ethers-discussion

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Group 1

As mentioned in the "Procedure" and "Results" sections, we had several difficulties with this lab. First, during reflux of our reaction (chloroacetic acid with phenol and NaOH), the temperature raised rapidly to close to 200 degrees C. We attempted to cool the reaction down, but this high temperature may have caused a slight loss in some of the reactants necessary for the reaction. For example, the boiling point of chloroacetic acid is 189.3 degrees C. Although the reflux system condenses the vapors that are created from boiling and heating of reactants, some of the chloroacetic acid could have escaped from the top of the apparatus. The chloroacetic acid was used with phenol in a 1 mol phenol : 1.5 mol chloroacetic acid. These molar values were determined based upon the study by Lin et al. (2004). If the molar ratios were disturbed due to loss of one of the reactants, the reaction may not have produced a high yield of product.

The refluxed reaction was acidified with HCl to protonate the phenoxyacetate ion product. However, when we tested the pH of the reaction after adding only 1 mL HCl, it was already below 3. This may have meant that we still had a lot of unreacted acidic reagents (e.g. the chloroacetic acid or the phenol) that was making the solution so acidic. Even after further acidification, only a very small amount of precipitate was observed. The next week in lab, the solution was put on ice and scratched, but still no precipitate formed. Solvent extraction was started, but only one round was completed. The reaction between whatever product of our reaction was present and the NaHCO3 was very strong with a high concentration of CO2 being produced, and the separatory funnel exploded even after venting. We lost all product except for the aqueous layer from the first round of extraction. This layer was boiled at a low temperature to remove any remaining ether and to cut the volume in half. The product was stored until the next week. Again, no crystals/precipitate had formed.

During the final week of lab, we were going to boil off even more of the aqueous layer and then put the product on ice crystallize. However, as I was bringing the product over to the lab station, it dropped and all product was lost. This was very disappointing after all of the work that had been done to crystallize our product. Of course mistakes happen in research labs, but it still was not what we had expected. For this reason, it is unknown whether or not our initial reaction was successful.

Group 2

Several attempts were made to create a KBr pellet of my product so that I could get an IR spectrum. Unfortunately, I was unable to create a pellet that would work successfully. Luckily, I was able to get an HNMR spectrum. I am not sure how accurate my HNMR spectrum that I obtained is however because there was no HNMR spectrum available for my product on the SDBS database. According to the structure of my product, there should be six signals present on the spectrum. The spectrum I obtained in lab (Figure 1) shows six signals. There appears to be a quartet around 6.5-7 ppm. This is most likely the signal from the 3 hydrogens on the aromatic ring. The singlet at 4.7 ppm is probably the hydrogen located on the -OH group. The methyl group located on the ring the signal located near 1.0 ppm. The -CH group on the ring should appear as a septet around 1.3 ppm, but I do not see a septet present on my HNMR spectrum. The septet may be present, but simply is not visible on Figure 1. Lastly, I the hydrogens located on the methyl groups attached to the -CH are most likely represented by the signal at 1.3. It is also possible that the sample could have been contaminated with acetone or another substance which would have altered my results.