1.
Introduction Nitration of methyl benzoate is an example of electrophilic aromatic substitution reaction. Aromatic compounds undergo EAS reactions. The process is the replacement of a hydrogen on the benzene ring with a nitro group. Procedure 1. Prepare an ice bath in a 100 mL breaker on a magnetic stir plate. 2. Pipette (0.20 or 20) mL of methyl benzoate into a clean dry 5 mL conical vial. 3. Add 0.45 mL of concentrated (18 M) sulfuric acid to the methyl benzoate and add a spin vane. 4. Attach an air condenser to the conical flask. (Carefully clamp the apparatus so that the vial is immersed in the ice bath. Begin stirring) 5. Add 0.15 mL of concentrated (18 M) sulfuric acid and 0.15 mL of concentrated (16 M) nitric acid into a clean dry 3 mL small Erlenmeyer flask. Cool this mixture by clamping it into a second ice bath. Using a Pasteur pipette, slowly add the cooled sulfuric-nitric acid mixture to the stirred solution of methv benzoate through the open end of the air condenser. (The addition should take approximately 15 minutes. You must add the nitrating agents slowly. Adding them rapidly increases the amount of by-products and decreases yield.) When all the nitrating agents have been added, carefully remove the ice bath. Continue to stir until the reaction has come to room temperature. 8. Let the reaction flask stand undisturbed for 15 min. 9. Place 2 g of ice in a 30 mL beaker. With a Pasteur pipette, transfer the reaction mixture to the beaker. 10. Rinse the reaction vial with 1 mL of cold water and add the rinse to the beaker. 11. Let the ice in the beaker completely melt. 12. Place a pre-weighed filter paper in the Buchner funnel and vacuum filter the crude crystals. 13. While the crystals are on the filter paper wash it two 1.0 mL, proportions of cold water. 14. Wash the crystals with two 0.3 mL proportions of cold methanol. 15. Dry the product and record the mass. Calculate the percent yield.
II.
Cleanup
Dilute the filtrate from the reaction with water, neutralize with sodium carbonate and flush down the drain. The methanol should be placed in the container for non halogenated waste.
Il.
Reaction This experiment involved the reaction between methyl benzoate and nitric acid, which formed methyl nitrobenzoate. When everything was added to the flask the solution was translucent and a light orange color, which indicated the nitration reaction occurring. The precipitate started to form when ice was added, and the ice was allowed to melt. The solid product was an off-white color. Some of the product was left in the flask
so added very little water to loosen it up and pour it out. The percent yield of the product was calculated and the melting point was obtained Results/Discussion *weight of the filter paper= 0.12g *weight of the watch glass= 50.59g *weight of the filter paper, watch glass, and sample= 51.38g *theoretical yield= 0.218 g 51.38