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CHY 224 REPORT FORM
PREPARATION OF CYCLOHEXANOL
NAME: ______________________________________________________________________
Partner: _____________________________________________________________________
Day: ______________ Time: ______________ Room: ______________
Please type the answers to the following questions.
1. Create a table to show the reactants, and products for the reaction that you performed.
Please be sure to include the pertinent physical data (citing your sources). This table should
include the observed boiling point ranges, literature boiling points, masses/volumes (and
molar amounts) of each of the reactants, and products. (4 marks)
2. Define the term “azeotrope” and which azeotrope was formed in this experiment? (1 mark)
3. What is the solid that may form in the condenser on the second week of this synthesis?
Why could it form? (1 mark)
4. Create a table showing the functional groups for cyclohexanol showing the expected region
for each infrared peak. Include the actual peaks from your spectra that you are assigning to
each functional group. Are there any cyclohexene peaks visible? Where would you expect
to see IR evidence of cyclohexene in your final product? (4 marks)
5. Calculate the percent yield for the synthesis of cyclohexanol. Please be sure to show all of
your calculations. (2 marks)
6. Show the calculation for the temperature co
ection of refractive index using your
experimental data. Comment on the purity of your product based upon the refractive index
measurement. (2 marks)
7. Write a formal discussion for this experiment. Be sure to include comments on the important
experimental data, reasonable sources of e
or, and comment on the purity of your prepared
cyclohexanol. Compare your actual yield versus the theoretical yield. (6 marks)
Agilent Plot
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Wavenumbe
CYCLOHEXANOL XXXXXXXXXXEXPERIMENT #4
PREPARATION OF CYCLOHEXANOL
LEARNING OBJECTIVES:
❖ To be able to develop a protocol for a reaction without step by step instructions
❖ Introduction to proposal creation. Increase written ability
❖ Produce, purify, and then test the purity of a marketable product
Introduction
It has often been said that necessity is the mother of invention. For this experiment you need 20 grams
of cyclohexanol. When you go to the storeroom, the bottle is empty and when you try to order it, you find
that it is on backorder.
Your research needs cyclohexanol to progress, and you cannot wait. Therefore you need to make the
equired 20 grams. You have both cyclohexene and cyclohexanone available. You must choose which
oute that you are going to use to make the cyclohexanol.
You will need to create a proposal showing the procedure that you will follow. The proposal must show
justifications for the choices that you made with respect to the procedure for making the cyclohexanol.
Please determine the cost of making the cyclohexanol. Be sure to include the cost of all reagents, and
factor in your time. You can assume that we have the basic organic glassware, so these do not need to
e part of the cost analysis. Be sure to include all pertinent physical data about your reactants and
product.
You will be working with your partner in the lab, but you need to produce your own proposal. Please
discuss with your partner how you intend to make the cyclohexanol but please ensure that you do not
commit academic misconduct by copying from each other.
CYCLOHEXANOL XXXXXXXXXXEXPERIMENT #4
CYCLOHEXENE OPTION: HYDRATION OF AN ALKENE
This is an acid catalysed addition. The acid that would be available would be sulphuric acid. Please be
mindful that this is an exothermic reaction and that cyclohexene is volatile. Adding water would be a
good source of hydroxyl groups.
Overall Reaction
XXXXXXXXXXCyclohexene XXXXXXXXXXCyclohexanol
Initially, cyclohexene is insoluble in the water-acid solution and appears as a two-phase mixture.
Cyclohexene will react with water and also with sulfuric acid to form two products: protonated
cyclohexanol and cyclohexyl hydrogen sulfate. Both of these products are soluble in the water-acid
solution, therefore, when the original two-phase mixture becomes homogeneous, the reaction is
complete. In practice, the degree of homogeneity is difficult to distinguish because of darkening of the
eaction mixture from cationic polymerization of cyclohexene.
Cyclohexanol is isolated from the reaction mixture by dilution with water followed by steam distillation.
When the water is added, a two-phase system results: an upper layer of cyclohexanol and a lower layer
of aqueous acid. When this mixture is heated, the cyclohexyl hydrogen sulfate by-product is converted
to protonated cyclohexanol that is in equili
ium with cyclohexanol.
Steam distillation separates the organic compounds from the sulfuric acid solution. The distillate consists
primarily of cyclohexanol and water plus a small amount of cyclohexene. Because cyclohexanol and
water form an azeotrope that boils at 98°C, the bulk of the material distills at this temperature. An
azeotrope is a mixture of two or three compounds which, when distilled, exhibit a fixed boiling point, like
that of a pure compound.
Salting out is a technique commonly used in extractions; its main purpose is to improve the yield of the
product. Salting out is done by adding enough salt to the aqueous phase to make it a saturated solution.
Salt helps to remove the organic compound from the aqueous phase by reducing the solubility of the
organic compound in water, forcing a transfer of the organic compound out of the aqueous phase and
into the organic phase. This step is followed by the separation of the organic phase from the aqueous
phase.
As a further precaution against mechanical loss (droplets clinging to the separatory funnel, etc.), diethyl
ether is used to extract the cyclohexanol from the salt-water mixture.
After separation, the organic layer is dried prior to distillation. Anhydrous magnesium sulfate is a suitable
drying agent; however, anhydrous potassium ca
onate is the agent of choice because it will neutralize
any trace of acid that may have been ca
ied through the work-up procedure. In the final distillation, a
trace of acid would cause dehydration of the cyclohexanol.
H2SO4
H2O
OH
CYCLOHEXANOL XXXXXXXXXXEXPERIMENT #4
Tips
- 14 mL of sulphuric acid would be a suitable volume for catalysis.
- Ice will be available to keep your reaction flask cool
- You should vigorously shake the reaction mixture for at least 30 minutes to ensure the reaction
proceeds towards the products. Vent periodically to prevent pressure build up.
- Please ensure that boiling chips and vacuum grease are used when performing a distillation, and
using ground glass
- The amount of salt required to make a saturated solution can be calculated in advance.
- It would be good to take note of any boiling points that were observed in both of the distillations
- Parafilm will be available to store your sample after salting it out. This would be a good place to
eak after the first lab session.
- Diethyl ether will be available on the second lab session for extractions.
- Potassium ca
onate will also be available on the second lab session to dry your sample and
neutralize any excess acid.
- After your final distillation, be sure to measure the quantity that you actually made (compare this
to the amount theoretically possible). Do not boil to dryness.
- Also be sure to test the purity of your sample (indicate in your proposal how you intend to do this).
CYCLOHEXANOL XXXXXXXXXXEXPERIMENT #4
CYCLOHEXANONE OPTION: REDUCTION OF A KETONE
Reducing cyclohexanone to cyclohexanol is a second option that you have. The reduction reaction can
e accomplished several ways but there are many factors to take into consideration in choosing which is
est suited for your purpose.
Metal hydrides of the Group III elements were first discovered in 1943, and were found to be very useful
educing agents. Lithium aluminum hydride, LiAlH4, reduces many compounds containing ca
onyl
groups, such as aldehydes, ketones, ca
oxylic acids, esters and amides. Sodium borohydride, NaBH4,
is less reactive and therefore can only reduce aldehydes and ketones to primary and secondary alcohols.
Sodium borohydride is mainly used in organic synthesis, while lithium aluminum hydride is used in organic
synthesis and other applications. Before these metal hydrides were known, ca
onyl groups were
educed to alcohols by treatment with hydrogen (H2) and sodium metal. All the metal hydrides work by
providing a hydride (H:-) that will act as a nucleophile to attack the electrophilic ca
onyl ca
on; however,
no free hydride ions are generated in solution. Kinetic studies indicate that a solvent molecule bonds to
the boron atom while hydride is being transfe
ed to the ca
onyl compound. Another solvent molecule
(if the solvent is protic) provides the proton for the ca
onyl oxygen that has the electrons from the
oken
π-bond. Therefore, while the overall reduction of ca
onyl requires two hydrogens, only one of these
comes from the reagent (that on ca
on); the other hydrogen comes from the protic solvent.
Sodium Borohydride and Lithium Aluminum Hydride Reduction Reaction
XXXXXXXXXXCyclohexanone XXXXXXXXXXCyclohexanol
In this equation 1 mole of sodium borohydride or lithium aluminum hydride can reduce