CHEM2314 Lab 7

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Jan 9, 2024

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Experiment #1 Diels-Alder Reaction Date Preformed—November 29, 2023 Date Due—December 6, 2023

Experimental Objective The goal of this experiment was to synthesize cis-norbornene-5, 6-endo-dicarboxylic anhydride from maleic anhydride and cyclopentadiene via Diels-Alder reaction. The product was purified using recrystallization techniques and characterized by melting point analysis. Reagents Used Cyclopentadiene Maleic Anhydride Cis-norbornene-5, 6-endo-dicarboxylic anhydride MW: 66.10 g/mol MW: 98.06 g/mol MW: 164.16 g/mol den: 0.80 g/mL den: 0.80 g/mL mp: 142-146 °C mp: -85.0 °C mp: 52.8 °C Reaction Scheme Figure 1. Reaction scheme taken from pre-lab PowerPoint. Balanced equation: C 5 H 6 + C 4 H 2 O 3 → C 9 H 10 O 4 Procedure Ethyl acetate (1 mL) was added to a test tube. Maleic anhydride (0.2 g) was then added to the test tube and dissolved in the ethyl acetate. Hexanes (1 mL) and cyclopentadiene (0.2 mL) were then added to the solution. The reaction heated up and was left to cool until crystals were formed. Once the crystals were formed a thick-walled vacuum tube was connected to a vacuum tap on the bench top and to the end of a filter flask. A 1.5 cm piece of filter paper was placed on top of a Hirsch funnel and the funnel was placed atop the filter flask. The crystal slurry in the test tube was poured onto the filter paper in the Hirsch funnel. The crystals were collected on the paper while the liquid was sucked into the filter flask. The crystals were left to dry in the Hirsch funnel and then residual crystals in the test tube were rinsed with hexanes and added to the Hirsch funnel. The crystals were left to dry for a few minutes before the filter paper was taken out and placed atop a piece of 11 cm filter paper. The 11 cm piece of filter paper with the

crystal product was used to dab the crystal product drier. The product was weighed, and its melting point was tested. Results Observations The solution was clear and when mixed a white precipitate was formed. The collected product were white crystals. Product Description The collected product was a white powder. Experimental Data Pure Product (g) 0.092 g Melting Point 164.9 °C Table 1. Experimental data for purified cis-norbornene-5, 6-endo-dicarboxylic anhydride. Yield Calculations Theoretical Yield ( 0.197 gSM ) ( 1 mol SM 98.06 gSM )( 1 mol P 1 mol SM )( 164.16 g P 1 molP ) = 0.340 g Where SM is maleic anhydride and P is cis-norbornene-5, 6-endo-dicarboxylic anhydride. Percent Yield ( 0.092 0.340 ) × 100% = 27.1% Conclusion The melting point of the collected product was expected and indicated cis-norbornene-5, 6-endo- dicarboxylic anhydride was successfully synthesized. The melting point of the collected product was 164.9 °C while the expected melting point was around 165-167 °C, indicating cis-norbornene-5, 6-endo- dicarboxylic anhydride was present. The product was a white powder collected in 27.1% yield. References National Center for Biotechnology Information (2023). PubChem Compound Summary for CID 7612, Cyclopentadiene. Retrieved December 3, 2023 from https://pubchem.ncbi.nlm.nih.gov/compound/Cyclopentadiene . National Center for Biotechnology Information (2023). PubChem Compound Summary for CID 7923, Maleic Anhydride. Retrieved December 3, 2023 from https://pubchem.ncbi.nlm.nih.gov/compound/Maleic-Anhydride . National Center for Biotechnology Information (2023). PubChem Compound Summary for CID 6541030, endo-Norbornene-cis-5,6-dicarboxylic acid. Retrieved December 3, 2023 from https://pubchem.ncbi.nlm.nih.gov/compound/endo-Norbornene-cis-5_6-dicarboxylic-acid .

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