However, after refluxing for a while, yellow precipitates begin to form near the top of the flask. It was assumed that the remaining starting material was concentrated from a decrease volume to reappeared in solution. Nevertheless, this may have been a sign of contamination that will negatively affect the entire reaction. This observation later resulted in a yellowish
This liquid is mixed using large paddles to mix air into the mixture and oxidize it. When the indoxyl is oxidized, it turns into indigotin. Indigotin is denser than the rest of the liquid, so it settles to the bottom of the vat. This pigment is then sent to the third and lowest vat. To prevent the pigment from fermenting, it is heated in the vat.
Reducing sugars are a carbohydrate that can either be straight chains with an aldehyde group at the end or as ring forms with a ketone group (Hill, 1982). Monosaccharides and most disaccharides will reduce copper (II) sulfate. The Benedict’s solution contains cupric ions and the aldehyde groups at the end of the sugars will reduce the cupric ions to cuprous ions (Cu+). There will be a precipitate of copper (I) oxide when the cuprous ions combine with oxygen (Hill,
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.
We then added 10cm3 ethanoic anhydride to the salicylic acid and swirled the contents, this mixes together the two chemicals. We then added 5 drops of concentrated sulphuric acid to the flask and thoroughly swirled the mixture, this creates the solution that makes the aspirin. We then warmed the flask for 20 minutes in a 400cm3 beaker of hot water which was approximately 60°C, we made sure the flask did not go above 65°C because this could have caused the contents to evaporate. Part 2: Using a 25cm3 measuring cylinder we measured out 15cm3 of ethanol into a boiling tube and then prepared a beaker half filled with hot water at approx. 75°C, we got this temperature by filling the beaker with cold water and slowly adding boiling water from a kettle until we reached the right temperature.
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.
When carbon dioxide reacts with water, carbonic acid is made. This 0.1% aqueous bromothymol blue solution (also known as Bromthymol Blue) is a commonly used pH indicator. Bromthymol blue changes color over a pH range from 6.0 (yellow) to 7.6 (blue). It is a good indicator of dissolved carbon dioxide (CO2) and other weakly acidic solutions. Despite its name, bromothymol blue solution may sometimes appear yellow or reddish depending on the pH of the stock water used to prepare this pH indicator solution.
The anthraquinone dye experiment has the purpose to identify the anthraquinone dyes from unknown mixture by using thin layer chromatography (TLC) of the unknown fraction. An anthraquinone is an aromatic organic compound obtained by the oxidation of anthracene. To separate the compounds in the mixture, column chromatography and thin layer chromatography uses portioning of a sample between a stationary solid phase and a liquid mobile phase. As the stationary phase, they use either silica gel or alumina, and organic solvents as the mobile phase. In order to accomplish the experiment, an unknown which is a solution of at least two anthraquinone dyes will be used.
In addition, phenolphthalein was added as an indicator. The aliquots were titrated against sodium hydroxide (NaOH) solution until end point was reached, after which volume of NaOH consumed was recorded. The value of the rate constant, k, obtained was 0.0002 s-1. The experiment was then repeated with 40/60 V/V isopropanol/water mixture and a larger value of k = 0.0007 s-1 was obtained. We concluded that the rate of hydrolysis of (CH3)3CCl is directly proportional to water content in the solvent mixture.
A five carbon sugar is reduced to a four carbon sugar. In step five Succlnyl-CoA is converted into Succinate. There is a strong negative standard of free energy from the hydrolysis. In the next step the energy that is released in breaking this bond is used to drive the synthesis of phosphoanhydrice used to create GTP nad ATP.
The acid catalyst then deprotonates the alcohol so it could retain its neutral charge and then the acid protonates the other hydroxide group, to produce H2O which separates from the main compound to stabilize its own charge and then carbocation rearrangement occurs to form a pi bond.
Two chemical reactions are carried by adding sodium hydroxide to the acidic solution from Part I. During the first reaction is the neutralization of the excess of nitric acid in the mixture by sodium hydroxide. The second reaction takes the place after naturalization is a complete and NaOH is in excess. While the liquid inside the beaker is being stirred, with the stirring rod, 10 ml of 6 M NaOH is poured into the solution from Part I at 1 mL at a time. After each 1 mL the solution is tested for acidity with red litmus paper.
The purpose of this experiment was to learn about metal hydride reduction reactions. Therefore, the sodium borohydride reduction of the ketone, 9-fluorenone was performed to yield the secondary alcohol, 9-fluorenol. Reduction of an organic molecule usually corresponds to decreasing its oxygen content or increasing its hydrogen content. In order to achieve such a chemical change, sodium borohydride (NaBH4) is used as a reducing agent. There are other metal hydrides used in the reduction of carbonyl groups such as lithium aluminum hydride (LiAlH4).
The first part of this lab was to get a chromatography, spinach and a quarter. The next step was to draw a line of the chromatography and rub the spinach leaf on it with the quarter. After this, the next step was to place the chromatography paper inside the tube and allow the solvent to rise to the paper. The final step was to remove the paper and mark the spots where the colors had shown up as they would disappear soon after. By doing this lab, it was possible to see all the different accessory pigments as well as the chlorophyll.