The purpose of this lab was to separate unknown compound 204, composed of an amine, a carboxylic acid, and a neutral component, into each of its three respective states. The unknown compound was separated using microscale separation of acidic, basic, and neutral components by liquid/liquid extraction. Liquid/liquid extraction is a very common method often used in work-ups and allows for isolation of neutral components using acid/base chemistry; this method is extremely helpful in separating reactants and products of a synthesis. The components were purified and dried by evaporation and vacuum filtration. The separated compounds were then classified by determination of their melting points and 1H NMR.
Results and Discussion In this …show more content…
The amine was initially classified as 4’-aminoacetophenone from the melting point. An experimental melting point of 101.4-104.8 C was determined for the amine component and was closer to 103-107 C melting point for 4’-aminoacetophenone provided in the Lab Guide. This melting point determination was also very close to the 3’-aminoacetophenone melting point range (94-98 C), therefore a 1H NMR was taken as well to confirm the components classification. From the NMR it was determined that the compound was 4’-aminoacetophenone since only a para substituted aromatic ring could produce two doublets, as is shown on the 1H NMR. 3’-aminoacetophenone would have projected a singlet, two doublets, and a triplet for the aromatic region which was not present in the 1H NMR. All other components of the 1H NMR, such as the 2.4 PPM ketone methyl group would be the same for both 3’-aminoacetophenone and 4’-aminoacetophenone, but the aromatic region (6-8 PPM) determined the correct …show more content…
This very low amount of benzoic acid recovered could have been caused by a number of possibilities. Some of the components may have been lost throughout the extraction process, some of the component may have stuck to the inside of the reaction tube or the filter paper used in vacuum extraction, or may have been human error in recording the masses. In all of these occurrences may have contributed to the recovery loss of benzoic acid.
Conclusions Overall, all three components benzoic acid, 4’-acetylbenzonitrile, and 4’-aminoacetophenone were recovered in very pure forms as melting point determinations and 1H NMR analyses were very clear and did not experience many shifts or deviations from what was to be expected. However, they were obtained in very low recovery rates, 24%, 25%, and 40% respectively, and better measures should be taken to prevent loss of recovery. Errors in extraction and isolation could be at fault and human error in measurements may be to blame as