The goal of this experiment was to isolate three different molecules (acidic, basic, and neutral) from a mixture and identify their molecular structure. This was accomplished by using acid/base liquid extraction and H NMR analysis. The neutral component of the unknown mixture #191 was fluorenone. This was evident due to an H NMR spectra that had a high presence of hydrogen signals in the 7.2- 7.7 ppm range. Chemical shift values for fluorenone stated in the lab manual were 7.27, 7.47, 7.48, and 7.6 (CITE), indicating that the corresponding H NMR spectra for the neutral unknown is of this chemical. The other possibility for the unknown neutral, 1,4-dimehtoxybenzone, would have had an H NMR spectra with two peaks; however, the spectra obtained did not show chemical shifts for an aromatic ester group and had many hydrogens in the aromatic …show more content…
When comparing the neutral unknown to the unknown mixture, there is a prevalent overlap in the aromatic hydrogen ppm range, presenting a distinct correlation between my isolated neutral and the mixture containing this chemical. Another indicator that was used to determine the identity of this neutral chemical was the melting range, which was tested to be 68.7 C to 71.5 C. The literature value for fluorenone is 80 C to 83 C (CITE), indicating that my compound was slightly contaminated. However, the melting point range for 1,4-dimehtoxybenzone is 57 C, and therefore, it can be concluded that the neutral compound isolated was indeed fluorenone. The contamination that caused this depression in melting point was likely due to acetone, which appeared on the H NMR spectra. Also, when weighing the watch glass after evaporating the ether the yield was not as high as predicted. Upon removing the fluorenone from the watch glass and re-weighing, a much more reasonable yield of 52 mg or 52% recovery was obtained. This discrepancy in weighing led to