The lab this week was the first step of a multi-step synthesis. The first part of the synthesis was to isolate benzoin from benzaldehyde through condensation. The product purity of the benzoin can be considered at best medium to low. The percent yield was very low at around 6%, which could have resulted from contamination leading to impurities in the product. Moreover, the IR spectrum of the product shows certain irregularities with the OH stretch at 3375.84 cm-1 and CH stretch for aromatics around 3000 cm-1. The CH stretch appears to have the most impurities since its peak size is diminished compared to regular and does not read a specific peak. However, the IR spectra were able to confirm the product formation of benzoin through the two functional peaks as well as the C=O stretch …show more content…
For the reaction, thiamine was used in our reaction in the formation of the product. Thiamine attacks the carbonyl carbon of an aldehyde in the same way a cyanide ion does. By removing a relatively acidic proton on the five-membered thiazolium ring of thiamine by a base, carbanion that is nucleophilic is produce and can attack the carbonyl. Moreover, thiamine hydrochloride was chosen as the reagent over cyanide because of dangers involved in the use of cyanide, which is a lethal poison that can kill with little warning. Thiamine HCL has been shown to be an efficient and safer catalyst for the condensation of benzaldehyde, which could qualify this reaction as a green chemistry reaction. This reaction turned the aldehyde into a hydroxy ketone by adding a benzyl alcohol, forming a new C-C bond. The Cannizzaro reaction did not occur in this reaction, as benzoic acid or benzyl alcohol would have formed instead of
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.
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 goal of this two week lab was to examine the stereochemistry of the oxidation-reduction interconversion of 4-tert-butylcyclohexanol and 4-tert-butylcyclohexanone. The purpose of first week was to explore the oxidation of an alcohol to a ketone and see how the reduction of the ketone will affect the stereoselectivity. The purpose of first week is to oxidize the alcohol, 4-tert-butylcyclohexanol, to ketone just so that it can be reduced back into the alcohol to see how OH will react. The purpose of second week was to reduce 4-tert-butylcyclohexanol from first week and determine the effect of the product's diastereoselectivity by performing reduction procedures using sodium borohydride The chemicals for this lab are sodium hypochlorite, 4-tert-butylcyclohexanone
Alcohol, which is the nucleophile, attacks the acid, H2SO4, which is the catalyst, forming oxonium. However, the oxonium leaves due to the positive charge on oxygen, which makes it unstable. A stable secondary carbocation is formed. The electrons from the conjugate base attack the proton, henceforth, forming an alkene. Through this attack, the regeneration of the catalyst is formed with the product, 4-methylcyclohexene, before it oxidizes with KMnO4. In simpler terms, protonation of oxygen and the elimination of H+ with formation of alkene occurs.
Wittig reactions allow the generation of an alkene from the reaction between an aldehyde/ketone and an alkyl halide (derived from phosphonium salt).The mechanism for the synthesis of trans-9-(2-phenylethenyl) anthracene first requires the formation of the phosphonium salt by the addition of triphenylphosphine and alkyl halide. The phosphonium halide is produced through the nucleophilic substitution of 1° and 2° alkyl halides and triphenylphosphine (the nucleophile and weak base). An example is benzyltriphenylphosphonium chloride, which was used in this experiment. The second step in the formation of the of the Wittig reagent, which is primarily called a ylide and derived from a phosphonium halide. In the formation of the ylide, the phosphonium ion in benzyltriphenylphosphonium chloride is deprotonated by the base, sodium hydroxide to produce the ylide as shown in equation 1.
This experiment synthesized luminol (5-Amino-2,3-dihydro-1,4-phthalazinedione) and used the product to observe how chemiluminescence would work. The starting material was 5-nitro-2,3-dihydrophthalazine-1,4-dione, which was, after addition of reaction agents, refluxed and vacuum filtered to retrieve luminol. Using two stock solutions, we missed our precipitated luminol with sodium hydroxide, potassium ferricyanide, and hydrogen peroxide, in their respective solutions, in a dark room, to observe the blue light
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
This week’s lab was the third and final step in a multi-step synthesis reaction. The starting material of this week was benzil and 1,3- diphenylacetone was added along with a strong base, KOH, to form the product tetraphenylcyclopentadienone. The product was confirmed to be tetraphenylcyclopentadienone based of the color of the product, the IR spectrum, and the mechanism of the reaction. The product of the reaction was a dark purple/black color, which corresponds to literature colors of tetraphenylcyclopentadienone. The tetraphenylcyclopentadienone product was a deep purple/black because of its absorption of all light wavelengths. The conjugated aromatic rings in the product create a delocalized pi electron system and the electrons are excited
Benzyl bromide, an unknown nucleophile and sodium hydroxide was synthesized to form a benzyl ether product. This product was purified and analyzed to find the unknown in the compound. A condenser and heat reflux was used to prevent reagents from escaping. Then the solid product was vacuum filtered.
We successfully achieved our goal of synthesizing benzhydrol, but we did not successfully reach the goals of the completion of the synthesis or purification of benzhydrol.
Based on the observed melting point range, the sample of Benzoic Acid was pure. The melting point range of the product read 122.5°C -123.2°C. The melting point fell within the melting point range of pure Benzoic Acid (121°C – 125°C), indicating both products are similar to one another. The melting point range of the sample was also very narrow (<1°C), indicating the sample was not comprised of any major impurities. Based on the observed melting point range, the sample of 2-naphthol was relatively pure. The sample’s melting point range (121.3°C – 122.6°C) was slightly below the range of pure 2-naphthol (123°C – 124°C), indicating the possibility of impurities. Yet, the melting point range of the sample was very narrow (≅1°C), indicating the sample was not comprised of any major impurities. Based on the observed melting point range, the sample of 1,4 – dimethoxybenzene was very impure. The sample’s melting point range (116.5°C – 120.9°C) was much higher than pure 1-4 dimethoxybenzene (58°C – 60°C), indicating major impurities within the sample. The wide observed melting point range also indicates a depressed melting point, leading to the conclusion that the compound is
The actual melting point of benzoic acid is known to be 122.4°C. Also, looking at Table1, the percent yield is shown to be 44.9%. The percent yield is how much product was recovered after the reaction was carried out. The percent yield can be used to explain why the melting point observed in the experiment didn’t match the known melting point. Obtained melting points are generally lower than the literature value melting points of a substance due to the number of impurities present in the obtained product. The percent yield of 44.9%, validates that the product could have had some impurities present, and thus the lower melting
Ensure gloves are worn at all times when handling strong acids and bases within the experiment of the preparation of benzocaine. 4-aminobenzoic acid (3.0g, 0.022 moles) was suspended into a dry round-bottomed flask (100cm3) followed by methylated sprits (20 cm3). Taking extra care the concentrated sulphuric acid of (3.0 cm3, 0.031 moles) was added. Immediately after the condenser was fitted on, and the components in the flask were swirled gently to mix components. It should be ensured that the reactants of the concentrated sulphuric acid and the 4-aminobenzoic acid were not clustered in the ground glass joint between the condenser itself and the flask. In order to heat the mixture to a boiling point, a heating mantle was used and then further left for gently refluxing for a constituent time of forty minutes. After the duration of the consistent forty minutes the rou...
The pure product was also analyzed under infrared spectroscopy. Due to time, the infrared spectrum obtained was of another’s product. According to Figure 1, the IR shows two areas of interest. There is a one band at 3463.97 cm-1, which indicates the presence of an alcohol. It is a small band though; the presence of alcohol is small. The is also another peak at 3061.88 cm-1, signifying C-H bonds for an aromatic ring. Even though the infrared spectrum was accurate, it doesn’t aligned with the product synthesized. The synthesis of triphenylmethanol was successfully completed, but the result was not
While reviewing the recent perspectives in the design of antiasthmatic agents, we observed that different angularly fused heterocyclic ring systems like imidazoquinolines, imidazonaphthyridines, thienopyrimidines, triazolothienopyrimidines, benzimidazolo -quinazolines, imidazoquinazolines, benzimidazolopyridopyrimidines, imidazothienopyrimidines and triazinoquinazolines are potentially useful compounds[12,13].