Dehydration Lab Report
Dehydration of 2-Methylcyclohexanol February 10, 2013 Introduction This experiment was done to demonstrate the practical use of dehydration reactions and produce three different products. Dehydration reactions are reactions that involve the leaving of an “-OH” or “-H” group resulting in the formation of a double bond between two carbons. For the experiment we used 2-Methylcyclohexanol as a beginning reagent to dehydrate and possibly form 3-methylcyclohexene, 1-methylcyclohexene, or methylenecyclohexane.
Drierite® (Calcium Sulfate) was used as a drying agent to help break the alcohol and hydrogen groups from the carbons. Concentrated phosphoric acid was used as a catalyst to help move the reaction towards the products motioned above. To determine the successfulness of the experiment and the amount of product(s) recovered, IR spectroscopy, Gas Chromatography and percent yield calculations were used. Equations and Structures 6. References 1. “18.
Dehydration of 2- Methylcyclohexanol. ” Organic Chemistry Lab 2040L. XU Chemistry, n. d. Web.
12 Feb. 2013. 2. Material Safety Data Sheet 2-Methylcyclohexanol. ” Http://www. coleparmer.
com/Assets/Msds/97403. htm. Coleparmer, 19 Mar. 1998. Web. 12 Feb.
2013. 3. “Material Safety Data Sheet Methylcyclohexane. ” Sciencelab. com. Science Lab, 09 Oct.
2005. Web. 12 Feb. 2013. 4.
Helmenstine, Anne M. , Ph. D. “How to Write a LabA Report. ” About. com Chemistry.
About. com Guide, n. d. Web. 23 Feb. 2013.
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Department of Chemistry and Biochemistry, n. d. Web. 23 Feb. 2013. .
7. Data Chemicals In Experiment| B.
P. | Amount Used| **Observations| 2-Methylcyclohexanol| 164-166°C | 0. 75mL| Colorless liquid that had similar smell to gasoline. | Calcium Sulfate (Drierite®)| 1193°C| Half Hickman Still| White powder that resembled kitty litter.
| Phosphoric Acid| 158°C| Approx. 1mL| Clear liquid & Odorless| 3-Methylcyclohexene| 104°C| N/A| Colorless liquid that had similar smell to gasoline. | 1-Methylcyclohexene *| 110°C| N/A| Colorless liquid that had similar smell to gasoline. | Methylenecyclohexane| 102°C| N/A| Colorless liquid that had similar smell to gasoline. *Major Product **Not All Observations were noted in lab manual, many stated are from memory from the experiment.
Observations: It took a lot of time for the Hickman Still to display any signs of condensation. The sand bath was adjusted to “60” power when “40” did not yield any visible results. The addition of a lid to the Hickman Still seemed to expedite the entire process. Colorless liquid began to collect rapidly in the first section of the Hickman Still. Weight of Vial without Product| 4. 284 grams| Weight of Vial with Product| 4.
550 grams| Weight of Product| 0. 266 grams|
Theoretical Yield| 0. 63 grams| Percent Yield of Product| 42% of Product was Recovered| GC Interpretation: The GC reading showed 3 peaks that were the products and one blip that is attributed to the air in the system. The different boiling points of the different molecules in the sample cause the different peaks to be expressed in the GC. Of the 3 peaks, 1-Methylcyclohexene proved to be the most abundant product due its large area percentage. Percent Air| Ignore| Percent Methylenecyclohexane| 1.
64555 = 2%| Percent 3-Methylcyclohexene| 17. 97600 = 18%| Percent 1-Methylcyclohexene| 79. 8650 = 80%| IR Spectroscopy Reading of Sample Gas Chromatography Data 8. Calculations 9. Conclusions In conclusion, we were successfully able to dehydrate 2-Methlycyclohexanol to synthesize all three of the above products most notably 1-Methylcyclohexene.
Adding approximately 1mL of 83% concentrated phosphoric acid to serve as the catalyst to the starting reagent and using calcium sulfate as a desiccant in the Hickman Still allowed the reaction to occur. The process of getting the products to condense on the first section of the Hickman Still took quite a while of time.
After the product was collected, IR spectroscopy was used to determine the chemical make up and purity of the product. The IR reading of the product collected in comparison to the IR of the starting reagent 2-Methylcyclohexanol showed in the 3400 cm? 1 that the –OH had went from a broad peak to a small blip. This gives evidence to the degree of successfulness of the dehydration preformed but also shows that some –OH was still in the product. The hypothetical GC data provided for this experiment demonstrates the purity of the sample along with the percent of each molecule found in the product.
-Methlcylcohexene proved to be the major product of the reaction due to the 80% area in the GC data and the regions expressed in the IR reading. Due to human errors such as not allowing enough time for the product to collect, using more desiccants than needed, allowing for the temperature of the sand bath to reach the boiling point of 2-Methylcyclohexanol or not retrieving the entire product, the percent yield was only 42%. The experiment is considered a success because all the expected products were produced and very little –OH was found in the sample.