Multistep Synthesis of Benzilic Acid

Experiment 55 consists of devising a separation and purification scheme for a three component mixture. The overall objective is to isolate in pure form two of the three compounds. This was done using extraction, solubility, crystallization and vacuum filtration. The experiment was carried out two times, both of which were successful.

The hydrobenzoin (meso) product of the benzil was isolated through the techniques of recrystallization and vacuum filtration. Because there NaBH4 was the limiting reagent in the experiment, 0.005604moles of NaBH4 should yield 1.2008g of hydrobenzoin (meso). The mass of the isolated product was 0.613g, resulting in a 51.1% yield. There are many reasons to account for the loss of 48.9% of

The product was placed in a Craig tube and several drops of hot (100°C) solvent (50% water, 50% methanol, by volume) was added and heated until all of the crystals dissolved. The Craig tube was plugged and set in an Erlenmeyer flask to cool. Crystallization was induced once the mixture was at room temperature by scratching the inner wall of the tube. It was then placed into an ice bath for ten minutes until crystallization was complete. The tube was then

In order to isolate benzoic acid, benzocaine and 9-fluorenone, each component needed to be separated from one another. All three compounds began together in one culture tube, dissolved in methylene chloride and formed into a homogenous mixture. In this culture tube, two milliliters of aqueous three molar hydrochloric acid was added, which immediately formed two layers, the top acidic aqueous layer was clear in color and contained benzocaine, and the bottom organic formed was yellow and contained benzoic acid and 9-fluorenone. Benzocaine’s amino group is protonated by the aqueous layer hydronium. This protonation forms the conjugate acid of benzocaine, benzocaine hydrochloride. Thus, the conjugate acid, benzocaine hydrochloride is a salt in which is soluble in water and furthermore can be isolated from the organic mixture. When testing out the pH levels in benzocaine, the pH test strip was dark blue in color, indicating a pH level of around 5 to 7. When isolating benzoic acid, two milliliters of aqueous three molar sodium hydroxide was added, which deprotonates the carboxylic group in benzoic acid, forming its conjugate base, sodium benzoate. As with benzocaine hydrochloride, sodium benzoate is a water soluble ionic salt in the aqueous layer that can then be separated from the bottom organic layer containing the 9-fluorenone. The pH test strip was a vibrant red for benzoic acid, indicating a pH of 2. Now the 9-fluorenone is left, deionized water is added to remove any excess

In order to generate a bicyclic lactone in this experiment, a Diels-Alder adduct was produced. The bicyclic lactone to be generated was cis-1,3,3a,4,5,7a-Hexahydro-5-methyl-3-oxo-4-isobenzofuran-carboxylic Acid and was produced using a Diels-Alder reaction. The product was also analyzed quantitatively using percent yield. To prepare the Diels-Alder adduct 0.40 g of 2,4-hexadien-1-ol was added to a flask, then 5.00 mL of toluene and 0.40 g of maleic anhydride were added to the flask in that order. The mixture was warmed and stirred to induce a reaction. The reaction progress was monitored using a TLC plate with 30:70 hexane used as the mobile phase and silica gel as the stationary phase. The TLC plate revealed a new spot for the crude product, indicating the reaction had begun.

The crude product was washed by taking the reaction product in the separatory funnel and adding 23 mL of deionized H2O. The mixture was shaken and allowed to settle until layers were observable. The top layer was the desired product and approximately 25 mL of aqueous layer was extracted from the separatory funnel. Next, 25 mL of 5% NaHCO3 was added to the separatory funnel in order to neutralize the acid. This mixture was swirled, plugged with the stopper and inverted. Built-up gas was released by turning the stopcock to its opened and closed positions, releasing CO2 by-product. This was done four times in one minute intervals. The solution was allowed to settle until layers were observable. The bottom layer that contained salt, base and water was extracted from the separatory funnel. The crude product was washed again as mentioned previously.

1. Purpose: to clarify the mechanism for the cycloaddition reaction between benzonitrile oxide and an alkene, and to test the regiochemistry of the reaction between benzonitrile oxide and styrene.

To tube 2 and tube 3 a boiling chip is added. The two tubes are boiled to remove any residual ether. Next, the tubes are cooled to room temperature and placed into an ice bath to allow for crystallization. The solution is then removed from the solid in each tube and discarded. To tube 2 and 3 ~0.5 ml of H2O is added for recrystallization, the tubes

Results: No substantial qualitative data was collected, except that the original reaction mixture turned a purple color. Upon the addition of anise oil and heat, the reaction mixture turned a brown color. And with the addition of NaHSO3 the mixture turned a white color. The mass of the final product sample was measured to be 0.08g (see Calculation 1). The melting point range for this sample was 172.8-185.4ºC in Trial 1 and 171.6-185.2ºC in Trial 2 (see Table 1). The IR spectrum of anise oil can be found attached. Peaks appear to exist at 3022.86, 3002.41, 2957.58, 2933.88, 2912.63, 2834.94, and 2723.19 (cm-1). Another set of peaks appear to exist at 1608.06, 1510.55, 1464.73, 1441.16, 1306.3, 1283.06, 1247.18, 1174.78, 1036.26, 964.58, 839.29, and 787.03 (cm-1). No other significant quantitative results were collected.

In this experiment, the main objective was to synthesize a ketone from borneol via an oxidation reaction and secondly, to produce a secondary alcohol from camphor via a reduction reaction. Therefore, the hypothesis of this lab is that camphor will be produced in the oxidation reaction and isoborneol will be the product of the reduction reaction because of steric hindrance. For the oxidation step, a reflux will be done and then a microscale reflux for the reduction step. The products will be confirmed using Infrared spectroscopy, the chromic acid test, 2,4-DNP test and 13C NMR spectroscopy. The results of this

The pipet was put into the top of the condenser and leaving no open spaces. The vacuum served to get rid of the nitrogen oxide gases that were formed during the oxidation reaction. The solution was heated for 30 minutes, beginning the time when the first sign of nitrogen oxide fumes were observed. After the 30 minutes, the solution was removed and cooled for a few minutes. The solution turned was a brownish-yellow color and all the crystal were dissolved, leaving a liquid. The solution was then transferred, using a Pasteur pipet, to 3 mL of water in a beaker. The reaction flask was rinsed to remove the remainder of the solution. The solution was stirred with a glass rod until room temperature of the solution was achieved. A yellow solid was to form, but instead the solution remained aqueous in the case of the specific experiment explained here. With additional scraping of the solution with a glass rod, no crystals formed at all. The next procedure, if the crystals had formed was to crush the solid with the glass rod and filter the solid until the crystals were dry. The mass would then be weighed and the crystals were to be recrystallized with 95% ethanol. The crystals were to be cooled in ice water to get full crystallization and then the crystals were to be filtered and air dried, then weighed.

Experiment 4A: Determination of a Partition Coefficient for Benzoic Acid in Methylene Chloride and Water, and Experiment 4B: Solvent Extraction I: Acid-Base Extraction Using the System Benzoic Acid, Methylene Chloride, and Sodium Bicarbonate Solution

The reaction took place in a conical vial and .2mL of each of the reactant samples were added to it along with some 95% ethanol. Two drops of NaOH were added shortly after and stirred at room temperature for fifteen minutes. The vial was cooled in and ice bath and crystallized. Vacuum filtration was performed to filter the crude product. The crude product was recrystallized using methanol and filtered again. We made one change to the procedure and instead of using .7mL of ethanol we

The week after, a recrystallization was performed on the previous week’s crude product. The product ethereal solution was first heated on a steam bath until dry. During the heating, a beaker of methanol was collected and also placed on the steam bath. Once the product was dry, it was cooled to room temperature and then placed in an ice-water bath. The now boiling methanol was added to the crude crystals and a recrystallization was performed. Once completed, the now purified product was collected via Buchner vacuum filtration and stored in drawer to dry for a week. Afterwards, a melting point range of the purified product was obtained by using a Mel-temp apparatus. Lastly, an

After all additional product ceased to form, the reaction mixture was cooled in an ice bath to allow precipitation of benzopinacol. The final product was then filtered off from the solution using a Buchener funnel. Its melting point, yield and infrared spetrum was then obtained.