Asasignment
Lab Report: Multi-Step Synthesis Part I and Part II: Electrophilic aromatic substitution of benzoic acid to produce m-nitrobenzoic acid; Fisher Esterification of m-nitrobenzoic acid to produce methyl m- nitrobenzoate
Lab Report Part I:
Goals: The goal of this experiment is to produce m-nitrobenzioc acid from benzoic acid via electrophilic aromatic substitution. We are using a nitrating mixture and a reaction mixture to conduct this experiment. in order to continue to the second part of the experiment, we will need to obtain m-nitrobenzioc acid.
Procedure changes:
Changes that were made: We used 1.5 grams of Benzioc Acid.
1. Prepare nitration mixture by slowing adding H2SO4 to concentrated HNO3.
2. Cool in Erlenmeyer flask to 0 degrees C or less.
3. Prepare reaction mixture
4. Add concentrated H2SO4 to flask
5. Add benzoic acid slowly to H2SO4 and making sure that the temperature remains below 0 deg. C. 6. when the benzoic acid is all added, there should be a paste like consistency.
7. Obtain a shirt pipette and transfer the chemical compound.
8. Make sure that this reaction remains under 0 deg. C.
9. Allow the mixture to cool for 10-15 minutes with occasional stirring.
10. Pour the mixture over ice/water slurry.
11. Stir vigorously and allow product to precipitate.
12. Filter the product via vacuum filtration.
13. Wash with cold water and dry the precipitate.
14. Obtain mass and calculate the theatrical yield, percent yield, MP, IR and or NMR.
Discussion: Discussion is dissertative. Use "It" instead of "I, She/He" when writing the discussion.Your discussion shall explain (not necessarily in the sequence below):
- What is aromatic substitution? What is the characteristic mechanism for aromatic substitution?
- What is the electrophile and the nucleophile species in the nitration of aromatic substitution reactions?
- How activating groups and deactivating groups affect the reactivity of aromatic compounds? How activating and deactivating groups direct the incoming substituent into the ortho, para or meta position of the ring? What is the role played by of carboxylic acid in benzoic acid?
- What is the function of nitrating mixture?
- Why temperature must be controlled in this reaction?
- Summarize your MP findings. Is your product pure? (DO NOT FORGET TO CORRECT TEMPERATURE, KEEP YOUR ORIGINAL MP RECORD AND YOUR CORRECT MP IN MIND WHEN DISCUSSING YOUR DATA)
- Analyze your 1H-NMR. Does your spectrum support your MP data?
- Would you expect that your 1H-NMR can differentiate between pure o-nitrobenzoic acid, m- nitrobenzoic acid and p-nitrobenzoic acid?
- What is the yield for the reaction? Is this a real yield for the reaction (if your product is impure, part of the mass you are calculating is not product of interest).
- Discuss the problems you faced in this experiment; what did you learned and what would you do different?
- Conclusion: what is your conclusion (what did you learned from your experiment?). Be sure your conclusion will correlate the goals you have for your experiment. It is fine to break your conclusion in parts.
Part II
Multi-step synthesis part II: Fisher Esterification of m-nitrobenzoic acid to produce methyl m- nitrobenzoate;
Date Performed:
Laboratory Partners: Shahad Ahallaza and Kris Patika
Goals: The goal of this experiment is to producemethyl-m-nitrobenzoate from m-nitrobenzoic acid via Fisher Esterification. The ester product will be formed alongside water. We are also learning about the esterification reaction.
Procedure change:
1. In a round bottom flask, add 1.5 g of completely dry m-nitrobenzioc acid, 12 mL methanol, 0.6 mL H2SO4 and a couple boiling stones.
2. Reflux for one hour and then allow time to cool.
3. Pour mixture into ic/water slurry which should be about 60 mL.
4. Make sure to stir vigorously.
5. Isolate the product via suction filtration and rinse with water.
6. Slowly add boiling methanol to solid product.
7. Stir until all the solid product has been completely dissolved.
8. Bring mixture to room temperature via an ice bath.
9. Filter and wash with cold methanol.
10. Dry crystals.
11. Calculate melting point and HNMR.
Results: Report all of your data acquired here, no data discussion. Use the data collected during your experiment; they will be compared to the data you left behind for your TAs. Report all your data in a clear way. Report the MP for your product; Include a copy of your recorded IR and 1H-NMR spectra, For the 1H- NMR, mark sets of peaks and relate to peaks in molecule o methyl -m-nitrobenzoate, but DO NOT DISCUSS YOUR NMR here!. When using tables and graphs need legend; be clear on which calculations you are showing and what your numbers represent. Any chemical structure must be done using ChemDraw or it will not be given credit.
Discussion:
Which carbonyl compounds belong to class I carbonyl compounds and which carbonyl compounds belong to class II compounds- What is the characteristic reaction mechanism for each of the carbonyl class compounds?
- What is Fisher Esterification? What is the function of the acid in this reaction?
- Summarize your MP data. Compare your values (original recording and corrected) to the real MP for methyl-m-nitrobenzoate and indicate if your product is or not pure.
- Would 1H-NMR be able to indicate if your final reaction product is impure with m-nitrobenzoic acid (or benzoic acid from your first reaction?).
- Analyze your 1H-NMR. Does your data reinforce your MP data?
- What can be said of your reaction yield? What can be said of your multi-step reaction yield- Is this a real yield- If not, what do you think it needs to be done for calculating the real yield?
- Discuss the problems you faced in this experiment, specially the ones that can affect your yield; what did you learned and what would you do different?
References:
Bruice, P. Y. Organic chemistry, 7th ed.; Pearson: Upper Saddle River, NJ, 2014
Pedersen, S.; Myers, A.; Gilbert, J.C.; Martin, S.F.; Williamson, K.L.; Masters, K.M.; Hill, N.; Esselman, B.; Organic Chemistry lab I/ II; (Chem lab 336/337); Custom Edition For Cleveland State University; Cengage Learning; 2015; ISBN:1-305-76438-2.
Attachment:- Lab_Details_and_Report.rar