Organic Chemistry 333L, 03M LaboratoryPre-LabDehydration of Cyclohexanol to CyclohexeneBy: Cameron Kahn5 November 2013TA: James Collie1 | P a g eObjective:In this experiment one will learn how to do an acid catalyzed dehydration of cyclohexanol into cyclohexene. Then use fractional distillation to purify the product. After purification, identify theproduct using qualitative organic tests.Intro/ Theory:In an acid catalyzed dehydration, an alcohol can proceed to change to an alkene. This process is cause by a molecule of water is eliminated from a carbon compound. This process is known to becalled dehydration. Dehydration is most commonly done through the means of heat and either the presence of phosphoric acid or sulfuric acid to catalyze the reaction (Sciences). In this lab, one will use a secondary alcohol because they undergo dehydration easier than primary alcohols (Handy). A secondary alcohol requires much lower temperature to perform the acid catalyzed dehydration. This will allow one to obtain the final product alkene much easier than the use of a primary alcohol.In this experiment, the reaction will undergo an E1 reaction. This is due to the water molecule being eliminated from the two adjacent carbons. The leaving group will leave first in order to create a carbocation in the molecule. Therefore, the first step is the slow “rate determining step” followed by a more rapid step. Alkenes that form from this process are known to undergo “alkene addition” reactions. In some instances, these reactions can be used to determine the presence of an alkene in the final product. In order to understand this theory, look at Bromine for example. Bromine is a brown liquid that turns clear with the presence of an alkene. KMnO4 will form a brown precipitate.2 | P a g eMechanism:*Mechanism is a photocopy from the Chemistry lab manual written by George HandyProcedures:Start by placing 0.9mL of water, 1.2mL of 85% phosphoric acid, 6.2mL of cyclohexanol, and a boiling stone into a 25mL round bottom flask. Next, heat the mixture using a heating mantle located under a fractional distillation apparatus. Make sure the bulb of the thermometer is positioned correctly inside the distillation head. Heat the mixture with the variac setting at an initial 60. Then gradually increase the variac setting until only 1mL of mixture is left in the flask and most of the material is done distilling. Water and product will be the two phases of the distillate. Record the boiling point of the solution. Transport the distillate into a separatory funneland then wash with 4mL of saturated aqueous NaCl solution. Using the separatory funnel, discard the bottom layer and retain the top layer in a test tube. Add a micro-scoop of anhydrous 3 | P a g emagnesium sulfate to the test tube, swirl, and then let the solution settle. Cap off the test tube holding the product and leave sit until next lab period.In the next lab period, use the shorter fractional column and set up the fractional distillation apparatus. Lightly grease all connections. Next, add a boiling stone and the product from the last lab period to a 25mL round bottom flask. Heat the mixture using a variac setting of 60 initially. Then after a few minutes, increase the heat by turning the variac setting up gently. Collect the product and determine the volume. Then calculate the mass of purified product using the volume and its density. Using a pipette, remove the product. Determine the volume and, using the density, calculate the mass of purified product (Handy). Then, one must clean and set up 4 small test tubes to perform qualitative tests on the product. In two test tubes, add 1mL of cyclohexanol and in the other two, add 1mL of the product (cyclohexene). Using a test tube from each pair, add10 drops of 1% KMnO4 solution and record the results for both test tubes. Take the other two testtubes and add 10 drops of Bromine water solution and record the results for both test tubes.Apparatus:Reagent Table:Name, Structure, MW (g/mol)Melting oCBoiling oCDensity g/mLProperties SafetyCyclohexanol 100.1620-22 161 0.962Colorless, viscousliquid with a faintcamphor odor.HYGROSCOPICToxic Irritant Flammable4 | P a g eFigure 2Figure 1: Fractional distillationFigure 2: Separatory funnel**Both figures are courtesy of UMass Amherst Department of Chemistry and Biochemistry Figure 1Phosphoric Acid 97.9921 158 1.685Viscous,colorless,odorless liwuidsolidifies at 70oCCorrosive to tissue and irritating to the skin, mucous membranes, upper respiratory tract and eyes. Fatal if swallowedSodium ChlorideNaCl 58.44801 1413 2.165White crystals,HYGROSCOPICThis compound may cause eye irritation. When heated to decomposition it emits toxic fumesMagnesium Sulfate 120.361124 - 2.66HYGROSCOPIC, drying agent,white powderDesiccantCyclohexene 82.15-104 83 0.811Colorless liquid Irritant to skin, mucous membranes, upper respiratory tract and eyesBromineBr-Br79.904-7.2 137.8 3.102Brown clearliquid with strongbromine smellTOXICKeep reagent under at or below 4oC at all times. Heating can cause decomposition and bromine gas being generated. Strong irritant to eyes, nose, and lungsPotassiumPermanganateKMnO4158.09270 - 2.7Purple crystalswith a staticchargeViolent oxidizer of alcohols. If ingested damage is done to kidneyand lungs resulting in edema and burns. Inhalation can cause serious irritation.Disposal:5 | P a g eThoroughly wash any and all glass wear using acetone and if approved by the TA, then rinse withwater. Dry all glass wear and properly put back any and all materials in the designated areas or drawers. Soiled gloves should be disposed of in the proper glove container. Any paper towels should be disposed of in the general waste basket. Organic solvents need to be properly disposed of in the organic liquid waste container located under the fume hood. Consult with the TA for further instructions or any questions one may have before disposing of any content inappropriately. References:1. Ali, George Handy and Salman. Essentials of Organic Chemistry. Montgomery, Al: QDE Press, 2012.Sciences, Department of Chemistry in the College of Natural. " Department of Chemistry in the College of Natural Sciences." 01 01 2012. UMass Amherst. 02 23 2013 <http://www.chem.umass.edu/~samal/269/aak.pdf>2.6 | P a g