Question

Discuss mass spectral feature uniquely characteristic of a compound containing a bromine Discuss mass spectral feature uniquely characteristic of a compound containing a chlorine Discuss mass spectral feature uniquely characteristic of a compound containing an alcohol Within each of the three sets of compounds, alcohols, alkyl bromides, and alkyl chlorides, described any relationships or trends between the intensity of the molecular ion peak or particular fragments and the molecular structure and, based on the chemistry studied in class, proposed a hypothesis to explain these trends

Please answer all but extra focus om the last bulletin point- im having trouble with this stiff and want to be well prepared for my test in two weeks

Answer 1

3) alpha cleavage is observed in both, balogen compounds and alcohols. Halides . M often weak; stronger in aromatic halides chloro and bromo compounds show strong M+2 peaks CI-M: M+2 3:1 Br-M: M+2 1:1 principle fragmentation is loss of halogen • Loss of HX also common . a-cleavage sometimes observed 2. Fragmentation of Alcohols The molecular ion of alcohols is usually small and sometimes undetectable especially in tertiary alcohols. In primary and secondary alcohols, the identification of the molecular ion is complicated by the prevalence of a M- 1] peak caused by the loss of a single hydrogen from the a carbon. Alcohols also frequently cleave to give resonance stabilized cations due to the breaking of the bond (Section 6.6). As a result of this cleavage, primary alcohols show a prominent peak at m/z 31 (Figure 6.13). H=- CH?" + +c=0 m/z 31 The presence of a m/z 31 peak is not confirmation of a primary alcohol. It is necessary for the peak to be relatively large in comparison to other peaks in the spectrum. This is because secondary alcohols and sometimes even tertiary alcohols can undergo a rearrangement resulting in a peak at m/z 31.