Preparation+of+Cyclohexene+REWRITE

= Preparation of Cyclohexene (REWRITE for Patricia Hooker and Jessica Corrales) = = = =

= =** __Introduction:__ **=

Cyclohexanol is used in this reaction to produce cyclohexene. Cyclohexene, a cycloalkene, is a colorless liquid that has a pungent odor. In this lab, cyclohexene will be produced by an acid catalyzed elimination reaction. Classically sulfuric acid would be used to complete the process of the E1 reaction, but for this particular lab phosphoric acid will be used which is less corrosive. In this reaction, phosphoric acid will initiate the OH from cyclohexanol to be removed. The removal of this OH group from the cyclohexanol results in a double bond within the carbon ring structure, producing a cyclohexene.

To complete the necessary reaction, cyclohexanol is combined with phosphoric acid and then distilled. The distilled liquid washed with water, further purifying the cyclohexene where it is then extracted into a separate collection flask. The collected cyclohexene is put into an Infrared Spectrometer to test its purity.



**__Procedure:__**
The procedure for the experiment can be located at the following link:

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__Procedural Changes:__
-Skip steps 6 and 7.

**__Data:__**

Cyclohexanol: 7.42 g 85% H3PO4: ~1.75 mL Transformer setting prior to first drop: 40% of maximum voltage First drop: 73.3 degrees Celsius Elapsed time until first drop: 24.0 minutes Transformer voltage after first drop: 50% of maximum voltage Time elapsed until reaction completion: 48.5 minutes H20 wash: 5 mL Boiling point of cyclohexene: 83 degrees Celsius Final mass of product: 3.88 grams cyclohexene



Graph : The graph above is the temperature inside the reflux tube throughout the distillation process.
**__Analysis:__**




 * ~  ||~ Interpretation of Above IR Chart ||~   ||~   ||~   ||~   ||
 * = **Peak Number** ||= **1** ||= **2** ||= **3** ||= **4** ||= **5-8** ||
 * = **Postions** ||= 3013.07 ||= 2916.25 ||= 2848.94 ||= 2828.84 ||= In the Fingerprint Region ||
 * = **Bond Decription** ||= alkene

Csp2-H ||= Alkane

Csp3-H ||= Alkane

Csp3-H ||= Not within a Given Range ||=  || knowing that Cyclohexene has this type of bond, this point is close enough to call it so. ||=  ||=   ||=   ||=   || in the rooms as the infrared spec is being done. ||  ||   ||   ||   ||
 * = **Other Comments** ||= This point does not fall into the exact range for an Alkene but
 * Observations: || There is a reverse peak at approximately 2200 that can be attributed to the amount of CO2

**__Conclusion:__** This experiment was to create a knowledge of how to perform an E1, or two step elimination reaction. The distillation process was used in order to purify the cyclohexene, not complete the reaction. From the infrared spectrum of the final product it is clear that the substance was very pure with no strange peaks on the spectrum, other than the reverse spike due to carbon dioxide levels. The copper added to the reflux condenser allowed the cyclohexene to condense and re-evaporate more giving a higher level of purity.The distillation process was successful as there was a 63.86 percent yield of final product.

__Temperature Graph Observations:__
The large dip at the end of the graph is when the probe was removed from the hot reflux tube. The gradual incline from zero around 40 minutes was what was expected and the small dips within the curve can be from the temperature probe moving to the sides and touching the glass. The gradual climb for the the first 20 minutes was expected as the reflux condenser was heating up and condensing. During this time it seems to have reached 75 degrees Celsius. After that there was a slight fluctuation, most likely due to the probe touching the glass, and then leveled off at around 80 degrees Celsius. This was the temperature until the probe was removed and the distillation finished.

== __Source of Error:__ One possible source of error could have came from the small amount of unknown liquid that was remaining in our reaction flask. This could have been left over from the previous lab. Also, some product remained in the distillation apparatus which was noticed upon dis-assembly leading to lower percent recovered product. ==