Experiment 12a and 12b: Diels-Alder Reaction 4- Cyclohexene-cis-1,2-dicarboyxlic

Question

Experiment 12a and 12b: Diels-Alder Reaction 4- Cyclohexene-cis-1,2-dicarboyxlic Acid Anhydride or 9,10-Dihydroanthracene-9,10--B-succinic Acid Anhydride Note: All glassware finely ground and protected from moisture. All solvents should be stored over Experiment 12a The optional semimicroscale preparation will be followed where all reagents are scaled up by a should be cleaned and dried prior to use. The maleic anhydride should be molecular sieves. factor of five. 1. Weigh and place 850 mg of 3-sulfolene, 450 mg of maleic anhydride and 0.40mL of xylenes in a 10MI round-bottom flask containing a stirring bar and equipped with a water condenser and a drying tube containing anhydrous calcium chloride. Place an insulating aluminum foil sheet around the top of the flask, covering the flask and the sand. Heat the mixture at 150-15SoC for 20 minutes. temperature. 2. Avoid overheating. Cool to room 3. Add 5 mL of toluene and transfer the solution to a 25 ML Erlenmeyer flask. If some of the material in the flask does not dissolve, the flask may need to be heated to dissolve the crystals. Add between 2.5 and 3.5 mL of 65-95% petroleum ether until a slight cloudiness persists. The flask may be heated on the sand bath until it becomes clear and then be allowed to cool to room temperature. Crystals of the product should form. Cool the flask in an ice bath to complete crystallization. The product should be isolated by vacuum filtration using a Hirsh funnel, wash the product with approximately 5mL of cold petroleum ether. The product may be dried by placing it on a clay plate. Weigh the product and calculate the percent yield for your reaction. Determine the melting point of the product and compare your melting point with the literature value. Calculate your percent error for the melting point 4· 5. 6. Take an IR of the product

Explanation / Answer

What is the purpose of this laboratory?

The purpose of this lab to cross-check (validate) the Diel's-Alder reaction and thereby to know the proof of the proposed mechanism.

What am I performing by doing it?

By following the standard protocol (stoichiometric ratio amounts of reactants and reagents from well balanced chemical reaction equation) to prepare the diel's-alder product and by using seperation technique to isolate the product in pure form. Then you have to cross-check whether you really got the right product or not by analytical methods such as crystallizing the product, physical properties such as appearance, melting point. Then you will check how much this scheme will give good amount of product by calculating theoretical yield and percent yield calculations. Finally you will cross-check product structure by using spectroscopic techniques such as NMR, Mass and IR spectra.

In conclusion you are going to validate the Diel's-Alder reaction practically.

Thank You So Much! Please Rate this answer as you wish.

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