CHM 1321 Lecture Notes - Lecture 6: Acetanilide, Regioselectivity, Nitric Acid

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Experiment 6: Regioselective Nitration of Acetanilide

Date Performed: March 30, 2106

Date Submitted: April 6, 2016

Alexa Kim

8181530

Partner: Meghan Chapados

8223004

TA: Chris Demone

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Procedure:

Refer to the procedure from the lab manual form page 53-54 of “Experiment 6:

Regioselective Nitration of Acetanilide”

Reaction Mechanism:

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Observations:

Creating the Reaction Mixture:

•Acetanilide is a solid product that is made up of light brown ﬂakes

•Sulphuric acid is a clear and colourless solution

•Nitric acid is a clear and colourless solution

•When the acetanilide started mixing with the sulphuric acid the mixture turned to a

clear, light brown solution

•When the acid mixture was added to the ﬂask the solution turned to a dark brown

colour

Isolation of Crude Product:

•When the reaction mixture was added to the icy water the solution turned to a bright

yellow colour

•After completing the suction ﬁltration a yellow chalky product was formed

Recrystallization:

•When the crude product was dissolved in the boiling ethanol a clear, yellow-brown

mixture formed

•When the solution was set to cool after a little while a yellow product formed

•After completing the suction ﬁltration a yellow chalky product was formed

Results:

Table 1: Table of Reagents

Reagent

MW (g/mol)

Amount (g or mL)

Density (g/mL)

Moles (mmol)

Acetanilide

135.17

1.0 g

1.12

7.40

Sulphuric Acid

98.08

6.2 mL

1.84

34.3

Nitric Acid

63.01

0.9 mL

1.42

20.3

Table 2: Quantitative Data of Puriﬁed Product

Starting Mass

1.33 g

Final Mass

1.2 g

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CHM 1321 Full Course Notes

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Refer to the procedure from the lab manual form page 53-54 of experiment 6: Isolation of crude product: when the reaction mixture was added to the icy water the solution turned to a bright yellow colour, after completing the suction ltration a yellow chalky product was formed. Table 5: ratios of ortho, para, meta and dinitro. Therefore there is an average ratio of 1:60:16:23 of the meta isomer, ortho isomer, para isomer and the dinitro in the mixture respectively. Screenshot of the peak areas used in the calculation to nd the percentage areas. Screenshot of the graph used to nd the areas. Theoretical yield of isomers = 0. 00740 mol (180. 16 g/mol) Theoretical yield of benzoic acid = 1. 33 g. Percentage yield = (actual yield / theoretical yield) x 100. Therefore the percentage yield of the puri ed product is 90. 2% Calculation of the percentage area of the ortho isomer in the crude product:

Related Questions

This is the only info I get

Organic Chemistry Laboratory II EXPERIMENTAL PROCEDURE . Borrow a stir bar from the instructor 2. Place 3.3 g of acetanilide into a 125-mL Erlenmeyer flask and then add 5 is of p-Nitroacetanilide mL of glacial (concentrated) acetic acid (CAUTION: strong irritant). Warm the flask on a hot plate in the hood until the acetanilide dissolves. Cool the flask in an ice bath to about 20Â°C; then add 5 mL of cold, concentrated sulfuric acid. The temperature of the mixture will rise to about 60Â°C. Chill the solution to about 10Â°C in an ice bath. (The solution may become very viscous.) 3. Mix 1.8 mL of concentrated nitric acid and 2.5 mL of concentrated sulfuric acid in a 50-mL Erlenmeyer flask (CAUTION: Use extreme care when preparing this nitrating mixture), and chill the flask in an ice bath for~4 minutes 4. When both solutions are cold, slowly add the nitrating mixture, 1 mL at a time, to the constantly stirred acetanilide solution. Keep the reaction flask in an ice bath so that the temperature of the reaction mixture is maintained between 10 - 20Â°C. The entire addition requires about 15 minutes. 5. After the addition is completed, allow the reaction to proceed at room temperature for 30 minutes (keep the stirrer going). Monitor the temperature; if it rises above 30Â°C, chill the flask in an ice bath to just below 30Â°C. Should the re-chilling be necessary, allow the reaction to proceed for an additional 10 minutes. 6. Pour the reaction mixture into a 250-mL beaker containing 50 mL of water and about 15 g of cracked ice. Stir the mixture for a minute or so during this time a light yellow solid should form. [If a white solid forms, then you have recovered unreacted acetanilide. If a dark yellow or yellow-orange solid is recovered, then the product has undergone hydrolysis. Should any of these two things occur, you must start the reaction all over again - consult with your instructor if you are unsure about the color.] 7. Vacuum filter the solution. Press down on the light yellow solid with a clean 50 mL beaker or Erlenmeyer flask to remove as much of the aqueous solution as possible. (CAUTION: Nitro compounds are toxic and can be absorbed through the skin.)

This is the description from my organic chemistry lab.

Lab Observations and Data

We obtained 1.17g of cyclohexene oxide (clear liquid) and 3 mL of water into a 50 mL flask with a stir bar. When added a single drop of sulfuric acid, the clear liquid started to change to a very, very light yellow/brownish color. We obtained an ice bath on the side in case our mixture started to boil. After the solution stirred for about 25 minutes, we added sodium hydroxide. We inserted a pH paper and it turned a dark blue, meaning basic. Added another drop of sulfuric acid to make it a little less basic. Added the mixture to a separation funnel, shook it around and ended with separated layers. We separated the layers, thinking the bottom layer was the organic layer, when it was really the aqueous layer. So we ended up mixing the wrong layers back together. After some error, we isolated our new organic layer and added some drying agent. We then put that mixture with the drying agent, NaOH, into the rotovap. Our final product was a white powder and weighed 1.51 grams. We then set up a vacuum filtration while boiling water. We boiled our dried organic layer into the hexane. Added two drops of ethyl acetate to help the boiling process go faster. After vacuum filtering it, it weighed .394 grams. The melting point is 91 to 93 degrees Celsius. Our IR spectra matches the "trans" conformation. So for our TLC plate we observed blue dots to match the trans conformation.

The question is "calculate your percent yield" Which is actual yield/theoretical yield x 100. I just dont understand how I get those numbers.

Here is the lab manual description as well.

Procedure for the Preparation of 1,2-Cyclohexanediol Place a mixture of 1.18 g (0.012 mole) of cyclohexene oxide and 3 mL water into a 50 mL Erlenmeyer flask, equipped with a magnetic stir bar. To this mixture with vigorous stirring add one drop of 6 M sulfuric acid (33% H2SO4) Caution: After a short incubation time, the reaction mixture will become quite warm. This epoxide ring opening reaction is very exothermic. (Why?) If the reaction mixture begins to boil, place the flask in a bath of ice and water. Allow the reaction mixture to stir for the next 15 minutes and let it cool to room temperature. Afterwards, add a small amount of 10% sodium hydroxide drop-wise to neutralize the stirring solution. (No more than 3 or 4 drops of 10% NaOH should be necessary.) Place a drop of the reaction mixture on pH paper to check the pH. Extract the product from the reaction mixture into ethyl acetate or diethyl ether (2 x 15 mL). Dry the combined extracts over sodium sulfate. Decant the solution and remove the solvent to yield the crude product (~1 g). The product can be purified by recrystallization from a small amount (~ 5 mL) of hot toluene or hexanes. Collection of the purified product by suction filtration yields 1,2-cyclohexanediol. The cis isomer has a melting point of 97-101 Â°C whereas the trans isomer melts at 101-103 Â°C. Determine the product(s) or products the reaction. Include a percent yield calculation in your report along with the results of your TLC analysis

Miniscale nitration of methyl benzoate was performed in the lab:

Procedure below:

1. Prepare and ice bath in a 100mL beaker on a magnetic stir plate.

2. To a clean, dry 25 mL Erlenmeyer flask, add 1.0 mL of methyl benzoate via pipet.

3. Calculate the mass of methyl benzoate.

4. To the methyl benzoate, add 2.25 mL of concentrated (18M) sulfuric acid and a spin bar.

5. Carefully clamp the flask so that it is immersed in the ice bath and begin stirring.

6. Prepare the nitrating solution by adding 0.75mL of concentrated (18M) sulfuric acid and 0.75mL of concentrated (16M) nitric acid to a clean, dry vial.

7. Cool the mixture in a second ice bath.

8. With a Pasteur pipet, slowly add the cooled sulfuric acid-nitric acid solution to the stirred solution of methyl benzoate. *Addition should take approximately 15 minutes. Adding the nitrating agent more rapidly will increase the amount of by-products and decrease the yield

9. After all of the nitrating agent has been added, carefully remove the ice bath.

10. Continue stirring until the reaction has come to room temperature.

11. Then let the reaction flask stand undisturbed for 15 minutes.

12. Place 10 g of ice in a 100mL beaker.

13. With a Pasteur pipet, carefully transfer the reaction mixture to the beaker.

14. Rinse the flask with 5mL of cold water.

15. When the ice has melted, vacuum filter the crude crystals using a Buchner funnel.

16. Wash the crystals with 2 5mL portions of cold water and finally with 2 1.5mL of cold methanol.

17. The crude product can be recrystallized from methanol.

18. Record the mass of the dry product and calculate the yield.

QUESTION: What is the major product formed in this reaction? Justify your reasoning..

CHM 1321 Lecture Notes - Lecture 6: Acetanilide, Regioselectivity, Nitric Acid

CHM 1321 Full Course Notes

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