1. The reaction performed in this experiment was bromination of an alkene, using trans-Cinnamic acid, Pyridinium Tribromide, and Glacial Acetic Acid. 2. Recrystallization and Melting Point were used to purify and identify the product of the reaction 3. In the reaction conducted in this experiment, three mechanisms were possible: Anti Addition, Syn Addition, and Anti and Syn Addition. Addition mechanisms involve removing a double bond between two adjacent carbons and adding one nucleophile (bromine in this case) to each of the carbons. Anti Addition results in a product in which the two bromines are anti-periplanar (or trans) to one another. Syn Addition results in a product in which the two bromines are syn-periplanar (or cis) to one another. Anti and …show more content…
The yield obtained was .391 g, and the percent yield was 94%. 6. The percent recovery obtained from recrystallization was 104.8%. 7. The melting point range was 200-208 °C. 8. The product obtained was the trans-product. This was decided because the melting point range of the product from recrystallization (200-208 °C) matched closest to the melting point of the trans- product (204 °C). The melting point of the cis-product is only 95 °C. 9. If the data lead to inconclusive results, mechanical errors were most likely the cause. 10. The yield of the product (.391 g) makes sense because it is lower than the calculated theoretical yield (.416 g). Since the percent yield was 94%, only a relatively small amount of product was lost due to recrystallization. 11. The melting point data make sense, as the range is relatively small and the known melting point of the trans-product falls right in between the measured melting point. 12. The identity of the product was trans-2,3-dibromo-3-phenylpropanoic acid, and it was concluded to be this from melting point data. This product resulted from an Anti Addition mechanism. 13. If the identification data was inconclusive or questionable, thin-layer chromatography could be
When 1-bromobutane is reacted with potassium t-butoxide there is only one product formed, 1-butene. This is because the halide is on a primary carbon thus producing only one product.
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%).
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.
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
The ratios for NaBH4, MPV, and L-selectride are 24.2:75.8, 43.6:56.3, 91.3:.86 respectively. According to analysis of the 1H-NMR spectrum, it is shown that the trans product formed over the cis. The mechanism for L-selectride is very similar to that of NaBH4, but NaBH4 primarily yields the more trans isomer whereas the L-selectride primarily the cis isomer. The reason for this is because in NaBH4, the hydride is not being blocked when convert to OH so it’s free to do a top attack to make a lot more of the the trans isomer. Whereas the L-selectride has bulky groups that block from the carbonyl oxygen which means that it must perform bottom attack and because of this, the isomer that gets made is the cis at 91%. In MPV, the proton is free to attack the carbonyl oxygen in a frontside attack to give more of the trans isomer The MPV reaction using aluminum isopropoxide gives reversible reduction of ketones and aldehydes and the cis or trans can revert back to starting ketone. Each step in the mechanism is reversible so the reaction is driven by the formation of the more stable product which favored thermodynamic. Overall, the stereoselectivity of reaction is affected how the hydride is opened was when it was attacking the carbonyl
At this point the identity of the unknown compound was hypothesized to be calcium nitrate. In order to test this hypothesis, both the unknown compound and known compound were reacted with five different compounds and the results of those reactions were compared. It was important to compare the known and unknown compounds quantitatively as well to ensure that they were indeed the same compound. This was accomplished by reacting them both with a third compound which would produce an insoluble salt that could be filte...
Wittig reactions allow the generation of an alkene from the reaction between an aldehyde/ketone and a ylide (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) 4 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. 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 an alkene.3
The reaction of (-)-α-phellandrene, 1, and maleic anhydride, 2, gave a Diels-Alder adduct, 4,7-ethanoisobenzofuran-1,3-dione, 3a,4,7,7a-tetrahydro-5-methyl-8-(1-methylethyl), 3, this reaction gave white crystals in a yield of 2.64 g (37.56%). Both hydrogen and carbon NMR as well as NOESY, COSY and HSQC spectrum were used to prove that 3 had formed. These spectroscopic techniques also aided in the identification of whether the process was attack via the top of bottom face, as well as if this reaction was via the endo or exo process. These possible attacks give rise to four possible products, however, in reality due to steric interactions and electronics only one product is formed.
This experiment was divided into two main steps. The first step was the addition of bromine to trans-stilbene. Trans-stilbene was weighted out 2.00g, 0.0111mol and mixed with 40ml of glacial acetic acid in 100ml Erlenmeyer flask on a hot bath. Pyridinium hydrobromide perbromide of 4.00g, 0.0125mol was added carefully into the flask.
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.
The general objective of this experiment was for the students to familiarise with the preparation of a simple organic compound and to purify the compound by recrystallization. This experiment allows the students to conduct synthesis of aspirin, reinforcing the skills of recrystallization and the technique of melting point determination.
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...
List the steps in the systematic procedure for miniscale recrystallization, briefly explaining the purpose of each step.
The Web. The Web. 28 Apr. 2014. The 'Standard' of the 'Standard'. Metal Melting 101 - How To.
The crystallization process can be explained by the DSC results which obtained at different heating rates. The kinetic parameters (activation energy for crystallization, Ec, and Avrami exponent, n) for the crystallization peaks determined. Kissinger method used to determine the activation energy for crystallization (Ep) considering the heating rate (α) dependence of the peak crystallization temperature (Tp) as shown in figure 5.