nitrogen
(Na fusion); but this does not
contain any Nitrogen.
The observed neutralization
equivalent (NE) is 164.5; but
NE of this molecule is much
lower.
2-Aminobenzoic acid (anthranilic acid)
144
137.14
The observed neutralization
equivalent (NE) is 164.5; but
NE of this molecule is lower.
(did not ruled out)
2,4,5-Trimethoxybenzoic acid (asaronic acid)
144
212.20
The unknown contains Nitrogen
(Na fusion); but this does not
contain any Nitrogen.
The observed neutralization
equivalent (NE) is 164.5; but
NE of this molecule is much
higher.
2-Chlorophenoxyethanoic acid
146
186.59
The unknown does not contains
Cl (Na fusion); but this contains
Chlorine (Cl).
The unknown contains Nitrogen
(Na fusion); but this does not
contain any Nitrogen.
2-Nitrobenzoic acid
146
167.12
This molecule fits all the
classification descriptions as
well as the observed
neutralization equivalent (NE).
(can not be ruled out)
2-Carboxyphenyl-2-oxoethanoic acid
146
97.07
The unknown contains Nitrogen
(Na fusion); but this does not
contain any Nitrogen.
The observed neutralization
equivalent (NE) is 164.5; but
NE of this molecule is much
lower.
212.25
The unknown contains Nitrogen
(Na fusion); but this does not
contain any Nitrogen.
The observed neutralization
equivalent (NE) is 164.5; but
NE of this molecule is much
higher.
67.05
The unknown contains Nitrogen
(Na fusion); but this does not
contain any Nitrogen.
The observed neutralization
equivalent (NE) is 164.5; but
NE of this molecule is much
lower.
Diphenylethanoic acid (diphenylacetic acid)
148
Oxodiethanoic acid (diglycolic acid)
148
MP range used to construct Table 9 (Carboxylic acids): ___135 – 148 oC ____
(Observed melting point of the purified unknown compound was 140-141oC. However if some specks of
impurities were present the melting point could be slightly lowered. Therefore in choosing the range, 5 oC was
taken below and 7 oC was taken above the observed melting point. No compounds were omitted.)
10. REFINED LIST
o
Compound Name
MP ( C)
NE
2-XXX
138
3-XXX
2-YYY
2-YYY
Derivatives and their Melting Points (oC)
(Amide)
(4-Toluidide)
123.11
107
104
141
167.12
143
162
144
137.14
109
151
146
167.12
176
203
11. PREPARATION OF DERIVATIVE
Name of Derivative
Observed MP range
Literature MP and Reference
Amide
139 – 140 oC
143 oC (text; pg 606)
12. CONCLUSIONS
The first unknown (A4), was a white solid. The first step was to carry out the solubility tests. The
compound was insoluble in cold water. It dissolved completely in hot/boiling water (The water was cooled and
the compound was recovered. This showed that the compound had not decomposed or reacted). Considering the
compound to be insoluble in water, it was treated with 5% NaOH, in which it dissolved. Next it was treated
with 5% NaHCO3 and it dissolved. This classified the compound in the A1 solubility class. It was a carboxylic
acid with more than six carbons, a phenol with electron withdrawing groups or a beta-diketone. Since the
compound was soluble in hot/boiling water, it was next treated with ether, in which it dissolved completely.
Next the partially dissolved compound was tested with litmus paper. It turned blue litmus to red color, showing
that it was an acid. This also classified the compound to the solubility class SA, which stated that the compound
would be a monofunctional carboxylic acid with five or fewer carbons or an arylsulfonic acid. This was done in
order to include all the possibilities. Since both solubility classes spoke of carboxylic acid either with more than
six carbons or less than six carbons, it could be inferred that the unknown was a boarder-line situation. However
this inference was not taken for granted; each possibility was tested.
Secondly, the melting point of the crude compound was measured to be 136-138 oC. Once purified and
recrystallized, a sharp melting point was observed; which was 140-141 oC (In recrystallizing the compound
water was used as the solvent for the unknown was partially soluble in water).
Thirdly, classification tests were carried out. The Sodium Bicarbonate test gave positive results. It was
inferred that a carboxylic group was present. This was enough evidence to have formed that first list of possible
compounds. However a Bromine Water test was carried out to look for the possibility of a phenol. This gave
negative results, making it possible to infer that a phenol was absent.
Next, a possible list of compounds was put together solely based on the melting point range and the
presence of a carboxylic group. Usually in the presence of impurities the melting point of compounds decreases
slightly. Although the unknown compound was purified there could have been a chance for some traces of
impurities to lower the observed melting point. Thus when listing the compounds 5oC were taken below and 7oC
were taken above, giving a range of 13 degrees (135-148 oC). There were 25 possible compounds in the list.
There structures were drawn-out and studied. Different functional groups were noted down. Among the
compounds the following functional groups were present; -NO2, -Cl, carbonyl, alkene, alkyne, -OH, NH2, and
ethers in addition to the carboxylic group.
Next, classification tests were carried out again to verify the possible functional groups that were present
in the compound list. Sodium Hydroxide test was carried out to look for the presence of a -NO2 group. The
colorization of the solution occurred after a prolonged period of time. This was not a very conclusive test for the
results should have been immediate. However the presence of the –COOH group which is also a EWG on the
benzene would have deactivated the system further. This explains the long time it took for the positive result
and could be concluded as a positive test. However, this result was not used to eliminate any possibility.
The other classification test that were carried out included; the Potassium Permanganate test for
unsaturations, the Chromic Anhydride test for the presence of 10 or 20 alcohols and the 2,4-DNP test for the
presence of carbonyl groups. All three of these classification tests gave negative results and the absence of
alkenes, alkynes, 10 or 20 alcohols, ketones or aldehydes was concluded. Other classifications such as the test for
amides, amines, amino acids, 30 alcohols and all the rest were not carried out, because they were not included in
the list of the possible compounds in the selected melting point range.
The next analysis/classification was the Na fusion analysis. Here the compound was tested for the
presence of Cl-, CN-, and S2-. The test for Nitrogen was positive, while it was negative for both Sulfur and
Halogens. This allowed shortening the list of the large amount of possible compounds. After the results of the
Na fusion and all the other classification tests, sufficient data was available to refine the table and reduce the
number of compounds to four. These compounds are included in the refined list (No.10).
Next a titration was carried out to compute the neutralization equivalent (NE). After three careful runs,
the NE was calculated to be 164.51. The NE was able to eliminate two more of the compounds on the refined
listed. However the NE was unable to distinguish between 3-XXX and 2-XXX, for they had the same
neutralization equivalent. Thus it was required to form derivatives to distinguish between the few possibilities
left (The NE value is unique to given compounds, but it was not use to discard the other two possibilities and
derivatives were formed in order to identify the proper compound).
After studying the differences between the melting points of the derivatives of the four possible
compounds, the amide and the 4-Toluidide derivatives were prepared. The purified amide had a melting point of
139 – 140 oC which clearly separated the 3-XXX acid from the rest of the possible compound and especially
from the 2-XXX, for the 2-YYY acid and 2-ZZZ acid could have been ruled out based on the neutralization
equivalent as well. To reconfirm the identity a second derivative was formed. However it was not as successful
as the amide, for its pure yield was significantly small and the melting point was significantly lower. Although
the melting point was about 10 units lower than the expected, this too supports the fact the compound was 3XXX over the 2-XXX, for there is a clear difference between the melting points of the 4-Toluidide derivatives
of the two compounds.
As in the case of all research, the unknown molecule did not identify itself directly. With the help of a
systematic elimination process, it was possible to identify 3-XXX. All the tests and analyses were in favor of 3XXX. The melting point of the purified compound 140-141 oC, is overlapping that of 3-XXX. The
neutralization equivalent 164.51 is close to that of 3-XXX, which is 167.21. The different of 3 units could be
due to the presence of slight impurities in the compound or a slight variation in the standardized solution of
NaOH. The presence of the only functional groups was WWW & VVV and this is true in the case of 3-XXX.
The solubility class was A1. This is true for 3-XXX which has X carbon atoms. The observed melting point of
the amide derivative 139 – 140 oC, is close to the literature value (143 oC). The depression could be due to the
slight contamination of compound. The identity of compound “X15” is 3-XXX.