The experiment of Diels-Alder reactions, in particular the furan and maleic anhydride as used in my experiment, observed the exo product as oppose to the exo product. This shows the tendency for the stereochemistry of the Diels-Alder to yield an exo product in preference to the endo product. To determine the stereochemistry, a melt temperature of the product was taken and compared to literature values. The melt temperature for the product was roughly around 113oC, corresponding to the exo Diels-Alder product of furan and maleic anhydride. When compared to the class data of melting ranges, the melting temperature from the reaction was relatively consistent to the majority. Based off this, the assumption can be made that the Diels-Alder prefers …show more content…
the exo stereochemistry to the endo, most likely due to the steric hindrance occasionally seen with endo products. At the end of the experiment, the products were weighed to determine the percent yield of the reaction. The amount of product recovered was about 98.5%, indicating a fairly pure product. A second Diels-Alders reaction was completed using maleic anhydride and antharcene.
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
acid.
The purpose of this lab was to perform an electro-philic aromatic substitution and determine the identity of the major product. TLC was used to detect unre-acted starting material or isomeric products present in the reaction mixture.
2-ethyl-1,3-hexanediol. The molecular weight of this compound is 146.2g/mol. It is converted into 2-ethyl-1-hydroxyhexan-3-one. This compounds molecular weight is 144.2g/mol. This gives a theoretical yield of .63 grams. My actual yield was .42 grams. Therefore, my percent yield was 67%. This was one of my highest yields yet. I felt that this was a good yield because part of this experiment is an equilibrium reaction. Hypochlorite must be used in excess to push the reaction to the right. Also, there were better ways to do this experiment where higher yields could have been produced. For example PCC could have been used. However, because of its toxic properties, its use is restricted. The purpose of this experiment was to determine which of the 3 compounds was formed from the starting material. The third compound was the oxidation of both alcohols. This could not have been my product because of the results of my IR. I had a broad large absorption is the range of 3200 to 3500 wavenumbers. This indicates the presence of an alcohol. If my compound had been fully oxidized then there would be no such alcohol present. Also, because of my IR, I know that my compound was one of the other 2 compounds because of the strong sharp absorption at 1705 wavenumbers. This indicates the presence of a carbonyl. Also, my 2,4-DNP test was positive. Therefore I had to prove which of the two compounds my final product was. The first was the oxidation of the primary alcohol, forming an aldehyde and a secondary alcohol. This could not have been my product because the Tollen’s test. My test was negative indicating no such aldehyde. Also, the textbook states that aldehydes show 2 characteristic absorption’s in the range of 2720-2820 wavenumbers. No such absorption’s were present in my sample. Therefore my final product was the oxidation of the secondary alcohol. My final product had a primary alcohol and a secondary ketone
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
In this experiment we produced a Nylon-6,10 polymer from a reaction with a sebacoyl chloride (decanedioyl dichloride)/dichloromethane mixture and a mixture of water, 1,6-hexanediamine and sodium carbonate. The name ‘Nylon-6,10’ indicates that the diamine that it was made from has 6 carbons and the diacid it was made from has 10 carbons. The sodium carbonate was used in the preparation of Nylon-6,10 because it is a strong base that will lower the acidity of the solution and neutralize the hydrochloric acid that was produced as a by-product. The HCl was produced as a by-product instead of water because we used milder conditions by substituting decanedioyl dichloride for decanedioic acid. The decanedioyl dichloride is a better alternative because it is more reactive towards the
By comparing the overall percent yields based upon pathway, the statistically superior pathway proved to be the Red pathway, which also happens to be the synthesis pathway I implemented. I determined that this was the best pathway based on the mean, median, and maximum overall percent yields of each pathway and are shown on Table 2. I hypothesize that this pathway was most successful because of the order of the reagents used, specifically that the nitration was the second step. I hypothesize that the addition of the nitro group to the benzoic acid was more successful than other reaction pathways because the attached carboxylic acid group is a moderate deactivator and meta director, more so than the attached ketone in the Blue pathway or the attached ester in the Green
The hypothesis expected that aniline and phenol would be tri-substituted, and anisole an acetanilide would be mono-substituted and have a bromine in the para position, because the para position is favored over the ortho position because of sterics. Results after the experiment were: phenol > aniline > acetanilide. Anisole was not applicable because the experiment was not ran during class and that data was not provided. The results for aniline were one group claiming 2,6 dibromoaniline and two groups claiming 2,4 dibromoanaline. 2,4 dibromoanaline seems more probable because it is preferred to have substituents spaced out on an aromatic ring, for less tension between substrates. The conclusion with phenol was that it was trisubstituted 2,4,6 tribromophenol. Although there are two melting points, it is the same product that was being analyzed, because only one group could correctly brominate phenol. The temperature difference is attributed to two different mel-temps being used, causing two different temperatures. The results for acetanilide, were that all three groups concluded that 4-bromoacetanailde was the product. This is predictable because acetanailde is a bulky substrate. Compounds favor that bulky substituents only attach in the para
This shows that our experiment yielded the correct form of each compound. The percent recovery was accurate for 4-Cloroaniline and Naphthalene yielding 99.9 and 109.9 % respectively while Benzoic Acid only yielded 45.95%. Possible reasons for Benzoic Acid yielding such a low percentage might be because of not capping the separator funnel while working to precipitate 4-chloraniline, also not removing all of the Benzoic Acid from the separatory funnel adds to a recovery less than
Converting 4-tert-butylcyclohexanol into 4-tert-butylcyclohexanone via oxidation reaction generated 0.270 grams. The product is confirmed through NMR. The second part of the experiment is to convert 4-tert-butylcyclohexanone into 4-tert-butylcyclohexanol via reduction reaction using the product obtained from earlier. However, due to the product having too many impurities, an industrial 4-tert-butylcyclohexanone was used for the experiment. The reaction generated 0.118 grams, a 99.2% yield rate. The NMR confirmed the product to be 4-tert-butylcyclohexanol, with a ratio of 85% trans and 15% cis isomers. In compare to the industrialized alcohol, it has almost the same ratio. Besides L-selectride, trans isomers are more common. The reason as
...Coauthor, ChemBioChem 2006, 7, 1-10; b) A. Author, B. Coauthor, Angew. Chem. 2006, 118, 1-5; Angew. Chem. Int. Ed. 2006, 45, 1-5.))
Fully describes the crystallochemical relationships between the structures and the temperature dependence of polymorphism. )
The tertiary product forms as a result of a hydride shift in order to form a more stable carbocation whereas the secondary (minor) product forms as a result of a direct substitution. The reaction was done via a hot water bath at approximately 55 degrees Celsius in order to overcome some of the activation energy requirements. The analysis of Infrared spectroscopy data showed that there was still a slight amount of alcohol left in the product therefore highlighting that this reaction did not go to completion. This could have been because of an excess of lucas
In this paper, Nicolaou and his associates describe how their goal was both the total synthesis of these CP compounds (achieved in 1999) along with the determination of their absolute configurations; methods used in initial attempts to determine absolute configuration at different carbons included X-ray crystallography and NMR. Nicolaou set about synthesizing this compound by thinking through possible reactions that he might use to begin to build the carbon skeleton needed for this molecule. His team decided on a type-II intramolecular Diels-Alder reaction as the key step to generation of the core skeleton. The Diels-Alder reaction utilizes a dienophile in order to form new carbon-carbon bonds in a single step, in this case to form multiple ring structures. However, Nicolaou ran into trouble when several reagent-based enantioselective approaches with the precursor failed to yield appreciable levels of the desired product. After much study of this problem, Nicolaou's team came to the conclusion that a Lewis acid catalyst would be their best shot at inducing the asymmetry needed for this particular absolute configuration.
Instead, the spectrum for station 2 was examined and compared to an IR spectrum of carvone. In the IR spectrum of carvone, the Peak located at ~1680 cm-1 indicates a carbon oxygen double bond, and the small peaks located just under 3000 cm-1 indicate carbon hydrogen bonds. In the spectrum for the product, the peak the broad Peak ranging from 3300 to 3400 cm-1 indicates an oxygen hydrogen alcohol bond. The peaks just below 3000 cm-1 also indicate hydrogen carbon bonds, and the peak just above 3000 cm-1 indicate vinyl carbon hydrogen bonds. Also the two peaks at around 1600 cm-1 and 1500 cm-1 with the small overtones located at the range of 1800 cm-1 to 2000 cm-1 indicate a benzene ring is present in the product. Based on these peaks, it indicates that the product is carvacrol, and station 2’s experiment was
Even though the percent yield was extremely low (19.106%) and the melting point was lower than expected (85-88 degrees C and not 92-94 degrees C), the IR spectrum proved that the final product does not have a carbonyl group, as it was reduced to the alcohol group. The nitro group remain on the IR spectrum, proving that it was not reduced to Aniline. The TLC plate also proves a reduction has occurred, as the product Rf value (0.2195) was lower than the starting material Rf value (0.9512). The primary reason is because the product is the reduced formed of the starting material, resulting in more hydrogens and more hydrogen
This suggests that the background scan may not have run properly. However, all of the ferrocene peaks are still clearly visible. The most important peaks in this spectrum are the aromatic ones, which show that the cyclopentadienyl ligand retains its aromaticity on binding to the metal centre. The aromatic C-H peaks occur higher than the C-H stretch in an alkene, and there are also aromatic overtones at 1636 cm-1.