Esterification Reactions of Vanillin: The Use of NMR to Solve a Structure Proof Problem1

I. Abstract: 

1. What was the intent of this experiment?

To investigate the esterification of vanillin under both acidic and basic conditions, identify the resulting products using NMR and IR spectroscopy, and propose mechanistic pathways to explain the differences in product formation.

I. Abstract: 

2. What did it utilize & monitor what progress?

Esterification techniques, crystallization, and the use of a Craig tube for recrystallization, along with NMR and IR spectroscopy to monitor the structural confirmation and assess the progress and outcomes of the reactions.

I. Abstract: 

3. What type of reaction was completed?

Esterification reaction, where vanillin reacted with acetic anhydride under both acidic and basic conditions to form ester products.

I. Abstract: 

4. What did this experiment include the use of?

Vanillin, acetic anhydride, sodium hydroxide (base), sulfuric acid (acid), crystallization techniques, a Craig tube for recrystallization, and analytical methods such as NMR and IR spectroscopy for product characterization.

I. Abstract: 

5. What other things where done to identify? What was found/conclusion?

NMR, IR, melting point measurements were conducted to identify and confirm the structures of the esterified products. The experiment concluded that the reaction conditions (acidic vs. basic) significantly influenced the properties and structures of the products.

II. Introduction: 

6. Background Information: What did this experiment rely on understanding to identify?

The experiment relied on an understanding of esterification reactions, phenol reactivity, and the nucleophilic addition reactions of aldehydes

III. Objective: 

7. Was to determine what, with what techniques?

The objective was to determine the products of esterification reactions of vanillin and confirm their structures using IR and NMR spectroscopy. Techniques included crystallization, filtration, and spectroscopy.

IV. Significance:

8. Of this experiment was to enhance our understanding skills on what-therefore strengthen problem solving?

This experiment enhanced skills in organic synthesis, structural determination, and analytical problem-solving through spectral data interpretation

IV. Significance:

9. What materials/methods were used

Preparation of 4-Acetoxy-3-Methoxybenzaldehyde (Vanillyl Acetate)

Vanillin (0.30 g), 10% Sodium Hydroxide (5 mL), Crushed Ice (6 g), Acetic Anhydride (0.8 mL), Rubber Stopper, Hirsch Funnel, Ice-cold Water (three 1-mL portions), Craig Tube, 95% Ethyl Alcohol, Hot Water Bath (60°C), Melting Point Apparatus, Infrared (IR) Spectrometer, Nuclear Magnetic Resonance (NMR) Spectrometer (CDCl3 as solvent)

Esterification of Vanillin in the Presence of Acid

Vanillin (0.15 g), Acetic Anhydride (1.0 mL), Magnetic Spin Vane, 3-mL Conical Vial with Cap, Pasteur Pipette, 1.0M Sulfuric Acid (1 drop), Centrifuge Tube with Screw Cap, Ice-Water Bath, Ice-Cold Water (3.5 mL), Hirsch Funnel, Ice-Cold Water (three 1-mL portions), Craig Tube, 95% Ethanol, Hot Water Bath

IV. Significance:

10. What techniques were used?

Technique 8: Filtration, Technique 11: Crystallization, Technique 25: Infrared Spectroscopy, Technique 26: Nuclear Magnetic Resonance Spectroscopy (Proton NMR)

IV. Significance:

11. What were the general breakdown of the topics of the produce covered?

• Base-promoted esterification: Precipitation and crystallization steps

• Acid-promoted esterification: Color change, cooling, and recrystallization

• Analysis using melting points and spectra

***IV. Significance:

12. Name this step in the procedure given the image below

13. Fill in the bozes for this technique, whats the technique called?

14. There are the key procedures I will take pics of tmrw

V. Data Analysis:

15. What did this experiment’s data demonstrate?

• That it is significant in ensuring the…?

Data demonstrated the importance of reaction conditions in ensuring successful ester formation, affecting yield and product characteristics.

V. Data Analysis:

16. What was accurately determined & used to validate the results?

Melting points, percentage yields, and spectral data were accurately determined and used to validate product structures.

V. Data Analysis:

17. How was data presented & what calculations/equations needed?

Data were presented in tabular form, including melting points and yields. Calculations involved percentage yield and structural verification through chemical shift analysis.

VI. Discussion: 

18. Source of Error: What did observing the successful completion of the RXN indicate?

Observing successful crystallization and reaction completion validated the success of the reaction.

VI. Discussion: 

19. Source of Error: What process validated a successful completion of the experiment?

Proper recrystallization and accurate spectral analysis validated successful product formation.

VI. Discussion: 

20. Source of Error: What measure could be done to avoid source of error?

• Cross contamination from the pipette transfer tolls from introducing foreign substances, being conscious leads to success. 

Cross-contamination from pipettes and introducing foreign substances could be mitigated by maintaining clean apparatus and being meticulous.

VIII. Limitations:

21. What is the greatest limitation we avoided ineffectiveness of?

Incomplete crystallization or poor separation was avoided by careful cooling techniques.

VIII. Limitations:

22. Was there a probability of incompleteness?

• This could have impacted what?

• Importance of being proactive/ conscientious. 

Incomplete crystallization could have impacted yield and product verification, emphasizing the importance of being proactive and conscientious during the experiment.