Week+5-+Distillation+of+Cyclohexene

=**Week 5- Preparation and Distillation of Cyclohexene**=

Introduction:
The purpose of this lab is to synthesize cyclohexene by alcohol dehydration. In the presence of a strong acid, an alcohol can be dehydrated to form an alkene. The alcohol that will be used is cyclohexanol and the acid will be phosphoric acid (H3PO4). When the cyclohexanol is heated in the presence of the phosphoric acid it causes an E1 elimination reaction. The first step of the mechanism is the protonation of the alcohol group by the acid, the water then leaves forming a secondary carbocation and in the final step a beta hydrogen is deprotonated forming the double bond. Below is an example of the reaction. Once the distillation is complete, the final product will be tested in an infrared (IR) spectroscopy to find its absorption patterns. Similar to melting points, IR spectroscopy are great at identifying products. NICE INTRO! Complete, thorough, but not unnecessarily wordy.

Procedure:
Be very careful about providing proper citations in your reports--I see that you have cited the database at the bottom of this page, but when you extract specific instructions and images you should also probably put an in-line citation somewhere. And make sure whatever you include is okay to post openly. 1. Combine 0.074 moles of cyclohexanol and 1.75 mL of 85% H3PO4 into a 50mL round bottom flask, including a magnetic stir bar or boiling chip. 2. Obtain some copper tinsel and evenly fill the Vigreux column (in this procedure, .609g was used because Carol said it "looked like a good amount") 3. Attach the round bottom flask to the Vigreux column attached to the distillation apparatus pictured below (Picture 2). Drying tube can be omitted due to dry climate. Wrap aluminum foil or glass wool around the Vigreux column to keep the column warm and prevent re-condensing before reaching the thermocoupler. 4. Heat the mixture at a gentle reflux for approximately 5 minutes, then heat more vigorously to distill the mixture into the collection flask. Continue distillation until only approximately 1mL remains in the distillation flask. 5. Transfer the distilled product to a separatory funnel and wash with 5mL water. 6. Carefully separate the layers and transfer the organic product to an Erlenmeyer flask. 7. To remove trace amounts of excess water, add a small amount of anhydrous sodium sulfate and let stand for about 5 minutes, gently swirling occasionally. 8. If the sodium sulfate is clumpy, add small amounts and swirl until there is a clear appearance with a small amount of solid free floating. 9. Decant or pipette the product away from the drying agent and put it in a vial for infrared spectroscopy (do be done by Carol) Label the vial clearly.



Data/Analysis:
C6H12O) = 7.4g ||
 * Calculation for amount of required cyclohexanol || 0.074 mol * (100.156 g/mol
 * Actual amount weighed out for use the in experiment || 7.421g cyclohexanol ||
 * Amount of 85% Phosphoric Acid (H3PO4) || 1.75 mL ||
 * Table #1. Calculations of the beginning contents in the round bottom flask. ||


 * **Time ** || **Temperature ºC ** || **Observations ** ||
 * 9:42 || 19.7 || Started heating, set at 40 set what? the transformer? ||
 * 9:48 || <span style="font-family: 'Arial','sans-serif'; font-size: 13px;">Lab Quest recording || <span style="font-family: 'Arial','sans-serif'; font-size: 13px;">Turned up to 50 ||
 * <span style="font-family: 'Arial','sans-serif'; font-size: 13px;">10:08 || <span style="font-family: 'Arial','sans-serif'; font-size: 13px;">Lab Quest recording || <span style="font-family: 'Arial','sans-serif'; font-size: 13px;">Started to notice condensation in the condenser packed with copper ||
 * <span style="font-family: 'Arial','sans-serif'; font-size: 13px;">10:34 || <span style="font-family: 'Arial','sans-serif'; font-size: 13px;">29.5 || <span style="font-family: 'Arial','sans-serif'; font-size: 13px;">Mixture began dripping in the collection flask. Checked the Lab Quest and it was not recording accurately. Could not produce a graph of this distillation due to the malfunction. Rats! ||
 * <span style="font-family: 'Arial','sans-serif'; font-size: 13px;">10:55 || <span style="font-family: 'Arial','sans-serif'; font-size: 13px;">76.5 || <span style="font-family: 'Arial','sans-serif'; font-size: 13px;">Ended the distillation ||
 * 11111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111 ||
 * <span style="font-family: 'Arial','sans-serif'; font-size: 13px;">Weight of vial and lid || <span style="font-family: 'Arial','sans-serif'; font-size: 13px;">6.224g ||  ||
 * <span style="font-family: 'Arial','sans-serif'; font-size: 13px;">Weight of vial and product || <span style="font-family: 'Arial','sans-serif'; font-size: 13px;">9.152g ||  ||
 * <span style="font-family: 'Arial','sans-serif'; font-size: 13px;">Final weight of product || <span style="font-family: 'Arial','sans-serif'; font-size: 13px;">2.928g || Of cyclohexene ||
 * <span style="display: block; font-family: 'arial','sans-serif'; font-size: 13px; text-align: center;">Table #1: Data/Observations of Distillation ||

[[image:perfectochemgems/IR.jpg width="697" height="476" caption="Graph #1. IR spectrum of Cyclohexene"]]

 * Based on the data in this chart, there are peaks present representing what one would expect from cyclohexene; sp2C-H, sp3C-H, and C=C. The large peaks around 2300 are not expected however, in comparison with the ideal IR spectrum pictured below (Graph #2).
 * **<span style="color: #632423; font-family: 'Arial','sans-serif'; font-size: 13px;">Peak #’s ** || **<span style="color: #632423; font-family: 'Arial','sans-serif'; font-size: 13px;">1 ** || **<span style="color: #632423; font-family: 'Arial','sans-serif'; font-size: 13px;">2 ** || **<span style="color: #632423; font-family: 'Arial','sans-serif'; font-size: 13px;">3 ** || **<span style="color: #632423; font-family: 'Arial','sans-serif'; font-size: 13px;">4 ** || **<span style="color: #632423; font-family: 'Arial','sans-serif'; font-size: 13px;">5 ** || **<span style="color: #632423; font-family: 'Arial','sans-serif'; font-size: 13px;">6 ** || **<span style="color: #632423; font-family: 'Arial','sans-serif'; font-size: 13px;">7 ** || **<span style="color: #632423; font-family: 'Arial','sans-serif'; font-size: 13px;">8 ** ||
 * **<span style="color: #632423; font-family: 'Arial','sans-serif'; font-size: 13px;">Position ** || <span style="display: block; font-family: 'arial','sans-serif'; font-size: 13px; text-align: center;">3021.99 || <span style="display: block; font-family: 'arial','sans-serif'; font-size: 13px; text-align: center;">2927.65 || <span style="display: block; font-family: 'arial','sans-serif'; font-size: 13px; text-align: center;">2856.67 || <span style="display: block; font-family: 'arial','sans-serif'; font-size: 13px; text-align: center;">2837.34 || <span style="display: block; font-family: 'arial','sans-serif'; font-size: 13px; text-align: center;">2359.64 || <span style="display: block; font-family: 'arial','sans-serif'; font-size: 13px; text-align: center;">2340.88 || <span style="display: block; font-family: 'arial','sans-serif'; font-size: 13px; text-align: center;">1448.33 || <span style="display: block; font-family: 'arial','sans-serif'; font-size: 13px; text-align: center;">1067.79 ||
 * <span style="display: block; font-family: 'arial','sans-serif'; font-size: 13px; text-align: center;">Peaks 5 and 6 come from Carbon Dioxide (CO2) built up in the room at the time of the test. ||
 * <span style="display: block; font-family: 'arial','sans-serif'; font-size: 13px; text-align: center;">Table #3: Peak finding results ||

<span style="font-family: 'Arial','sans-serif'; font-size: 13px;">Percent Yield Calculations:

<span style="font-family: 'Arial','sans-serif'; font-size: 13px;">0.074 C6H12O mol * (1 mol C6H10<span style="font-family: 'Arial','sans-serif'; font-size: 13px;">/ 1 mol C6H12O<span style="font-family: 'Arial','sans-serif'; font-size: 13px;">)= 0.074 mol C6H10 <span style="font-family: 'Arial','sans-serif'; font-size: 13px;">0.074 C6H10mol * (82.14 g<span style="font-family: 'Arial','sans-serif'; font-size: 13px;">/ 1 mol C6H10)<span style="font-family: 'Arial','sans-serif'; font-size: 13px;">= 6.078g = 6.1 g Theoretical Yield <span style="font-family: 'Arial','sans-serif'; font-size: 13px;">Actual Yield is 2.928 g C6H10

(2.928 g C6H10<span style="font-family: 'Arial','sans-serif'; font-size: 13px;">/ 6.1 g C6H10) <span style="font-family: 'Arial','sans-serif'; font-size: 13px;">* 100 = 48% yield Nicely shown, and good job attending to the sig figs rules.

Conclusion:
The procedure seems to have been at least somewhat a success! The procedure was carried out with little or no hiccups or unexpected traumas. Avoid judgments such as these first two statements! I know you want to share the excitement, and I want you to do so, but not here. Keep the tone neutral. The experimental IR spectrum is mostly what one would expect. However, there are unexpected peaks rearing their ugly heads in the IR spectrum. According to Dr. Higginbotham and her infinite wisdom, the rogue peak around 2350 cm-1 is most likely due to carbon dioxide that tends to build up in the room when lots of people (breathing out CO2) are present. I was back there breathing over the HATR for quite a while. Lots of CO2. In addition to the CO2 explanation, some other potential sources of error are as follows: inaccurate molar mass or density conversions to come up with the initial amounts of substances, This is preventable and so should not be listed. using too little drying agent, imprecise separation of water and the organic product, and any number of mechanical glitches/failures associated with the IR spectrometer. Also, as mentioned earlier, the LabQuest machine was freezing up, making temperature reading possibly inaccurate. This error may have compromised the integrity of the distillation, either leading to allowing the distillation to go too long or to cut it short. This could result in yield and product purity issues. Absolutely. This is the most important difficulty you encountered in the day's activities. The relatively low percent yield could also be a result of the distilled product condensing back into the initial flask. How?

The final product was a clear liquid with perhaps a slight yellow tint. Include this in your data section.
 * Post Lab Questions:**

<span style="font-family: 'Arial','sans-serif'; font-size: 13px;">Atom Economy illustrates the conversion efficiency of a chemical process in terms of desired products produced. Atom economy is written as: <span style="font-family: 'Arial','sans-serif'; font-size: 13px;">% atom economy = x 100

<span style="font-family: 'Arial','sans-serif'; font-size: 13px;">Do not include catalysts or solvents in this equation. The desired product in this lab is cyclohexene having a molecular weight of 82.14 g/mol. The reactant in this case is cyclohexanol with a molecular weight of 100.156: <span style="font-family: 'Arial','sans-serif'; font-size: 13px;">% atom economy = x 100 = 82.01% calculation OK

<span style="font-family: 'Arial','sans-serif'; font-size: 13px;">**Some of the post lab questions pertained to a second distillation that was not part of this procedure, so the questions have been omitted from the report.

Works Cited:
<span style="color: black; font-family: 'Arial','sans-serif'; font-size: 13px;">"Atom Economy." //Wikipedia, the Free Encyclopedia//. Web. 17 Feb. 2012. [].

<span style="font-family: 'Arial','sans-serif'; font-size: 13px;">Higginbotham, Carol. Ph.D. “Preparation and Distalation of Cyclohexene. ” CH-335: Organic Chemistry Course. COCC/UO: Blackboard, Winter 2012. Web. 15 Feb 2012.

<span style="color: black; font-family: 'Arial','sans-serif'; font-size: 13px;">"Overview." //GEMs Home//. Web. 17 Feb. 2012. []. (procedure/apparatus picture)

<span style="color: black; font-family: 'Arial','sans-serif'; font-size: 13px;">"Synthesis of Cyclohexene from Cyclohexanol by Acid Catalyzed ( E1 )Elimination." //Keystone College Academic Server//. Web. 17 Feb. 2012. [].