REWRITE+-+DIstillation+of+Cyclohexene

**Introduction:**
Distillation is the process of separating two chemicals based on their boiling points. This process works by having the mixture in a round bottom flask on one side with heat. Once the mixture reaches the boiling point for one of the chemicals the chemical evaporates up a column. When the vapor reaches the top of the column it encounters a cool condensing tube that brings the vapor back to a liquid to travel down the condensing tube and into a separate round bottom flask. Cyclohexanol can easily undergo a chemical reaction transforming it into cyclohexene using a strong acid. After the reaction, to separate the cyclohexene out from the water and leftover cyclohexanol, distillation is a very good option. The mechanisms involved with this reaction are E1 mechanisms where there is a carbon cation intermediate causing a hydrogen to leave to form a pi bond. To check how well the procedure was executed one effective method is infrared spectroscopy, which shows you what kind of bonds are within a sample so you can determine how much of your expected product was formed. This reaction is an equilibrium, also, so distilling the product away from the reactants as they form drives the reaction to produce more product.


 * Reaction for this Experiment:**



**Procedure:**
First, put the distillation apparatus together with the fractioning column lightly packed with copper wire before attaching the water condenser. The condenser filled with copper needs to be wrapped in glass wool and tin foil. Make sure there aren't clumps of copper wire. Once everything is put together 7.4g of cyclohexanol can be obtained along with 1.75ml of 85% phosphoric acid. Mix the two gently in a 50ml round bottom flask and add a boiling chip. Next connect the flask to the distillation apparatus and heat moderately for five minutes. After five minutes the heat can be bumped up to put the mixture at a steady simmer. After about 15-20 minutes the first drop should come through the condensing tube--Record this temperature. Watch the thermometer and note the changes in temps, careful to not let the temp. spike and drop suddenly. Once only 1ml of mixture is left in the heated flask, stop the process and allow the product to cool off. Then put the product into a separation funnel; the layer on the bottom is water so it is drained out leaving behind the wanted product.Sodium Sulfate is added to pick up any of the remaining water left in the mixture. Once the product is separated from the clumpy sodium sulfate, calculate the percent yield and receive an infrared spectroscopy of the final product, from your professor.

**Data:**

 * Initial Starting Material:** 7.442g of Cyclohexanol, 1.75 mL of Phosphoric Acid.


 * Observations:**
 * It took 15 minutes for the distillation to begin, with the power supply dial at 55.
 * The distillate slowly made it through a clump of copper wire in the fractioning column. No clumps are best!
 * Substance in the Distillation Flask turned cloudy before it started distilling and had reached the collection flask.
 * Distillate was black when the distillation process was complete.
 * The pure distilled product was a white, opaque liquid substance.
 * A strong, disgusting, toxic-like odor was released when cleaning up the apparatus. Cyclohexene is nasty stuff. It has that heavy, solvent smell that NOBODY likes.

**Results:**
2.02 g Cyclohexene * mol/82.14g Cyclohexene = 0.025 mol
 * Grams to Moles Conversion**: 7.44g Cyclohexanol * mol/100.16g Cyclohexanol = 0.074 mol

.338 mol * 100% = 33.8%
 * Percent Recovery:** 0.025 mol cyclohexanol / 0.074 mol cyclohexene (recovered) = 0.338 mol


 * Theoretical Yield**: 0.074 moles Cyclohexanol * (1 mol cyclohexene/ 1 mol Cyclohexanol) * (82.14 g Cyclohexene/ 1 mol Cyclohexene) = 6.16 g

Some sig figs issues in these calculations--though the math is okay.
 * Percent Yield**: 2.02 g Cyclohexene Recovered / 6.16 g Theo. Yield = 32.8%


 * Infrared Spectrum Comparisons:**
 * Our Spectrum:**
 * Actual IR Spectrum of Cyclohexene:**


 * Boiling Temperature of Product:** Temp. was recorded by Meltemp apparatus during the distillation:76.8 Degrees Celsius to simmer --->>> 79.4 Degrees Celsius Boiling Point.

Actual Cyclohexene Boiling Range: 80-85 Degrees Celsius

**Discussion:**
During the experiment the last step was looked pasted which is the addition of sodium sulfate. The sodium sulfate is used to soak up any remaining water that is left in the product. The result of the product was very high in percent yield most likely because of the water in the mixture. To test this hypothesis an infrared spectroscopy is taken of the product sample. Looking at the infrared spectroscopy there are a few things that stand out. First, from 3200-3700 there is a strong broad swoop. This indicates a substantial amount of OH bonds within the sample. Seeing this the assumption can be made that there is, in fact, a worthy amount of water and possibly remaining cyclohexanol. Continue to move from left too right, right after the OH bond there is a thin needle like point around 3100. Now this is a sp2 carbon to hydrogen bond, suggesting a carbon to carbon double bond. The C=C bond is evidence that cyclohexene was synthesized during the experiment. Comparing the spectroscopy measured to the known spectroscopy of cyclohexene found on the internet the major difference is the appearance of the OH bond. The best guess for this impurity would be water because of missing the last step in the experiment.

**Errors:**
Be careful reading the procedure so that a key step is not looked past. Missing the last step definitely affected the results of the final product but the fact that product mixture was cloudy indicates another problem. The fact that the mixture is cloudy suggests that there is something undissolved and polar. A guess would be that it is the starting material, cyclohexanol. If the starting material ended up in the final product an error during distillation may have occurred. Quite possibly the mixture was heated too much during the distillation process causing the molecule with a higher boiling point to cross over which is the unwanted product cyclohexanol.

good job.