ORGANIC CHEMISTRY LABORATORY II, SUPPLEMENT
CHEMISTRY 3611
Spring 2004
http://www.uark.edu/campus-resources/allison/OC2Lab/index.htm
Department of Chemistry and Biochemistry
University of Arkansas
Fayetteville, AR 72701
CHEM 3611, SCHEDULE AND TABLE OF CONTENTS FOR SPRING 2003
PAGE
1
SCHEDULE FOR SPRING 2004
Week
Date (Monday)
Experiment
1
2
3
4
5
6
7
8
9
10
11
12
13
14
January 19
January 26
February 2
February 9
February 16
February 23
March 1
March 8
March 15
March 22
March 29
April 5
April 12
April 19
Check-in, Safety, Disposal
Dehydration of t-Amyl Alcohol
Synthesis of Stilbene and Diphenylacetylene
Synthesis of Stilbene and Diphenylacetylene
Diels-Alder Reaction
Aromatic Nitration: Nitration of Methyl Benzoate
Identifying an Unknown: Aldehydes and Ketones
Identifying an Unknown: Aldehydes and Ketones
Spring Break
Aldol Condensation (Dibenzalacetone)
Preparation of Tetraphenylcyclopentadienone
Preparation of Acetylsalicylic Acid (Aspirin).
Preparation of Nylon
Checkout
TABLE OF CONTENTS
SCHEDULE FOR SPRING 2004.................................................................................................................. 1
TABLE OF CONTENTS ............................................................................................................................... 1
GENERAL INFORMATION .......................................................................................................................... 2
LABORATORY SAFETY REGULATIONS .................................................................................................. 4
LOCKER APPARATUS LIST....................................................................................................................... 6
DEHYDRATION OF T-AMYL ALCOHOL; REACTIONS OF ALKENES & ALKANES.............................. 7
BROMINATION OF STILBENE AND SYNTHESIS OF DIPHENYLACETYLENE.................................... 11
DIELS-ALDER REACTION ........................................................................................................................ 13
AROMATIC NITRATION: NITRATION OF METHYL BENZOATE ........................................................... 16
IDENTIFYING AN UNKNOWN: ALDEHYDES AND KETONES............................................................... 18
ALDOL CONDENSATION (DIBENZALACETONE).................................................................................. 21
PREPARATION OF TETRAPHENYLCYCLOPENTADIENONE............................................................... 23
PREPARATION OF ACETYLSALICYLIC ACID (ASPIRIN). .................................................................... 25
PREPARATION OF NYLON ...................................................................................................................... 27
CHEM 3611, ORGANIC CHEMISTRY LAB, GENERAL INFORMATION
PAGE 2
GENERAL INFORMATION
Unless otherwise indicated, all reading assignments are to the laboratory text, Williamson,
Macroscale and Microscale Organic Experiments, 3rd Edition, and/or the lecture text, Vollhardt
and Schore, Organic Chemistry, 4th Edition, and should be studied prior to the lab. Quizzes will
cover this material. Except when indicated in the experiment assignment, the Williamson text
may not be brought to the lab; all necessary information from it should be entered in the pre-lab
write-up in your laboratory bluebook (see below). If an assigned experiment contains both
macroscale and microscale directions, use the microscale version.
Experiment Assignments: The assigned work and a report form for each experiment will
be provided in this supplement.
Laboratory Notebooks: Instead of using a single laboratory notebook for all experiments,
as described by Williamson, each experiment is to be recorded in a separate blue examination
booklet and on the report form. The type of information that should be entered in the bluebook
is described on pp. 17-19 of Williamson. Use the following format:
1. Title of Experiment
2. Introduction
3. Balanced Equations for all reactions
4. Table of reagents and products, with pertinent physical constants
5. Safety data and precautions for chemicals to be used (consult the Merck Index and/or
the Sigma-Aldrich Library of Chemical Safety Data, on reserve in the Chemistry
Library for the first laboratory; safety data will be supplied by the TA one week
before the rest of the laboratories.)
6. Answers to any assigned pre-lab questions
7. Outline of procedures (as concise as possible, but complete enough that you will
know exactly what to do and how to do it)
8. Cleaning up: waste disposal requirements
****All entries should be in ink and sections 1-8 of this format MUST be completed prior to
lab. The TA will briefly check your pre-laboratory outline for content and organization early in
the period. If it is particularly deficient you may be denied permission to start the experiment.
Report Forms: The report form will summarize your results. All entries on it should be
available directly or by calculation from data you have recorded in your bluebook. It may also
require attachment of graphs or other types of data (spectra, etc.), and may require answers to
post lab problems.
Reports and bluebooks are to be turned in to your TA at the end of the lab period, except when
a later submission time is specified in the experiment assignment. Reports submitted later than
the due date receive grades of zero.
CHEM 3611, ORGANIC CHEMISTRY LAB, GENERAL INFORMATION
PAGE 3
Attendance: There are no periods for lab make-ups, so attendance is mandatory. Absentees
receive grades of zero for the experiment. It may be possible if a lab is missed due to
circumstances such as severe illness, etc. that a laboratory can be made up later in the week if
space is available. Permission for this must be obtained from Dr. Allison (nallison@uark.edu).
A medical doctor’s excuse would expedite this arrangement. If you must miss a lab, inform your
lab instructor (TA) in advance as to the reason. If through unusual circumstances you miss a
laboratory and cannot make it up later in the week, contact Dr. Allison.
Grading:
The labs will be grades as follows:
20 points
Bluebook (if all sections are filled out)*.
15 points
Technique, etc.**
30 points
Quiz
35 points
Report Form***
*Bluebooks will be docked 5 points for a missed section, 1-2 points for missing
detail
**Some reasons for docking technique points ($ signifies relative number of points
taken off): Not bringing or improperly using goggles ($$$$). Students who copy
from others ($$$$). Sloppy technique such as chemical spills in the sink and
violation of safety rules ($$-$$$$). Foam inserts in the lab kit that disintegrate due
to acetone vapors ($$). Not preparing (that is, do not have any idea of what is
going on at the start of the laboratory) ($$$, it is encouraged for a prepared
student to ask questions, such as those regarding the clarification of details: this
will not be counted against the student.). Syringe needles found in trashcan (not
properly disposed) can result in penalizing ($$) all lab students in that section
(unless person improperly disposing of needles is known). Improper disposing of
waste ($-$$$).
***Postlab questions will be answered on the back of the report form.
Proper checkout (last laboratory date) will receive 40 points, based on clean and complete
equipment and laboratory general areas (clean balances, desks, etc.) present at the last
laboratory. Your instructor will inform you of the general area cleanup necessary. This lab will
be grades as follows:
10 points
kit full, clean, and dry
10 points
other glassware complete, clean, and dry
10 points
your bench, hood, and the front bench cleaned
10 points
general area cleanup
The total number of points will determine your overall course grade.
CHEM 3611, ORGANIC CHEMISTRY LAB
PAGE 4
LABORATORY SAFETY REGULATIONS
Laboratory Safety Equipment
Know the location and operation of the fire extinguishers, fire alarm, safety shower,
eyewash, and fire blanket, and two exits from your laboratory. You will be asked to show these
on the safety quiz!
Personal Safety Equipment
Everyone in the laboratory must always wear safety eye goggles (NOT safety glasses)
whenever chemicals are in use. Students who do not follow this requirement during any
experiment will be told to leave the lab. Goggles must meet current departmental chemical
splash standards. Side shields, top vents, or other parts of goggles may not be altered in any
way.
Everyone in the lab must have nitrile gloves at their disposal to wear when instructed by the
Teaching Assistant (TA) or when handling chemicals whose Material Safety Data Sheet (MSDS)
indicates wearing gloves. Be aware that gloves, like clothes and shoes, are a first line of
defense and are not impervious to all chemicals.
Clothing should cover as much of the body as practical. A lab coat or apron is highly
recommended. Clothing that protects the individual’s body from the neck to mid-calf is required.
Sleeveless shirts, tank tops or other clothing that does not cover the shoulders or abdominal
area is not allowed. Shorts or short skirts are not acceptable except under a full-length lab coat
or apron.
Persons with long hair or beards should recognize that these constitute fire hazards. Hair
beyond shoulder length should be tied back.
Shoes covering the entire foot (including the heel) are required.
Laboratory Accidents - Emergency Action
If anyone is splashed with a burning solvent or corrosive chemical or has any clothing on
fire, the affected area must be doused quickly with running water. Use laboratory water taps or
the safety shower (whichever is appropriate). For corrosive chemical spills on clothing, the
contaminated clothing must be removed as quickly as possible so water flushes the skin
directly.
For chemicals in the eye, immediately help the injured person to the nearest eyewash and
copiously irrigate the eye with water for at least 15 minutes. Hold the eye(s) open to allow water
to cleanse the eye and eyelid. If the injured person is wearing contact lenses, wash for several
minutes, have the wearer remove the lens, and continue washing.
Minor cuts and thermal burns should be flushed with water.
Report any accident, injury, or chemical spill IMMEDIATELY to your Teaching Assistant (TA)
as soon as emergency action is taken.
CHEM 3611, ORGANIC CHEMISTRY LAB
PAGE 5
General Rules
•
Laboratory work is restricted to established, supervised periods.
•
Only experiments authorized by the TA are permitted.
•
Smoking, drinking, or eating is not permitted in the lab. Do not taste any food or
chemical that is in the laboratory.
•
Hoods in the labs should never be turned off. Hoods should always be kept clean
and free from any mess (paper towels, dirty glassware, etc.) The hood sash should
be at or below the red arrow at all times especially when in use. The TA will instruct
you when certain chemicals must remain and specific chemical reactions must be
done in the hoods.
•
All spills anywhere in the lab (including hoods) must be cleaned up and reported to
the TA immediately.
•
Keep bench top, shelves, and floor uncluttered. Leave your work area, sink, and
reagent bench clean after each period. Pay special attention to keeping the balance
and other community areas clean.
•
Syringes and needles should never be discarded in the trashcans. Dispose only in
specially marked “Sharps” containers.
•
Broken glass should be placed in “Broken Glass” container not in the trashcans. A
special container is provided for broken thermometers. Broken thermometers should
not be placed in the broken glass container.
•
Chemical waste should be discarded as directed by your TA. Specific waste
containers will be provided for proper disposal of all hazardous materials.
CHEM 3611, ORGANIC CHEMISTRY LAB
PAGE 6
LOCKER APPARATUS LIST
(Rev. 7/01)
Name (print):____________________
TA :_________________________
Course #_____________________
Room # _____________________
Locker #: _________________________
Lock combination: _________________
Lock serial number:________________
Kit #_____________
Check - in
_____
_____
_____
_____
_____
_____
_____
_____
_____
_____
_____
_____
_____
5 Beakers:1 each - 30ml, 50ml, 100ml, 150ml, 250ml
2 Erlenmeyer flasks: 1 each - 25 ml, 50 ml
2 Rubber Bulbs for Pasteur pipettes
1 Graduated Cylinder and Plastic Base - 10ml
1 Scoopula
1 Spatula - Stainless Steel
2 Stirring rods - 3 mm
2 Test tubes - 6”
4 Test tubes - 4”
1 Wire test tube holder
1 Thermometer - 360° or 400°
1 Rubber tubing piece, 1” long for pipette/syringe connection
2 Watch glass - 100 mm diameter
Check - out
_____
_____
_____
_____
_____
_____
_____
_____
_____
_____
_____
_____
_____
CHECK-IN DATE
STUDENT SIGNATURE
____________________
__________________________________
CHECK-OUT DATE
KIT COMPLETE
T. A. SIGNATURE
CHEM 3611, Dehydration of t-Amyl Alcohol, Reactions of Alkenes and Alkanes,
PAGE 7
Dehydration of t-Amyl Alcohol; Reactions of Alkenes & Alkanes
Reading: Vollhardt and Schore, Section 11-9; Williamson, Chapter 11; Chapter 19, pp 282-283 (yield
calculations); Chapter 18, pp 272-277.
Pre-Lab Questions: Pre-lab exercise on p 183 of Williamson; Questions 1 and 8 on p 191 of
Williamson; Question 1 below.
1. A student dehydrated 1.50 ml of 2-methyl-2-butanol by the procedure you will use in this experiment,
and obtained 0.85 g of the methylbutene mixture. What is the theoretical yield of combined
methylbutenes, and what was this student’s percent yield? Show your calculations.
Safety Information:
2-methyl-2-butanol(t-Amyl alcohol)
Sulfuric Acid
Cyclohexane
Cyclohexene
3%(w/v)Bromine in Dichloromethane
3%(w/v)Bromine in water
Sodium Thiosulfate
1% KMnO4 in 10% H2SO4
Calcium Chloride, Anhyd.
Sodium Hydroxide
Flammable, Toxic
Highly Corrosive
Flammable, Irritant
Extremely Flammable, Irritant
Toxic, Irritant
Toxic, Irritant
Irritant, Hygroscopic
Corrosive, toxic
Irritant, Hygroscopic
Corrosive, Toxic, Causes severe burns
Cleaning Up: There will be special test solution waste jars for a) Br2/CH2Cl2 test waste, b) Br2/water test
waste, c) KMnO4 test waste and d) conc. H2SO4 test waste. Put the entire contents of reaction or test
tube from the test reactions in these jars. Other materials should be disposed as described in
Williamson.
Experimental Work:
Chapter 11, Exp. 1 (pp 186-188, Micro scale Procedure). Dehydrate 2-methyl-2-butanol. Assay the
crude product by GC (p 274) and determine the ratio of 2-methyl-1-butene to 2-methyl-2-butene which is
produced.
Chapter 18, Exp. 4 (pp 275-277). Carry out tests A - D on cyclohexene and on cyclohexane. Use
procedures below titled “Tests for Alkenes and Alkanes” rather than those in Williamson, but read the
Williamson procedures and note his precautions. The handout procedures only change the amounts of
materials to use and do not repeat the precautions. We will not use purified and unpurified ligroin as
described by Williamson. Use tests of your own selection from A - D to determine if an unknown
contains unsaturated material. The unknowns will be commercial products such as turpentine, mineral
spirits (paint thinner), lighter fluid, rubber cement, mineral oil, etc. labeled by code letter. Run the
unknown assigned by your lab instructor.
==============================================================
Notes: Wash the crude distillate (first fraction) with NaOH solution and dry it over Na2SO4 as described
by Williamson, but omit the redistillation. During distillation keep the receiver vial in ice and have the
side arm far down in the cold vial (see Fig. 11.6). Keep the product cold during all other manipulations to
prevent loss of the very volatile product by evaporation.
Use 3 N NaOH in place of 10 % NaOH in the dehydration procedure.
The TA will run the GC of your product from the dehydration. Attach the recording to your report.
CHEM 3611, Dehydration of t-Amyl Alcohol, Reactions of Alkenes and Alkanes,
PAGE 8
CAUTION: Concentrated sulfuric acid is very corrosive. It will cause serious burns to the skin. If any get
on your skin, wash at once with water. Clean up any drips or spills on the bench top at once by dilution
with water, then neutralization with solid sodium carbonate, and finally clean-up with water.
CAUTION: Bromine is very corrosive. It will cause serious burns to the skin. If any gets on your skin,
wash at once with water. Clean up any drips or spill on the bench tip at once by dilution with water, then
reduction with sodium thiosulfate solution and finally clean up with water.
CHEM 3611, Dehydration of t-Amyl Alcohol, Reactions of Alkenes and Alkanes,
PAGE 9
Chapter 18, Experiment 4 Modified Procedures
Tests for Alkenes and Alkanes
These procedures are adapted from Chapter 18, Experiment 4 on pp 275-277 of Williamson which
should also be read in preparation for the experiment. The differences are only in the amounts of
materials and the knowns to be tested. Before starting any tests, take ca 1 ml each of cyclohexane and
cyclohexene from the stock bottles to your bench in small test tubes so you do not have to go back and
forth to the stock bottles for samples for each test.
(A) Bromine in Nonaqueous Solution. Treat 3 drop samples (ca 0.1 ml) of cyclohexane and
cyclohexene with 1 drop of a 3% solution of bromine in dichloromethane. If decolorization occurs,
breathe across the mouth of the tube to see if hydrogen bromide can be detected. Omit the illumination
part of the test described by Williamson.
(B) Bromine Water. Measure 0.5 ml of a 3% aqueous solution of bromine into each of two reaction
tubes. Add 3 drop portions (ca 0.15 ml) of cyclohexane to one of the tubes and 3 drops of cyclohexene
to the other. Shake each tube and record the initial results (decolorization or not). Omit the illumination
part of the test described by Williamson.
(C) Acid Permanganate Test. To 3 drop portions (ca 0.1 ml) of cyclohexane and cyclohexene add 1
drop of an aqueous solution containing 1% potassium permanganate and 10% sulfuric acid. Shake. Of
the initial portion of the reagent is decolorized, add further drops. Record the results.
(D) Sulfuric Acid. Cool 3 drop portions (ca 0.1 ml) of cyclohexane and cyclohexene in ice, treat each
with 0.5 ml (10 drops) of concentrated sulfuric acid and shake. Observe and interpret the results. Is
any reaction apparent? Any warming? If the mixture separates into two layers, what are they? (Put
answers on the back of your report form.)
CHEM 3611, Dehydration of t-Amyl Alcohol, Reactions of Alkenes and Alkanes,
Report for Dehydration of t-Amyl Alcohol;
Reactions of Alkenes and Alkanes
PAGE 10
Name_____________________________
Date______________________________
I. Dehydration of t-Amyl Alcohol:
Starting amount of t-amyl alcohol:
______ ml;
Crude product:
bp ______°C;
Theoretical Yield:
_________ g
Percent Yield:
_________ %
density _______ g/ml;
_______ torr;
mass ______ g
mass ______ g
II. Product GC:
Conditions:
column length
Column diameter
Stationary phase
Chart speed
_________ ft.
He flow _______ ml/min.
_________ inches
Temperature _______°C
______________________________________
_________ cm/min.
2-Methyl-1-butene: retention time __________ min;
2-Methyl-2-butene: retention time __________ min;
(Attach your GC trace to this report.)
percent of mixture ________%
percent of mixture ________%
III. Test Reactions: Concisely describe your observations.
(A) Br2 in CH2Cl2
Cyclohexene:______________________________________________________
Cyclohexane:______________________________________________________
(B) Br2 water
Cyclohexene:______________________________________________________
Cyclohexane:______________________________________________________
(C) KMnO4
Cyclohexene: ______________________________________________________
Cyclohexane: ______________________________________________________
D) H2SO4
Cyclohexene: ______________________________________________________
Cyclohexane: ______________________________________________________
(G) Unknown:
Code Letter: _______
Enter S for saturated or U for unsaturated: _____
==================================================================
The lab instructor will fill this in when your report is returned:
Your unknown was _________________________________
CHEM 3611, Bromination of Stilbene and Synthesis of Diphenylacetylene,
PAGE 11
Bromination of Stilbene and Synthesis of Diphenylacetylene
Reading: Vollhardt and Schore, Section 12-5 and 13-4; Williamson Ch 59 pp. 635-644.
Pre-Lab Questions: Handed in before you start the lab on a separate piece of paper.
1. Why does the addition of bromine to E-stilbene give the meso-dibromide? Draw a
mechanism to account for this fact.
2. Draw a mechanism for the conversion of meso-stilbene dibromide to diphenylacetylene.
There is an intermediate compound, what is its structure? (include the stereochemistry of the
compound)
Safety Information:
Acetic Acid
Pyridiniumhydrobromide Perbromide
Potassium Hydroxide
Ethyl Ether
Triethylene glycol
3 M HCl
Methanol
95% ethanol
Highly Corrosive
Corrosive, Lachrymator
Highly Corrosive
Flammable, Toxic
Irritant, Hygroscopic
Corrosive, Toxic
Flammable, Toxic
Flammable, Toxic
Experimental Work:
You should plan on completing the formation of meso-stilbene dibromide this week, so that you
have plenty of time the following week to finish this experiment and to take all the necessary
melting points.
1. meso-Stilbene Dibromide: Follow the procedure on pp. 639-640 with the modification of
doubling the amount of all reagents and solvent. Doubling the reaction allows enough product
to be generated for the next step. After adding the pyridinium hydrobromide perbromide swirl
the mixture until the solution's red color disappears. The remaining solvent trapped in and
around these crystals will mainly be methanol if you have washed them well. Methanol is not
extremely volatile and will take a few hours to evaporate fully. Therefore, you should try to finish
this section before the end of the first lab day for this experiment so that the crystals may dry
over the weekend. You will then have clean pure material to run the next step and to use for the
melting point determination.
2. Synthesis of Diphenylacetylene: Follow the procedure on p 642. Be very careful with the hot
potassium hydroxide mixture, it is extremely corrosive. If you do not have 80 mg of the product
from the previous reaction consult with your TA. After heating as instructed in the text, the
solution should be allowed to cool slowly. Instead of collecting the crystals using the Pasteur
pipette as instructed, suspend the solution into a pipette and then filter the crystals on your
Hirsch funnel. Wash with a minimum amount of ice cold ethanol (until the color disappears in
the filtrate (no more than 5 mL).
Recrystallize using a minimum amount of ethanol. To dissolve the crystals, adding slowly hot
ethanol one drop at a time only until the solid dissolves.
Post Lab Question: Answer this on the back of the report form.
Now that you have crystallized the diphenylacetylene and collected two crops, why do you think
there were two crops?
CHEM 3611, Bromination of Stilbene and Synthesis of Diphenylacetylene,
Report for Synthesis of Stilbene and Diphenylacetylene
PAGE 12
Name__________________________
Date___________________________
1. Formation of meso-Stilbene Dibromide :
Weight of E-stilbene used
___________g
Moles of E-stilbene used
_________mol
Time of Heating
_________min
Wt of meso-Stilbene Dibromide isolated
_____ g
Moles of meso-Stilbene Dibromide isolated
_____ mol
Percent yield of meso-Stilbene Dibromide
_____ %
mp of meso-Stilbene Dibromide
_____ oC
2. Synthesis of Diphenylacetylene :
Wt of meso-Stilbene Dibromide used
_______g
Moles of meso-Stilbene Dibromide used
_______mol
Time of Heating
_______min
Wt of Recovered Product
_______g
Moles of Recovered Product
_______mol
Percent yield
_______%
mp of Recovered Product
_______oC
Show your calculations on the report form. They will be part of your “Report” grade.
CHEM 3611, Diels-Alder Reaction,
PAGE 13
Diels-Alder Reaction
Reading: Vollhardt and Schore, Section 14-8; Williamson Chapter 49 pp. 572-588.
Pre-Lab Questions: Handed in before you start the lab on a separate piece of paper.
1. In order for a Diels-Alder reaction to occur, the diene has to have a certain conformation.
What is this conformation?
2. Diels-Alder reactions work best when there is an electronic difference between the diene and
the dienophile. Explain with an example.
Safety Information:
Dicyclopentadiene
Dichloromethane
Ethyl Acetate
Ligroin
Maleic Anhydride
Mineral Oil
Sodium Carbonate
Sulfuric Acid
Sodium Sulfate
Flammable, Toxic, Irritating to eyes and skin
Carcinogenic
Flammable, Irritant
Flammable
Irritant; harmful if swallowed; do not breath dust; may
cause sensitization by inhalation
Flammable, Irritant
Toxic, Irritant
Corrosive, Causes severe burns
Irritant, Hygroscopic
Experimental Work:
Your instructor will crack the dicyclopentadiene for you.** You should complete the Diels-Alder
reaction during the first lab period, so that you have plenty of time the following lab period to
finish this experiment and to start the next experiment.
1. Formation of cis-Norbornene-5,6-endo-dicarboxylic Anhydride: Follow the procedure on pp.
578-579. The crystals that you obtain should "dry" (the solvent should evaporate from them)
quite quickly. If you leave the crystals while you clean up (washing etc.), they should be dry
enough to take the melting point. Do not recrystallize the product but continue with this
compound for the next part.
2. cis-Norbornene-5,6-endo-dicarboxylic Acid: Follow the procedure on p 580. The resultant
crystals may be allowed to dry over the following week. The water from the reaction mixture will
take a long time to evaporate. Recrystallize your product and record the melting point on the
report form.
CHEM 3611, Diels-Alder Reaction,
PAGE 14
Post Lab Questions: (Answer on the back of your report form.)
Answer questions #1, #2 and #3 on page 583 of Williamson.
Also answer the following question:
What diene and dienophile would be needed to form the molecule
shown to the right?
O
O CH3
O
O CH
3
**Your TA will be doing the cracking for you. S/he will follow the procedure on pp. 575-578 but
scaled up so that each student will have enough material (do macroscale).
**Notes on cracking: The distillation of dicyclopentadiene is “cracking” it into two molecules of
cyclopentadiene. If the distillation is too rapid the dicyclopentadiene will not be cracked and this
dimer is inert to the Diels-Alder reaction. The cyclopentadiene must be kept on ice until used
for it slowly dimerizes even at 0oC.
CHEM 3611, Diels-Alder Reaction,
Report for Diels-Alder reaction
PAGE 15
Name_______________________________
Date________________________________
Cracking of Dicyclopentadiene:
Approx. vol. of distillate
___________ml
1. Diels-Alder Reaction:
Moles of Maleic Anhydride used
Moles of Cyclopentadiene used
Theoretical Yield
Wt of Recovered Product
Moles of Recovered Product
Percent yield
mp of Recovered Product
________moles
________moles
________g
________g
________mole
________%
________oC
2. Hydrolysis of the Anhydride:
Amount of Anhydride used
Moles of Anhydride used
Theoretical Yield
Wt of Recovered Product
Moles of Recovered Product
Percent yield
mp of Recovered Product
________g
________moles
________g
________g
________moles
________%
________o C
CHEM 3611, Aromatic Nitration: Nitration of Methyl Benzoate
PAGE 16
Aromatic Nitration: Nitration of Methyl Benzoate
Reading: Vollhardt and Schore Sections 15-10 and 16-3; Williamson” Chapter 28 pp. 355-359.
Pre-Lab Questions:
1. Show the mechanism for the nitration of benzene.
2. Which intermediate in the above mechanism is the electrophile?
Safety Information:
Methyl Benzoate
Sodium Carbonate
Sulfuric Acid
Nitric Acid
Methanol
Irritant, Harmful if swallowed
Toxic, Irritant
Corrosive, Causes severe burns
Corrosive, Causes severe burns
Highly flammable; Toxic by inhalation and if swallowed
Experimental Work:
Follow the procedure on pp. 356-357. This is a very straightforward reaction and should be
completed easily within a laboratory time period. Do not do the TLC and IR analysis, just obtain
a melting point of the recrystallized sample.
Be very careful when working with concentrated sulfuric acid and nitric acid. Both of these
acids can cause severe burns and nitric acid will turn your skin brown for a few days.
Post Lab Questions: (Answer on the back of your report form.)
1. Give the mechanism for the formation of the electrophile nitronium ion (see Vollhardt and
Schore).
2. Answer question #2 on p 358 of Williamson.
3. What are the two roles of sulfuric acid in this reaction?
CHEM 3611, Aromatic Nitration: Nitration of Methyl Benzoate
Report for Nitration of Methyl Benzoate
PAGE 17
Name_________________________
Date__________________________
Wt of methyl benzoate used
________g
Moles of methyl benzoate used
________moles
Theoretical Yield
________g
Wt of methyl 3-nitrobenzoate isolated
________g
Percent yield of methyl 3-nitrobenzoate
________%
mp of methyl 3-nitrobenzoate
________ C
o
CHEM 3611, Identifying an Unknown: Aldehydes and Ketones
PAGE 18
Identifying an Unknown: Aldehydes and Ketones
Reading: Vollhardt and Schore, Sections 17-9 (dinitrophenylhydrazone), Section 17-14
(Tollens' Test) and Section 18-3 (Highlight 18-1, Iodoform test); Williamson Chapter 36 pp. 422440.
Pre-lab Questions: (Answers in your bluebook.)
1. Among the imines that can be generated from the reaction between amines and aldehydes or
ketones are the 2,4-dinitrophenylhydrazone (2,4-DNP) derivatives. Why are 2,4-DNP
derivative important in distinguishing between carbonyl group compounds?
2. Draw acetone and benzophenone. What chemical test can be used to distinguish between
them?
Safety Information:
Sodium Carbonate
Nitric Acid
Methanol
2,4-Dinitrophenylhydrazine
Silver Nitrate
Ammonium Hydroxide
Glucose
Benzaldehyde
Iodine Solution
1,2-Dimethoxyethane
Haxane-2,5 dione
Acetophenone
Bisulfite Solution
Ethanol
Sodium Hydroxide
Toxic, Irritant
Highly Toxic, Corrosive
Flammable, Toxic
Flammable, Irritant
Highly Toxic, Oxidizer
Corrosive, Lachrymator
Hygroscopic
Highly Toxic, Cancer suspect agent
Highly Toxic, Corrosive
Flammable
Flammable
Irritant
Flammable
Flammable, Toxic
Corrosive, Toxic, Causes severe burns
Experimental Work:
The goal of this experiment is to illustrate the various techniques and approaches that may be
used to identify an unknown material. You will be given 1 g of an unknown aldehyde or ketone
which appears in Table 36.1 on 430. Your task is to perform the following exercises and to
eventually identify your unknown. We will perform only four parts of this lengthy experiment.
You will have two lab periods to finish your work.
1. Formation of a 2,4-Dinitrophenylhydrazone Derivative. Follow the procedure on p. 429-430.
The scale that the book suggests is acceptable, but you may wish to double the scale in order
to have enough material to recrystallize the derivative. Unless you want yellow fingers for a few
days avoid all contact with both the 2,4-DNP solution of the derivatives. You should allow plenty
of time for this derivative to dry after the recrystallization in order to get an accurate mp.
Don't use the alternative procedure.
2. Tollens' test for aldehydes: Follow the procedure on p. 431. This experiment should be
conducted in a test tube.
CHEM 3611, Identifying an Unknown: Aldehydes and Ketones
PAGE 19
3. The Iodoform test: Follow the procedure on p. 433-434. The iodoform product need not be
isolated and recrystallized as suggested, but you should note the color and relative amount of
the yellow solid that forms. Also, you don't need to do the mp for the product.
4. The Bisulfite test: Follow the procedure on p. 434.
Post Lab Questions: (Answer on the back of your report form.)
1. Now that you have done the Tollens' test, what do you think causes a silver mirror to occur?
2. Why are weak acidic conditions (phosphoric acid) needed in making the 2,4-DNP derivative?
CHEM 3611, Identifying an Unknown: Aldehydes and Ketones
Report for Identifying an Unknown: Aldehydes and Ketones
PAGE 20
Name_____________________
Date______________________
Give the code number of your unknown:
1. Preparation of the 2,4-Dinitrophenylhydrazone Derivative:
Wt of derivative isolated
________g
mp of recrystallized derivative
________o C
Color of the crystals ____________________________________
2. Tollens’ test for Aldehydes:
Name the reference compounds you used:
A:
Is the test (+) or (-) ?
B:
Is the test (+) or (-)?
Was a silver mirror observed for your unknown? What does this mean?
3. Iodoform test:
Name the reference compounds you used:
A:
Is the test (+) or (-)?
B:
Is the test (+) or (-)?
Was a yellow solid observed for your unknown? What does this mean?
4. The Bisulfite test:
What did you observe for the unknown? What does this mean?
5. Unknown:
What is the identity of your unknown? (Name and Structure)
CHEM 3611, Aldol Condensation (Dibenzalacetone),
PAGE 21
Aldol Condensation (Dibenzalacetone)
Reading:
Vollhardt and Schore, Section 18-5; Williamson Chap. 37 pp. 441-446.
Pre-Lab Exercise: (Answer in your bluebook.)
Using the mixed aldol reaction of acetone and 3-pentanone as an example, describe the
mechanism using structures and words.
Safety Information:
Benzaldehyde
Ethanol
Sodium Hydroxide
Hydrochloric Acid
Acetone
Highly Toxic
Flammable, Toxic
Corrosive, Toxic, Causes severe burns
Highly Toxic, Oxidizer, Corrosive, Cause Burns
Flammable, Irritant
Experimental Work:
Synthesis of Dibenzalacetone: We will follow the procedure on page 442 of Williamson. Be
warned that if you do not allow the reaction to proceed to completion before you start to isolate
the crystals, you will probably obtain a contaminated product that is difficult to recrystallize.
Allow the full 30 minutes before starting to isolate the initial product. If this initial product does
not recrystallize, scratch the inside of the reaction tube as indicated in Williamson. Cooling the
reaction tube in an ice bath may help at this stage.
Post Lab Questions:
1. If one treats hexane with base, OH-, no reaction occurs. However, base with acetone will
result in deprotonation (breaking a C-H bond). Why can acetone be deprotonated with base but
not hexane?
2. What starting compounds give the following aldol product?
Starting
Compounds?
O
OH
CHEM 3611, Aldol Condensation (Dibenzalacetone),
Report for Aldol Condensation (Dibenzalacetone)
PAGE 22
Name___________________________
Date ____________________________
1. Dibenzalacetone:
Vol. of benzaldehyde used
_____ ml
Wt. of benzaldehyde used
_____ g
Moles of benzaldehyde used
_____ mol
Vol. of acetone used
_____ ml
Wt of acetone used
_____ g
Moles of acetone used
_____ mol
Vol. of sodium hydroxide solution used
_____ ml
Concentration of sodium hydroxide solution used
_____ M
Moles of sodium hydroxide solution used
_____ mol
Theoretical Yield
_____ g
Wt of crude wet product
_____ g
Vol. of ethanol used for the recrystallization
_____ ml
Wt of purified dibenzalacetone
_____ g
Percent yield of dibenzalacetone
_____ %
mp of dibenzalacetone
_____ o C
CHEM 3611, Preparation of Tetraphenylcyclopentadienone
PAGE 23
Preparation of Tetraphenylcyclopentadienone
Reading: Vollhardt and Schore, Sections 18-6 and 18-7; Williamson Chap. 52 pp. 600603.
Pre-Lab Questions: (Answer in your bluebook.)
1. What is the relationship between the boiling point of the solvent used in this experiment
and the rate of the reaction? (the reaction ran under refluxing temperature).
2. Tetraphenylcyclopentadienone was prepared from benzil and 1,3-diphenylacetone in
the presence of a base. What is the mechanism of this reaction?
Safety Information:
Benzil
1,3-Diphenylacetone
Titron B
Methanol
Triethylene glycol
Irritant
Irritant
Highly Toxic, Flammable
Flammable, Toxic
Irritant, hygroscopic
Experimental Work:
Follow the procedure on pp. 601-602 for the Preparation of Tetraphenylcyclopentadienone from benzil and 1,3-diphenylacetone. This is a very straightforward reaction and
should be completed easily within the laboratory time period. Be careful when handling
benzyltrimethylammonium hydroxide (Triton B). Triton B is a very strong base, toxic and
extremely corrosive. Wash the product with cold methanol until the brown color change
to purple. Also, you should check for impurities with a mp.
Post lab question: (Answer on the back of the report form)
Now that you have done this experiment successfully, why do you think you have been
o
asked to cool the mixture to 100 C before you added the 40% solution of
benzyltrimethylammonium hydroxide (Triton B) in methanol?
CHEM 3611, Preparation of Tetraphenylcyclopentadienone
PAGE 24
Report for Preparation of Tetraphenylcyclopentadienone Name___________________
Date____________________
1. Preparation of Tetraphenylcyclopentadienone :
Wt of benzil used
_____ g
Moles of benzil used
_____ mol
Wt of 1,3-diphenylacetone used
_____ g
Moles of 1,3-diphenylacetone used
_____ mol
Vol. of triethylene glycol used
_____ ml
Vol. of (Triton B) used
_____ ml
Vol. of methanol used
_____ ml
Theoretical Yield
_____ g
Color the crystals is _______________________________
mp of the product: Trial #1_______ o C
If the mp of your product is not close to 219
Trial #2________o C
C:
Wt of crude product
_____ g
Vol. of triethylene glycol used for the recrystallization _____ ml
Wt of pure product
_____ g
Percent yield of Tetraphenylcyclopentadienone
_____ %
CHEM 3611, Preparation of Acetylsalicylic Acid (Aspirin)
PAGE 25
Preparation of Acetylsalicylic Acid (Aspirin).
Reading: Vollhardt and Schore, Section 20-3; Williamson, Chapter 41, pp. 486-491.
Pre-Lab Questions:
In the synthesis of aspirin, salicylic acid reacts with acetic anhydride.
1. What compound is considered to be a nucleophile and why?
2. What is considered to be the leaving group?
Safety Information:
Salicylic Acid
Toluene
Acetic Anhydride
Phosphoric Acid
Harmful to skin and if swallowed; Irritating to eyes
Flammable
Highly Toxic, Corrosive, Causes burns
Highly Toxic, Corrosive, Causes burns
Experimental Work:
Synthesis of Acetylsalicylic Acid : Follow the procedure on pages 488-489. Be careful with
both the 85% phosphoric acid and the acetic anhydride, both are corrosive. Similarly, when
quenching the reaction with water, add the water slowly and have an ice bath at hand. Isolate,
and dry your product. Do not re-crystallize the product. Record the mp. We will not record the
IR spectrum of your product. Compare your product with a fragment of a commercial aspirin
tablet. Record any differences.
CHEM 3611, Preparation of Acetylsalicylic Acid (Aspirin)
Report for Preparation of Acetylsalicylic Acid (Aspirin)
PAGE 26
Name______________________
Date_______________________
1. Preparation of Acetylsalicylic Acid (Aspirin) :
Weight of salicylic acid used
_____ g
Moles of salicylic acid used
_____ mol
Volume of acetic anhydride used
_____ mL
Density of acetic anhydride
_____ g/ml
Grams of acetic anhydride
_____ g
Moles of acetic anhydride used
_____ mol
Theoretical Yield
_____ g
Weight of crude product
_____ g
mp of the isolated product
_____ o C
Percent yield of the isolated product _____ %
solvent
water
toluene
solubility of your sample
solubility of the commercial
aspirin
CHEM 3611, Preparation of Nylon
PAGE 27
Preparation of Nylon
Reading: Vollhardt and Schore, Section 21-12 (Highlight 21-4); Williamson, Chapter 69, pp.
719-741.
Pre-Lab Question:
Give the structure of Nylon 6,6.
Safety Information:
Thionyl Chloride
Sebacic Acid
N,N-Dimethylformamide
Corrosive; Reacts violently with water;
Causes burns; irritating to respiratory
system
Corrosive
Sodium Hydroxide
Hexane-1,6-Diamine
Harmful by inhalation and skin contact;
Eye irritant
Corrosive, Toxic, Causes severe burns
Flammable, Corrosive,
Causes burns; Harmful by
inhalation and skin contact..
Hydrochloric Acid
Dichloromethane
Corrosive, Toxic
Toxic, Irritant, Harmful by inhalation;
Possible carcinogen
Thionyl chloride: .
N,N-Dimethylformamide: .
Dichloromethane: .
Hexane-1,6-diamine:
Experimental Work:
Preparation of Nylon by Interfacial Polymerization: We will follow the procedure on pp 725-726.
Be especially careful when handling thionyl chloride, it is highly corrosive and gives off noxious
fumes. Heat the reaction mixture until all the solid has dissolved and no more gas evolution is
evident. Do not disconnect the gas trap before allowing the mixture to cool, otherwise you will
suck liquid back into the acid chloride that you have just prepared. The beaker for the
polymerization should be coated with a fine layer of silicone oil, NOT grease. This may be
achieved by placing ONE DROP of the oil in the beaker and spreading around with a paper
towel. The oil will prevent the polymer from adhering to the beaker, facilitating an easier clean
up of the experiment. The dichloromethane solution of the acid chloride should not stand for
more than a few minutes before the aqueous amine solution is added. This solution should be
carefully poured or pipetted on to the surface of the dichloromethane solution. DO NOT disturb
the interface between the two solutions. When you start to remove the polymer with the copper
wire, note that the nature of the polymer will depend upon how fast you pull the polymer out of
the beaker.
CHEM 3611, Preparation of Nylon
Report for Preparation of Nylon
PAGE 28
Name______________________
Date_______________________
1. Preparation of Nylon by Interface Polymerization:
Describe the wet nylon filaments:
Color:
Texture:
Strength:
Describe the dried nylon fibers:
Color:
Texture:
Strength:
Length: