Preparation of Azo Dyes

Bleach: when combined with BTB this cleaner changed orange, indicating that the cleaner has an acidic ph.

The recrystallization technique utilizes the ability of a compound to dissolve within a hot solvent and produce a solution. As this solution cools, the solute reforms without impurities in a crystal lattice structure.1 For this to work properly, an appropriate solution that will not dissolve the solute at low temperatures, but will at high temperatures, must be used.1 There is no single solvent that will work well for every solute’s recrystallization; different solvents are better suited for some solutes than others.2 Some impurities that do not dissolve within the solvent can be filtered out while the solution is still hot, while other impurities that readily dissolve within the solvent shouldn’t recrystallize with the pure substance (as they are not concentrated enough to

The mixture was heated at 120°C using an aluminum block and was stirred gently. After all of the solid dissolved, it was heated for 20 additional minutes to ensure the reaction was complete.

The sodium hydroxide acts to pull the hydrogen off the oxygen in the 2-methylphenol so that the oxygen has a negative charge and can attack the sodium chloroacetate. Again, using a 1:1 molar ratio, 0.34 g (2.9 mmol) of sodium chloroacetate (the good leaving group) was added to 1 ml of water and dissolved. Following dissolving all of the 2-methylphenol (to avoid the sodium hydroxide reacting concurrently with the sodium chloroacetate and 2-methylphenol) in the sodium hydroxide, the aqueous solution of sodium chloroacetate was transferred to the reaction flask. This mixture was then heated to reflux, using a medicine dropper affixed to the top of the flask as an alternative method to boil without

In the Cannizaro reaction an aldehyde is simultaneously reduced into its primary alcohol form and also oxidized into it 's carboxylic acid form. The purpose of this experiment is to isolate, purify and identify compounds 1 and 2 which contain 4-chlorobenzaldehyde, methanol, and aqueous potassium hydroxide. Compounds 1 and 2 are purified by crystallization. . The purified product will be characterized by IR spectroscopy and melting point.

24) Separate the formed crystals (benzoin) and allow them to dry, then take the MP.

In the United States and in most of the world food dyes are exceedingly common. In addition to this, they have been brought into question as being dangerous for human and environmental health. From general observation and knowledge about this topic I knew that Red #40 dye (Allura Red AC) is at the height of this controversy. After some initial research, I discovered more information on Azo dyes, their effect on the environment, as well as wastewater treatment used to decontaminate water containing these dyes. This led to my interest on the topic of Electrochemical Advanced Oxidation Processes (EAOPs) as a fairly recent solution to environmental issues regarding contaminants in water. I was curious to see how these processes work, as well as

Catechol oxidase is an enzyme that speeds up the oxidation reaction when catechol is exposed to oxygen. When the reaction occurs, benzoquinone is produced turning the oxidized substance brown. It was hypothesized that the higher the concentration of catechol oxidase, the browner the substance will turn, and the faster it will achieve the color. In the present lab, different concentrations of catechol oxidase were mixed with pure catechol and the rate at which each solution browned was measured using a colorimeter. The

6. 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 purify the crude product of either trans-stilbene, cis-stilbene, or styrene reaction.

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.

To a 5 mL conical vial with a spin vane, 5-nitro-2, 3-dihydrophthalazine-1, 4-dione (.151 grams) was added. Next, sodium hydroxide (2 mL, 3M) was added to the conical vial and stirred until a reddish brown color was obtained. The addition of sodium hydrosulfite (.254 grams) followed, and the sides of the conical vial were

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

From the Figure 4.15 and Figure 4.16 it can be seen that there was decrease in color removal from pH9 to pH10 with the maximum color removal efficiency of 83.43% for cationic dye and 71.68% for anionic dye solution. However the trend of increase in color removal with the increase in WTR dose was also observed.

In this experiment, methyl benzoate was synthesized from benzoic acid and methanol with acid catalyze using Fisher Esterification. First benzoic acid and methanol were mixed in 100 mL round bottom flask. We cooled the mixture in ice and poured 3 mL of conc. H2SO4 and swirled to mix compounds. Then we refluxed the mixture for 1 hour. We let the solution cool and then decanted into a separatory funnel containing 50 mL of water and rinsed the round bottom flask with 35 mL of tert-butyl methyl ether and added that to a separatory funnel. We shook and vented thoroughly and drained the aqueous layer which contained a bulk of methanol and H2SO4. We washed the solution in the separatory funnel with 25 mL of water, followed by 25 mL of sat. sodium bicarbonate

Subsequently, 10mL of 3.5% H2O2 were added dropwise to the reaction mixture and was stirred for 20 minutes before heating to boiling at 80°C for 5 minutes. The reaction mixture was then taken off heat and allowed to cool undisturbed in an ice-bath for 30 minutes. Suction filtration was performed after to collect the crystals from the chilled solution The product was then washed with chilled 95% ethanol (2 x 15mL) and followed by diethyl ether (2 x 10mL). The crude product was then left to dry before recording the yield. 20mg of the crude product is then accurately weighed out and dissolved in deionized water in a 25mL volumetric flask. Deionized water was added to the volumetric flask to the mark and the UV-vis absorption spectrum of the crude product was recorded.