If contact occurs, wash the contacted area immediately with cool water. Add 2 drops of acetone to tube 1,2 drops of butyraldehyde to tube 2, 2 drops of flavoring agent to tube 3, 2 drops of your unknown to tube 4. Mix well by agitationand noth the almost instantaneous formation of precipitate in tubes 1 and 2. Record all your observations for samples in table 20.1. B. Tollens Reagent.
After the mixture was heated, there was solid on the bottom and liquid on the top of the flask. The set up was let cool to room temperature. Next, we decanted the mixture in to a clean 100 ml beaker. We rinsed the remaining solid with 10 ml of DCM and swirled the mixture. The mixture was decanted again in to the same beaker.
1.0 mL of conc. sulfuric acid was slowly added and the mixture was allowed to genly boil under reflux for about 75 minutes. After reaction, the mixture was allowed to cool and was transferred to a beaker containing 30 mL of water. 10% sodium carbonate solution was added until gas was no longer evolved and the pH was around 8. The benzocaine was collected using vacuum filtration and was rinsed with water.
Each organic extract is then dried over anhydrous calcium chloride pellets and evaporated to dryness. The extract is then wet with a minimal amount of dichloromethane and a sample of each is obtained and mixed together with 200 mg of alumina and again evaporated to dryness. This mixture is then placed in the prepared chromatography column and eluted with hexanes until the yellow β-carotene band is collected. The solvent is then switched to a 90/10 mix of hexanes and acetone to speed up the elution of the more polar lycopene band, which is also collected in its own flask. Each of these samples is evaporated to dryness and rehydrated with a minimal amount of dichloromethane.
LAB REPORT: Hydrolysis of Acetylsalicylic Acid PURPOSE: The purpose of this lab is to become familiar with the identification of ester, carboxylic acid and alcohol functional groups, to understand that formation and hydrolysis of esters are equilibrium processes, to understand how ester hydrolysis yields carboxylic acid and alcohol products, and to understand what a sympathetic ink is and how such inks are visualized. PROCEDURE: 1. Crushed two 325mg aspirin tablets into powder; placed the powder in a 50 or 100mL beaker; added 2 grams of sodium carbonate; then measured and added 20mL of water. 2. Stirred the mixture occasionally; covered it with plastic wrap and allowed to stand overnight in a safe place undisturbed to hydrolyze the aspirin to salicylic acid; noticed the odor of acetic acid in the beaker the following morning.
Lab 2: Preparation of Triphenylmethanol by a Grignard Reaction Introduction: The Grignard addition of an organomagnesium compound to a carbonyl to form an alcohol is one of the classic reactions in organic chemistry. First, magnesium will be inserted into a carbon-halide bond to form nucleophilic phenylmagnesium halide Grignard reagent. This reaction is an oxidation of the metal converting Mg0 to Mg2+ carried out in anhydrous ether solvent. This process will be done with care due to the moisture sensitivity of the phenylmagnesium halide. Second, methyl benzoate is added to form a new carbon-carbon sigma bond.
* Pour a little ether over the nutmeg residue on the filter paper so that any Diethyl ethanol traces clinging to it is washed down and mixed with the filtered liquid underneath. * Filter the mixture by gravity filtration, washing the nutmeg residue with 10ml of diethyl ether. Evaporate the Ether from the filtrate * Recrystallize the product from ethanol. Filter using a Buchner funnel and wash them with cold water as shown in the diagram (see figure 2). * Let the crystals dry for one week, record the weight and take a sample and put into a glass capillary tube to obtain a melting point using the Melt-Temp machine.
Transfer the extracts to a simple-distillation assembly and distill off all but 10 mLof the solvent on a steam bath. Save the recovered solvent. Evaporate the combined solutions to dryness on a steam bath or hot-water bath in a hood. To purify the crude product, dissolve it in about 5 mL of acetone by warming the mixture on a steam bath; add dropwise just enough mixed “hexanes” to turn the warmed solution faintly cloudy; then allow the solution to cool and allow the product to crystallize. Collect the green-tinged crystals on a small vacuum filter and wash them with a little mixed “hexanes.” The melting point of caffeine reported in the literature is 236°.
In attempt to remove all the waste, I likely removed from 0.5mL of product. During the drying stage, 0.5g of anhydrous sodium sulfate was recommended to dry the crude ester, approximately 2g of anhydrous sodium sulfate was used. This seemed like an excess of anhydrous sodium sulfate but may not have affected the pure product in the long run. The product yielded produced a scent of a banana which is consistent with the production of banana oil. This equation displays the synthesis of isopentyl acetate by Fischer Esterification between isopentyl alcohol and acetic acid with sulfuric acid as the catalyst.
Once all the water from the beaker was gone the clamp was carefully replaced so there were no air bubbles in the tube. The tube connected to the aspirator was then removed and connected to the test tube. The gelatin capsule was placed in the tube before adding 10 mL of HCl that had been measured in a graduated cylinder beforehand. The stopper was quickly and firmly placed into the test tube and the pinch clamp was removed again. After a few minutes the acid dissolved the capsule creating a black foam that then turned into a clear liquid again.