Friedel-Crafts Alkylation Of P-Xylene

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The objective of this experiment was to conduct the Friedel-Crafts Alkylation of p-xylene. This reaction substituted an alkyl group instead of a hydrogen atom on the aromatic ring. The compound used was p-xylene, the reactant was n-propyl chloride, and the Lewis acid catalyst was aluminum chloride. The products consisted of the group of n-propyl that combined with p-xylene to form 1,4 Dimethyl-2-propylbenzene, and the group of isopropyl that combined with p-xylene to form 2-isopropyl-1,4-dimethylbenzene

The good symmetry in para-xylene, makes all of the hydrogen atoms equivalent. As such, if any hydrogen atom is substituted with an alkyl group, it leads to a similar alkylated product. The reaction is electrophilic substitution in which …show more content…

The base peak is generally not the same as the molecular ion peak. The base peak is the peak with the greatest intensity and corresponds to the ion that is found in most abundance. The molecular ion peak should be the tallest and most intense, but most of the times this does not happen. This is because in organic compounds, the intensity diminishes due to branching and accumulating mass in homologous series. In addition, if there are no heavy isotopes, the peak for M+ should be the heaviest. However, this is not the case for most compounds because there may be other peaks with m/z ratios higher than the molecular ion peak because of isotope distributions. The tallest and highest intensity peak is called the base peak, and as discussed, may not be the molecular ion. If the molecular ion peak can be identified in the mass spectrum, the molecular weight of the unknown substance can be …show more content…

Given that the shapes of the peaks are not ideal, they are different from the percentage height for each component. As such, the area measurement is used, to determine the concentration. For the first peak, the percent area of total was 49.65% and for the second peak, the percent area of the total was 50.35%, which reflects the quantity of the analyte that exists in the chromatogram. The retention time in both cases is constant and the pattern of peaks is constant which reflects that the conditions of testing are constant. Based on the percentages it can be seen that the major product was 2-isopropyl-1,4-dimethylbenzene at 50.35% and the minor product was 1,4-Dimethyl-2-propylbenzene at 49.65%. Therefore, on Figures 2 and 3 the peak at 2.93 is the major peak and it represents 2-isopropyl-1,4-dimethylbenzene and the peak at 2.58 is the minor peak and represents

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