Water will act as initial solvent for caffeine extraction. This is due to water that slowly soluble with caffeine at ambient temperature but highly soluble when temperature is at 100°C. Then, methylene chloride is chosen as the extraction solvent, due to its miscibility with caffeine and immiscibility with water. As mentioned above, the immiscible pair is chose for the extraction part because to allow the aqueous and organic layers to be separated. Basically, the bottom layer is the aqueous layer while the upper layer is the organic compound.
To optimize this yield, consider the steps in how the reagents are introduced to the reaction mixture in terms. It is understood the mechanism is acid-catalyzed where protons coordinate with the carbonyl oxygen to make the carbonyl carbon more electropositive for nucleophilic attack (Scheme 1). In the experimental procedure all reactants were added together, this is inefficient as the protons can coordinate with either trans-cinnamic acid or methanol. Coordination with methanol is unnecessary as it reduces its nucleophilicity and makes less protons available to coordinate with the carboxylic acid. To improve
Solubility matters since organic compounds tend to not be soluble in aqueous solvents, but ionic salts do easily dissolve in water. And acidity matters since we can adjust the base strength to only react with one component of Excedrin at a time, allowing for the components to be isolated. By adding a 1M solution of a basic salt, like K2HPO4 or KOH, to organic compounds, we could convert the organic components of Excedrin into ionic salt that will dissolve in aqueous solvents. Next, by adding a strong acid, like HCl, the Excedrin component is protonated causing a decrease in solubility leading to the component precipitating out of the solution and crystallizing. Acid-base extraction offers a method to separate the active components of Excedrin based on acidity and what bases they will react with.
N-(1-Carboxymethyl-1H-tetrazol-5-yl)-hydrazinium nitrate (3). A solution of AgNO3 (0.10 g, 0.60 mmol) in distilled water (1.5 mL) was added dropwise in the dark to the solution of compound 2 (0.10 g, 0.60 mmol) in Deionized water (1.5 mL) under stirring. After 2-3 hour, the precipitate was filtered, and rinsed with 4 mL distilled water. The solvent was removed by rotary Evaporation to produce a white solid at 88% yield (0.10 g); N-(1-Carboxymethyl-1H-tetrazol-5-yl)-hydrazinium nitrate: Yield: 88%; yellow crystals;. IR (KBr): 3396, 3329, 3140, 3008, 1628, 1494, 1383 cm-1; UV (H2O): λmax = 293-296
In this experiment, racemic 2-methylcyclohexanone was reduced using sodium borohydride as a nucleophile to give a diastereomeric mixture of cis and trans secondary alcohols. The products were analyzed for purity using IR spectroscopy and gas chromatography. 1.2 g of 2-methylcyclohexanone and 10 mL of methanol were combined in a flask and cooled in an ice bath. Two 100 mg portions of sodium borohydride were added to the flask and stirred. 5 mL of 3M sodium hydroxide, 5 mL of de-ionized water, and 15 mL of hexane were added to the reaction flask and stirred.
Water acts as a leaving group in the third step and is removed from the reaction intermediate. In the fourth step, the molecule undergoes deprotonation with the help of the concentrated sulfuric acid to form isopentyl acetate. The reaction that was carried out in the experiment was a reversible reaction. In order to obtain as much isopentyl acetate as possible, Le Chatelier’s principle was used to ensure that we were able to collect a sufficient amount of isopentyl acetate. Le Chatelier’s principle says that if you disturb a system in equilibrium the equilibrium will shift in order to account for the disturbance.
Because it is a tertiary benzylic halide, the reaction is considered an SN1 type. To test the purity, the class then uses a TLC. When one places,” a spot of the substance on the absorbent surface of the TLC plate, the solvent (or solvents) run up through the absorbent,” (Zubrick223). The initial mass of the reactant, triphenylmethyl chloride was 2.006 grams. The experiment yield is 1.589g, which is a 80.3% yield.
We added sodium carbonate until the pH of the mixture was 8. After neutralize, we collected benzocaine by vacuum filtration. We used a Buchner funnel to collect benzocaine. We used three 10 ml of water to wash the product. After the product was dry, we weighed, calculate the percent yield and determined the melting point of the product.
The ester studied was “3,” the acid used was 9.5 mL of “B,” and the alcohol used was 18.1 mL of “C.” A few substances were added to augment the production of the ester. Sulfuric acid (H2SO4) was added using a dropper bottle to catalyze the reaction. The desiccant in this reaction was drierite and was used to absorb the water byproduct. This prevented the ester from breaking apart into its constituents. The cold finger condenser was used to trap evaporated gas from the heated mixture, and condense it back into
1,3-butadiene is formed from 3-sulfolene by thermal decomposition. It is important to work with very concentrated solutions of two different reagents because they help create the bonds in the six-membered ring. The reagent that was taken in excess was xylene. Xylene, a non-polar solvent, can be used for this reaction because it will not react with the solvents. Xylene should be dried because it will be removed from the product.