Question

1. Read about electrophilic aromatic substitutions reactions in general. You need to be familiar with the mechanism. Louden text (if using) Chapter 16 sections 16.4 and 16.5. Ask your lecture professor which chapters this correlates to if you are using a different text.

2. Write the structure, hazards, and molecular weight for all the reactants and products.

Table 1. Chemical Information for Reactants and Products.

Compound	MW (g/mol)	Density (g/mL)	Hazrads
nitric acid	63.01	1.513	corrosive, oxidizer
Sulfuric acid	98.075	1.84	corrosive
toluene	92.14	0.8638	toxic, flammable, explosive
o-nitrotoluene	137.14	1.39	toxic, flammable, carcinogenic
p-nitrotoluene	137.14	1.39	toxic, flammable

Table 2. Chemical Information for Workup Solutions and Solvents.  

Compound	BP (°C)	Density (g/mL)	Purpose	Hazards
Diethyl ether	34.6	0.713	Used to extract the organic layer.	irritant, flammable, explosive
Sodium bicarbonate	N/A	N/A	Used to wash the organic layer.	irritant
Brine	100.17	1.025	Used to wash the organic layer	None

During Lab

Formation of the Electrophile.

NO₂⁺, the electrophile in this reaction is formed from the reaction of sulfuric acid with nitric acid. Essentially the sulfuric acid dehydrates the nitric acid.

Reaction

NO ACETONE WILL BE USED IN THIS LAB. IF YOU USE ACETONE YOU WILL LOSE ALL TA POINTS FOR THE DAY !

1. Make an ice bath in an evaporating dish and place on a magnetic stirrer. Clamp a 25 mL round bottom flask charged with a magnetic stir bar, so it is immersed in the ice water bath (Mostly ice). Attach a Clasien head and set up a condenser on the side arm.
2. Pour 1.0 mL (use a plastic transfer pipet to the 1 mL mark) of concentrated nitric acid (will be 1.413 g) into the round bottom flask. While stirring, slowly add 1.0 mL of concentrated sulfuric acid (use a clean new transfer pipet to the 1 mL mark) will be (1.840 g).
3. After the addition of sulfuric acid is complete, add 1.0 mL of toluene dropwise and very slowly over a period of 5 minutes (slow down if you see boiling. Reaction produces a lot of heat). You will add this through the Clasien adaptor. Keep the reaction on ice and stir for an additional 20 minutes. This reaction is very exothermic and will produce a lot of heat. If NO₂ (Brown Gas) get help immediately from your TA.

Workup

1. Add 10 mL of water to a small separatory funnel. Then transfer the contents of the flask (from step 4) into the funnel. Rinse the contents with 4 mL of diethyl ether and add it to the separatory funnel. Repeat the ether rinsing one more time with a fresh 4 mL portion of ether.
2. Gently shake the contents of the separatory funnel, let settle, and remove the aqueous layer.
3. Wash the organic layer with a 10 mL portion of 10% sodium bicarbonate (shake and VENT due to the formation of gas), and finally, wash it with 5 mL of water. Wash with 10 mL of brine instead of drying with MgSO₄. The brine will remove the water.
4. Discard the aqueous layer and add the organic layer to a tarred round bottom flask.
5. Remove the solvent on the rotovap. and obtain the isolated nitrotoluene.
6. Calculate % yield. Obtain an IR spectrum of the product.

1. When adding sulfuric acid to the nitric acid during the nitration of toluene lab, it is important to keep the solution warm.

                True

                False

2. What should you do if you spill a very small amount of nitric acid?

                Dump acetone on the spilled acid, clean up with a paper towel, and throw the paper towel in the trash.

                Pull the fire alarm and evacuate the building.

                Clean up with a paper towel, thoroughly rinse the paper towel to remove the nitric acid, and then throw the paper towel in the trash.

                Clean up with a paper towel and throw it in the trash.

3. What is the purpose of washing the organic layer with brine?

                To neutralize the solution.

                To remove excess water and ions.

                To stabilize the product.

                To add more ions to the product.

Answer 1

1.Nitration should be done in ice bath. Because the reaction is
exothermic,heat will be released.In order to control heat ice bath
is needed

SO answer is false ***

2)Clean up with a paper towel ,rinse the paper towel to
remove the nitric acid and then throw the paper in the trash***
Acetone cannot be used as it react with HNO3.
  
3) to remove excess water and ions***

Thank you!