Indexpagechem234
Chemistry 234
Organic Chemistry Laboratory
Schedule of
Experiments
General Information
Check-in
Laboratory Safety
Lab 1 -- Melting
Point
Lab 2 -Recrystallization
Lab 3 -- Fractional
Distillation
Lab 4 -- Extraction
Lab 5 -2-chloro-2-methylpropane
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Lab 6 -Methylbenzoate
Lab 7 -- Methyl
m-nitrobenzoate
Lab 8 -Cyclohexene
Lab 9 -Anisalacetophenone
Lab 10 -Identification of
Unknowns
Check-out
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Expschedulechem234
Chemistry 234
Organic Chemistry Laboratory
Experiment Schedule
Chemistry 234 - Spring, 2002
Text: Experimental Organic Chemistry* [EOC] by J. C. Gilber and S. F. Martin. Publisher:
Saunders, 2001, 3rd Edition
Part I - Introduction to Laboratory Techniques (55 points)
Date Range
Jan 22 - 28
Jan 29 - Feb 4
Feb 5 - Feb 11
Feb 12 - Feb 18
Lab
Periods
1
1
1
1
Experiment
Check In, Melting Points
Recrystallization
Fractional Distillation
Extraction
Reading* [EOC]
37-39, 107-111
88-107
116-140
70-73, 141-158
Credit
10
10
15
20
Part II - Synthesis (130 points)
Date Range
Feb 19 - Feb 25
Feb 26 - March 11
March 12 - 25
March 26 - April 1
April 2 - 8
Lab
Periods
1
2
1
1
1
Experiment
2-chloro-2-methylpropane
methyl benzoate
methyl m-nitrobenzoate
cyclohexene
anisalacetophenone
Reading* [EOC]
423-427, 435-439
Syllabus
Syllabus
Syllabus
569-573
Credit
20
40
25
20
25
Part III - Identification of Organic Compounds (45 points)
Date Range
April 9 - 22
April 23 - 29
Lab
Periods
2
Experiment
Reading* [EOC]
735-738, 746-748,
Identification of an aldehyde,
751-767, 777-781,
amine, alcohol or ketone
788-794
Make-up and checkout
Credit
45
*Note: All pages indicated in this column refer to the text book, Experimental Organic
Chemistry, 3rd Edition. Before coming to lab, you are expected to read these pages indicated
above as well as the corresponding pages in this Lab Manual.
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Hour Exams: 7:00 p.m. February 28 and April 24, 2002
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GeneralInformationchem234
Chemistry 234
Organic Chemistry Laboratory
General Information
Course Objectives
Chem 234 provides you with an opportunity to learn about the properties,
syntheses, separation, purification, and identification of organic compounds. The
course consists of lecture sessions and laboratory sessions.
In lecture sessions you learn the theory and detailed background behind certain
organic experimental techniques.
In laboratory sessions you conduct experiments designed to introduce you to a
variety of these experimental techniques. Chem 234 is also designed to provide
you with the opportunity to learn how to keep the records of scientific research in a
laboratory notebook, a skill which is required in many scientific fields.
You are, of course, expected to perform the assigned experiments in the
laboratory, but you are also expected to understand the principles behind these
experiments. Near the end of the course, you will be expected to carry out the
chemical syntheses of organic compounds and determine the structures of
unknowns.
Experiments
The techniques and background material for each experiment will be presented in
the weekly lecture session. You must read the appropriate text and syllabus
material before coming to each lecture
You will perform the experiments only in your assigned laboratory period. We
expect that you will come to each laboratory session well-prepared and ready to
use your laboratory time efficiently. There are times when you may need to work on
two different experiments in the same laboratory session, so you must plan ahead.
If you miss a lab period for a valid reason (medical or a pre-approved absence),
you may be able to do the experiments at another time (preferably that same
week). However it is your responsibility to schedule these make-ups with your TA
and with the Storekeeper. Unexcused absences cannot be made up and will be
scored zero.
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Each new technique will be described to you in detail before you will have to use it,
but thereafter you will be expected to be able to use that technique without any
further detailed directions. To do this, you must acquire not only good manipulative
skills in the laboratory but also a good sense about what a given procedure
accomplishes and when it should be used.
Occasionally, you may encounter difficulties with an experiment. If you are
responsible for this difficulty and require additional laboratory time and/or starting
material, a penalty of 10% of the grade for that experiment will be assessed. If,
however, it is not your fault that you need extra time and/or material, no penalty will
be assessed.
Lab Quiz
There is a on-line quiz associated with each experiment in WebCT. To receive
credit for the quiz it must be completed before the scheduled starting time of your
laboratory section.
ChemNet Lessons
ChemNet lessons are available to aid in your understanding of the experiments and
to make your laboratory work easier. Although you can work at these lessons any
time you wish, it is most helpful if you do the appropriate lessons shortly before
going to the laboratory. You will earn 2 points toward your grade for each organic
laboratory ChernNet lesson you complete.
In Chem 234 the ChemNet lessons are on the Internet. You access them through
WebCT.
To log onto ChemNet select the ChemNet icon in WebCT. Next you have to type
your NetID and choose a secret password that you must remember. The password
may be the same as for your e-mail. You will be asked for this password each time
you log onto ChemNet. The graded ChemNet lessons for Chem 234 are listed
below (in the order you will want to complete them):
Melting Points
Phase Diagrams
Mixed Melting Points
Recrystallization
Boiling Points
Mole Fractions
B.P. of Mixtures
Distillation Experiment
Fractional Distillation
Distillation Columns
Extractions
Extraction Experiment
t-Butyl Chloride
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Chemical Tests
Try Known Compound
Qualitative Unknown
Getting Help:
There will be time at the end of each laboratory session to get help from your
teaching assistant. In addition, TAs are available in the Chemistry Learning Center,
212 Chemistry Annex, Monday - Thursday afternoons to answer questions.
Missed Labs:
For medical or true emergency reasons we will attempt to accommodate students
who cannot carry out their experiments at the assigned times by scheduling them to
do these experiments at other times. However, to receive credit for such
experiments, the student must inform their own TA of the rescheduling and
reschedule the experiment with the storeroom manager (469 Noyes Lab) at least 2
days in advance of the make-up date. Such rescheduling will only be provided for
significant medical reasons or emergency situations. More than one rescheduled
lab per semester will require the written approval of the instructor in charge
of the course. Students will receive a grade of zero for labs not made-up and more
than one zero on a lab will almost certainly result in failure of the course.
Grading
The grading in Chem 234 is based upon the results of the ten experiments, the two
one-hour written exams, 10 on-line quizzes, and the 16 ChemNet lessons.
The semester of Chem 234 is divided into three parts. Part 1, Introduction to
Techniques, emphasizes theory and principles. Most of the points in Part I are
earned on a 50 minute written exam covering these topics.
Part II, Synthesis, emphasizes laboratory work. Most of the points in Part II are
earned from the results (yields, purity, calculations) of the three experiments. Part
III, Identification of Organic Compounds, also emphasizes laboratory work, with
most of the points being based upon your ability to identify and support your
identification of an unknown organic compounds.
Near the end of the semester, the second (and last) 50 minute written exam will
cover the theory and practice of the laboratory experiments in Parts 11 and 111,
including the applications of spectroscopy.
The points assoicated with these activities are:
Activity
Laboratory Work 10 for a total of 230 points
On-line Quizzes 10@10 points each
50 Minute Exams 2 @ 100 pts each
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Points
230
100
200
GeneralInformationchem234
ChemNet Lessons 16 @ 2pts each
-10 points for each time goggles not worn
Total
36
-10*n
566-10*n
The grade distribution for Chem 234 will be approximately 15% A, 30% B, 50% C,
and 5% D plus E. Therefore, an "average" student will receive the "average" grade
of C in this course. You must complete every experiment in order to receive at least
a grade of D.
Any requests for regrading of laboratory reports or quizzes must be submitted in
writing within one week of the day it is handed out in class. No requests will be
accepted after this time period. All laboratory reports to be regraded should be
submitted to your TA.
If you cheat on any lab (i.e., report false data for the melting points or gram yields
of the samples you turn in), you will automatically receive a grade of zero for that
experiment andlor an F grade for this course.
Your TA will check the melting point and gram yield of your samples.
On-line quizzes must be completed before the start of your scheduled laboratory
period.
Laboratory Notebooks and Reports
Your laboratory notebook is the complete and permanent record of your activities in
the laboratory. Your notebook should be patterned after the form discussed in
Chapter I of the textbook. All data, observations, etc., should be entered directly
into the laboratory notebook during the laboratory session. As part of your
pre-laboratory preparation, you should enter the quantities and physical properties
of all the compounds and solvents to be used for an upcoming experiment. Your
notebook will not be turned in each week, but it will be checked during the semester
by your TA.
Your laboratory report is different from your laboratory notebook. Your report is a
complete and readable summary of the experiment you have just performed. The
report is written on a sheet of paper separate from your laboratory notebook. Each
laboratory report is due one lab period after you finish the particular experiment.
Laboratory reports should be turned in at the beginning of the laboratory session. A
late laboratory report incurs a penalty of 10% of the grade for that experiment. No
report will be accepted more than two lab periods after it is due unless extenuating
circumstances prevail.
Since your laboratory reports will be graded, you should write them
legibly, clearly, and in good English. The laboratory report should state
a reference to the procedure followed and list any changes that were
made from the stated procedure. DO NOT copy the entire procedure
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into your report, as it is not expected and is a waste of time. DO include
the following items:
(1) Balanced equations for the chemical reactions,
(2) Summaries of data and yields, including the appropriate calculations,
(3) Graphs or tables, if appropriate,
(4) A discussion of errors and their possible effects upon the results of the
experiment,
(5) Answers to all assigned exercises,
(6) Anything else assigned, and
(7) Anything you feel is pertinent to a good summary of the experiment.
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Chemistry 234
Organic Chemistry Laboratory
Chem 234 Check-In Procedure
You will not be charged for stocking your drawer during this initial check of its contents. After
this, however, you will be charged for replacing any damaged or missing items. You MUST
have the contents of your locker checked by a TA or a storeroom manager upon your
termination of enrollment in Chem 234 or your completion of this course. Failure to have your
locker checked will result in a fine of ten dollars. This fine will be in addition to the charges that
will be made for replacing any broken or missing equipment. Finally, you are responsible for
the cleanliness of your own work area. For safety reasons, keep it clean!
1. Remove the equipment in your drawer, and check it against the Equipment List.
2. Return any extra equipment you find in your drawer to the storeroom manager in
469 Noyes Lab.
3. Mark on the Equipment List any items you find broken or missing. Remember to
check for "star" cracks in glassware. Make sure that your thermometer is not
cracked, and that the 0-ring is inside the thermometer adapter. Also check to see
that the four indentions at the bottom of your distilling column are intact.
4. Bring your completed Equipment List to the storeroom manager in room 469
Noyes Lab. Also bring him any repairable damaged equipment for replacement. He
will replace your damaged equipment with good items and will provide you with any
items you have found missing. Your drawer should now have a full set of
equipment as listed on the Equipment List.
5. Return all checked items to your drawer. Matches, rubber bulbs, and glass
stirring rods should stay in your drawer.
6. Leave the Bunsen burner on the top of your desk. Leave the Thiele tube in the
clamp provided for it above your work area. DO NOT put the Bunsen burner, Thiele
tube, or vacuum hoses in your locker. All ironware is to be kept in the bins at the
ends of the lab. If you use these items during a laboratory session, remember to
return them to the proper bins at the end of the laboratory session. DO NOT put
them in your locker. All tubing (except that on the steam bath or Bunsen burner)
and wire gauze should be kept in the boxes at the east and west ends of the lab.
To identify the names of equipment consult the display just inside the door or the equipment list
shown below.
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Chemistry 234 equipment display in 464 Noyes Lab.
Chem. 234 Equipment List
1 Adapter, Bent, 105° 14/20standard taper joint
1 Adapter, Distilling, 14/20, w/10/18 Thermometer joint
1 Adapter, Teflon, Thermometer,10/18 w/ O-ring
2 Beaker, Griffin, w/spout, 30 mL
1 Beaker, Griffin, w/spout, 50 mL
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1 Beaker, Griff in, w/spout, 100 mL
1 Beaker, Griff in, w/spout, 150 mL
1 Beaker, Griffin, w/spout, 250 mL
1 Beaker, Griff in, w/spout, 400 mL
1 Bulb, pipette, pure gum rubber
2 Clamps, i.e., Plastic, yellow, for 14/20 joint
2 Clips, Tubing, Steel (used to attach gum rubber hoses to glass
joints)
1 Column, Distilling, 14/20 standard taper joint.,10 x 130 mm,
1 Condensor, Leibig, 14/20 standard taper joint
1 Cylinder, pyrex glass, graduated, 10 mL
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1 Cylinder, poly, graduated, 50 mL
2 Flask, Erlenmeyer, 25 mL
2 Flask, Erlenmeyer, 50 mL
2 Flask, Erlenmeyer, 125 mL
1 Flask, Erlenmeyer, 250 mL
1 Flask, Filter, 125 mL&
1 Flask, Pear-shaped, 14/20 standard taper joint, 25 mL
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1 Flask, Recovery, 14/20 standard taper joint, 25 mL
1 Flask, Recovery, 14/20 standard taper joint, 50 mL
1 Flask, Recovery, 14/20 standard taper joint, 100 mL
1 Funnel, Buchner, Porcelain, #2, 67 mm 01); Includes one
rubber stopper w/ center hole
1 Funnel, Hirsch, Porcelain, 4/0, 55 mm OD
1 Funnel, Polyethylene, 31, 4" x 4"
1 Funnel, Powder, P.E., 65 x 15 mm
1 Funnel, Separatory, 250 mL,- Includes one each #22 glass
stopper & teflon stopcock. (Note: TefIon stopcock has two
O-rings. One black rubber O-ring & one white teflon O-ring)
1 Glass rod, 9mm x 255mm
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1 Holder, Test Tube
1 Rack, Test Tube
1 Spatula, Stainless Steel, double bladed
1 Stopper, Glass, 14/20 standard taper joint.
6 Test Tube, Pyrex, 13 x 100 mm
3 Test Tube, Pyrex, 25 x 150 Mm
1 Test Tube, Pyrex, 25 x 200 mm
1 Test tube, w/Side-arm, 25 x 200 mm
1 Thermometer, -100 to 260°C
1 Tube, Drying, Polyethylene
1 Wash bottle, Polyethylene, 250 mL
1 Watch Glass, Plain, 75 mm diameter
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labsafetychem234
Chemistry 234
Organic Chemistry Laboratory
LABORATORY SAFETY
Read Chapter 1, especially pp. 15-23, of the textbook before coming to your first laboratory
session. You will fill out the Safety-device Location Worksheet during your first laboratory
session.
The importance of safety precautions in a Chemistry laboratory cannot be overemphasized.
The following safety rules must be followed. Use common sense when working with chemicals
and laboratory apparatus. As safety is an integral part of this course, your TA will be grading
you for compliance with these safety rules.
Laboratory Safety Rules
1. You must NOT be in the laboratory without a TA present. The laboratory
sessions are four hours in length. You will not be allowed in lab after your lab
session has ended.
2. Safety goggles for eye protection must be worn properly in the laboratory at all
times. If you need to remove your goggles, step outside the laboratory to do so.
Prescription eyeglasses (even with safety lenses) do not provide adequate eye
protection, especially from the sides. Therefore, you will be removed from the
laboratory if you are found without safety goggles covering your eyes. It is very
strongly recommended that you NOT wear contact lenses of any kind in the
laboratory. You should read the safety information on contact lenses and laboratory
accidents posted outside the lab. Please check with your TA if you absolutely need
to wear contact lenses. If you get anything in your eyes, use the eye wash station
or the eye wash faucet to wash your eyes thoroughly with plenty of water and notify
your TA immediately.
3. Closed-toed shoes that completely cover the foot MUST be worn in the
laboratory at all times. Sandals or perforated shoes are not permitted, as broken
glass and spilled chemicals are constant hazards.
4. Shorts and short skirts (above the ankle) will NOT be allowed. Shirts/blouses
should protect the upper body. Loose clothing should not be worn. Do not wear
hosirey as it will "melt" upon contact with acid and some chemicals.
5. You MUST note the location of the fire extinguishers, safety showers, eye
washes, and first-aid kits in the laboratory, so that you will know where to obtain
these items if they are needed. You will fill out the Safety-device Location
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Worksheet during your first laboratory session.
6. Many of the chemicals used in the laboratory experiments will be new to you.
You should become acquainted with the properties of every new chemical you use.
The Merck Index and www.chemfinder.com are good sources for finding the
properties and toxicities of many organic compounds. Access to material safety
data sheets through various web sites can be obtained on the School of Chemical
Sciences Safety Resources Web Page at safety.scs.uiuc.edu. All chemicals should
be treated as though they are toxic. Compounds can enter the body by being
absorbed through the skin, or by being inhaled or ingested. Therefore,
(a) Keep vessels covered. Put the caps back on the solvent bottles
immediately. Never evaporate solvents other than water into the
atmosphere. Wipe up any spills immediately. In order to check for an
odor, hold the sample about a foot away from your face and gently fan
the vapors towards your nose. Do not put anything in your mouth.
(b) You should use the gloves that are available. Keep your bench top
clean! DO NOT rub your eyes or your face without first washing your
hands. If something does get into your eyes, remember to wash your
eyes with plenty of water and notify your TA. You should protect your
clothing by wearing a laboratory apron or lab coat. Always wash your
hands thoroughly before leaving the laboratory session. If you have any
cuts or scrapes, cover them with band-aids, etc., before coming to the
laboratory.
(c) To dilute acids, carefully and slowly add the concentrated acid to the
water, never the other way around. This avoids dangerous splattering.
"Do like you oughta, add acid to water".
7. Never heat a closed system! Always use boiling chips when heating any liquid,
even water. When heating a test tube, never point it at yourself or at anyone else.
Never heat flammable solvents (i.e., anything other than water) in an open
container with a Bunsen burner.
When you want to use a Bunsen burner, make sure that none of your neighbors is
using a flammable solvent and that there are no flammables in the immediate area.
Light the match first, then turn on the gas while holding the match close to the top
of the burner. Long hair must be tied back. Do not wear garments with floppy
sleeves or loose wrist cuffs. Turn off the Bunsen burner immediately when you are
finished with it.
8. Do not use cracked or chipped glassware. Examine your glassware for "star"
cracks. Broken glassware should be replaced immediately with new glassware from
the storeroom. Do not handle broken glass with your hands. Sweep it up, or use a
piece of toweling to grasp the pieces. The storeroom has leather gloves to wear
while cleaning up broken glassware.
9. Only aqueous solutions (e.g., aqueous acids and bases) may be discarded down
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the drain. Flush them down with plenty of water. Other waste materials, both liquid
and solid, should be disposed of into the properlabeled waste containers located in
the hoods. Broken thermometers should be put into jars located in the hoods. Ask
your TA to assist you in cleaning up any spilled mercury.
10. In the case of an accident (cuts, burns, reaction to a chemical, etc.), inform
your TA immediately. A limited degree of first-aid is available in the storeroom,
469 Noyes Lab. If you are seriously injured, you will be taken to the medical center.
Report all accidents immediately.
Your health is more important than your grade in Chem 234!
11. Never pour chemicals directly from the storage containers directly into your
reaction vessel.
12. Smoking, eating, and drinking are not permitted in the laboratory. Do not bring food or
beverages into the laboratory.
13. No pets are allowed in the laboratory.
14. No "horseplay" is allowed in the laboratory.
15. No radios or CD players are allowed in the laboratory.
A good perception of your surroundings is very important in a chemical
laboratory. This state of mind requires your full attention. Take care of
yourself and your neighbors. Immediately warn your neighbor if you see
him/her doing something dangerous. It is natural for you to feel somewhat
confused at times. Do not be hesitate to ask your TA or the storeroom
manager for guidance with the use of the laboratory equipment or for advice
on safety matters. Please respect the fact that other students must use the
common laboratory equipment, such as the balances, melting point apparati,
hoods, etc. Take care of this equipment, and clean up your messes
immediately.
Safety and Emergency Equipment In 467 Noyes Lab
The Chem 234 laboratory sessions will be held in 467 Noyes Laboratory. This lab
contains the following safety and emergency equipment:
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Fire Blanket
Fire Extinguisher
Overhead Shower
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Safety shower with
curtain.
Eye-Wash Faucets
Eye wash station
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Two drench hoses.
Fire Alarm
First Aid Kit
Before you begin laboratory work in this course, you must complete the Safety Device Location
Worksheet.
.Locate each of the items listed below and mark their locations on the Worksheet by using the
symbols shown in the table. Indicate where your own area is located, and then indicate where
the six nearest Eye-Wash Faucets are in relation to your work area.
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Quantity
Equipment
13
Eye-Wash Faucets
1
Eye-Wash Station
2
Drench hoses
7
Overhead Shower
1
Safety Shower with Curtain
1
Fire Blanket
6
Fire Extinguisher
1
Fire Alarm
1
First-Aid Box
2
Exits
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Symbol
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You must wear appropriate clothing in the laboratory at all times. You MUST wear your safety
goggles over your eyes at all times in the laboratory! DO NOT wear loose or skimpy clothing
(saris, neckties, shorts, halter-tops, overly large or ragged laboratory coats). DO wear closed
shoes in the lab. DO NOT wear sandals or perforated shoes. Long hair must be tied back.
For additional laboratory safety information and resources access the School of Chemical
Sciences Web page at safety.scs.uiuc.edu
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Chemistry 234
Organic Chemistry Laboratory
Experiment 1: Melting Points (10 points)
I. Summary
Melting points are very useful in determining the purity of a compound. Throughout this class
you will measure the melting point of your products in order to assess purity. You will practice
this technique on a sample of benzoic acid.
Put open end of tube in
the sample.
Tape tube so sample
falls to the bottom of the
tube.
Impure samples have lower melting points than pure solids. You can use this information to
determine the identity of an unknown through the mixed melting point method. You will be
given an unknown from the list below. By determining the melting point of your unknown, you
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will be able to narrow the choices to three, based on the melting point ranges. You will then mix
your unknown with EACH of the three possibilities. You can determine the melting point of
each of the mixtures. In the two mixtures that contain two different compounds, you should see
a drastic change in the melting point since the samples are not pure. One of the samples will
contain only one compound, and this should be reflected by the melting point.
Compound
acetanilide
p-aminobenzoic acid
camphoric acid
trans -cinnamic acid
malonic acid
p-nitrophenol
resorcinol
succinic acid
urea
Melting Point
113-115 °C
188-189 °C
183-186 °C
133-134 °C
135-137 °C
113-115 °C
110-113 °C
187-189 °C
133-135 °C
First obtain a sample of benzoic acid from your TA (about a spatula-tip). Grind the sample into
a fine powder, and take two melting points, one fast, one slow (2 °C/min). Obtain your unknown
from the stockroom, and grind this sample if necessary. Take two melting points of your known
(one fast, one slow). You should now be able to determine the three possibilities for the identity
of your unknown.
Mix a spatula-tip of your unknown with a spatula-tip of each of the three possible compounds.
These samples should be well mixed to ensure the best results. Take the melting points of
each of the mixtures, and use this information to determine the identity of your unknown,
Samples of two
compounds for mixed
melting point.
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Grind samples together.
You should measure the melting point with the Thiele tube at your bench or the electrically
heated melting point apparatus in the lab.
Thiele tube melting
point apparatus
Electrically heated
melting point
apparatus
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III. Report
Your report should include the following:
1. Reference to the procedure with any changes noted
2. Data for melting points of benzoic acid
3. Data for melting points of unknown sample
4. Data for the three mixtures
5. Identity of your unknown
6. Interpretation of data and a short conclusion
7. Use the data in figure 3.1 on page 108 of the textbook to answer these
questions.
a. If a liquid with a composition of 80 mole % B were cooled what is the
composition of the solid that forms first?
b. If a liquid with a composition of 20 mole % B were cooled what is the
composition of the solid that forms first?
c. If a solid with the composition 80 mole % A and 20 mole % B were heated what
is the composition of the first liquid that forms?
d. If a solid with the composition 80 mole % A and 20 mole % B were heated what
is the composition of the last solid to melt?
You should complete the web-based ChemNet tutorials on melting points before coming to the
lab.
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Expt2recrystchem234
Chemistry 234
Organic Chemistry Laboratory
Experiment 2: Recrystallization (10 points)
Summary
You will be learning several techniques for purification of organic compounds. One very
effective way to purify solids is through recrystallization. In this experiment, you will be given an
impure sample of benzoic acid that you will purify by recrystallization. You will also detennine
the melting point of the recrystallized benzoic acid to assess the purity.
Impure sample of
benzoic acid.
Benzoic acid after
recrystallization.
Procedure
The procedure for recrystallization is found in your text, page 96. You will make the following
changes to the procedure:
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1. Scale up the procedure so that it accommodates 2 grams of benzoic acid.
2. Weigh the sample of impure benzoic acid before you begin recrystallization.
3. Skip the "Decoloration" section.
Heat the sample with enough
water to dissolve all soluble
material.
Add more water if needed.
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Filter the hot solution to
remove insoluble material
Boil off some of the water.
Use a boiling stick when you
boil off the solvent.
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Be sure to use the GLASS
powder funnel for your hot
filtration rather than the plastic
funnel.
Crystals form as solution is
cooled.
Cool to complete
crystallization.
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Filter, wash, and dry the
product.
Note: You will need a total of 40-5O mL of water for this experiment. If you add too much water
you can boil some off after filtration.
Report Requirements
Your lab report should include the following:
1 . References to procedure with any changes noted
2. Weight of recrystallized benzoic acid
3. Percent recovery of benzoic acid
4. Melting point of recrystallized benzoic acid and literature melting point
5. A description of the purified benzoic acid
6. Interpretation of data and short conclusion (discuss purity, recovery, and overall
effectiveness of recrystallization)
7. Answer these questions in your report:
a. Why did you do a hot gravity filtration?
b. Why did you do a cold filtration?
c. The solubility of benzoic acid in water at C° is 0.020 g/100 mL of water. If you used 3.0
g of impure benzoic acid and 100 mL of water, what is the maximum yield of benzoic acid
that could be recovered?
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Exp3fractionaldistchem234
Chemistry 234
Organic Chemistry Laboratory
Experiment 3: Fractional Distillation (15 points)
Summary
Fractional distillation is a technique used to separate volatile compounds with
boiling points that differ by less than 50° C. In this experiment, you will distill a
mixture of methanol (b.p. 65°C and water (b.p. 100°C). Using data obtained in this
experiment, you will graphically demonstrate how head temperature changes with
the composition of the distillate.
Procedure
Obtain 60 mL of a sample of one of the methanol/water mixtures from the carboys
in the lab. Record which sample you chose (A, B, or Q). Add the mixture and a few
boiling chips to a clean 100 mL round bottom flask. Set up the apparatus for
fractional distillation as demonstrated in lab.
Use the Thermowell to
heat the flask.
Plug it into the Variac
on your bench.
Do not plug directly in
the wall outlet.
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Use a distilling column
to help separate the
mixture.
The thermometer
adapter allows you to
put the thermometer
into the distilling
adapter.
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Use joint clamps and
hose clamps.
Here is the completed
apparatus.
Have your set-up approved by your TA before you begin.
Begin heating the sample on a low setting and increase the temperature as
needed. Collect the distillate in a graduated cylinder. Record the head temperature
when you collect the first drop of distillate, and then record the head temperature at
every two milliliters of distillate collected. Stop the distillation when you have
recorded three readings at about 100°C, even if you haven't distilled all of the
sample.
DO NOT heat the flask to dryness.
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Report
Your report should include the following:
1 . References to procedure with changes noted
2. Table of recorded data (volume collected and head temperature)
3. Graph of distillation data: Make a plot with the head temperature on the y-axis and the
volume of distillate on the x-axis (see page 125 of your text). Draw an AVERAGE line
through the data points. DO NOT simply connect the dots.
4. Summary table of data: Use your graph to determine the volume and boiling point
range of each "fraction." Make a table that includes Fraction number, collected volume,
and boiling range. Here is a sample table structure.
5. Interpretation of data and conclusion, including the methanol/water ratio of your
sample.
Answer these questions in your report:
1. Sketch and label the apparatus you used for a fractional distillation.
2. Using figure 4.3 on page 125 of the textbook, if a mixture has 60 mole % toluene and
40 mole % benzene:
a. At what temperature will the solution start to boil?
b. What is the composition of the first small amount of vapor that forms?
c. If the vapor formed in question 2b is condensed and the resulting liquid heated to its
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boiling point what is the composition of the new vapor?
Tutorials
You should work the web-based ChemNet tutorials on distillation before going to
the lab.
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Exp4extractionchem234
Chemistry 234
Organic Chemistry Laboratory
Experiment 4: Extraction (20 points)
Summary
Extraction is a technique used to separate and/or purify compounds. In this
experiment, you will be separating a mixture of anthracene, p-nitroaniline, and
benzoic acid into the individual components based on their differing solubilities in
immiscible phases.
Mixture of anthracene,
p-nitroaniline, and benzoic acid.
Purified benzoic acid
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Purified anthracene
Purified p-nitroaniline
Prelab
BEFORE class, prepare a flow chart that outlines every step of the experiment. The
flow chart should show a branch point at every extraction step (including isolation of
the three compounds), and you should note which compounds are in each layer at
each step. You must have this flow chart completed before you will be allowed to
begin the experiment,and the flow chart will be handed in with your lab report.
Procedure
Be sure to wear rubber gloves when doing this experiment.
Obtain a mixture of benzoic acid, p-nitroaniline, and anthracene. Weigh the mixture,
and then dissolve the mixture in 75 mI, of methylene chloride. If some solid doesn't
dissolve after several minutes of stirring, filter the solution. Add the solution to the
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separatory funnel and proceed through the following steps:
First Period:
1 . Add 50 mL of 3M HCI to the separatory funnel. Shake and vent the funnel as
described in the textbook readings.
Be sure to vent the separatory funnel to avoid pressure build up. If you get hydrochloric
acid on your skin be sure to wash with large amounts of water. Contact your TA for
assistance.
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2. Allow the layers to separate in the funnel. Drain the bottom layer into a flask labeled
"organic," and pour the top layer into a flask labeled "acidic extract"
3. Return the organic layer to the separatory funnel, and repeat steps 1 and 2. Add the
top layer from this extraction to the flask labeled "acidic extract".
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4. Place the organic extract into the separatory funnel, and add 50 mL of 3M NaOH.
Shake and vent the separatory funnel as before.
If you get sodium hydroxide solution on your skin be sure to wash with large amounts of
water. Contact your TA for help.
5. Allow the layers to separate. Drain the bottom layer into a flask labeled "organic," and
pour the top layer into a flask labeled "basic extract."
6. Return the organic layer to the separatory funnel, and repeat steps 4 and 5. Add the
top layer from this extraction to the flask labeled "basic extract."
7. Cool the ACIDIC EXTRACT in an ice bath. Basify the ACIDIC EXTRACT with 6M
NaOH (calculate how much you need). Check the pH of the solution with pH paper to
make sure it is BASIC. Filter the resulting precipitate by vacuum filtration. Place the solid
on a piece of filter paper, and allow it to air dry until the next lab period.
USE CAUTION IN HANDLING THE SODIUM HYDROXIDE.
8. Cool the BASIC EXTRACT in an ice bath. Acidify the BASIC EXTRACT with 6M HCl.
Check the pH of the solution with pH paper to make sure it is acidic. Collect the resulting
solid by vacuum filtration. Place the solid on a piece of filter paper and allow it to air dry
until the next lab period.
9. To the ORGANIC layer, add a few spatula tips of Na2S04 to dry the organic layer.
Allow the solution to stand for 10 minutes.
10. Filter the solution through fluted filter paper into an Erlenmeyer flask. Evaporate the
methylene chloride using the apparatus that will be demonstrated in lab.
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Second Period:
1. Obtain weights of benzoic acid, p-nitroaniline, and anthracene and melting points of
benzoic acid and p-nitroaniline.
2. Place all solids in tared, labeled vials, and give them to your TA.
Report Requirements
Your report should contain the following:
I . Reference to procedure with changes noted
2. Flow chart described above. Draw structures of all species. Show ionic structures were
appropriate.
3. Weights of all three solids. Descripte their physical properties.
4. Melting points of benzoic acid and p-nitroaniline (both weights and melting points
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should be reported in tabular form).
5. Describe the solids
6. Interpretation of data and conclusion
-How pure are the extracted compounds?
-How could you purify them further?
-What was the composition of the original mixture, i.e., the ratio of benzoic
acid: p-nitroaniline: anthracene?
- recovery
Answer these questions in your report:
1. If you have 10 grams of A in 100 mL of water and extract 3 times with 50 mL of ether what is
the total yield of A in the combined ether solutions? Assume the distrbution coefficient for A is
2.0. Show all of your work.
2. What physical property determines which layer is on the top in an extraction?
3. How would you extract N,N-dimethylaniline from methylene chloride into water?
4. How would you extract p-nitrobenzoic acid from methylene chloride into water?
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Exp52_chloro_2_methylpropanechem234
Chemistry 234
Organic Chemistry Laboratory
Experiment 5: Preparation of
2-chloro-2-methylpropane (20 points)
Summary
In the experiment, you will be preparing 2-chloro-2-methylpropane from 2-methyl-2-propanol
via an SN1 reaction.
Procedure
You will follow the procedure from the text (pages 435-439). Note that you will be using
2-methyl-2-propanol instead of 1-methyl-2-butanol. However, all other reagents remain the
same. You should double all quantities listed in the procedure.
Shake the t-butyl alcohol with HCl.
Be sure to vent the separately funnel to avoid
pressure build up.
If you get hydrochloric acid on your skin
wash immediately with large amounts of
water. Contact your TA for assistance.
Separate, wash, and dry the t-butyl chloride.
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The crude t-butyl chloride is washed to remove
excess acid.
Add the sodium bicarbonate solution slowly to
avoid rapid formation of CO2 as shown here.
Setup for distillation of
the t-butyl chloride.
Collect the product in a
cooled, tared container.
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Use joint clamps on the
condenser and hose
clamps on the water
lines.
Report Requirements
Your report should contain the following:
1 . Reference to the procedure with changes noted
2. Equation of the reaction showing structures of reactants and products. Below each
reactant, list the molecular weight, and amount used in grams (or mLs) and moles. Below
each product, list the theoretical yield in grams and moles. Give the density and boiling
point of liquids.
3. Mechanism of the reaction: use arrows to show electron movement; include all
intermediates and side reactions
4. Calculation of the theoretical yield
5. Weight of product and description including color
6. Boiling range of the product
7. Interpretation of data and conclusion. Give chemical and physical reasons for not
obtaining a 100% yield.
8. Answer the following questions in your report.
1. Washing the crude t-butyl chloride with aqueous sodium bicarbonate resulted in gas
evolution. Write a balanced equation for this reaction.
2. Could anhydrous NaOH be used to dry the t-butyl chloride instead of sodium sulfate?
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3. Write the mechanism for the reaction of n-butyl alcohol with HCl and compare it to the
reaction of t-butyl alcohol with HCl.
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Exp6 prepmethylbenzoate chem234
Chemistry 234
Organic Chemistry Laboratory
Experiment 6: Preparation of methylbenzoate
(40 points)
I. Summary
In this experiment you will prepare methylbenzoate by reacting benzoic acid with
methanol using sulfuric acid as a catalyst. Since this is a reversible reaction, it will
reach an equilibrium that is described by the equilibrium constant, Keq .
In this experiment, you will isolate the product, methyl benzoate and any unreacted
benzoic acid. Using this data, you will calculate the equilibrium constant for the
reaction as described in part III.
II. Procedure
First Period
Obtain a 10g (0.082 mol) sample of benzoic acid from
the storeroom (weigh the benzoic acid to obtain an
exact weight before you begin). Add to it 0.62 mol of
methanol in a 100 mL round-bottomed flask.
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Cautiously, add 3 mL concentrated H2S04 down the
side of the flask. After gently swirling the contents of
the flask, attach a reflux condenser and reflux the
mixture for about 60 min.
Sulfuric acid causes acid burns on the skin. If you
get some on your skin be sure to wash with large
amounts of water. Contact your TA!
Allow the solution to cool. Add 50 mL of water to a separatory funnel, then add the
contents of the flask. The flask should then be washed with 40 mL of
dichloromethane (CH2Cl2) and the washings transferred to the separatory funnel.
Use the separatory funnel to extract the ester into the CH2Cl2 (organic) layer.
Wash sequentially with 25 mL water and 25 mL 0.6M sodium bicarbonate*
(Caution, CO2 will be given off with effervescence).
After shaking and venting the funnel, remove the sodium bicarbonate layer and test
to see if it is basic. Then wash the organic layer with NaCl (salt) solution, separate
the organic layer and dry with anhydrous magnesium sulfate. Remove the MgS04
by gravity filtration, and concentrate the solution using the same apparatus used to
remove CH2Cl2 from anthracene in Experiment 4.
*The aqueous layer from the sodium bicarbonate wash should be acidified with
concentrated HCl The unreacted benzoic acid should precipitate. Remove the
solvent by vacuum filtration. Collect and dry the solid benzoic acid and let it air-dry
in your drawer until the next lab period.
Second Period
Distill the crude methyl benzoate (b.p. 199°), collecting anything that boils between
170°C and 200°C. Weigh the sample of methyl benzoate and determine the yield.
Weigh the sample of recovered benzoic acid. Place both samples in labeled vials,
and give them to your TA.
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Caution:
1. Methanol is flammable and toxic
2. Dichloromethane is toxic
3. Handle concentrated H2SO4 and HCl with great care
4. Vent the separatory funnel frequently after swirling and subsequent shaking.
CO2, gas is evolved and will build up pressure in the funnel.
III. Calculation of the Equilibrium Constant, Keq.
Calculate a value for the equilibrium constant Keqbased upon your weight of
recovered benzoic acid. In addition, calculate the percent yield of your synthesis
based upon the amount of starting benzoic acid used, and another percent yield
based upon the amount of benzoic acid that actually reacted (as determined by the
weight of recovered benzoic acid).
Calculation of the Equilibrium Constant Keq:
Since the volume of the reaction mixture is the same for each component, we can
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use moles instead of molarities as the units in our Keq expression. Let Bi = initial
moles of benzoic acid, let Mi = initial moles of methanol, and let X = final moles of
methyl benzoate produced at equilibrium.
Based upon the stoichiometry of equation 1, we can conclude three things about X,
namely that X = final moles of water produced at equilibrium, X = moles of benzoic
acid consumed when equilibrium is established, and X = moles of methanol
consumed when equilibrium is established. Using our definitions, equation 2
becomes:
We know Bi and Mi. All we need to do before we can calculate Keq is to Put X in
terms of something known, like the amount of benzoic acid recovered. Let Bf = final
moles of benzoic acid present at equilibrium. Thus Bf = Bi - X, or X = Bi - Bf.
Substituting(Bi - Bf) for X in equation 3 gives:
We can now calculate Keq by entering the appropriate values of the moles of
benzoic acid used (Bi), the moles of methanol used (Mi), and the moles of benzoic
acid recovered (Bf) into equation 5.
Calculation of the % Yield based upon initial amount of benzoic acid used:
Let E = moles of methyl benzoate ester obtained. Note that this calculation is valid
only if benzoic acid is the limiting reagent.
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Calculation of the % Yield based upon amount of benzoic acid that is consumed:
IV. Report Requirements
Your lab report should contain the following information:
1 . Reference to procedure with any changes noted
2. Equation of the reaction showing structures of reactants and products.
Below each reactant, list the molecular weight, and amount used in grams (or
mLs) and moles. Below each product, list the theoretical yield in grams and
moles.
3. The complete mechanism showing all intermediates and arrows to
demonstrate electron movement
4. Flow chart for the isolation of methyl benzoate and unreacted benzoic acid
5. Weight of recovered benzoic acid
6. Weight and boiling point of methyl benzoate
7. Calculations
a. percent yield based on amount of benzoic acid with which you
started
b. percent yield based on amount of benzoic acid consumed
c. Calculate the equilibrium constant two ways and compare the
results.
8. Interpretation of data and conclusion. Explain what was done in this
experiment to drive the reaction toward ester formation.
9. Answer these questions in your report:
1. How is sulfuric acid involved in the formation of methyl
benzoate?
2. Write a balanced equation for the formation of ethyl acetate
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from ethanol and acetic acid.
3. Using K=3.0, calculate the number of moles of methyl benzoate
which could be formed from 0. 1 mol of benzoic acid and 0.3 mol
of methanol.
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Exp7methyl_m_nitrobenzoatechem234
Chemistry 234
Organic Chemistry Laboratory
Experiment 7:
Preparation of methyl-m-nitrobenzoate (25 points)
I. Summary
In this experiment, you will synthesize methyl-m-nitrobenzoate from methyl
benzoate via electrophilic aromatic substitution. The isolated product will be purified
by recrystallization, and purity will be determined from the melting point.
II. Procedure
Bring a clean, dry 25 x 150 mm test tube to the storeroom manager and trade it in
for a 6.2 mL (6.8 g, 0.050 moles) sample of methyl benzoate (weigh the sample
before you begin to obtain an exact weight). Place 14.5 mL (26.7 g) of concentrated
sulfuric acid in a 125 rnL Erlenmeyer flask, cool it to 0 °C in an ice/water bath, then
add all of the methyl benzoate with swirling.
Separately, prepare a mixture of 5.0 ml- (9.2 g, 0.094 moles) of concentrated
sulfuric acid and 5.0 mL (7.1 g, 0. 113 moles) of concentrated nitric acid.
Cool the nitric acid in an ice bath and then very slowly add the sulfuric acid keeping
the mixture cold.
Be very careful in handling the concentrated sulfuric acid and nitric acid. If
you get acid on you be sure to wash with large amounts of water and contact
your TA immediately for assistance.
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When it has cooled, add this cold
acid mixture dropwise over 5
minutes to the methyl benzoate
solution, which is kept swirling in
the ice bath.
After the addition is complete,
allow the reaction mixture to stand
at room temperature for an
additional 10 minutes, swirling it
occasionally.
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Pour the mixture, with stirring,
over about 150 cc of crushed ice.
Collect the solid precipitate by
suction filtration, and wash it
thoroughly with water to remove
any traces of acid.
Recrystallize your product from a
small amount of methanol.
Collect the crystals by vacuum
filtration and wash with a small
amount of COLD methanol.
Allow the product to air dry in your drawer until the next lab period. Obtain the
weight and melting point of your dry product. Give your sample to your TA.
III. Report Requirements
Your report should contain the following information:
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1. Reference to the procedure with changes noted
2. Equation of the reaction showing structures of reactants and products. Below each
reactant, list the molecular weight, and amount used in grams (or mLs) and moles. Below
each product, list the theoretical yield in grams and moles
3. Mechanism of the reactions showing the structures of intermediates and arrows to
demonstrate electron movement
4. Experimental yield and percent yield (show calculations)
5. Color and physical properties of your product
6. Melting point of product
7. Give chemical and physical reasons for not obtaining 100% yield. Write equations for
side reactions and explain how side products were removed from the product.
8. Interpretation of data and conclusion.
9. Answer these questions in your report:
1. Draw all resonance structures for the nitration of methyl benzoate occurring at the
ortho, meta, and para positions. Be sure to include all charges.
2. Circle any resonance structures that demonstrate why the ortho-para positions are
unfavorable sites for nitration.
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Exp8Dehydrationchem234
Chemistry 234
Organic Chemistry Laboratory
Experiment 8: Dehydration of Cyclohexanol
I. Summary
In this experiment, you will synthesize cyclohexene via acid-catalyzed dehydration
of cyclohexanol. This reaction will be carried out by heating the components and
collecting impure product. A second distillation will be necessary to purify
cyclohexene. Purity will be determined by the boiling point of the collected product.
The product will be tested for unsaturation using the Baeyer test.
II. Procedure
Bring a clean, dry 25 x 150 mm test tube to the storeroom manager, and trade it for
a sample of cyclohexanol. Obtain a weight or volume for the sample (around 14.2g
or 15 mL). Be sure to use the mass of your sample for all of your calculations. Into
a 50 mL round bottom flask, add the cyclohexanol, 9 M sulfuric acid (7.5 mL), and a
few boiling chips. Mix the contents of the flask with gentle swirling.
Equip the flask for fractional
distillation (see experiment 3).
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Use a heating mantle with
sand to heat the distillation
flask.
Use an erlenmeyer flask as the collection vessel, and cool it in an ice bath during
the distillation. Heat the reaction mixture, and collect all distillates while maintaining
a head temperature in the range of 80-85 °C. Discontinue the reaction once about 5
mL remains in the distillation flask.
If water separates as a distinct layer,
remove it with a pipet.
Add several spatula-tips full of
potassium carbonate to the crude
product in the Erlenmeyer flask. Swirl
the mixture occasionally over a 10-15
minute period, and add more
potassium carbonate IF the liquid
remains cloudy.
Thorough drying is very important (why?).Transfer the product to an 25 mL round bottomed
flask by decanting or using a pipet.
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Add a few boiling stones to the
flask, and purify the product by
simple distillation. Use a tared
vial as a receiver, and cool the
receiver in an ice bath.
Collect distillate with a head temperature between 80-85 °C. Obtain a weight of
your purified product. Note: If product is cloudy, add several spatula-tips full of
potassium carbonate to the vial, and transfer the dried product to another tared vial
by pipet before weighing.
Bayer Test for Unsaturation:
To test your product for unsaturation, follow the procedure on pages 653-654 of
your lab text for the Baeyer test. Perform both the test and the blank.
III. Report Requirements
Your report should contain the following information:
1. Reference to procedure with changes noted.
2. Equation of the reaction showing structures and products. Below each reactant,
list molecular weight, amount used in grams (or mL) and moles. Below each
product list the molecular weight and theoretical yield in grams and moles.
3. Mechanism of the reaction showing structures of intermediates and arrows to
demonstrate electron movement.
4. Experimental yield and percent yield (show calculations)
5. Weight of product.
6. Boiling point range of product.
7. For the Baeyer test, include both the equation for the reaction and your results
for cyclohexene and the blank.
8. Interpretation of data and conclusions
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9. Answer these questions in your report:
1. Write the mechanism for the dehydration of cyclohexanol with sulfuric acid.
2. Why was it necessary to dry the crude cyclohexene before the final distillation?
3. Write the equation for the addition of bromine to cyclohexene. Show the
sterochemistry of the product.
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Exp9 anisalacetophenone chem234
Chemistry 234
Organic Chemistry Laboratory
Experiment 9:
Preparation of trans-p-Anisalacetophenone
(25 points)
I. Summary
In this experiment, you will be preparing trans-p-anisalacetophenone (m.p. 77-78°) from p-anisaldehyde and
acetophenone via a crossed aldol condensation. The product will be purified by recrystallization, and purity
will be assessed by taking the melting point of the product.
II. Procedure
Follow the procedure found on pages 572-576 in your text (omit the "Analysis" portion of the
procedure. You will need to scale the procedure to six times that listed in the text. Take a clean,
dry 25 x 150 mm. test tube to the storeroom manager and trade it in for a sample of
p-anisaldehyde. Weigh the sample before you begin the experiment, and adjust the amount of
acetophenone accordingly. Once you have obtained the recrystallized product, allow the product
to air-dry in your drawer until the next lab period. Obtain the weight and melting point.
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Locate starting material
Measure reactants
Mix
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Let stand
(Use an erlenmeyer instead of
a beaker)
Filter crude product
Recrystallize
(Use an erlenmeyer instead of
a beaker)
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Purified product
III. Report Requirements
Your report should contain the following:
1. Reference to procedure with changes noted.
2. Equation of the reaction showing structures of reactants and products. Below each reactant,
list the molecular weight, and amount used in grams (or mLs) and moles. Below each product,
list the theoretical yield in grams and moles.
3. Mechanism of the reactions showing the structures of intermediates and arrows to
demonstrate electron movement
4. Mass of product and physical properties
5. Percent yield (show calculations)
6. Melting point of product (include literature melting point)
7. Interpretation of data and conclusion, including detailed error analysis
8. Answer these questions in your report:
1. Write the mechanism for the condensation of acetophenone with itself.
2. Write the mechanism for the Cannizzaro reaction of anisaldehyde.
3. Why is the product trans-anisalacetophone instead of cis?
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Expt10unknownchem234
Chemistry 234
Organic Chemistry Laboratory
Experiment 10: Identification of an Aldehyde,
Amine, Alcohol, or Ketone (45 points)
I. Summary
In this experiment you will be given an unknown that is either an aldehyde, ketone,
amine or alcohol. The possible unknowns are listed in tables in the lab. You will be
given IR and NMR spectra to help you determine the functional group and structure
of your compound. You will also obtain the boiling point or melting point of your
compound, perform classification tests, and make a derivative.
II. Procedure
The week before this experiment begins, you will receive IR, 1H NMR, and 13C
NMR spectra of your compound.
BEFORE the first day of this experiment, make a tentative functional group
assignment. You do not need to determine the structure of the unknown before
class, but you will need to analyze you spectra for structural information at some
point during the course of the experiment. During the class periods assigned for
this experiment, do the following in the order listed:
1. Distill your unknown, if it is a liquid, to obtain a
boiling point of the pure compound.
If your unknown is a solid, take a melting point.
To obtain a boiling (or melting) point range, subtract 10°C from the
observed temperature to get a lower limit, and add 10° to the observed
temperature to get an upper limit.
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2. Perform all three of the following classification tests.
You should first perform these tests on the provided known compounds for
comparison.
A. DNP - follow the
procedure on
pages758-759 of your
book.
B. Ceric nitrate test follow the procedure on
page 783 of your text.
C. Test for pH - If your compound is water-soluble, use pH paper to
test an aqueous solution of your unknown. An amine, since it is basic,
will have a high pH. If your unknown is not water-soluble, dissolve the
unknown in an ethanol-water mixture, and test the pH.
3. Make a derivative
Once you have determined the functional group present in
in your unknown, choose the appropriate derivative from the list below:
Aldehyde/ketone: 2,4-DNP (pg 765-766)
Alcohol: 3,5-dinitrobenzoate (780-781, Method A, see Note 1 for amounts of
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reagents)
Amine: benzenesulfonamide (pg 793-794) or benzamide.
III. Lab Report Requirements
Your lab report (due the day scheduled for check-out) should contain the following:
1. Reference to the procedure of EACH chemical test and the derivative
2. Melting/boiling point of the unknown
3. Results of each chemical test and your interpretation of the results. Write
chemical equations for the tests.
4. Data table for 1H NMR (see example)
5. Data table for 13C NMR: For each relevant peak, report the chemical shift and
assignment.
6. Data table for IR (assign bands above 1500 cm-1): For each band, report position
(in wavenumbers), a description of the band (strong, medium, or weak; sharp or
broad), and your interpretation
7. Type of derivative and the melting point (include the reference melting point).
Write chemical equations for the formation of each derivative.
8. Identification of the unknown with a THOROUGH explanation of how you arrived
at this conclusion. Draw the STRUCTURE of your unknown.
Notes:
1. Preparation of the 3,5-dinitrobenzoate derivative (amounts):
0.5g 3,5-dinitrobenzoylchloride (this will be preweighed and available from
the storeroom)
1.5mL of your unknown alcohol
20 drops of pyridine (Caution! Pyridine should be used in the fume hood
since it has a VERY unpleasant odor. Do not pour pyridine or
filtrates containing pyridine down the drain)
EXAMPLE 1H data writeup
Spectrum
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Label hydrogens
Make table
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checkoutchem234
Chemistry 234
Organic Chemistry Laboratory
Chem 234 Check-Out Procedure
Any student who fails to be checked out of the lab by a TA or by a storeroom manager will be
charged with a fine of ten dollars. This fine is assessed in addition to the charges that are made
to replace any broken or missing equipment.
1. Remove all equipment from your drawer and wash each item with Tetrox and water.
2. Place new blotter paper lining in your drawer.
3. Check your equipment against the Equipment List. Return any extra equipment to the
storeroom and replace any missing or broken items with new ones from the storeroom.
4. Place all ironware (except the metal stand) in the bins at the ends of the lab.
5. Place all tubing (except that on the steam baths and Bunsen burners) and wire gauze in
their proper storage boxes located at the east and west ends of the lab.
6. All matches, rubber bulbs, and stirring rods should be left in the drawer.
7. Leave the rubber stoppers on the Hirsch and Buchner funnels. Throw out any cork
stoppers.
8. Make sure that the four indentations at the bottom of your distilling column are intact.
9. Make sure that your thermometer is not cracked and that the O-ring is still inside the
thermometer adapter.
10. Remove the calcium chloride from inside the drying tube.
11. Remove any stopcocks and stoppers from the separatory funnels. Tie them to the
funnels with string.
12. Place all the cleaned equipment back into your drawer. Your drawer should now have
a full set of equipment as listed on the Equipment List.
13. Sign the equipment list (pg. 24) and have your TA sign the equipment list. Take this
list to Mike Eubanks (room 469) to receive your breakage card.
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