Organic Chemistry Laboratory CHE 327
Addison Ault, Andrea Pionek,
Jeff Cardon, Charley Liberko
Laboratory
Information
Required:
Text: Addison Ault, Techniques and Experiments for Organic
Chemistry, 6th Edition. You should have the textbook with you in the lab at
all times.
Goggles may be purchased from the
stockroom for $5.00.
Carbonless notebooks may be purchased from the
stockroom for $9.
Daily Schedule
Each day we will meet at
Preparation
Before coming into the lab each day,
each student must be adequately prepared in order that the lab time is spent
safely and efficiently. Proper
preparation includes reading the lab procedure and relevant background material
(you may need to do this several times in order to understand it), and
preparation of the notebook with all necessary physical data (relevant melting
points, boiling points, densities, and solubilities).
Notebooks and reports
All data and observations will be recorded directly
in the notebook. The carbonless copy
from your notebook is due as you leave the laboratory each day or as soon as
you have finished collecting data for that experiment. Staple a copy of the Laboratory Notebook
Grading Rubric to your pages. Lab
reports, products, and extra credit questions are due at
Point Breakdown Points Approx. %
Notebook 130 19
Write-ups 260 37
Products 33 5
Quizzes 120 17
Final Exam 100 14
Technique 35
5
Other
22 3
Total 700 100
As
a general guide for grading, the following cut -offs will be used:
90% A- 80% B-
70%
C- 60% D-
Schedule
|
Day |
Experiment |
Reference (pages) |
Techniques / Reactions |
|
M 3 / 3 |
1.
Isolation of Acetylsalicylic Acid from Aspirin Tablets |
43-54,
150-159, 332-333 |
heating,
filtration, crystallization, melting points |
|
Tu 3 / 4 |
2.
Distillation of a methanol
/ water mixture |
62-72;
75-80, 305 |
Distillation |
|
W 3 / 5 |
3.
Separation of malachite green and phenolphthalein |
92-109 |
Acid
base extraction |
|
Th 3 / 6 |
4. Preparation of 2,4-Dinitrodiphenylamine |
475-476 116-119 |
Nucleophilic
aromatic substitution, recrystallization, TLC |
|
F 3 / 7 |
Quiz 1
|
|
|
|
M 3 / 10 |
5. Prep. of Cyclohexene from Cyclohexanol |
376-380 122-128 |
acid
catalyzed dehydration GC
analysis |
|
Tu 3 / 11 |
6.
Prep. of Cyclohexanone from cyclohexanol |
387-389 87-90 182-199 |
oxidation,
steam distillation, IR |
|
W 3 / 12 |
7. Preparation of “banana oil” |
417-426 |
Fischer
esterification, SN2
substitution |
|
Th 3 / 13 |
8.
Unknowns |
169-181 239-272 |
Solubility,
chemical tests for functional groups |
|
F 3 / 14 |
Quiz 2 |
|
Proposals
due for Expt. 12: 9:00AM |
|
M 3 / 17 |
9. Preparation of
tetraphenylcyclopentadieneone |
595-597 |
Aldol
reaction |
|
Tu
3 / 18 |
10.
Preparation of a photochromic compound |
564-566 |
electrophilic
aromatic substitution, nitration |
|
W
3 / 19 |
11.
Preparation of Malachite Green, Crystal Violet |
439-440 |
Grignard
reaction, preparation of dyes |
|
Th 3 / 20 |
12.
Student's Choice |
|
Proposals
due: Friday, March 14 at |
|
F 3 / 21 |
Quiz 3 |
|
|
|
M 3 / 24 |
13. Preparation of norbornene-2,3-dicarboxylic
anhydride |
507,
510-514 |
Diels-Alder
reaction |
|
Tu
3 / 25 |
Review,
Check out Pizza
Frenzy |
|
|
|
W 3 / 26 |
Final Exam 9:00 - Noon |
|
|
Safety
Keeping the lab safe is the number
one priority and it is everyone’s responsibility. Before you begin, read Section 1 in your lab
book. Several rules are worth repeating:
Eye protection
must be worn at all times in the lab.
Appropriate attire must be worn in the lab. Clothing
must cover all parts except the head, hands, and forearms. Long hair should be tied back.
Memorize the location of all exits, showers,
eye-washes, fire extinguishers, and fire blankets.
No food or beverages are allowed in the lab. Leave
backpacks and coats in the hallway.
Be certain that there are no flammables in the area
when lighting a flame. (Warning: artificial fingernails are extremely
flammable.)
Be alert for hazards in the lab. Do not proceed with any experiment until you
understand the hazards involved.
Report all injuries to your instructor, even if they
appear to be minor.
Do not come into contact with any of the solvents or
reagents used in this lab other than soap and water. Remove gloves and wash hands before leaving
lab.
Clean up all chemical spills immediately,
this includes drips on bottles.
Do not leave any bottle uncapped.
Dispose of all wastes as directed. (Ask before you dump.)
Come to the lab prepared.
Material Safety Data Sheets
(MSDS)
You have a right to be informed as
to all the known hazards and potential hazards of the materials you will work
with. MSDSs are provided by chemical
suppliers which describe risks and proper handling of the reagents you will
use. Copies of these forms are available
from the stockroom.
As an example, consider the MSDS for
acetone. Pay particular attention to the
“Precautionary Labeling” section. Each
compound is rated for its health, flammability, reactivity, and contact
hazards. The rating is on a scale of 0 (very low or nonexistent hazard) to 4
(extreme hazard). Acetone poses a low
health and contact hazard (rating of 1), it has a very low reactivity (rating
of 0), but severe flammability (rating of 3).
Keep in mind that you may already be familiar with acetone as it is
commonly used as a “nail polish remover”.
A few danger words that you should
get to know include:
Toxic - poisonous
Mutagen / carcinogen – causing mutations or cancer
respectively
Teratogen – (literally “monster-forming”) causing
birth defects
Lacrymator – causing watering of eyes irritation to
mucus membranes
Caustic – causing chemical burns
Grading
Guidelines
Notebooks
Each student must keep a notebook
with all data recorded immediately in ink. For each experiment, your notebook will be
graded on a 10-point scale. The work
should include the following, be in the order listed, and have the headings in
bold.
Pre-lab: To be done prior to
1 Descriptive title and date - This
is also the title that you should enter in your Table of Contents along with
the page numbers that the experiment is on.
2 Chemical structures / balanced chemical equations -Draw the structures for all organic reagents used
including solvents. Write a balanced chemical
equation for each reaction including acid/base reactions. Also include moles, masses, and/or volumes
required to perform the experiment and theoretical yield in a well organized
way. Refer to p. 30 in your text
book. Note: Equations in this manual are not balanced.
2 Data table of reagents
- Fill in a table with information for
all chemicals required in that particular experiment and their properties. (see Appendix 2-4 in this
manual)
1 Procedure reference - Write a bibliographic reference or references to where
the procedure can be found. Be
specific. Be sure you are including all
important parts of the procedure from the text and the Cornell lab manual. If you
prefer to write out procedure, you may.
During lab
1 Procedure summary as performed - Give a brief summary of the experiment including
chemicals used, lab techniques, and product analysis. Record anything that you performed
differently from the referenced procedure and all things unique to only your
experiment. If nothing was changed, make
a statement to that effect. This should
only be a couple of sentences or less and may be very similar to something
required in your formal report. (A good
way to refine your writing is to have to write something more than once.)
1 Qualitative observations during procedure - What do you see, smell, hear during
the experiment?
Post-lab
2 Results - This is a well-organized,
brief presentation of the results of your experiment. A table would work. When reporting measured physical data, include the
literature value with reference for comparison.
Include physical appearance,
melting point or boiling point, amount
obtained in grams and moles, theoretical yield and percent
yield in grams and moles with units and how they were calculated, limiting
reagent, and anything else specific to the final results of you experiment.
10 Total
Odds and ends- the following
may influence your technique points.
A copy of all spectra should be stapled into the notebook
behind that experiment. Spectra may be
photocopied and reduced or trimmed down to size if necessary to fit into your
report. Be sure to include a caption.
Notebooks will be collected Friday
mornings and at the final exam to be checked for table of contents and spectra.
Don’t forget to staple a grading
rubric to your notebook pages before you turn them in (See Appendix 5).
Reports
After the lab has been completed you will prepare a
short but formal report. These reports
should be word processed (hand drawing of structures is allowable if they are
done neatly) and are limited to two pages, excluding graphs and spectra. Text sections should be double spaced with
one inch margins and 12 point font. The reports
are due at
Experiment Number and Title
10% Claim – This statement
should lay claim to the results that you think you got (not what you were
supposed to have gotten). The claim is
essentially a conclusion and should typically include qualitative information on yield, quality, and purity of product.
20% Evidence – This
section must support the claim and will be a concise listing of what you did
and observed. All data (for example
number of grams and mmoles of reagents used, melting or boiling points of
products etc.) should be included here.
50% Discussion – This
section will convince the grader of the reasonableness of the claim in light of
the evidence. For maximum points, be
sure to include the any/all of the following when applicable:
a. A concise discussion
of any new technique and how this technique
relates to the particulars of the experiment.
b. A discussion
of yield (or recovery), including discussion of systematic losses due to the
limitations of the technique.
c. A balanced
chemical equation and a mechanism for
any reactions carried out in the labs.
d. Structures
for all reagents.
e. Spectra or
graphs with proper meaningful captions.
10% Visual Presentation – For maximum points, the report needs to
follow the required format, including title, section headings, and appropriate
length, be well organized and neatly presented.
10% Stylistic Presentation – For maximum points, the report needs to
be written using correct spelling, grammar, and references. There needs to be appropriate use of
significant figures. (Be warned: Good writing style will not make up for poor
or nonexistent content.)
Refer to the sample write-ups below. The samples are not shown with double spaces
text. Your reports should have double
spaced text. For the fun of it, what grade
would you give the first report? What
grade would you give the second? Has the
student forgotten anything in the first report?
__________________________________________
[Preferred Write-up]
Experiment 15
Isolation of caffeine from tea
Ben der Dunthat
Claim: A relatively pure sample of caffeine was recovered from black tea by extraction into hot water.
Evidence: The procedure was carried out as described by Ault[1] using 4 Lipton brand tea bags (11.6g), 120mL water, and 12.0 g CaCO3. The mixture was heated to boiling for 21 minutes and filtered by suction. After cooling the filtrate, the product was extracted into chloroform. Evaporation of the chloroform gave a white semisolid (0.47g) that was recrystallized from 95% ethanol (~3 mL) giving small colorless needles. 0.23g, 1.2 mmol, 1.8% isolated recovery, Mp 229-232, (235-236 lit.[2])
Discussion: Caffeine is an organic compound with a high degree of polarity and it is quite soluble in both hot water and chloroform. The high solubility in hot water (0.67g/ml) allows caffeine to be extracted from the tea leaves. The tannic acid in tea, however, is also water soluble and is extracted along with the caffeine. Since calcium salts of carboxylic acids are insoluble, the calcium carbonate acts to de-protonate the tannic acid and to precipitate it as the calcium salt making it possible to remove it by filtration. As the aqueous solution cools, the solubility of caffeine is greatly decreased allowing most of it to be extracted into the chloroform layer. Since caffeine is soluble in the cold water (0.02g/ml), the extraction will not remove all of the caffeine and some will remain in the aqueous layer. Caffeine has a reasonable solubility in cold ethanol (0.02 g/ml) and a fair amount would have remained in the ethanol solution after the recrystallization. The recovered yield is 1.8%, which compares to the reported range of caffeine in tea of 2-5%. The isolated compound melts over a three-degree range close to the reported value for caffeine showing it to be reasonably pure.
____________________________________________________________________________
[Less-than-desirable
Write-up]
Isolation of caffeen from tee
Sara N. Dipity
Claim: We made caffine from tea. We got it from the bags using isolation. The melting point was good.
First, we followed the proceedure and got caffene crystals. Then we preformed a recrystallization on our crystals. Then we dried our crystals. Then we weighed our crystals. They weighed .0032. A melting point was run on the crystals. The melting point on the crystals was 128o. This is not to bad.
We got cafeine from tea.... I don’t like tea unless its iced when its hot out and then it’s ok if you use lots of suger but not that pink stuff. We heated the water to make it more soluble. During the extraxion caffein was on top because its is organic. The sepertory funnell seperated the caffin because it is more poler. The calcium carbonate crystals looked like a white powder and their was some chunks in they’re: but I could have spilled some on the bench maybe. When I suction filtrated the crystals it took to long so more may have been lost. The calcium crystals were used because it is a base and it protonated the tannic so it is less soluble and it didn’t dissolve. I think that when I dried my stuff I let it dry two long so I lost some because some of it may have evaperated away. It is yellow and sticks to the vile and smelled like a keytone. It is mostly impure but more pure then my last product. My percent thearetical yeild was 4.27452% wich is not very good do to error. I wonder what would happen if we used instent tea instead. I think it would be more.
(Did you spot any errors? This could be worse. It could be hand scribbled and it could be three pages in length! Please don’t make us read anything like this.)
_________________________________________________
Answers to questions
Questions are presented for each
experiment to stimulate thinking about important concepts and should be
considered before writing your discussion.
The questions may serve as fodder for quizzes and exams. Answers to questions may be written on a
separate piece of paper and turned in for extra credit. Be sure to include your
name and the experiment number. Bonus
points will be given for answers to the questions as follows:
2 thoughtful,
correct answers
1 reasonable
answers
0 poor
or no answers
Extra
bonus points for exceptional work may be awarded at the discretion of the
instructor.
Product Labels
Each product should be properly
labeled and placed on the appropriate lab table with an accompanying
information card. The product vial
should contain a meaningful identification number containing the student’s initials
and notebook page number (i.e. CAL-43).
The accompanying card should contain the student’s name, product ID
number (matching the vial), product name, product amount (in grams), percent
yield (or percent recovery if appropriate) and measured physical data such as
melting or boiling point range. If a
spectrum was obtained, a labeled copy should be stapled to the card.
Product Quality
The quality of your products will be
graded on a three-point scale as given below:
3 High
yield, good quality
2 average
yield, average quality
1 poor
yield, poor quality
0 no
product
Technique
Your technique will be evaluated at
the end of the term and will be worth five percent of your overall grade. Technique points will be awarded at the
discretion of the instructors. The maximum
number of points will be awarded to students who:
-
Show up on time and are properly dressed
-
Are fully prepared for lab
-
Follow all safety rules
-
Perform laboratory functions safely and efficiently
-
Work carefully in the lab to avoid breakage, spills, contamination, and fire
-
Properly dispose of waste
-
Clean up their bench and common work areas daily
-
Overall quality and completeness of notebook
Time Management
It is expected that students will
come to lab fully prepared with major glassware setup in advance and will work
at a reasonable pace when in lab. All of
our experiments have been designed and tested so that they may be completed in
less than two and one-half hours if the student is adequately prepared. If for some unforeseen circumstance a fully
prepared student who works efficiently is unable to complete an experiment by
Describing your products
Science begins with observation. Communicating science must always include
descriptions of your observations. In
the organic lab, we must not only say that we obtained a product, but we must
be able to describe it. The most
fundamental distinction will be the phase of matter of your product; is it a
solid, liquid, or a gas? But that is
only the beginning; you should also describe its physical appearance and
properties. For example, if it is a
liquid, you should describe whether it is clear or cloudy (opaque). You should describe whether it is colored or
colorless. Note that clear and colorless
are two different properties. If you
obtain a solid you should describe its crystalline form; are the crystals needle-like,
platy, or prismatic? If the crystals are
too small to be observed they could be described as powdery. Smell is also an important distinguishing
characteristic; is the smell pleasant or pungent? Words to describe smells might include sweet,
fruity (esters), sour (carboxylic acids), fishy (amines), balsamic (cinnamon,
cocoa, vanilla etc.), camphoric, citrus (lemon or lime), floral or earthy to
name just a few.
Science is worthless without good
communication. When communicating, it is
important to spell and use words correctly.
The following are lists of words commonly misspelled or misused in this
course. Learn to use these words
properly.
Commonly misspelled words
Dye
/ dyed
Ketone
Perform
Precipitate
Separated
Separatory
funnel
Summary
Theoretical
Vial
Yield
Commonly misused words
Data
(a noun, plural)
Distillate
(the object; a noun)
Filter
(the action; a verb), Filter (the object; a noun)
Filtrate
(the material, a noun), (“Filtrated” will not be recognized in this course)
Precipitate
(the action, a verb), Precipitate (the material, a noun)
To
(a preposition), Two (a number), Too (an adverb)
Then
(for order in time), than (for comparison)
Their
(possessive form of they), There (a place), They’re (contraction of they are)
Experiment 1
Isolation of
Acetylsalicylic Acid from Aspirin Tablets
Read
pp. 43-54, 150-159, 332-333
Aspirin is an analgesic, an antipyretic, and an anti-inflammatory
agent. It was first produced
synthetically by Felix Hoffmann in 1893 and marketed by Bayer as a wonder-drug. Recently, aspirin has been marketed for its
ability to thin the blood and prevent or lessen the severity of heart attacks
and strokes. In this experiment, we
will isolate the acetylsalicylic acid from aspirin tablets.
Aspirin tablets contain acetylsalicylic
acid (the active ingredient) as well as “inert” binders to hold the tablet
together. We will take advantage of the
fact that acetylsalicylic acid is quite soluble in hot ethanol while the
binders are insoluble and can be removed by filtration. The solubility of
acetylsalicylic acid will be reduced by the addition of water to the solution,
allowing the acetylsalicylic acid to crystallize out.
Follow the procedure in the text for
isolating acetyl salicylic acid. After
allowing your product to dry overnight, determine its mass and melting point
range.
Report
Discuss the chemical principles used in this
lab. Be sure to record the amount of
product you obtained (recovered yield) as well as calculate the percent
recovery. The amount of acetylsalicylic
acid in each tablet is reported on the product label. In your discussion, include the theory of
purification by crystallization.
The following information may be helpful for this
experiment: Acetyl salicylic acid, M.W. 180.15 g / mol, pKa 3.49,
m.p 135 oC. Solubility: 1 g
acetylsalicylic acid dissolves in 300 ml water at 25 oC or 100 ml
water at 37oC, 5 ml ethanol, or 17 ml CHCl3.
Balances: Use only the top
loading balances in this course (not the analytical balances). If you spill on
a balance, consult with the instructor on how to clean it up. Never leave a
spill!
Water hoses: Keep your water
hoses for the entire term.
Melting points: Never leave the melting point apparatus “on” unless it
is in use. It could overheat and blowup
the thermometer.
Broken glassware: Put all broken
glassware in the bucket beside the waste basket. Remove and save any stoppers, stopcocks, or
plastic parts.
Clean-up: If detergent and water
are not sufficient to clean your glassware try rinsing with a small amount of acetone. If that
doesn’t work, try rinsing with dilute acid or base.
|
Substance |
Amount |
Properties |
sol. |
||||||
|
|
mmoles |
grams |
mL. |
M.W. |
dens.
|
m.p.
|
b.p. |
w |
o |
|
Acetylsalicylic
acid |
18 |
3.25 |
|
180 |
|
140 |
|
N |
Y |
|
Ethanol |
|
0.79 |
10 |
46 |
0.79 |
-130 |
78 |
Y |
Y |
|
Water |
|
50 |
50 |
18 |
1.00 |
0 |
100 |
Y |
N |
Experiment 2
Simple vs. Fractional
Distillation of a Methanol / Water Mixture.
Read
pp. 62-72; 75-80, 305
In this experiment you will perform both a simple
and a fractional distillation on a mixture of methanol and water and compare
the two techniques based on the composition of the distillate as a function of
the volume collected. While the goal of most distillations is to separate a
mixture of volatile substances by collecting them in separate containers, the
goal of these particular distillations is to compare the mole fractions of the
distillate as a function of volume collected for the two techniques. We will do this by monitoring the temperature
of the distillate and using the vapor diagram to relate temperature to
composition.
You will work with a partner, one will perform the
distillation and the other will record the data. You will trade duties for the second
distillation.
Prepare a 0.5 mole fraction methanol/water mixture
by combining 40 ml methanol with 18 ml water.
You will use this mixture for both distillations. After the first distillation, make the
necessary modifications in the glassware setup and pour the distillate back
into the boiling flask.
Fractional
distillation
For this experiment, we will modify a fractional distillation apparatus in order to help us understand the role of the fractionating column. (All future fractional distillations will use the standard glassware set-up.) We will use two thermometers, one below the fractionating column and the other in the standard place above the column in the still head (connecting adapter). This will allow us to monitor the difference in vapor composition in the two regions of the apparatus. The lower thermometer will be placed in the straight neck of a Claisen adaptor and adjusted so that the bulb is just above the boiling liquid. The fractionating column will be placed on the other neck of the Claisen adaptor. When carrying out your distillation, record the volume collected and temperature of both thermometers every 3-4 ml. Note whether or not any mixing lines are observed as the distillate is being collected. Continue the distillation until at least 50 ml distillate has been collec