CHE235L4Spring2017.pdf FW (g/mol) mp ( o C) bp ( o C) mmol mass (g) density (g/mL) volume (mL) N/A N/A bismuth(III) nitrate pentahydrate N/A N/A N/A N/A sodium chloride, saturated (brine) N/A N/A N/A N/A N/A ethyl acetate N/A N/A cis -1,2-cyclohexanediol N/A N/A N/A trans -1,2-cyclohexanediol, (±) N/A N/A N/A Prelab 4: Green Lewis Acid-Catalyzed Hydrolysis of Cyclohexene Oxide Name: Reaction equation: Note: For those reagents that are in solution, the FW, mmol, and mass columns refer to the solute in the solution. Limiting reagent: Reagent Table water Theoretical yield: Chemical cyclohexene oxide EXPERIMENT #4 GREEN LEWIS ACID-CATALYZED HYDROLYSIS OF CYCLOHEXENE OXIDE Introduction: Epoxides are three-membered ethers. They are special because unlike most ethers, they can react with nucleophiles to form a new bond between carbon and the nucleophile and break a bond between that carbon and oxygen. This ring-opening reaction makes epoxides versatile functional groups for organic synthesis. (In fact epoxide is the functional group that makes epoxy resins possible.) Scheme 1. Ring opening of an epoxide in the presence of a nucleophile. Ring-opening of the epoxide can occur under basic or acidic conditions. Under basic conditions, the reaction is similar to an SN2 reaction so that the nucleophile attacks the less substituted carbon of an unsymmetrical epoxide by backside attack. Sodium ethoxide reacts with this epoxide in the following reaction. Scheme 2. Ring opening of an unsymmetrical epoxide under basic conditions. Under acidic conditions, the reaction is more complicated. It is similar to an SN2 reaction because the nucleophile reacts by backside attack. However, because there is partial positive charge on the Reference Material: MAHHS Chapter 1: Safety in the Laboratory MAHHS Chapter 2: Protecting the Environment MAHHS Chapter 3: Laboratory Notebooks and Prelaboratory Information MAHHS Chapter 4: Laboratory Glassware MAHHS Chapter 5: Measurements and Transferring Reagents MAHHS Chapter 10: Filtration MAHHS Chapter 11: Extraction MAHHS Chapter 12: Drying Organic Liquids and Recovering Reaction Products MAHHS Chapter 17: Thin-Layer Chromatography, especially section 17.8 MAHHS Chapter 20: Infrared Spectroscopy Klein Chapter 14: Ethers and Epoxides; Thiols and Sulfides three atoms of the epoxide ring, the nucleophile attacks where the partial positive charge is more stabilized, the more substituted carbon of an unsymmetrical epoxide. Ethanol in the presence of sulfuric acid reacts with this epoxide in the following reaction. Scheme 3. Ring opening of an unsymmetrical epoxide under acidic conditions. While sulfuric acid is an inexpensive acid catalyst, it is difficult to handle. It is very corrosive and can cause severe burns. In addition, it is viscous, which makes it difficult to handle on the scale of the reactions perfor ...

1. CHE235L4Spring2017.pdf
FW
(g/mol)
mp (
o
C) bp (
o
C) mmol mass (g)
density
(g/mL)
volume
(mL)
N/A
N/A
bismuth(III) nitrate pentahydrate N/A N/A N/A N/A
sodium chloride, saturated (brine) N/A N/A N/A N/A N/A

2. ethyl acetate N/A N/A
cis -1,2-cyclohexanediol N/A N/A N/A
trans -1,2-cyclohexanediol, (±) N/A N/A N/A
Prelab 4: Green Lewis Acid-Catalyzed Hydrolysis of
Cyclohexene Oxide
Name:
Reaction equation:
Note: For those reagents that are in solution, the FW, mmol, and
mass columns refer to the solute in the
solution.
Limiting reagent:
Reagent Table
water
Theoretical yield:
Chemical
cyclohexene oxide
EXPERIMENT #4
GREEN LEWIS ACID-CATALYZED HYDROLYSIS OF

3. CYCLOHEXENE OXIDE
Introduction:
Epoxides are three-membered ethers. They are special because
unlike most ethers, they can react
with nucleophiles to form a new bond between carbon and the
nucleophile and break a bond
between that carbon and oxygen. This ring-opening reaction
makes epoxides versatile functional
groups for organic synthesis. (In fact epoxide is the functional
group that makes epoxy resins
possible.)
Scheme 1. Ring opening of an epoxide in the presence of a
nucleophile.
Ring-opening of the epoxide can occur under basic or acidic
conditions. Under basic conditions,

4. the reaction is similar to an SN2 reaction so that the nucleophile
attacks the less substituted carbon
of an unsymmetrical epoxide by backside attack. Sodium
ethoxide reacts with this epoxide in the
following reaction.
Scheme 2. Ring opening of an unsymmetrical epoxide under
basic conditions.
Under acidic conditions, the reaction is more complicated. It is
similar to an SN2 reaction because
the nucleophile reacts by backside attack. However, because
there is partial positive charge on the
Reference Material:
MAHHS Chapter 1: Safety in the Laboratory
MAHHS Chapter 2: Protecting the Environment
MAHHS Chapter 3: Laboratory Notebooks and Prelaboratory
Information
MAHHS Chapter 4: Laboratory Glassware
MAHHS Chapter 5: Measurements and Transferring Reagents
MAHHS Chapter 10: Filtration
MAHHS Chapter 11: Extraction

5. MAHHS Chapter 12: Drying Organic Liquids and Recovering
Reaction Products
MAHHS Chapter 17: Thin-Layer Chromatography, especially
section 17.8
MAHHS Chapter 20: Infrared Spectroscopy
Klein Chapter 14: Ethers and Epoxides; Thiols and Sulfides
three atoms of the epoxide ring, the nucleophile attacks where
the partial positive charge is more
stabilized, the more substituted carbon of an unsymmetrical
epoxide. Ethanol in the presence of
sulfuric acid reacts with this epoxide in the following reaction.
Scheme 3. Ring opening of an unsymmetrical epoxide under
acidic conditions.
While sulfuric acid is an inexpensive acid catalyst, it is difficult
to handle. It is very corrosive and
can cause severe burns. In addition, it is viscous, which makes
it difficult to handle on the scale of
the reactions performed in the teaching laboratory.
An alternate to protic (Brønsted) acid catalysts that can
sometimes be used are Lewis acid catalysts.
Many of the Lewis acids that are used as catalysts in organic

6. chemistry are metal-centered. These
include aluminum chloride and iron(III) bromide, which will be
discussed in the lecture with the
reactivity of aromatic compounds. Those salts are very harsh
and sometimes must be used in large,
often stoichiometric, quantities. Milder Lewis acids that are
safer to use and that would be effective
in smaller quantities are needed.
Recent research in green chemistry has led to the discovery of
several new Lewis acids that meet
these conditions.1 Among these is bismuth(III) nitrate
pentahydrate. This salt is known to be quite
reactive, but it is easy to handle even on a small scale and is
relatively nontoxic. (An illustration
of bismuth(III)’s lack of toxicity is that bismuth subsalicylate
appears as the active ingredient in
Pepto-Bismol® and Kaopectate®.)
Scheme 4. Bi3+ acting as a Lewis acid with water or
cyclohexene oxide.
In this experiment you will perform a reaction to determine the
stereochemistry of the product
formed when Bi(NO3)3•5H2O catalyzes the reaction of
cyclohexene oxide with a nucleophilic

7. solvent, water (Scheme 4).2 You will examine the reaction
product by TLC to determine if the
reaction generates the cis- or trans-1,2-cyclohexanediol as the
product. Remember that because
these two compounds are diastereomers, generally they will
have different physical properties,
including polarity. We expect that they will appear as different
spots on TLC. You will also
characterize the product using IR and 1H NMR spectroscopies.
Scheme 5. Hydrolysis of cyclohexene oxide in the presence of a
Lewis acid catalyst.
Because this reaction involves the solvent as a reactant, it is an
example of a solvolysis reaction.
A solvent molecule acts as the nucleophile that adds to the
substrate.
The other main focus of this lab is to illustrate the ideas of
green chemistry. Both of the
experiments that you will perform possess some characteristics
of green chemistry. The ideas of
this discussion are outlined below.
Organic chemistry is essential for preparing many of the

8. products in our everyday lives. Organic
synthesis is used in the production of many medicines. For
example, the cholesterol-lowering drug
atorvastatin (Figure 1) is a completely synthetic pharmaceutical
agent. Atorvastatin may be sold
under the brand name Lipitor®. Lipitor® is the best-selling
prescription drug of all time. In addition,
two research groups recently have developed more efficient
processes for making the anti-flu drug
oseltamivir (Tamiflu®) (Figure 2).
Figure 1. Atorvastatin (Lipitor®) has improved the health of
millions of patients.
Figure 2. Oseltamivir (Tamiflu®) is expected to be the first line
of defense against an outbreak of
bird flu.
However, there have been drawbacks to the widespread use of
organic synthesis to prepare
commercial products. In some places and during some periods,
improper disposal of effluents have

9. polluted the environment. Inefficient processes have wasted
valuable resources. Petrochemicals
serve as starting materials for many processes, but they are
being consumed ever more rapidly as
fuels.
Clearly the current situation cannot continue forever. Some
leaders in chemical research are
advocating the research, development, and application of
sustainable processes. They recognize
that while organic synthesis is essential to the standard of living
in the developed world, it can be
implemented more wisely.
This experiment also demonstrates some of the principle of
green chemistry. As mentioned in an
earlier experiment, these principles are associated with more
sustainable chemical processes.
These twelve goals are listed here:3
1. Prevention of waste
2. Atom economy
3. Less hazardous chemical syntheses
4. Designing safer chemicals
5. Safer solvents
6. Energy efficiency
7. Renewable feedstocks
8. Fewer derivatives
9. Catalysis

10. 10. Design for degradation
11. Real-time analysis for pollution prevention
12. Inherently safer chemistry for accident prevention
This experiment will illustrate how several of these principles
(in this case, goals 1, 2, 3, 5, 6, 9,
and 12) can be realized, using safer reagents in safer process to
prepare safer products. The product
incorporates all of the atoms of the reactants, so it is atom
economic. It proceeds by a relatively
nontoxic catalyst, so that it is a safe process that generates little
waste.
Your discussion of this experiment will focus on three aspects.
The first aspect is to analyze the
characterization data of the product; it is important to clearly
explain why the data support your
conclusions. The second aspect is to use the identity of the
product to help complete a reasonable
mechanism for the reaction. The third aspect that should be
addressed in your report is to assess
the “greenness” of this experiment.2 Identify the procedures and
reagents that were green and those
that were not.
1. Gaspard-Iloughmane, H.; Le Roux, C. Eur. J. Org. Chem.
2004, 2517-2532.

11. 2. Mohammadpoor-Balturk, I.; Tangestaninejad, S.; Aliyan, H.;
Mirkhani, V. Synth. Commun.
2000, 30, 2365-2374.
3. Anastas, P. T.; Warner, J. C. Green Chemistry: Theory and
Practice, Oxford University Press:
New York, 1998, 30.
Experimental: Green Lewis Acid-Catalyzed Hydrolysis of
Cyclohexene Oxide
Safety Precautions: Cyclohexene oxide is corrosive and
harmful. Bismuth(III) nitrate
pentahydrate is an irritant and is hygroscopic. Ethyl acetate is
extremely flammable and harmful.
Chloroform-d is harmful. Wear gloves while manipulating the
reagents for this experiment.
Dispose of wastes in the appropriate waste containers.
Procedure:
Set up the reaction in a fume hood. To a 50 mL Erlenmeyer
flask containing a small magnetic stir
bar, sequentially add water (5 mL) and bismuth(III) nitrate

12. pentahydrate (0.030 mmol). To the
rapidly stirred mixture add cyclohexene oxide (1.00 mmol). Stir
the reaction mixture rapidly at
room temperature.
After the reaction mixture has stirred for 30 minutes, work up
the reaction mixture according to
the following procedure. Dilute the reaction mixture with
saturated sodium chloride (5 mL), and
remove the stir bar from the flask using a magnet. Transfer the
mixture to a separatory funnel.
Extract the aqueous layer with ethyl acetate (3 × 10 mL).
Combine the organic layers. If there is a
small aqueous layer in the bottom, remove it using a Pasteur
pipet or a separatory funnel. Dry the
organic layer over sodium sulfate. Carefully decant the dried
liquid into a tared 125 mL Erlenmeyer
flask. Evaporate the solvent under a stream of air until a
constant mass of product has been
achieved. For our purposes, constant mass is when two
successive measurements differ by less
than 3 mg. Your final product should not contain any water; if it
does, redissolve your sample in a
small amount of ethyl acetate, separate the water, and re-
evaporate the organic layer. Show your

13. final product to your instructor. Record the appearance of the
crude product and calculate its
percent yield.
Analyze the sample using TLC and IR and 1H NMR
spectroscopies. For TLC elute the plate using
ethyl acetate, and visualize the spots using anisaldehyde stain.
Collect the IR spectra of both the
reaction substrate and your product. Prepare a sample of your
sample for analysis by 1H NMR
using chloroform-d as the solvent.
Dispose of the aqueous layers in the waste container labeled
“aqueous bismuth wastes.” After the
ethyl acetate has evaporated from the sodium sulfate, it can be
washed down the drain. After you
have collected the characterization for your product, wash it
into the organic waste container using
acetone.
Postlab exercises:
1. Identify the product of the reaction. Explain how the data
support this structure.
2. Draw the substrate and the product. Identify any chiral

14. centers within the molecules, and
identify whether each molecule is chiral or achiral. If the
product is chiral, explain whether
you expect a single enantiomer or a mixture of enantiomers to
be formed.
3. Complete a proposed mechanism for the reaction, using the
prelab material to help get you
started.
4. Predict the major organic product of each of the following
reactions.
conclusion.docx
The reaction product was determined to be trans 1,2 –
cyclohexanediol. This was concluded when examination the
polarity of both of the cis/trans cyclohexanediol by using TLC.
The Rf (retention factor) of the cis-1,2- cyclohexanediol was
0.687 and the trans version was 0.562. this method suggested
the polarity was the most similar btw the product and the trans-
1,2-cyclohexanediol.
Conclusion:
From the results obtained in the experiment, we inferred that the
product was trans-1,2-cyclohexanediol. With the IR spectrum
peaks from the product varied when compared to the starting
material. In the IR spectrum of the product ~ 3271.77 cm-1
wave length there were various peaks indicating Trans diol.
Then with the TLC, we noticed three spots due to the use of the

15. die, indicating correlation in polarity.
Formal-Report-Guidelines-2016-2017.pdf
Formal Lab Report Guidelines
Style and Presentation: The lab report must be word-processed,
double-spaced, with 1 inch
margins on all sides (top, bottom, left, right), and the pages
must be numbered. The font should be
either Arial (10 pt) or Times New Roman (12 pt). Each section
of the report should have a clearly
labeled title (i.e., Abstract, Introduction, Results, Discussion,
Conclusion, Appendix).
As mentioned above, you should write in a fashion that is
appropriate for communicating science.
Specifically, please follow the rules below.
1. Use an accepted acronym for a chemical, technique, or
instrument, provided the first reference
includes the full name. For example, for the first mention of a
technique is it appropriate to
write, “The reaction mixture was analyzed using gas
chromatography (GC).” After this point
it, would be acceptable to simply use the acronym GC.

16. 2. Chemical formulas must be written using proper subscript
notation; e.g., sodium carbonate is
Na2CO3, not Na2CO3.
3. All data must be reported using the correct number of
significant figures and units.
4. Proper symbols should be used where applicable, e.g., °C.
Title page: A separate word-processed page at the front of your
report that includes the following:
the experiment number and a descriptive title, your full name,
your lab partner’s full name, the
date the experiment was performed, and the date the report was
submitted.
Abstract: The abstract should provide a concise summary of
what was done in the experiment, the
methods used, and the subsequent results.
Introduction: This section should include an introduction that
discusses the basic theory and
purpose of the experiment, and mentions the key techniques that
will be used both in the
experiment and to analyze the products. The purpose of the
experiment must be written from the

17. point of view of a scientist rather than a student; e.g., the
purpose of the experiment was “to
separate a mixture of cyclohexane and toluene using fractional
distillation,” not “to help students
become familiar with the technique of fractional distillation.”
Be aware that during a lab
experiment you may work with only one set of reagents, but you
may be asked to hypothesize
about overall trends. You may need to extrapolate beyond just
the reagents used in the experiment;
e.g., overall trends on what sort of selectivity is observed when
a particular reagent adds to an
alkene.
Figures/Mechanisms: Figures must be referred to in the body of
the text. Each figure in the report
should have a label that includes the figure number and a
descriptive title, such as “Figure 1:
Mechanism for the hydrolysis of butyl acetate in acidic
solution.” The label for the figure should
be on the same page as the figure, directly below the figure.
Figures should not be split between

18. two pages if possible. If a figure must be split because it is
longer than one page, then there should
also be a title on the second page: e.g., “Figure 1: Mechanism
for the hydrolysis of butyl acetate
in acidic solution cont.” All chemical structures should be
drawn neatly by hand, and bond lengths
and angles should be reasonable. Reaction mechanisms should
show all relevant lone pairs of
electrons and curved arrows should precisely show the
movement of electrons. Figures and
mechanisms should be included in the appropriate section of the
lab report. If a mechanism of a
reaction is known before the experiment is performed then it is
background information and should
be included in the introduction. If you learn about the reaction
mechanism in the experiment, then
the mechanism should be included in the discussion section of
the report.
Procedure: The procedure should be a description in your own
words of what you actually did in
the lab, written in proper scientific language using third person
past tense. The procedure should
be in paragraph form.

19. Results: Proper labeled tables containing all measurements that
you made in the lab, reported with
the proper number of significant figures and units, should be
included in this section. Each table
in the report should have a label that includes the table number
and a descriptive title, such as
“Table 1: Proton NMR data from unknown alkene product.” The
label for table should be on the
same page as the table, either directly above or below the table
(you choose the location, but be
consistent throughout your report). Tables should not be split
between two pages if possible. If a
table must be split because it is longer than one page, then there
should also be a title on the second
page: e.g., “Table 1: Proton NMR data from unknown alkene
product cont.”
Relevant observations should also be noted. Be careful to
separate observation from inferences.
You may observe that two compounds have a similar
appearance, but do not make any comments
about what this means at this point; you should present this in
your discussion. Calculations should

20. be clearly shown in your laboratory notebook, and copies of
these pages should be included in
your appendix.
Example calculations generally do not need to appear in your
formal report, but they should be
included in your notebook pages.
Discussion: Here is where you will present your findings from
the experiment, and what
information they provide about the question being studied. Use
the data to support your
conclusions. When comparing data to your hypothesis, restate
the actual values (using the proper
units and significant digits) in your comparison. Any problems
or limitations with performing the
experiment should be described and discussed in terms of how
they may have affected the results
of the experiment. You will often be asked to address specific
points and questions in a report-be
sure to include them all.
Conclusion: The conclusion should be a concise paragraph that

21. clearly states the objective of the
experiment and the outcome of the experiment, including key
evidence.
Works Cited: Any reference material (books, scientific journal
articles, etc.) used in writing the
report must be properly noted and cited in this section. Use
numerical superscripts to cite the
references in the body of the paper. References should be
formatted in accordance with the ACS
Style Guide.
Appendix: Attach supporting documents that your instructor
may ask to include with your report,
perhaps the copy pages from your notebook and any additional
raw data such as IR or NMR
spectra. Notebook pages should be included in order and will be
evaluated for data organization,
observations, and calculations.
Table 1. Elements of Writing and Related Skills1
Component Corresponding Skills
Audience and purpose Avoiding command language (e.g., “Stir

22. the solution.”)
Avoiding informal and imprecise words (e.g., “to see”, “very”)
and ordinal words (e.g., “first”, “next”)
Hedging (e.g., the data suggest rather than the data prove)
Including appropriate details when describing instrumentation
Omitting lists of common equipment
Writing concisely
Writing Conventions Abbreviating units correctly
Avoiding bulleted lists
Formatting figures and tables correctly
Including a space between numbers and units (e.g., 10 mg)
Referring to figures correctly in the text
Reporting “zero” concentrations appropriately
Selecting conventional verb tense (past, present, future) and
voice
(active or passive)
Using ACS-endorsed numerical formats for citations
Using leading zeroes with numbers less than 1 (e.g., 0.5)
Using lower case for chemical names
Using “we” appropriately
Grammar and Mechanics Using correct subject-verb number
agreement (e.g., the correct

23. verb form with the word “data”)
Using parallel language in a series
Literature cited:
1. Robinson, M.S.; Stoller, F.L.; Horn, B.; Grabe, W. J. Chem.
Educ. 2009, 86, 45-49.
H-NMR.jpg
IR-spec.jpg
reagent-table.jpg
sample-from-another-lab-formal.docx
Abstract
The purpose of this experiment was to study the mechanism
behind Friedel-Crafts acylation, acetylate ferrocene and purify
it by column chromatography, and to compare the final product
and its characteristics to those of the starting material.
Acetylation of ferrocene is a specific example of an
electrophilic aromatic substitution. The active electrophile was
prepared by reacting acetic anhydride with a strong Lewis acid
— phosphoric acid. In turn, the active electrophile reacted with
the nucleophile, ferrocene, to produce acetylferrocene. The data
collected from TLC, mixed MP, and IR spectroscopy supported
the identity of the final product as acetylferrocene. TLC
monitored the different stages of the reaction; the final TLC
plate exhibited the disappearance of a ferrocene spot. The
experimental melting point of the final product was observed at

24. 84 °C – 86 °C. IR spectroscopy of the product showed a strong
carbonyl stretch at 1650.66cm-1.
Introduction
The nucleophile in this experiment, ferrocene, is an
organometallic compound composed of two cyclopentadienyl
rings that “sandwich” an iron ion.2 Ferrocene is not strictly
limited to a laboratory setting. In fact, it has many practical
applications that are essential for life: it helps make compounds
like polyethylene and polypropylene, which are used to make
quality tubes that are vital for keeping a large city safe from
infectious disease, and less obvious, it is encountered by
diabetes sufferers many times a day because it is a vital
molecule that makes up the small electronic devices used to
measure blood sugar levels.3
Friedel-Crafts acylation is a widely used method of carbon-
carbon bond synthesis that proceeds by electrophilic aromatic
substitution.1 The formation of the active electrophile was a
result from reacting acetic anhydride with a mild catalyst and
strong Lewis acid — phosphoric acid. The active electrophile
attacks the ring of ferrocene, and a proton on the ring is
exchanged for an acetyl group. The final expected product was

25. acetylferrocene, and thin layer chromatography (TLC), mixed
melting point (MP), and infrared (IR) spectroscopy were used to
support identification of the final product. The purpose of this
experiment was to study the mechanism behind Friedel-Crafts
acylation of ferrocene (scheme 1), acetylate ferrocene and
purify it by column chromatography, and to compare the final
product and its characteristics to those of ferrocene.
Scheme 1: electrophilic aromatic substitution of ferrocene to
produce acetylferrocene
Experimental
Phosphoric acid (85%, 0.13 mL) was added to a test tube
containing fully dissolved ferrocene (0.50 mmol) and acetic
anhydride (0.50 mL). The mixed contents were heated in a water
bath at 80 °C for 8 minutes; color changes were observed and
recorded. The mixture was transferred onto crushed ice in a 25
mL Erlenmeyer flask and stirred until the ice melted. Hexanes
(2 x 10 mL) were used to extract the aqueous suspension, and
TLC (1:4 either: hexanes) tested the leftover combined organic
layers in comparison to ferrocene. Organic layers were dried
over anhydrous potassium carbonate, and decanted into a flask
solvent was evaporated until solid (~5 mL) formed on the
bottom. An alumina column with a frit and stopcock attached
was used for chromatographing the crude product. Adding a tiny
amount of sand, filling ¾ full of hexanes, and sprinkling dry
alumina into the hexanes prepared the column. Once the
hexanes drained to the level of the alumina, another tiny layer
of sand was added to the top of the column. After the column
was completely eluded with hexanes and level with the sand on
top, the crude product was added to the column and drained to
give the first fraction. The less polar compound in the mixture
was eluted with more hexanes to give the second fraction. The
eluent was changed to ether to elute the product to give the
third fraction. TLC (1:4 ether: hexanes) determined which
fractions contained the product with comparison to an authentic

26. standard of acetylferrocene. The solvent of the fraction(s) that
contained product was evaporated; experimental yield of
product and percent yield were calculated, along with mixed MP
data and IR spectrum.3
Results
Several different methods were used throughout this experiment
to monitor the reaction and formation of the desired product.
Color changes were observed during three main stages of the
reaction (Table 1): first when sequentially mixing ferrocene
(0.094 g), acetic anhydride (0.50 mL), and phosphoric acid
(85%, 0.13 mL) and heating the mixture in a 80 °C water bath
for eight minutes; next when transferring the mixture onto
crushed ice; last when extracting the aqueous layers with
hexanes.
Reaction Stage
Observed Color Changes
Initial mixture of ferrocene (0.094 g), acetic anhydride (0.50
mL), and phosphoric acid (85%, 0.13 mL)
Deep, dark, clear orange-brown
After 1 minute of heating
Dark, “bloody”, red; persisted for all 8 minutes of water bath
Reaction mixture over ice
Rusty orange
Extraction of aqueous layers
Aqueous layers appeared a bright, clear orange
Table 1: Observed color changes throughout acetylation of
ferrocene
Alumina chromatography was used to purify the product. This
part of the experiment yielded three different fractions, which
were then tested via TLC to determine exactly which fractions
contained the desired product (Table 2).
Fraction
Rf Values

27. Fraction 1: hexane flush
Ferrocene spot
0.9
Acetylferrocene spot
0.2
F1 Reaction spot
—
Fraction 2: light orange
Ferrocene spot
0.95
Acetylferrocene spot
0.20
F2 Reaction spot
0.95
Fraction 3: dark bright orange
Ferrocene spot
0.9
Acetylferrocene spot
0.19
F3 Reaction spot
0.19
Table 2: Summary of Rf calculations
The mixed melting point experiment compared experimental
melting points to literature melting points of the starting
material, an authentic standard of the product, and the crude
product (Table 3):
Chemical
Literature Melting Point (°C)
Experimental Melting Point (°C)

28. Ferrocene
172.5
172-173
Acetylferrocene
81-83
82-84
Reaction product
—
84-86
Table 3: Literature and experimental mixed melting point data
IR spectroscopy of ferrocene lacked a carbonyl stretch,
whereas the IR spectroscopy of the final product exhibited a
strong carbonyl stretch at 1650.66cm-1.
Discussion
Traditional Friedel-Crafts acylation reactions generate the
electrophile by reacting an alkyl halide, acyl halide, or acid
anhydride with a strong Lewis acid1. The reaction mechanism in
this experiment stayed true to the mechanism, with phosphoric
acid acting as a strong Lewis acid to protonate acetic anhydride.
The mechanism behind the formation of the active electrophile
is shown below (Scheme 2).
Scheme 2: Formation of active electrophile via Friedel-Crafts
acylation mechanism
Also,unlike most organic compounds, ferrocene and
acetylferrocene are highly colored. Ferrocene possesses a
yellow-orange color, and acetylferrocene possesses an orange-
red color. These characteristics made it easier to understand and
follow the reaction mechanism as certain stages were occurring
(refer to Table 1).
TLC was useful for monitoring the reaction. The first TLC plate
was prepared to compare pure starting material, ferrocene, with
the combined organic layers of the reaction mixture. This plate

29. indicated that ferrocene was still present. A second round of
TLC was performed; three different plates were each spotted
with small amounts of pure ferrocene, commercial
acetylferrocene, and crude product. The plates for fraction 1 and
fraction 2 did not indicate product. However, the plate for
fraction 3 did indicate product was present — ferrocene Rf was
0.9, commercial acetylferrocene Rf was 0.19, and the crude
product Rf was also 1.9.
The IR spectroscopy of the final product differed from the IR of
ferrocene because the final product’s IR exhibited a strong
carbonyl stretch at 1650.66cm-1. This carbonyl stretch indicates
the presence of a ketone, which is what was expected of the
reaction. When the active electrophile attacked the ferrocene
ring, a substitution occurred between one ring proton for one
acetyl group.
Performing a mixed melting point experiment was helpful in
identifying the unknown/desired product because melting point
is characteristic to a particular compound. In this experiment,
the melting point data helped corroborate evidence that the
reaction proceeded as expected, ending with the formation of
acetylferrocene. The literature value for the melting point of
acetylferrocene is 81-83 °C. The experimental value for the
melting point of the product was extremely close to that range
except for only a few degrees higher. Overall, this suggested
that the crude product contained only trace amounts of the
starting material ferrocene.
The experimental mass of crude product collected was
0.018 g, while the theoretical mass was 0.114 g. This lead to a
15.78% yield. A possible source of error was during TLC; plates
were not given enough time to dry before developing them.
Conclusion
The purpose of this experiment was to study and observe a
greener approach to the mechanism behind a Friedel-Crafts

30. acylation reaction. Specifically, ferrocene acted as the
nucleophile, and the active electrophile was formed by reacting
acetic anhydride with phosphoric acid. The experiment
proceeded as predicted, which was indicated by the color
changes that took place throughout the experiment. TLC, MP,
and IR spectroscopy also suggested that the desired product —
acetylferrocene — was formed via Friedel-Crafts acylation. The
TLC of the three fractions suggested that only fraction three
contained the desired product; therefore, only fraction three
underwent evaporation and further testing. The experimental
melting point for commercial acetylferrocene was 83 °C – 84
°C; the experimental final product was 84 °C – 86 °C. This data
supported that the reaction went as planned because the final
product melted over a short range of 2 degrees, which suggested
high purity, and in close proximity to the authentic standard of
acetylferrocene. The IR spectrometry of the final product
differed from the IR of ferrocene because the final product’s IR
exhibited a strong carbonyl stretch at 1650.66cm-1. The
theoretical yield was calculated to be 0.114 g; however, the
experimental yield was only 0.018 g, resulting in a 15.78%
yield.
References
1. Klein, D. R. (2012). Organic chemistry. Hoboken, NJ: John
Wiley.
2. Ballard, C.E., Henechey, L., Leslie, J.M., Struss, J.A.,
Theodore, C. CHE 235L Organic Chemistry II Laboratory
Spring 2016 Laboratory Manual; Florida, 2016; pp 41-46.
3. Senthilingam, M. (2013, May 2). Ferrocene. Retrieved April

31. 09, 2016, from
http://www.rsc.org/chemistryworld/2013/05/ferrocene-podcast