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Name: Mbayo Shahiya Chardi Student number: 219009910 Date performed:19/04/2021 Group Partners: Luc Date submitted: 26/04/2021 Meshack Experiment 4: Organic chemistry 2 (ORG601S) Title: The Diels-Alder reaction Lab technician: Ms Martha
1. Aim: was to perform a Diels-Alder reaction with the compounds malic anhydride and anthracene by using processes such as heating under reflux in order to produce our product of 9,10- dihydroanthracene- 9,10- α, β-succinic acid anhydride. 2. Introduction: The reaction for this experiment is between anthracene and maleic anhydride and it is a Diels- Alder reaction. This reaction is a cycloaddition reaction in which the conjugated pi-systems of the two reactants join to form a new ring. The pi-system in this case is referring to a carbon-carbon double bond within the ring[ CITATION Bro14 \l 1033 ]. The reaction involves a carbon group called a diene and an alkene called a dienophile. When the reaction occurs, conjugate addition of the diene and the dienophile produces a six membered cyclohexene ring. The Diels-Alder reaction is very practical because it occurs faster than a lot of other organic reactions and always produces a six membered ring. These reaction products are very useful and can range from being used as antioxidants to insect anti-feedants[CITATION Bar11 \l 1033 ]. Figure 1.1: The figure below is an example mechanism for a Diels-Alder reaction. This reaction is concerted, which means it occurs in a single step with no intermediates or radicals. The double bonds on the diene and the dienophile react with each other and form two single bonds and also lose two of the double bonds. In the reaction between anthracene and maleic anhydride, the center ring of anthracene goes through the reaction and forms a Diels- Alder adduct. Figure 1.2: The figure below shows the reaction of anthracene with maleic anhydride to form the Diels-Alder adduct that was formed in this experiment. The reaction happens with the center ring because it forms two benzenoid rings after the reaction. The term “benzenoid” refers to the two rings with three double bonds in the Diels-
Alder adduct in Figure 1.2, which is very stable. The IUPAC name of the Diels-Alder adduct is 9,10-dihydro-9,10-ethanoanthracene-11,12-dicarboxylic anhydride. 3. Materials: Chemicals used: Name Amount used(grams or mls) Maleic anhydride 0.25 g Anthracene 1.0 g Xylene 6 ml Heptane: ethyl acetate 80:20 ml ethyl acetate 3 ml 9,10- dihydroanthracene9,10- α,β-succinic anhydride 2.7 g Equipment used: Filter flask Condenser Round-bottom flask Hirsch funnel Heating mantle 4. Procedure: To start the experiment, 1.0 g of anthracene and 0.25 g of maleic anhydride were put into a round bottom flask. Then, 6 mL of xylene was added to the mixture and stirred. The solution was then refluxed for around 30 minutes. A reflux condenser was put snugly on top of the round bottom flask containing the solution. Also, a boiling stone was put in the solution and the flask and condenser were held in place by a clamp. The reaction was allowed to cool to room

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