Electrophilic Aromatic Iodination of Vanillin

The objective of this lab was to create a ketone through an oxidation reaction using a using a secondary alcohol and oxidizing agent in order to use that ketone in a reduction reaction with a specific reducing agent to determine the affect of that reducing agent on the diastereoselectivity of the product. In the first part of this experiment, 4-tert-butylcyclohexanol was reacted with NaOCl, an oxidizing agent, and acetic acid to form 4-tert-butylcyclohexanone. In the second part of this experiment, 4-tert-butylcyclohexanone was reacted with a reducing agent, either NaBH4 in EtOH or Al(OiPr)3 in iPrOH, to form the product 4-tert-butylcyclohexanol. 1H NMR spectroscopy was used to determine the cis:trans ratio of the OH relative to the tert-butyl group in the product formed from the reduction reaction with each reducing agent. Thin-layer chromatography was used in both the oxidation and reduction steps to ensure that each reaction ran to completion.

During recrystallization, the solution was to be cooled to room temperature before placing it in an ice bath. Doing this allows enough time for the crystals to be formed because as the temperature decreases, the rate of crystallization slows down. If the solution was placed in the ice bath too quickly, then the cold would have blocked out the impurities and trapped them in the solution. The more impurities present, the lower the melting point so data would have been inaccurate. Also, if the melting point apparatus wasn’t set up correctly, the data would have been imprecise.

6. Summarize in a few sentences the halogenation and controlled oxidation reactions of 1°, 2°, and 3° alcohols.

There are four major systematic errors in the laboratory, which are the fact that some of the Alka-Seltzer pills were chipped, some of the water splashed out of the beaker, we didn’t know when the reaction was actually finished, and the mass of the Alka-Seltzer might have been different.

The Purpose of this experiment is for the students to learn how to use sodium borohydride to reduce benzil to its secondary alcohol product via reduction reaction. This two-step reaction reduces aldehydes by hydrides to primary alcohols, and ketones to secondary alcohols. In order for the reaction to occur and to better control the stereochemistry and yield of the product, the metal hydride nucleophile of the reducing agents such as LiH, LiAlH4, or NaBH4 must be carefully chosen. Being that LiAlH4 and NaBH4 will not react with isolated carbon-carbon double bonds nor the double bonds from aromatic rings; the chosen compound can be reduce selectively when the nucleophile only react with

In reference to the analysis of anions, Table 1 shows that a precipitate was formed when our unknown was combined with HNO3 and AgNO3, thus indicating the presence of a chloride ion. Because our unknown did not form a precipitate due to HCl and BaCl2, separate, effervesce, or smell, we concluded that neither sulfate, nitrate, carbonate nor

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

thiosulfate anion needed to react with each mole of hypochlorite anion in the bleach sample.

Each scenario below describes an operational error that can lead to low yield and/or low purity of product(s) or during the extractions of this experiment. In each case specify the component(s) whose percentage(s) would be too high or too low, and briefly explain your answer.

One of these errors could have possibly been that the solutions were left uncovered during the testing phase. An uncovered solution can be contaminated with certain particles of elements found in the air that settle in the solutions, creating colors that are not are not linked with that specific element. This can be compensated for by covering the solutions with a lid prior to testing, in order to limit exposure to any outside factors.

The solution was let cool in ice water then using vacuum filtration to obtain the final product. Although the obtained product was white like powder, the identity of the product couldn’t be confirmed as cyclododecanone yet. Letting the obtained product stay open on the watch glass overnight to make sure all methanol evaporated. Following the third part was infrared spectroscopy and melting point to characterize the

3. a. The first error will be when transferring the benzoic acid from the weigh paper to the vial. The benzoic acid is spilled. Then, the second one will be when pipetting and transferring the methylene chloride because I might spill some of the methylene chloride. The third one will be when pipetting the two layers, either I could not pipet all of the bottom layer or I accidentally pipet the top layer.

In this preparative lab, an aldol (trans-p-anisalacetophenone) was produced from the reaction between p-anisaldehyde and acetophenone with the presence sodium hydroxide. The reaction also showed the importance of an enolate and the role it played in the mechanism. Sodium hydroxide acts as a catalyst in this experiment and is chosen because of its basic conditions and pH. The acetophenone carries an alpha hydrogen that has a pKa between 18 and 20. This alpha hydrogen is acidic because of its location near the carbonyl on acetophenone. When the sodium hydroxide is added, it deprotonates the hydrogen and creates an enolate ion. This deprotonation creates a nucleophilic carbon that can attack an electrophilic carbon (like a parent

Aromatic compounds can undergo electrophilic substitution reactions. In these reactions, the aromatic ring acts as a nucleophile (an electron pair donor) and reacts with an electrophilic reagent (an electron pair acceptor) resulting in the replacement of a hydrogen on the aromatic ring with the electrophile. Due to the fact that the conjugated 6π-electron system of the aromatic ring is so stable, the carbocation intermediate loses a proton to sustain the aromatic ring rather than reacting with a nucleophile. Ring substituents strongly influence the rate and position of electrophilic attack. Electron-donating groups on the benzene ring speed up the substitution process by stabilizing the carbocation intermediate. Electron-withdrawing groups, however, slow down the aromatic substitution because formation of the carbocation intermediate is more difficult. The electron-withdrawing group withdraws electron density from a species that is already positively charged making it very electron deficient. Therefore, electron-donating groups are considered to be “activating” and electron-withdrawing groups are “deactivating”. Activating substituents direct incoming groups to either the “ortho” or “para” positions. Deactivating substituents, with the exception of the halogens, direct incoming groups to the “meta” position. The experiment described above was an example of a specific electrophilic aromatic

One of the drawbacks of using iodine is its low solubility in water, as well as its potential staining of teeth. One path to overcome these disadvantages is changing the drug delivery of iodine. Iodine complexed with polyvinyl pyrrolidone(PVP),to form povidone-iodine(PI), increase water solubility, decrease irritation and decrease the staining caused by pure iodine.(13)