Question

I need help calculating theoretical yield for my Diels-Alder lab experiment. This reaction was between 1,3-butadiene and maleic anhydride, forming cis 1,2,3,6-tetrahydrophthalic anhydride. In this experiment 1.0g of maleic anhydride was combined with 1.8g 3-sulfolene and 2 mL dry xylene and refluxed for 30 mins. 6 mL of xylene was added to dissolve solids and then decanted, then warm pet. ether was added to form crystalline product after cooling. some of this info may be irrelevant in what is needed for the calculation but I wanted to be descriptive in case additional info was needed.

PROCEDURE 1. In the hood, carefully grind 1.0 g of maleic anhydride in a mortar and pestle into a fine powder (irritating dust!). 2. Still in the hood, place the anhydride in a clean, dry 50 ml (or 100 mL) round bottom flask. Add 1.88 of 3-sulfolene, 2 mL of dry xylene, and a few boiling stones. 9. In the hood, set up a reflux apparatus. Warm the flask while swirling to dissolve the solids. Then heat the mixture to a gentle reflux, and continue heating for 30 minutes after it is boiling. So, is toxic and foul smelling! light brown son colored Soluton 4. Remain in the hood. Allow the mixture to cool to room temperature, then add about 6 mL of xylene. Gently heat the mixture on a steam bath with swirling to dissolve all of the solid, and decant the clean hot solution to a small beaker, leaving any impurity (brown color) behind. If any solid crystallizes in the flask during this transfer, heat the mixture until the solid redissolves. 5. Remain in the hood. Carefully add warm petroleum ether with a pipet until the solution appears cloudy, and set it aside to cool to room temperature. Wait until most of the product crystallizes before cooling the solution further in an ice bath. If you get only a small amount of product, add more petroleum ether to induce further crystallization. The product dissolves well in xylene but poorly in petroleum ether, so this mixed solvent system is used for recrystallization. 6. Remain in the hood. Collect the solid product by vacuum filtration. Wash the solid 1-2 times with a small amount of cold petroleum ether. If the product shows color (tan, brown, beige, etc.), you need to recrystallize it using warm xylene plus petroleum ether, as above (steps 4 & 5). Transfer the crystals along with the filter paper to a watch glass or evaporating dish and let it air dry overnight (or longer in your drawer. 8. At lab next week, record the weight of the dry product, determine its melting point, and analyze your product by IR and NMR.

attached is the methods for this experiment. I am wondering how to calculate the theoretical yield of cis 1,2,3,6-tetrahydrophthalic anhydride formed from the Diels-Alder reaction.

Answer 1

20 Xylen U (4H O3 M. Mass 116.139|midt mor H Cg Hg 93 152.149 g/mol 98.86g/ml M. Mass of product Theoretical = No. of millmiles X Yield of himmeling Starting material - wt x M. Mass of product M.at " Limmiting reactant in this reaction is Malie anlydside theoretical yield = lg x 152.149 g/mol 98.06 g/mol = 19 x 152.149 98.06 Theonfal = 1.5 Ľ yield - worry un Don't worry about amount of 3- Selfholene taken it is source of Butadiene in the Exn.