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
The percent yield of products that was calculated for this reaction was about 81.2%, fairly less pure than the previous product but still decently pure. A carbon NMR and H NMR were produced and used to identify the inequivalent carbons and hydrogens of the product. There were 9 constitutionally inequivalent carbons and potentially 4,5, or 6 constitutionally inequivalent hydrogens. On the H NMR there are 5 peaks, but at a closer inspection of the product, it seems there is only 4 constitutionally inequivalent hydrogens because of the symmetry held by the product and of this H’s. However, expansion of the peaks around the aromatic region on the NMR show 3 peaks, which was suppose to be only 2 peaks. In between the peaks is a peak from the solvent, xylene, that was used, which may account to for this discrepancy in the NMR. Furthermore, the product may have not been fully dissolved or was contaminated, leading to distortion (a splitting) of the peaks. The 2 peaks further down the spectrum were distinguished from two H’s, HF and HE, based off of shielding affects. The HF was closer to the O, so it experienced more of an up field shift than HE. On the C NMR, there are 9 constitutionally inequivalent carbons. A CNMR Peak Position for Typical Functional Group table was consulted to assign the carbons to their corresponding peaks. The carbonyl carbon, C1, is the farthest up field, while the carbons on the benzene ring are in the 120-140 ppm region. The sp3 hybridized carbon, C2 and C3, are the lowest on the spectrum. This reaction verifies the statement, ”Measurements have shown that while naphthalene and benzene both are considered especially stable due to their aromaticity, benzene is significantly more stable than naphthalene.” As seen in the reaction, the benzene ring is left untouched and only the naphthalene is involved in the reaction with maleic
The positive charge on the phosphorus atom is a strong EWG (electron-withdrawing group), which will trigger the adjacent carbon as a weak acid. 5 Very strong bases are required for deprotonation such as an alkyl lithium, however in this experiment 50% sodium hydroxide was used as reiterated. Lastly, the reaction between ylide and aldehyde/ketone produces alkene. (Eq. 1) As shown in equation 2, the reaction between the phosphonium salt and the sodium hydroxide produces the ylide/carbanion that is stabilized due to the positive charge on phosphorus and the conjugation that occurs in the benzene ring as shown by the structure B in equation 2.
benzaldehyde to synthesize after protonation into diphenylmethanol which is a secondary alcohol. This reaction takes place due to the nucleophilic carbonyl group
A weak peak was at a position between 1600-1620 cm-1 can also be seem in the IR, which was likely to be aromatic C=C functional group that was from two benzene rings attached to alkynes. On the other hand, the IR spectrum of the experimental diphenylacetylene resulted in 4 peaks. The first peak was strong and broad at the position of 3359.26 cm-1, which was most likely to be OH bond. The OH bond appeared in the spectrum because of the residue left from ethanol that was used to clean the product at the end of recrystallization process. It might also be from the water that was trapped in the crystal since the solution was put in ice bath during the recrystallization process. The second peak was weak, but sharp. It was at the position of 3062.93 cm-1, which indicated that C-H (sp2) was presence in the compound. The group was likely from the C-H bonds in the benzene ring attached to the alkyne. The remaining peaks were weak and at positions of 1637.48 and 1599.15 cm-1, respectively. This showed that the compound had aromatic C=C function groups, which was from the benzene rings. Overall, by looking at the functional groups presented in the compound, one can assume that the compound consisted of diphenylacetelene and ethanol or
The purpose of the lab is to figure the concentration of the unknown solution by using the equation of the coordination curve formed by the absorbance of the solution of known
The Sandmeyer reaction is a versatile means of replacing the amine group of a primary aromatic amine with a number of different substituents.
This fits with the Diels-Alder reaction taking place a... ... middle of paper ... ... teraction of the HOMO of the diene and the LUMO of the dienophile. This reaction was done at relatively low temperatures as the dry ether has a boiling point of 34.6 °C. At low temperature the endo preference predominates unless there is extreme steric hindrance, which in this case there is not.
The spots moved 3.8cm, 2.3cm, 2.1cm, 1.8cm, and 2.5 cm, for the methyl benzoate, crude product, mother liquor, recrystallized product, and isomeric mixture, respectively. The Rf values were determined to be.475,.2875,.2625,.225, and.3125, for the methyl benzoate, crude product, mother liquor, recrystallized product, and isomeric mixture, respectively. Electron releasing groups (ERG) activate electrophilic substitution, and make the ortho and para positions negative, and are called ortho para directors. In these reactions, the ortho and para products will be created in a much greater abundance. Electron Withdrawing groups (EWG) make the ortho and para positions positive.
Reacting 1-butanol produced 2-trans-butene as the major product. 1-butanol produces three different products instead of the predicted one because of carbocation rearrangement. Because of the presence of a strong acid this reaction will undergo E1 Saytzeff, which produces the more substituted
Before using ethylene to produce polyethylene, the compound needs to be purified to almost 100%. In order to reach this level of purity the ethylene needs to be freed of olefins, acetylenes, dienes and water through several processes such as: driers are used to take out the water, a demethanizer is used to remove methane, etc. ...
In a small reaction tube, the tetraphenylcyclopentadienone (0.110 g, 0.28 mmol) was added into the dimethyl acetylene dicarboxylate (0.1 mL) and nitrobenzene (1 mL) along with a boiling stick. The color of the mixed solution was purple. The solution was then heated to reflux until it turned into a tan color. After the color change has occurred, ethanol (3 mL) was stirred into the small reaction tube. After that, the small reaction tube was placed in an ice bath until the solid was formed at the bottom of the tube. Then, the solution with the precipitate was filtered through vacuum filtration and washed with ethanol. The precipitate then was dried and weighed. The final product was dimethyl tertraphenylpthalate (0.086 g, 0.172mmol, 61.42%).
It could have been lower than 100% because some product was lost during the recrystallization process, or due to an incorrect separation of the impurities when cooling the mixtures. The melting point data confirmed that the synthesized crystals were likely identical to the methoxybenzyl phenol ether because the mixed melting point was the same as the purified crystals. If the products were different or the synthesized product had to many impurities in it then the mixed melting point would have been lower than that of just the crystals, by themselves. The TLC made sense, after looking at the TLC plates under UV light and the calculation of the Rf values, it was confirmed that the 4- Methoxy-phenol was present in the unknown.
Toluene hydrodealkylation process is irreversible process and requires catalyst. The catalyst used in this process consist of molybdenum oxides or chromium, platinum oxides or platinum, silica or alumina. Minor reversible side reaction is:
Analyze each fraction by spotting 10 times with capillary tubes on a TLC plate, which is exposed to iodine vapor for 15 minutes.
During the experiment of the 50% concentration of isopropanol, the chromatography paper touched the walls of the graph. The experiment was repeated a 2nd with the 50% concentration but again the paper touch the glass walls. This is not good, because the solvent has the potential to attract to the glass. This results to inaccurate data because the pigment would be travelling towards the side of the paper and the Rf value would change.