Researcher

Mark Mangir

Objective

Exp262 yeilded unexpected results, instead of a benzalaniline forming, a carboxylic acid formed. One possible contributing factor is that a 1:2 aldehyde to amine ratio was used instead of the chosen 1:1 ratio. This experiment will synthesize benzalaniline with different ratios of aldehyde to amine in ethanol at 0.2M and 1.18M to test amine effect of concentration. The imine is formed from the reactions of aniline and 4-chlorobenzaldehyde).

Procedure

Weigh equimolar amounts of each aldehyde and amine for sample one, a 1:2 ratio for sample 2, a 1:3 ratio for sample 3, and a 1:1 ratio at a higher molarity for sample 4. Add each aldehyde to its own 20mL test tube. 10mL of ethanol was added to vials1-3, and 6mL of ethanol was added to vial 4. Add the amines dropwise to the aldehyde. Mix until the color is uniform. Let sit over night. Evaporate the solvent, and recrystalize the product in ethanol.

Results

Mass and Yield Calculations

NMR of Sample 1-2011-02-03

NMR of Dried Sample and Wash Solution

Discussion

-The peaks shown in the Dried sample that had been washed with ethanol had the exact peaks expected with the formation of the 4-chlorobenzoic acid, with a trace amount of ethanol. Peaks for the CDCL3 and DMSO-D3 explain the other visible peaks.
-The wash solution has the peaks identifying the product we had expected, as well as the peaks for the acid.
-An extremely small Hemiacetal peak can be seen in the wash solution.

Conclusion

The synthesis of the acid definitely occurs in this reaction, and the desired product was also synthesized in smaller amounts than expected. When the literature was reviewed, the paper used to develop the procedure referenced another paper that indicates our desired product reacts with methanol, so ethanol may not be the proper solvent.


Log

2012-02-01

[put all dates as heading 2 JCB]13:00 Added 0.311g of 4-chlorobenzaldehyde to vials 1,2, and 3, and 0.9931g of 4-chlorobenzaldehyde to vial 4.
13:10 Added 10mL of ethanol to vials1-3, and 6mL of ethanol to vial 4. Sonicated all the sample until all solute was dissolved in 1-3, it will take longer to dissolve vial 4.
13:27 Added 0.23g of aniline to vial 1, mixed by inversion until a pale yellow color was uniform.
13:30 Added 0.46g of aniline to vial 2,mixed by inversion until a pale yellow color was uniform.
13:33 Added 0.70g of aniline to vial 3,mixed by inversion until a pale yellow color was uniform.
14:00 Sample 4 still had not fully dissolved by this point, so it will not be reacted with analine, instead samples will be taken of both the supernatant and the solute portions.

2012-02-03
Took NMR sample of Sample 1. A small portion of the product still in ethanol was added to the NMR tube. CDCl3 was used as the solvent. The NMR was taken on Drexel's 300MHz NMR.

2012-02-20
The sample on the Rotovap finally dried, the impure sample was feathery and orange. A sample was taken and run on the 500MHz NMR in CDCl3.

2012-02-22
13:25 Washed the Orange dried product until all of the color had dissapeared, leaving white crystals. The orange washings were saved.
13:28 The crystals were placed in a vial, covered with parafilm, and a hole punctured in the top. The vial was placed in a desiccator under vacuum.

2012-02-24
13:00 Took and NMR samples of the dried sample that had been in the desiccator and the wash solution that had been used on the 500MHz NMR. The NMR had mantainance performed and the side bands that had been occurring have disappeared. [Name all the NMRs directly in the log - specify briefly how processed also JCB]