Organic 2 Lab Report

6389 WordsSep 30, 201226 Pages
Exp.11) Identification of unknown ketones. Introduction: Given five samples of a known ketone derivative, the purpose of this experiment is to identify which unknown ketone derivative corresponds to the five known samples. In other words, using specific methods of compound detection, it is possible to match an unknown compound with a known compound because similar compounds will display similar characteristics. In this experiment, identification of the unknown ketone is accomplished through thin layer chromatography, melting point, and 1H-NMR spectroscopy. The unknown ketone is from a homologous series of methyl ketones. CH3CO (CH2) nCH3 The first step in the lab is the preparation of the solvent used in the developing chamber for thin…show more content…
As mentioned in the introduction, a sample of the unknown is placed in the spectrometer, more specifically, in the midst of a magnetic field.[1] To conclude, it is evident from the Rf values obtained that unknown # 3 Rf is closest to that of 2 – Octanone. With a 7.2 % error, this can be due to the reagent being diluted with too much ethanol or still containing traces of the acid, however if traces of the acid are present then the melting point[3] should be significantly lower. From the melting points we can determine that unknown # 3’s melting point is closest to that of 2 – Octanone with an 8.6% error. This can be attributed by either the unknown being diluted with too much ethanol and water or the mixture containing traces of acid. However, as aforementioned, traces of acid would only lower the melting point not raise it, therefore it is unlikely that traces of acid can be attributed to the error.[3] From the H NMR spectrum, integration suggests that at 1.9 and 2.25 there is some indication of possible ketone fragments. 1H-NMR Spectra for 2-octanone: [5] 2-Octanone’s structure contains a hydrocarbon chain therefore the spectrum has indicated the presence of methyl groups giving further evidence that the unknown is in fact 2-Octanone. To conclude, TLC, melting point
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