Synthesis of Cyclohexene PDF

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Synthesis of Cyclohexene...

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Michaela Scott Geetha 2423-520 Apr. 16, 2017 Experiment 9: Synthesis of Cyclohexene Lab Report

Purpose:

To generate cyclohexene from the acid catalyzed dehydration of cyclohexanol through E1 mechanism. Materials Used: - Small distillation tube - 250 mL beaker - 50 mL round bottom flaks - 25 mL round bottom flask

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Graduated cylinder Thermometer Erlenmeyer flask

Table of Chemicals: Chemical Name

Chemical Structure

Cyclohexanol

Molar Mass

Physical State

100.158 Colorles g/mol s Liquid

Meltin g Range 24C

Boilin g Point

Refractiv e Index

Quantit y Used

160C

1.465

3 mL

1.431

Phosphoric Acid

98 g/mol

Colorles s Liquid

20C

158C

Calcium Chloride

110.984 g/mol

White Solid

782C

1600C

Sulfuric Acid

98.078 g/mol

Colorles s Liquid

10 C

337C

Diagrams and Equations:

Theoretical YieldsCylcohexanol 3.0 mL * .9624 g/mol= 2.8872 g/ 100.158 g/mol= .0288 mol * 1/1= .0288 mol * 82.143 g/mol= =2.36879g Cyclohexene Sulfuric Acid .25 mL * 1.84 g/mol= .46 g/ 98.079 g/mol= .0047 mol * 1/1= .0047 mol * 82.143 g/mol= = .3861g Cyclohexene

Phosphoric Acid .25 mL * 1.88 g/mol= 7.52 g/ 98 g/mol= .0767 mol*.85= .0652 *1/1= .0652 mol*82.143 g/mol= = 5.3577 g Cyclohexene Limiting ReactantCyclohexanol Procedure: A 25 mL round bottom flask was obtained and 3 mL of cyclohexanol was measured and poured into the flask. 4 mL of 85% Phosphoric acid was added as well as 5 drops of Sulfuric Acid. A simple distillation apparatus was set up with a beaker full of ice at the receiving end. Boiling chips were added to the mixture and placed into the heating mantle with at stirring magnet. The mixture was distilled until it reached 90C. The distillate was then transferred to a large test tube to remove the acid layer on the bottom. The organic layer was dried by adding Calcium Chloride and then decanted into a pre-weighed flask to determine the percent recovery of the product. Potassium permanganate was added to a sample to determine the cyclohexene had formed. Data and Observations: Percent Recovery: 100* 1.499g/2.3769g= 63.07% The product turned from purple to brown when potassium permanganate was added, indicating that the double bond in cyclohexene had formed.

Discussion: In this experiment cyclohexanol is taken which has an OH attached and when an acid is added the hydrogen protons attach to the OH to form H2O. This water is then removed and forms a carbocation to which the hydrogens then form a double bond on either side of the carbocation. This process can be tested by applying the Zaitsev rule which predicts the most stable product will be the product that is the most substituted. Potassium permanganate is used to determine if the process was completed. When cyclohexene meets the Potassium permanganate it decolorizes the reagent to form Manganese dioxide which is brown and a diol. This experiment offered a low percent recovery rate but this can be improved by either distilling to dryness or by being more careful when decanting after drying. Conclusion: The formation of Cyclohexene was performed by adding two acids and then tested by using potassium permanganate

References “ChemSpider” ChemSpider. N.p., n.d. Web. 2017. Mohrig, Jerry R., David G. Alberg, Gretchen Holifmeister, Paul F. Schatz, and Christina Noring Hammond. Laboratory Techniques in Organic Chemistry. New York: W.H. Freeman, 2014. N. page. Print.

Michaela Scott Geetha 2423-520 Apr. 16, 2017 Experiment 9: Synthesis of Cyclohexene Post Lab Questions

1. 1-methylcyclohex-2-ene would be the product of a E1 dehydration of 2methylcyclohexanol. 2.

3. An alkane would be produced from a reaction with CH3Cl2 and bromine....