EAS: Nitration Electrophilic aromatic substitution is a broad category of reactions capable of adding various substituen

[answerhappygod]

Eas Nitration Electrophilic Aromatic Substitution Is A Broad Category Of Reactions Capable Of Adding Various Substituen 1 (55.07 KiB) Viewed 43 times

Eas Nitration Electrophilic Aromatic Substitution Is A Broad Category Of Reactions Capable Of Adding Various Substituen 2 (55.07 KiB) Viewed 43 times

Eas Nitration Electrophilic Aromatic Substitution Is A Broad Category Of Reactions Capable Of Adding Various Substituen 3 (28.85 KiB) Viewed 43 times

EAS: Nitration Electrophilic aromatic substitution is a broad category of reactions capable of adding various substituents to benzene cores. In general, a hydrogen atom on a benzene ring is replaced by an electrophilic intermediate. Nitration is an example of an EAS reaction which installs a nitrogen atom directly on the benzene core. Substituted benzenes exhibit regioselectivity when subject to EAS reactions depending on the substituent already in place. Goal In this experiment methyl benzoate will be nitrated using a mixture of concentrated nitric and concentrated sulfuric acids. A mixture of products (ortho, meta and para isomers) will form with one constituting the major product regioselectively. Analysis of the purified product will enable the determination of which product has formed. OMe methylbenzoate concHNO, conc H₂SO, NO₂ methylnitrobenzoate mportho mp meta mp para Experimental 1. Obtain a long test tube and a magnetic stir bar. Add 1.0 mL of concentrated HSO to the test tube and place into an ice bath. Note: an effective ice bath is made by adding ice to a beaker to 2/3 full and just barely covering the ice with cold water. This will get the temperature as close to 0°C as possible. Allow the acid to cool for 5 minutes. 2. Obtain a smaller, graduated test tube and combine approximately 0.25 mL of concentrated HNO, and 0.25 mL of concentrated H;SO, and homogenize using a Pasteur pipette. Place this mixture in the ice bath as well. 3. Using a syringe add 0.5 mL of methyl benzoate to the test tube and stir using the stir plate so the mixture is homogeneous. Allow 5 minutes for the mixture to cool to 0°C. Note: as steps 1-3 are conducted the ice bath will begin to melt and the temperature will rise. It will be necessary to remove some of the water and replace it with fresh ice to keep the temperature as close to 0°C as possible. 4. Begin adding the 1:1 concentrated HNO/HSO mixture to the test tube containing the methyl benzoate at a rate of 1 drop every 30 seconds. This keeps the temperature of the reaction as low as possible. 5. After all of the acid mixture has been added, remove the test tube from the ice bath and allow it to come to room temperature while stirring the contents. Stir the reaction for 15 minutes once at room temperature. 6. Obtain approximately 2.5 g of crushed ice and add it to the flask to quench the reaction and encourage crystallization of the product. Continue to stir the reaction until all of the ice has melted. 7. Isolate the crude product using vacuum fitration with a Hirsch funnel 8. Recrystallize the product from methanol. a. Transfer the crude product to a 10 mL Erlenmeyer flask b. With gentle heating dissolve the solid in a minimum amount of methanol. Be careful to not evaporate the methanol as the product should be in solution. c. Once dissolved remove the flask from the hot plate and place on the bench to cool. d. When the flask has reached room temperature, place the flask into an ice bath to complete the recrystallization process. e Collect the purified product using vacuum filtration with a Hirsch funnel and rinse with a small amount of ice-cold methanol. 1. Allow the vacuum to draw air across the crystals drying them in the funnel 9. Obtain mass and melting point data for the purified product. 10.Submit your product for HNMR analysis.

Data Table for EAS: Nitration Mass of methyl benzoate (show calc) Theoretical Yield of methyl nitrobenzoate (show calc) Mass of purified methyl nitrobenzoate Melting Point of purified methyl nitrobenzoate % Yield of purified methyl nitrobenzoate (show calc) Identity and structure of product 0.1529 74°C Using the ¹HNMR spectrum assign the signals that correspond to your product.