Pre-labs:
For each preparative lab you are required to submit at least 24 hours before the lab a pre-lab
write-up. The pre-lab is to be written in your lab notebook and the carbon copies submitted for
review. These carbon copies will later be attached to your lab report.
1. Title (be specific, eg. "Reduction of Acetophenone with Sodium Borohydride"), name &
date.
2. Balanced chemical equation(s) for the reaction(s) that you are going to carry out.
3. Table of Physical Properties summarizing the physical properties of the reactants,
solvents, and products. Make photocopies of the sample provided, or make up your own.
4. A step-by-step procedure for the reaction, separation, and purification. Be specific as to
amounts (moles & weight or volume).
5. For multi-step syntheses prepare a separate Table of Physical Properties for each
reaction in the sequence.
You may turn in pre-labs directly to the instructor or they may be placed in his mailbox in
the Chemistry Office (NSM B-202). If you have not submitted a pre-lab before the lab you will not
be allowed to begin the experiment until the pre-lab has been completed and okayed. Failure to
submit pre-labs on time can severely affect your grade.
Lab Reports
A typed lab report is required for each experiment and is worth 20 pts (180 pts total) or
approximately 45% of your total course grade. Reports are due one week after the scheduled
completion of the experiment at 1:00 pm for section 01 and 9:00 am for section 02. Labs turned in
after these times will be penalized 10% per day late.
Follow the following format for preparative reports:
1. Title, name & date (unknown #)
2. Balanced equation(s) for the reaction(s) you carried out.
3. Step-wise mechanism(s) for the reaction(s).
1
4. Physical data for your product(s) (weight, mp or bp, %yield, & literature mp or bp for
comparison).
5. Tabulation of spectral data. (Tables summarizing the IR and nmr spectra and your
interpretation). see attached.
6. Conclusions, comments, deviations, etc. Discuss your results.
7. Answers to the questions at the end of each preparation.
8. Attach to the end of the report:
a) the pre-lab including table of physical properties
b) any additional carbon copies from your lab notebook
c) IR & nmr spectra, glc's, etc.
Products
With your lab reports you are to turn in the products that you have synthesized in the
laboratory. Note, the labels must contain your name, the date, the identity of the contents, the net
weight, and the mp or bp. Solid products should be in wide-mouth bottles and liquids in narrowmouth containers.
2
TABLE OF PHYSICAL PROPERTIES (This table must be completed before coming to lab!)
Reactants and
bp
solvents
(0C)
MW
mp
(g/mol)
(0C)
Moles
solubility
Product(s)
3
weight
volume
density
(g)
(mL)
(g/mL)
TABLE OF PHYSICAL PROPERTIES (This table must be completed before coming to lab!)
Reactants and
bp
solvents
(0C)
MW
mp
(g/mol)
(0C)
Moles
solubility
Product(s)
4
weight
volume
density
(g)
(mL)
(g/mL)
NITRATION OF A HALOARENE
NOTE
WEAR GLOVES AND LAB COAT DURING THE ENTIRE PROCEDURE
Haloarenes and their nitration products are irritating to sensitive skin areas. If you should have
these materials on your hands and then accidentally touch your face, this can cause a severe
burning sensation in the affected area. If this should happen,
IMMEDIATELY:
1. Go to the restroom and wash the affected area with lots of soap and water.
THE SOAP IN THE LAB IS NOT SUITABLE FOR THIS PURPOSE.
2. Return to the lab and apply mineral oil to the affected area.
3. The summary to this warning is NOT TO TOUCH ANY PART OF YOUR BODY
WHILE PERFORMING THIS EXPERIMENT.
If you must leave the lab for any reason:
1. First dispose of your gloves in the waste container
2. Immediately go to the restroom and wash your hands
thoroughly with soap and water.
AGAIN, LAB SOAP WILL NOT DO A SUFFICIENT CLEANING
JOB
3. Upon returning to the lab, obtain another pair of
gloves from the front of the room, and proceed with
the experiment.
5
NITRATION OF A HALOARENE
Equation:
RBr + HNO3
H2SO4
--------------> RBrNO2 + H2O
Locker #
Compound
4 Bromobenzene
1,4-Dichlorobenzene
1,3-Dichlorobenzene
1-Bromo-4-chlorobenzene
Chlorobenzene
1,4-Dibromobenzene
1,2 Dichlorobenzene
1, 10, 20, 4
2, 12, 22, 9
3, 13, 19
5, 15
6, 16, 11
7, 17, 21
8, 18, 14
------------------------- FOR SAFETY REASONS -------------------------1.
2.
3.
Add 700mL of tap water to your 1 L Beaker.
Discard any acid washings, plus the contents of the filter flask (from step 9 below) into your
1 L Beaker, WITH STIRRING.
Wash the contents of your 1 L Beaker down the sink.
PROCEDURE
1.
Obtain 0.025 mole of your haloarene ( See table above ) to a small beaker/graduated
cylinder, and place it in your
hood area.
2.
Prepare a mixture of 5 mL conc HNO3 and 5 mL conc H2SO4 in a 25x150 mm test tube,
take it back to your hood workstation and clamp it to your hotplate/stirrer, immersing the
tube in a 150 mL beaker containing 100 mL tap water. Allow the tube to cool to 30 deg. C,
measured using your glass thermomtter.
3.
To the test tube, add your haloarene, gently stirring to mix the contents. Continue to
stir/agitate the test tube contents until the haloarene begins to transform into solid
nitrohaloarene immersed in the acid mixture. Keep the reaction mixture between 50 - 55
o
C. DO NOT ALLOW THE REACTION MIXTURE TO EXCEED 60 oC.
4.
After the exothermic reaction has subsided, heat the test tube for 10 min. on your hot plate
set at ~ 2.5 to maintain the temperature below 60oC during this period.
5.
Cool the test tube in an ice bath to room temperature
6.
Pour the reaction mixture into 50 mL of distilled water which is in a 150 mL beaker.
6
7.
Isolate the crude product by vacuum filtration.
8.
Wash the filter cake thoroughly with cold (0-10oC) distilled water and dry the filter cake by
allowing the vacuum apparatus to draw air through it after you have finished washing.
9.
Place the washings into the 1L beaker. Transfer the crystals to a TARED 50 mL beaker
and obtain the weight of your wet product
10.
Calculate the volume of 95%(v/v) ethanol needed to just dissolve the halobromobenzenes.
You will need approx. 5 mL 95% ethanol per gram of crude product. Round the amount of
ethanol needed to the next 5 mL increment. (e.g.: 5.6 g. x 5 mL/g = 28 mL => use 30 mL).
SHOW THIS CALCULATION IN THE PROCEDURE PORTION OF YOUR
REPORT.
11.
Bring this mixture to boiling to dissolve the crude product. If the product does not
completely dissolve boiling, add 5 mL of 95%(v/v) ethanol. If solid still remains you will
have to do a hot filtration. Once your crude product has dissolved, set the flask onto your
lab bench and allow the contents to cool slowly to room temperature.
12. Isolate the nearly pure crystals of your product by vacuum filtration. If there is solid
material in the filter flask at this point, pour it into a beaker and vacuum filter this solution
again through the funnel containing the first crop of nitrobromobenzene. Save the filtrate.
13. Wash the crystals with a little ICE COLD ethanol, allowing the washes to drain into the
filter flask containing the filtrate. The filtrate may now be poured into the recovered
organic solvents container at the east end of the lab.
14. Allow air to be drawn through the Buchner funnel for 5 min. then detach the vacuum hose
from the filter flask, turn off the water and transfer the solid from the Buchner funnel onto
11cm filter paper which is on a watch glass. Spread the solid over most of the filter paper,
breaking large clumps into small particles and put it in your drawer to dry overnight. Place
another piece of filter paper lightly over the crystals to keep the dust out.
Thin-Layer Chromatography
1.
Take a few crystals of haloarene isomer, place in a 5 ml beaker, and add 5 drops of acetone
to the beaker to dissolve the crystals. Do the same with your known haloarene standards
2.
Take a 2.5 x 7.5 cm strip of silica gel, mark the origin 1 cm from bottom and make 2 pencil
marks lightly on the origin.
3.
Apply one drop of the solution containing the 4-nitro isomer on one spot & one drop of oil
containing the 2-nitro isomer on the other spot. Be sure that neither application results in a
spot more than 2 mm in diameter. Allow the strip to dry at your hood workstation .
7
4.
Place dried strip in jar containing the solvent solution Hexane: Chloroform 9:1.
5.
When the solvent system reaches within 1 cm of the top of the strip, remove the strip, allow
to dry at your hood workstation & view under ultraviolet light in the U.V. box. Outline the
spots with a pencil by stippling around each spot while the chromatogram is still in the U.V.
box.
6.
Dispose of the remainder of your product into the jar provided at the front of the lab.
8
Infrared Spectroscopy
The natural frequencies of vibration of covalently bonded atoms correspond to radiation
frequencies that lie in the infrared region of the electromagnetic spectrum. If infrared radiation is
directed at an organic molecule, one of whose vibrational frequencies is the same as the frequency
of the radiation, that radiation is absorbed to some degree and vibration is stimulated. The radiant
energy absorbed is equal to the difference on the energies of the vibrational levels: ΔE = hv. In
order for interaction with infrared radiation to occur, it is essential that the electronic dipole
moment of the absorber vary during the course the vibrational motion. Thus not all vibrational
modes are active in the infrared spectrum.
Particular vibrational modes (and their associated infrared absorption frequencies)
can often be identified with a specific molecular fragment. In many cases organic functional
groups constitute such fragments.
Vibrational modes can be divided into two general catagories: stretching and bending
modes. These modes can be further differentiated into asymmetric and symmetric stretching and
rocking, scissoring, twisting and wagging, which are associated with bending.
Table of IR Absorptions
Functional
Group
Characteristic
Absorption(s)
(cm-1)
Notes
Alkyl C-H
Stretch
2950 - 2850 (m
or s)
Alkane C-H bonds are fairly ubiquitous and
therefore usually less useful in determining
structure.
Alkenyl C-H
Stretch
Alkenyl C=C
Stretch
3100 - 3010 (m)
1680 - 1620 (v)
Absorption peaks above 3000 cm-1 are
frequently diagnostic of unsaturation
Alkynyl C-H
Stretch
Alkynyl C=C
Stretch
~3300 (s)
2260 - 2100 (v)
Aromatic C-H
Stretch
Aromatic C-H
Bending
Aromatic C=C
~3030 (v)
860 - 680 (s)
1700 - 1500
(m,m)
9
Bending
See "Free vs. Hyrdogen-Bonded Hydroxyl
Groups" in the Introduction to IR Spectra
for more information
Alcohol/Phenol
O-H Stretch
3550 - 3200
(broad, s)
Carboxylic Acid
O-H Stretch
3000 - 2500
(broad, v)
Amine N-H
Stretch
3500 - 3300 (m)
Nitrile C=N
Stretch
2260 - 2220 (m)
Aldehyde C=O
Stretch
Ketone C=O
Stretch
Ester C=O
Stretch
Carboxylic Acid
C=O Stretch
Amide C=O
Stretch
1740 - 1690 (s)
1750 - 1680 (s)
1750 - 1735 (s)
1780 - 1710 (s)
1690 - 1630 (s)
The carbonyl stretching absorption is one of
the strongest IR absorptions, and is very
useful in structure determination as one can
determine both the number of carbonyl
groups (assuming peaks do not overlap) but
also an estimation of which types.
Amide N-H
Stretch
3700 - 3500 (m)
As with amines, an amide produces zero to
two N-H absorptions depending on its type.
Primary amines produce two N-H stretch
absorptions, secondary amides only one,
and tetriary none.
Nuclear Magnetic Resonance Spectroscopy ( NMR )
Unlike Infrared and Ultraviolet spectroscopy, Nuclear Magnetic Resonance Spectroscopy
requires exposure of the organic substance to the radiofrequency portion of the electromagnetic
spectrum while the substance is simultaneously subjected to a strong external magnetic field.
Certain atomic nuclei have magnetic properties, and thus absorption or emission of energy by the
nuclei may occur. The hydrogen atom is the simplest atom containing nuclei having a magnet
moment. A spinning proton posses a magnetic moment which may be aligned with or against an
externally applied magnetic field. Protons whose spin magnetic moments are aligned with the field
are in a more stable ( lower energy ) state than those whose spin magnetic moments are antiparallel
to the applied field.
Chemical Shift
10
Not all of the hydrogen nuclei in a molecule respond to the same degree when effected by a
circulating magnetic field. We use this principle to differentiate between one type of hydrogen
molecule, from one in a different location/environment. The actual location in the spectrum is
arbitrarily aligned to a zero reference point – tetramethylsilane
( TMS ), which is assigned a value of 0 ppm. A mixture of an organic compound dissolved in a 5%
TMS in CCl4 solution will yield an NMR spectrum where the peaks
are the hydrogen nuclei reacting to the NMR magnets magnetic field. These chemical shifts
correspond to particular types ho hydrogen nuclei in their specific orientation/
environment within the molecule. The magnitude of the chemical shift depends very much upon
the electron density in the area of the proton. Chemical shift tables should be used as a general
guide, since combinations of effects of neighboring structures can affect
a protons shift slightly.
Spin-Spin Splitting
More complex molecules yield spectra where the total number of peaks observed is far
greater than the number of different hydrogens present. The multiplicity of peaks grouped together
is a consequence of the interaction of the magnetic fields associated with one type of hydrogen with
those of nonequivalent neighboring hydrogens, a phenomenon known as coupling. The net effect
usually is the splitting of the signal into n + 1 smaller closely spaced peaks, where n is the number
of adjacent hydrogens that are equivalent to one another.
CHE-313
Reporting IR and nmr spectra
Report the results of infrared and nmr spectroscopy in tabular form. See example below:
For the nmr:
1. Draw the structure of the compound and label the groups of hydrogens that give rise to
each signal using a, b, c ... (let a = most up-field).
2. Make a table showing the chemical shift, integration and splitting pattern for each group
of hydrogens assigned to the structure.
example: ethoxybenzene
Ph-O-CH2CH3
c
b
a
3H
triplet
a
1.3 ppm
b
3.9 ppm
2H
quartet
c
6.6-7.2 ppm
5H
complex
11
For the IR:
Make a table listing in decreasing order all of the absorbances and identify those that are
important.
example: ethoxybenzene
frequency (cm-)
interpretation
3040
3000
2940
1600
1580
1500
1480
1390
1300
1240
1170
1120
1050
880
800
750
690
C-H stretch unsaturation, Ar-H
C-H stretch saturation
C=C stretch, aromatic ring
C=C stretch, aromatic ring
C-H bend, saturated
" " "
C-O stretch, ether
C-H out of plane bend mono-substitution
12
Oxidation of a side chain & introduction to IR and nmr
You will oxidize an unknown arene with KmnO4 to a benzoic acid. See the procedure in
this supplement. Because the starting material is an unknown, the table of physical properties is a
little different from the ones you have previously prepared. You will be given (on the unknown
bottle) the molecular formula of your unknown. Calculate the gram formula weight and the
number of moles contained in 1.0 grams. The amount of KMnO4 you will use is based on the
formula of your unknown.
You will identify the unknown arene from the melting point of the acid product and the IR
and nmr spectra of the unknown. Be sure to balance your chemical equations correctly. No
mechanism is required for this report. Include the answers to the following questions in your
report.
Answer the following questions:
1. Write a balanced chemical equation for the permanganate oxidation of p-xylene under
basic conditions. See your general chem text for review of balancing oxidation-reduction
equations.
2. Write a balanced chemical equation for the permanganate oxidation of tolune.
3. Write chemical equations to show how you would oxidize toluene to benzaldehyde
rather than benzoic acid. see M&B
4. Why is benzoic acid more soluble in base than in aced?
What is this difference in solubility used for?
5. Tert-butylbenzene is not oxidized by permanganate to benzoic acid. Why not?
6. a) Draw all of the arenes with formula C7H7Br and show the products of oxidation for
each one. b) Look up the mp of each product. c) Can you identify every isomer based on the
melting point of the carboxylic acid derivative? Explain.
7. Write a balanced equation for the reaction of potassium permanganate with sodium
bisulfite.
13
Identification of an unknown arene by oxidation to the carboxylic acid; introduction to IR and nmr
spectroscopy.
A classical approach to the identification of some aromatic compounds is the oxidation of
side chains to carboxylic acid groups. Measurement of the derivative's melting point and
comparison with the known melting points of different benzoic acids provided a means of
identifying or eliminating certain possible structures. For example: if a compound was found to
have the formula C8H10, it could be four different compounds: ethyl benzene, o-xylene, m-xylene,
or p-xylene. If you look up the boiling points of these four compounds, they are very close to each
other. On the other hand, the melting points of the corresponding carboxylic acids produced from
the oxidation of the side chains are distinctly different. When combined with additional
information, such as the IR and nmr spectra, the melting point of the derivative will usually be
sufficient to determine the structure of the unknown.
You will be given a small sample of an unknown arene for which the only information
provided is the molecular formula. You are to carry out the permanganate oxidation in alkalai
solution and isolate the carboxylic acid. You will measure the melting point of the acid and
compare it to the melting points of the possible derivatives from your molecular formula. In
addition, you will obtain the IR spectrum of your original uknown and the nmr spectrum.
procedure:
1. The apparatus consists of a 250 mL round-bottom flask fitted with a reflux condenser.
2. Place about 1 gram (40 drops) of the unknown into the flask.
3. Add approx. 80 mL of water and 1-2 mL of 6M NaOH to the flask.
4. Using the powder funnel, introduce the required amount of potassium permanganate (see table
below) into the flask and add a couple of boiling chips.
compound formula
C7H8
C8H10
C9H12
g KMnO4/g unknown
4g
6g
8g
5. Attach the reflux condenser and begin heating the mixture with a heating mantle. Be careful
when the mixture first starts to boil as it has a tendency to "bump".
6. Continue the reflux for 2-3 hours. At the end of the first period, cool the flask, label it, cork it,
and place it in one of the hoods until next lab.
7. Suction filter the contents of the round-bottom flask to remove the solid MnO2.
8. Transfer the filtrate to a 250 mL beaker. Place the beaker in a ice bath, and after the solution
has cooled for 10 minutes, acidify with 10 mL of 6 M H2SO4, while stirring. (If the solution is still
purple due to excess permanganate, destroy it by adding no more than about 2 mL of 20% sodium
bisulfite.
9. Test the solution with litmus to verify that it is acidic; if not add more sulfuric acid.
10. Filter the precipitated acid with suction through a small buchner funnel and wash with a few
mL of cold water. (If no acid has precipitated, consult with the instructor).
11. Recrystallize the acid from a suitable solvent (try water first).
12. Let the product air dry, weigh it, package it, and obtain its melting point.
14
Identification of an unknown carbonyl
In this experiment you will be given an unknown aldehyde or ketone. You will obtain the IR and
nmr spectra, do the Tollen's test, and prepare two solid derivatives. In the report, identify the
unknown and compare the experimental values with the ones given in the text; make a TABLE for
comparison. Be sure to include balanced equations for the Tollen's test, the preparations of the
derivatives, as well as appropriate mechanisms. Do not weigh derivatives or calculate % yield.
Prepare the 2,4-dinitrophenylhydrazone derivative of your unknown. The reagent is already
prepared. Mix 10 drops (0.5 mL) of your unknown in 20 mL of 95% ethanol. To this solution, add
15 mL of the 2,4-DNPH reagent. Shake the mixture vigorously. If a precipitate does not form
immediately, let it stand for 15 minutes. Suction filter the solid derivative and recrystallize from
95% ethanol. After air drying, obtain the mp.
Make an additional derivative, the semicarbazone, according to the directions on page 1014 and
obtain the mp.
Test the unknown with Tollen's Reagent (p 494) to see if it is a ketone or an aldehyde. Page 10001001 lists possible aldehydes in increasing order of boiling point and the melting points of easily
prepared derivatives. Ketones are listed in the table on pages 1001-1003.
Do a simple distillation to measure the boiling point of your unknown carbonyl compound.
Obtain the IR and nmr spectra of your unknown carbonyl compound.
Answer the following questions:
1) An unknown organic compound (b. 212-216 oC) gives a positive 2,4-DNPH test and is
positive with Tollen's reagent. A semicarbazone derivative is made that melts at 228-232 oC. What
is the identity of the unknown? What would you do next?
2) Predict the products of the reaction of the following with silver nitrate in ammonium
hydroxide:
cylcohexanone
formaldehyde
acetone
acetophenone
butyraldehyde
3) In the reaction of an aldehyde or ketone with derivatives of ammonia, the reaction can be
catalyzed by sulfuric acid. However, it is important that the pH not be too low since the reaction
will slow down at very high acid concentrations. Explain.
4) Ketones do not oxidize readily. However, cyclohexanone will react with powerful
oxidizing agents at high heat to adipic acid (HO2C-(CH2)4-CO2H). The reaction is not really one of
the ketone, but the enol. Write equations to show how this is possible.
15
Reduction of acetophenone to 1-phenylethanol
- 0.5 g NaBH4 + 10 mL EtOH (95%)
- dropwise (controlled addition; keep temperature < 50o ) of 5 mL of acetophenone
- let stand 15 minutes
- acidify with 5 mL (6M) HCl
- boil down on hot plate until you have two layers
- extract with (1) 20 mL Et2O
(2) 10 mL Et2O
-dry combined ether extracts over anh. MgSO4 TWICE!
-distill off Et2O (  waste bottle )
-residue = crude product (bp 102.5 – 103.5 @ 19 Torr), do not distill
IR, nmr of product AND acetophenone
We will not purify the product with vacuum distillation. After the removal of the diethyl ether,
package, weigh and label the crude product. Obtain IR and nmr on both the acetophenone and the
product.
Answer the following questions:
1. What was the molar ratio of NaBH4 to acetophenone that you used in the experiment. What is
the theoretical ratio? Why did you use more than the theoretical ratio?
2. After the reaction of the carbonyl with sodium borohydride, the mixture is treated with water
and acid to produce the desired alcohol. Indicate the source of the alcoholic hydrogen in the
product.
3. Although sodium borohydride reacts slowly with methanol, when mineral acid was added, it
rapidly decomposed with the evolution of hydrogen. Explain.
4. Why is 1-phenylethanol more prone to dehydration than 2-phenylethanol?
5. What is the structure of the white precipitate that forms in the reaction of acetophenone with
NaBH4?
16
6. Write an equation for the reaction of the white ppt with water and HCl.
7. Draw the structure of the products of the reduction of each of the following with NaBH4:
a) cyclohexanone
b) 3-cyclohexen-1-one
c) 1,4-butanedial
d) 4-oxohexanal
8. Draw the structure of the products for the reduction of each of the compounds in question 7 with
excess hydrogen gas over Nickel.
9. Why does the concentration of the ethanolic reaction mixture, followed by the addition of HCl,
result in the formation of two layers?
17
Esterification
PREPARATION OF METHYL BENZOATE
1. Take your 100-mL round-bottomed flask, cork ring and wide stem funnel to one of the lab
balances and add 10-gm benzoic acid, followed by 25-mL methanol.
2. From the repipettor, carefully add 3-mL conc. H2SO4 down the side of the flask.
3. Swirl the flask to mix the reagents. Add your magnetic stirring bar to the flask.
4. Attach a reflux condenser, and gently reflux for one hour.
5. Transfer the solution in the flask to a 250-mL separatory funnel containing 50-mL water.
6. Rinse the flask with 40-mL diethyl ether and add the rinsing to the funnel.
7. Shake the funnel thoroughly, ( venting the funnel frequently ), to facilitate extraction
of the methyl benzoate into the ether layer.
8. Remove the aqueous layer and wash the organic layer with a second 25-mL portion of
water.
9. Separate the layers, (leaving the organic layer in the funnel), and cautiously add 25-mL
0.6M NaHCO3 to the organic layer remaining in the funnel.
10. Shake the mixture, (venting frequently), to wash the product of any remaining acids.
( Which acid(s) ?).
11. Remove the aqueous layer and test to see it is basic to litmus. If not, Wash the organic
layer with another 25-mL portion of NaHCO3 and test the aqueous wash again with
litmus.
12. Once the NaHCO3 wash is basic to litmus, wash the organic layer a final time with
Saturated NaCl. (why ?).
13. Dry your product over anhydrous MgSO4.
14. Decant the dried organic layer into your 100-mL round-bottomed flask and simple distill
off the remaining ether - hotplate set at 3.
15. Allow the flask to cool and weigh the product.
16. Save this product for use in the Grignard Experiment.
18
Answer the following questions as part of your report:
1) a) If the Keq for the esterification of acetic acid with isopentyl alcohol is 3.0, what is
the maximum amount of isopentyl acetate that can be recovered at equilibrium if a 1:1 mole ratio of
acid:alcohol is used?
b) If a 1:5 mole ratio is used?
c) 5:1 mole ratio?
2) What role does sulfuric acid play in this reaction? Explain; show equations.
3) Tell what effect doubling the concentration of sulfuric acid would have on the yield of
the ester.
4) Why were the contents of the round bottom flask after reflux poured into 10 mL of
water?
5) Why do we wash the ester with sodium carbonate solution?
6) Why would solid NaOH not be a good drying agent for the ester?
7) How would you distinguish between the nmr spectra of methyl benzoate and phenyl
acetate?
8)
Organometallics
Glassware to be used in Grignard Reaction
Your 250-mL round-bottomed flask, claisen connecting tube, condenser, 2 test tubes, and 125-mL separatory funnel,
should be dry. Leave it out on your desktop for.
19
PREPARATION OF TRIPHENYLMETHANOL
H2SO4(aq)
Eq: 2Mgo + 2C6H5Br + C6H5COCH3 ------------------> (C6H5)3· COH + CH3OH + 2Mg+2 + SO4-2 + 2Br
Amounts of reactants actually used and maximum amounts possible of product
Compound
MW
Mgo
C6H5Br
C6H5COOCH3
(C6H5)COH
24.0
157
136
260
1.522
1.094
Moles
Grams
2.4
Density (g/ml)
ml
-
12.4
5.6
MPoC
-
-31
-12.4
164
BPoC
-
156
196
-
Assemble your apparatus as shown in the lab demo.
1.
Working quickly, bring your reaction flask to the front of the room and add to it 2 shots (10 mL) of
ANHYDROUS diethyl ether, and the contents of the vial of Mg provided.
2.
Reassemble your reaction flask to your apparatus.
3.
Take your separatory funnel (with stopcock CLOSED) to the front of the room and add to it 3 shots (9.3 mL)
bromobenzene and 5 shots (25 mL) diethyl ether. Swirl the funnel to mix its contents and reassemble the funnel to
your apparatus.
4.
Prepare an ice bath in case it is needed.
5.
Begin water running through your condenser.
6.
Start your magnetic stirrer and add a 2- to 3-mL portion of the funnel contents to your reaction flask.
7.
Take the dried test tube to the front of the room and add to it 1 shot of bromobenzene and 1 shot of ether.
8.
Add enough magnesium turnings to barely cover the bottom of the tube.
9.
With a stirring rod or spatula mix the contents of the tube.
10. Scrape the magnesium against the bottom and the sides of the tube frequently, to promote reaction between the
bromobenzene and the magnesium.
11. Once the reaction has started, the ether will begin to reflux, and the tube will become warm to the touch, and
subsequently the solution will turn brown.
20
12. At this point quickly remove your separatory funnel and add the contents of your tube to your flask. Return the
separatory funnel to apparatus. When the contents of the flask begin to reflux, start adding the rest of the contents
of your separatory funnel DROPWISE at a rate just fast enough to allow one drop of ether to fall from the
condenser tip into this flask every second. Adding the contents too quickly causes coupling and overheating (see
"explanations of procedure"). If the reaction becomes too vigorous, cool the reaction flask with your ice bath and
reduce the rate of addition from your separatory funnel. If the reflux becomes too slow heat the reaction flask
gently by cupping you’re your hands around the flask. The entire addition should be finished in 30 minutes.
13. Allow the reaction to proceed until only a few slivers of Mgo remain (about 2 hrs.). The contents of the flask now
should be milky brown.
14. Once the Grignard Reagent has cooled to room temperature, add 5.6 mL of Methyl Benzoate and 20 mL anhydrous
diethyl ether to your dropping funnel.
15. Begin s l o w, dropwise addition of the contents of the dropping funnel to the reaction flask. As in the preparation
of the Grignard Reagent, control the rate of reaction by adjusting the rate of addition from the dropping funnel, and
occasional icing of the reaction flask, should it become necessary. When the reflux has stopped the mixture may
be heated to reflux for another 30 minutes to finish the reaction. Cool the flask, and once cooled to room
temperature, stopper it.
Return any excess Methyl Benzoate to the recovery bottle at the end of the west bench.
Failure to turn in your remaining methyl benzoate to the proper recovery container will result in a 5 point
reduction in your lab report score.
DAY 2
16. Your reaction flask should contain approx. 100 mL of a solid/liquid mixture. IF NOT, add additional diethyl ether
to bring the volume to about 100 mL.
17. In a 250-mL Erlenmeyer flask add enough ice to cover the bottom of the flask, followed by 50 mL of 6M H2SO4 swirl the ice-acid mixture.
18, Add the contents of the reaction flask to the erlenmeyer, with swirling. Continue swirling until all solid matter has
dissolved, and the solution is homogeneous. If there is still solid in the upper ether layer, continue adding ether
and swirling the flask until all of the solid has dissolved.
19. Transfer the mixture back into the reaction flask, to collect any solid left behind.
20. Transfer this solution to a 250-mL separatory funnel and shake it vigorously but carefully, with frequent venting.
If solid persists, add aliquots of ether.
21. Remove the aqueous layer from the funnel and pour the organic layer back into your reaction flask
22 Return the organic layer to your separatory funnel and wash the organic layer with 10 mL of 3M H2SO4.
23. Remove the aqueous layer from the funnel and wash the organic layer with 10 mL of saturated NaCl.
Test this aqueous layer with blue litmus paper. If the paper turns red, repeat step #23 until the NaCl aqueous layer
no longer tests acidic to blue litmus paper.
24. Dry the organic layer with anhydrous Na2SO4, and decant it into a 150 mL beaker.
25. Add a boiling stick to the beaker, and boil off the ether on your hot plate set at "2”. The Triphenylmethanol
remains in the flask. Pour your aqueous phases down the drain.
21
26. Recrystallize the residue from your beaker, using a 2:1 mixture of cyclohexane:Absolute Ethanol; as follows:
a.
Place 40 mL of the solvent mixture into a 100 mL beaker.
b.
Place the beaker with solvent onto a hotplate and allow it to come to a boil.
DO NOT ADJUST THE HEAT SETTING ON THE HOT PLATE - LEAVE IT AT "2"
c.
Remove the beaker of boiling solvent off the hot plate and add just enough solvent to dissolve the
contents of your flask (swirl the flask contents during solvent addition, to insure only a minimum of
solvent is used to dissolve your crude product.). The remainder of the solvent is to be iced, to wash your
crystals.
d.
Transfer the contents of your flask to a 100 mL beaker. Allow your product to cool to room temperature
on your desktop.
e.
f.
Place the beaker in an ice bowl, to recrystallize your product.
Vacuum filter the contents of the beaker, to recover your product.
g.
Wash your product with a small portion of ice-cold solvent.
h.
Leave the vacuum on for an additional 5 minutes, to help dry your product.
i.
Detach the hose from the filter flask then turn off the vacuum and place your product into your drawer to
dry overnight.
27.
Weigh your product and determine its melting range.
Put these data in the results of your notebook and laboratory report.
28.
Place your product in the jar provided at the end of the west bench.
Failure to turn in your remaining product to the proper recovery container will
result in a 5 point deduction from your lab report score.
Answer the following questions:
1) Why must all equipment be dry when reacting tolyl magnesium bromide with carbon
dioxide? (show equations)
2) a) Explain the difference between "inverse" and "normal" addition of organometallics
and substrates.
b) Which was done in this experiment? Why?
3) Write chemical equations to show all of the different methods that can be used to
synthesize tertiary alcohols with Grignard reagents.
4) Write all steps in the mechanism for the reaction of an ester with a Grignard reagent.
5) What side reactions are possible during the formation of a Grignard reagent? Write
structures. How were these separated from the product?
Answer questions 1, 2, 5 on page 314.
22
Aldol condensation
You are to prepare anisalacetophenone (AKA 4-methoxychalcone) via an aldol
condensation Using the following protocol. You will recrystallize the crude product from 95%
ethanol. Run the nmr and IR (CCl4) spectra of your product.
Transfer 0.65 mL p-anisaldehyde to a tared 50-mL Erlenmeyer flask and reweigh the flask to
determine the weight of the material transferred.
Add 0.60 mL acetophenone and 4.0 mL of 95% ethanol to the flask and swirl to mix the contents
and dissolve any solids present. If the solids do not dissolve after about 5-10 minutes of swirling,
heat the flask on a hotplate set at 2-3 and srirl until solid is dissolved.
The contents of your flask should be at room temperature before adding one pellet of NaOH to the
flask.
Swirl the flask until a solid forms.
Add 10 mL of ice water to the flask and stir the mixture with a spatula to break up any clumps of
solid present.
Transfer the mixture to a beaker containing 15 mL of ice water and stir the mixture with a spatula
to break up any clumps of solid present.
Vacuum filter, and wash the filter cake with a small portion of ice-cold water.
Allow the product to dry overnight before obtaining its melting point.
Save your product..
answer the following questions:
1) In the aldol condensation you ran:
a) Why doesn't the ketone undergo a self-condensation?
b) Why doesn't the aldehyde undergo the Cannizzaro
reaction?
c) Write equations for both of the above reactions.
2) Are there geometric isomers of the product of this synthesis? Draw them. Is the
reaction stereoselective or stereospecific? Which product is actually formed and why.
3) Predict the products of the following:
a) butyraldehyde, dil. NaOH
23
b)
c)
d)
e)
formaldehyde, conc. NaOH
acetone, p-tolualdehyde(2 mol), dil NaOH
2,2-dimethylpropanal, formaldehyde, conc. NaOH
benzaldehyde, methyl acetate, sodium methoxide
4) Why does the intermediate in the synthesis undergo spontaneous dehydration?
5) Show the stereochemistry of the hydroxylation with potassium permanganate of transanisalacetophenone using Fischer projections.
Answer question 4 on page 325 of your lab text.
24
Diels Alder
Run the Diels Alder condensation reaction between alpha-phellandrene and maleic
anhydride according to the directions below. Obtain IR (KBr pellet) spectrum of the product.
Write up a pre-lab for the condensation of α-phellandrene (2-methyl-5-isopropyl-1,3cyclohexadiene) and maleic anhydride.
You won't find the product in the CRC.
The α-phellandrene that we have is not pure, it only contains 70% α-phellandrene by
weight. You will need to figure how much of the impure compound to weigh out that will contain
0.050 mole of the α-phellandrene.
In a 100-mL round-bottom flask put 0.050 mole of maleic anhydride and the weight of
impure α-phellandrene that contains 0.050 mole. Add 25 mL of ethyl acetate, attach a reflux
condenser, and heat on a hot water wath for one hour. Cool in an ice-water bath and then suction
filter. Recrystallize the product from ethyl acetate, vacuum filter, let air dry, weigh, package, and
obtain the IR spectrum (KBr method).
Put all remaining product into the recovery bottle provided at the front of the lab.
answer the following questions:
1) Why is the endo product usually preferred in Diels-Alder condensations?
2) In your product, which way is the isopropyl group pointed? Explain.
3) The product of your synthesis has three chiral centers. Draw the product and label each chiral
center with and asterisk (*). How many stereosiomers are theoretically possible? Only one
stereoisomer is actually formed in this reaction, explain.
4) Predict the products of the following:
a)
b)
c)
d)
e)
1,3-butadiene + 2-butyne
1,3-cyclopentadiene + cis-2-butene
1,3-butadiene + dimethyl maleate(methyl ester of maleic acid)
(2 mol)1,3-cyclopentadiene + p-benzoquinone
dicylopentadiene + heat (retro Diels-Alder)
5) Explain why the diene must be in the sigma-cis conformation in order to undergo a Diels-Alder
reaction.
25
Preparation of an α,β-unsaturated ketone via Michael Addition combined with an aldol
condensation.
Day 1
Add 1.2 gm of your aldol product, 0.75 gm ethyl acetoacetate and 25 mL 95% ethanol to a 50 mL
RBF.
Swirl to dissolve the flask contents.
Add your magnetic stirrer and one pellet of NaOH to the flask.
Equip the flask with a reflux condenser and heat at a gentle reflux for 60 mins.
Allow the flask contents to cool to room temperature, then add 10 mL of H2O and stir/scratch the
bottom of the flask with a stirring rod to promote crystallization.
Cool the flask in an ice bath and vacuum filter the flask contents, washing the flask and crystals
with 4 mL of ice water.
Rinse the flask with an additional 3 mL of ice-cold 95% ethanol and pour this over the drying
crystals in your Buchner funnel.
Day 2
Transfer your crude product to a 100 mL beaker and add 7 mL acetone. Stir with a spatula to
dissolve any solid present. Add additional aliquots ( 1 or 2 ) of acetone, if necessary, to dissolve
the solid.
Decant the liquid into a large test tube and centrifuge for 2-3 minutes.
Decant the liquid into a tared 50-mL Erlenmeyer flask and evaporate the acetone by heating on a
hotplate set at 1-2, blowing a gentle stream air into the flask.
Your flask should contain a solid product. If you have an oil, scratch the bottom of the flask with a
stirring rod to promote crystallization.
Weigh the flask to determine the amount of product obtained.
Recrystallize the product with 95% ethanol.
Vacuum filter. Wash the flask and product with 3 1 mL portions of ice-cold 95% ethanol.
Weigh. Mp.
26
Put all remaining product into the recovery bottle provided at the front of the lab.
You will obtain the IR spectrum of the product.
Answer the following questions :
1. Draw a mechanism for the enamine synthesis of Δ1,9-2-octalone.
Why is this octalone rather than the Δ9,10-2-octalone the main reaction product ?
Why is there a substantial amount of Δ9,10-2-octalone produced ?
2. (a) The enamine formed from pyrrolidine and 2-methylcyclohexanone has the A structure.
Why is the less substituted enamine being formed rather that the more substituted B ?
N
N
CH3
H
A
B
(b) Draw the structure that would result from the reaction of enamine A with methyl vinyl
ketone. Compare its structure with the product obtained in question 3.
3. (a) The enolate formed from 2-methylcyclohexanol has the following structure. What is
the structure of the other possible enolate, and why is it not as stable as the one shown ?
O-
CH3
(b) Draw the structure of the product that would result from the reaction of methyl vinyl
ketone. Compare its structure with the product obtained in question 2.
27
4. Draw the structures of the Robinson annelation products that would result from the following
reactions:
O
+
O
+
O
O
O
28
Lidocaine
You will synthesize lidocaine via a series of synthetic reactions according to the instructions
below. A single report is required with IR and nmr spectra of the final product. Be sure to
calculate % yield for each step of your synthesis as well as the overall % yield.
multistep synthesis of lidocaine
first lab:
Reduction of 1,3-dimethyl-2-nitrobenzene to 2,6-dimethylaniline
Ar-NO2 + SnCl2.2H2O, HCl ---> Ar-NH3+,Cl- + SnCl4
-make up the following two solutions:
solution 1: 0.10 mole (22.6 g) SnCl2.2H2O in 40 mL of conc. HCl (warm to dissolve)
solution 2: 0.033 mole (5 g, 4.5 mL) 1,3-dimethyl-2-nitrobenzene in 50 mL acetic acid
-mix the two solutions and let stand for 15 minutes
-after fifteen minutes, cool in ice bath and vacuum filter
Ar-NH3+,Cl- + KOH ---> Ar-NH2
-tranfer solid to a flask and add 25 mL of water, make strongly basic with 40-50 mL of 8M KOH
(caution!)
-cool to room temperature with ice bath
-extract with (1) 25 mL diethyl ether
(2) 10 mL diethyl ether
-wash combined ether extracts with 10 mL water; repeat
-dry over anh. K2CO3
-filter into pre-weighed RB flask and remove diethyl ether by distillation (ether --> waste bottle)
-reweigh flask
29
α-chloro-2,6-dimethylacetanilide
Ar-NH2 + Cl-CH2COCl ---> Ar-NHCOCH2-Cl
-residue from above + 25 mL acetic acid
-add (3.7 g, 2.6 mL) α-chloroacetyl chloride (caution!)
-warm to 40-50oC
-add solution: (5 g NaO2CCH3.3H2O in 100 mL water)
-cool, vacuum filter, air dry, weigh, mp
second lab:
lidocaine
Ar-NHCOCH2-Cl + NH(CH2CH3)2 
Ar-NHCOCH2-N(CH2CH3)2
-note: all reagents and apparatus must be dry!
-in a 250 mL RB flask, combine the α-chloro-2,6-dimethylacetanilide from above with 45 mL
toluene
-calculate the number of moles of α-chloro-2,6-dimethylacetanilide
and add three times that number of moles of diethylamine to the RB.
-attach a water cooled condenser and reflux for 90 minutes.
-cool in an water bath and vacuum filter off the solid that forms. (this is not your product!)
-transfer the filtrate to a separatory funnel and extract with two 25 mL portions of 3M HCl.
-combine the aqueous layers in a 250 mL Erlenmeyer flask and add 50 mL of 8 M KOH to make
the solution stronly basic.
-warm the mixture and blow across the surface to remove any excess diethylamine
-cool in an ice bath, continuing to blow and scratch until crystals form.
-vacuum filter the crude lidocain, wash the crystals with cold water and remove from the filter
paper immediately.
-let dry on a watch glass, package, weigh, mp, IR & nmr spectra.
30
Answer the following questions:
1) Write a balanced chemical equation for the reduction of
nitrobenzene with Fe in HCl to form aniline. (Fe --> FeCl3)
2) Draw the structures of at least two by-products produced in the reaction in 1).
3) Why does 2,6-dimethylaniline react with chloroacetyl chloride to produce an amide rather than
a secondary amine?
4) Lidocaine is commercially sold in the form of the hydrogen chloride salt. Why?
5) In the reduction of 2,6-dimethylnitrobenzene with stannous chloride, what is the structure of the
ppt that is collected by suction filtration?
6) What is the precipitate collected by filtration after the reaction with diethylamine?
7) Why do we use three moles of diethylamine for every mole of the anilide?
31
Qualitative analysis
You will receive three unknown organic compounds, which you are to identify by a
traditional qualitative analysis scheme. The report will consist of three forms that you will fill out
and is worth 100 pts or approximately 10% of your total course grade. Read p 468-516 in your
text.
Preliminary Classification
Solubility tests:
To carry out the solubility tests, approximately 0.1 g or 0.1 mL of the
substance is added to 3 mL of the solvent. If most of the material appears to dissolve, the
compound is considered soluble. If there is no immediate change, especially with a solid unknown,
the mixture should be thoroughly stirred with a glass rod and at least 2 minutes allowed to elapse
before a decision is made.
The solubility tests must be applied in the sequence given below to avoid misleading
observations.
a. Solubility in water. A compound that is soluble in water must be at least somewhat polar.
b. Solubility in aqueous acid or base. A water-insoluble organic acid should dissolve in an
aqueous base; an organic base that is not soluble in water should dissolve in aqueous acid. The
observed solubility in each case is the result of the formation of an ionic salt which remains
dissolved in the aqueous medium. It should be obvious that these tests are applied only if the
original compound does not dissolve in water. If the substance is found to be soluble in 5% NaOH,
indicating that it is an acid, it is tested further with 5% sodium hydrogen carbonate. Only acids
stronger than carbonic acid will dissolve. A compound may therefore be classified as a strong or
weak acid on the basis of these two solubility tests. An organic base can be identified by its
solubility in 5% hydrochloric acid. No further classification is possible. If a compound is found to
be an acid, it should also be tested with hydrochloric acid on the chance that it may contain both
acidic and basic functional groups (e.g., an amino acid).
c. Solubility in sulfuric acid. A compound that is insoluble in water, hydrochloric acid, and
sodium hydroxide is considered to be neutral. Those substances that contain nitrogen or sulfur are
not tested further and are classed as nitrogen-sulfur neutrals (class M). Other compounds are tested
for solubility in concentrated sulfuric acid. In this test, a solution in the sense of an ordinary
aqueous solution is not necessarily formed. If heat is evolved, a color develops, or any other
change indicative of a reaction is seen, it is concluded that the substance is "soluble" in H2SO4.
Solubility classification of some organic compounds:
S : soluble in water and soluble in diethyl ether
Low MW Amines and neutral compounds
32
A (weak acids) : soluble in dilute sodium hydroxide
1
phenols, beta-diketones.
A2 (strong acids) : soluble in dilute sodium bicarbonate
carboxylic acids, polynitrophenols, polyhalophenols, acyl halides.
B (bases) : soluble in dilute hydrochloric acid
amines (except diaryl and triarylamines)
N1 (neutrals) : soluble in conc. sulfuric acid
alkenes, some arenes, ethers, water-insoluble: alcohols, aldehydes, esters, ketones.
N2 (neutrals) : insoluble in conc. sulfuric acid
alkanes, halides, diarylethers.
M (nitrogen-containing neutrals)
amides, nitrocompounds, diaryl- and triarylamines, nitroarylamines.
33
Indicator Classification Method:
The solubility method suffers from several shortcomings. One is that it is difficult to
estimate solubility in borderline cases. There are also some instances in which a solid substance
dissolves, only to react with the solvent to form an insoluble product. The indicator method
overcomes these difficulties and also provides a more specific classification. That is, it is possible
to classify an acid as weak, intermediate, or strong, rather than just weak or strong as in the
solubility system. Bases can also be classified as weak, intermediate, or strong.
A set of four indicators, A-I, A-II, B-I, and B-II is required. To carry out the test, 1 mL of
the indicator is placed in a small test tube and one drop of a liquid or about 30 mg or a solid (about
as much as can be carried on the tip of a small spatula) is added to the indicator. The effect on each
indicator solution is described below:
A-I Indicator (original color: purple)
If the color changes from purple to yellow, the compound is an intermediate acid (Ai) or a
strong acid (As). If the color change is from purple to green, the unknown is a weak acid (Aw). To
distinguish between Ai and As, you must use the A-II indicator.
A-II Indicator (original color: blue-violet)
A change from blue-violet to yellow occurs if the unknown is an intermediate acid. A
strong acid causes a change from blue-violet to a shade of red.
B-I Indicator (original color: Purple)
Any base changes the color from purple to yellow.
B-II Indicator (original color: Yellow)
A weak base (Bw) has no effect (color remains yellow), while an intermediate base (Bi)
produces a change from yellow to blue-violet. (There are relatively few strong organic bases.
Although it is possible to detect strong organic bases by special treatment of the indicators, they
will not be considered here.
Caution: The indicators are made up in nonaqueous solvents. The addition of water to any of the
indicators may cause a color change. It is imperative therefore that a clean, dry test tube be used
for each test, and the sample tested must be free of water.
34
Indicator Classification of Some Organic Compounds:
Strong acids (As): acyl halides, some carboxylic aicds, nitrophenols.
Intermediate acids (Ai): carboxylic acids, o- and p-hydroxyaromatic aldehydes and ketones,
polyhalophenols.
Weak acids (Aw): phenols, beta-diketones, some aryl esters.
Intermediate bases (Bi): aliphatic amines, heterocyclic amines.
Weak bases (Bw): primary arylamines, arylalkylamines, heterocyclic amines.
Neutrals (do not contain nitrogen): hydrocarbons, halides, alcohols, aldehydes, ketones, esters,
ethers.
Neutrals (contain nitrogen): diarylamines, triarylamines, nitriles, nitrocompounds, amides,
polynitroarylamines, polyhaloarylamines.
35
Chemistry 313
QUALITATIVE ORGANIC ANALYSIS REPORT (33 pts)
Name
Date
Unkn. No.
1.
Identity of Compound
Physical properties of purified material:
physical state
b.p.
color
m.p.
refractive index (liq. only)
other
2.
Preliminary Classification
a) Solubility tests (write "s" if soluble; "i" if insoluble).
H2O
Et2O
HCl
NaOH
NaHCO3
H2SO4
Classification
b)
Indicator tests (note the color change, if any)
A-I
A-II
B-I
B-II
Classification:
3.
Functional Group Tests
On a separate sheet of paper, prepare a table with the column headings: Reagent, Result, and Inference. In the
appropriate spaces, list the actual reagent and observed result of every functional group test applied to the
unknown, and the inference drawn in each case. (See sample below.)
Reagent
Result
Inference
2,4-DNPH
orange ppt; red color with alc.KOH carbonyl group
Tollens no silver mirror or ppt
ketone(no aldehyde)
NH2OH, KOH no purple color
no ester group
4.
Probable Compounds: List all compounds with m.p. or b.p. within 5o of that of the unknown, which could be
identical to the unknown. Also list the useful derivatives and their m.p.'s.
5.
6.
Derivatives made: List the derivatives of the unknown that were actually prepared and their observed m.p.'s.
Spectroscopic Data: Tabulate ir and nmr data, if obtained.
36
Chemistry 313
QUALITATIVE ORGANIC ANALYSIS REPORT (33 pts)
Name
Date
Unkn. No.
1.
Identity of Compound
Physical properties of purified material:
physical state
b.p.
color
m.p.
refractive index (liq. only)
other
2.
Preliminary Classification
a) Solubility tests (write "s" if soluble; "i" if insoluble).
H2O
Et2O
HCl
NaOH
NaHCO3
H2SO4
Classification
b)
Indicator tests (note the color change, if any)
A-I
A-II
B-I
B-II
Classification:
3.
Functional Group Tests
On a separate sheet of paper, prepare a table with the column headings: Reagent, Result, and Inference. In the
appropriate spaces, list the actual reagent and observed result of every functional group test applied to the
unknown, and the inference drawn in each case. (See sample below.)
Reagent
Result
Inference
2,4-DNPH
orange ppt; red color with alc.KOH carbonyl group
Tollens no silver mirror or ppt
ketone(no aldehyde)
NH2OH, KOH no purple color
no ester group
4.
Probable Compounds: List all compounds with m.p. or b.p. within 5o of that of the unknown, which could be
identical to the unknown. Also list the useful derivatives and their m.p.'s.
5.
Derivatives made: List the derivatives of the unknown that were actually prepared and their observed m.p.'s.
6.
Spectroscopic Data: Tabulate ir and nmr data, if obtained.
37
Chemistry 313
QUALITATIVE ORGANIC ANALYSIS REPORT (33 pts)
Name
Date
Unkn. No.
1.
Identity of Compound
Physical properties of purified material:
physical state
b.p.
color
m.p.
refractive index (liq. only)
other
2.
Preliminary Classification
a) Solubility tests (write "s" if soluble; "i" if insoluble).
H2O
Et2O
HCl
NaOH
NaHCO3
H2SO4
Classification
b)
Indicator tests (note the color change, if any)
A-I
A-II
B-I
B-II
Classification:
3.
Functional Group Tests
On a separate sheet of paper, prepare a table with the column headings: Reagent, Result, and Inference. In the
appropriate spaces, list the actual reagent and observed result of every functional group test applied to the
unknown, and the inference drawn in each case. (See sample below.)
Reagent
Result
group
Tollens no silver mirror or ppt
NH2OH, KOH no purple color
Inference
2,4-DNPH
orange ppt; red color with alc.KOH carbonyl
ketone(no aldehyde)
no ester group
4.
Probable Compounds: List all compounds with m.p. or b.p. within 5o of that of the unknown, which could be
identical to the unknown. Also list the useful derivatives and their m.p.'s.
5.
Derivatives made: List the derivatives of the unknown that were actually prepared and their observed m.p.'s.
6.
Spectroscopic Data: Tabulate ir and nmr data, if obtained.
38