Redox Chemistry - Organic Chemistry

In order to drive the reactant, we must first convert the alcohol group on the ethanol into a carboxylic acid. We do so by using the oxidizing agent, , a very strong oxidizing agent that is well known to oxidize primary alcohols into carboxylic acids (among other functions). Once we have our carboxylic acid, we can simply use to convert our carboxylic acid into an acid halide to attain our desired final product.

is a strong oxidizing agent.

Not only can reduce secondary alcohols into ketones, but it can reduce primary alcohols and aldehydes into carboxylic acids.

Any time we have a Grignard reagent and a primary haloalkane, we will see a substitution reaction, identical to an reaction. In this case, the Grignard can easily attack the haloalkane as the bromine leaves to create hexene.

To solve this question we need to calculate the oxidation number of oxygen in both molecules. The formula for water is . The oxidation number of hydrogen is +1. Since there are two of them, the hydrogen atoms contribute to a charge of +2. The water molecule is neutral; therefore, the oxygen must have an oxidation number of to balance the charge. The formula for hydrogen peroxide is . Using the same logic as water, we can determine that hydrogen contributes +2. We have two oxygen atoms in this case; therefore, each oxygen atom will have an oxidation number of to give a charge of . This will balance the charges and provide a neutral hydrogen peroxide molecule.

Recall that have a negative charge suggests that an atom has extra valence electrons. A charge of suggests one extra valence electron and a charge of suggests two extra valence electrons. An oxygen typically has six valence electrons. The oxygen in water has oxidation number; therefore, it will have two extra valence electrons (eight total). On the other hand, oxygen in hydrogen peroxide will have one extra valence electron (seven total); therefore, oxygen in hydrogen peroxide has one less valence electron than oxygen in water.

Potassium bromide has a formula of . This molecule is made up of an alkali metal (potassium) and a halogen (bromine). Alkali metals have one valence electron that they readily lose to obtain octet whereas halogens have seven valence electrons and they readily gain an electron to obtain octet. Recall that losing an electron will give you a oxidation number whereas gaining an electron will give you a oxidation number. This means that alkali metals always have an oxidation number of whereas halogens always have an oxidation number of ; therefore, potassium has an oxidation number of .

The following reaction schemes show the oxidation of all substrates, indicating that substrate II is in the highest oxidation state possible, and that an oxidation of this compound will not proceed.

Remember that in sulfuric acid and water, Na2Cr2O7 will be converted to CrO3, the active oxidant species. Furthermore, the oxidation mechanism involving this species includes the key step in which a hydrogen bonded to the carbon in question is eliminated_,_ and simutaneously, a double bond from that carbon to an oxygen is installed. Thus, all substrates that feature at least one hydrogen bonded to the carbon to be oxidized can and will be oxidized in the precense of chromium trioxide.

Lastly, remember that these reactions are taking place in the prescence of water. While substrates such as compound III do not appear to be oxidizable, attack of water at the aldehyde carbon will give a dialcohol tetrathedral intermediate that can be immediately oxidized by chromium trioxide to the corresponding carboxylic acid. A similar mechanism occurs for substrate I, wherein, after the ketone oxidation state is achieved, an attack of water furnishes the same dialcohol intermediate that is oxidized to the carboxylic acid. Remember that the highest oxidation state available for organic compounds containing more than one carbon is the carboxylic acid oxidation state. Chromium trioxide will oxidize all organics to this oxidation state, unless directly-bonded hydrogens are not present in lower oxidation states, such as shown with substrate IV.

The reaction given would give a ketone. This type of reaction is called an oxidation reaction. Oxidation of a secondary alcohol as in the reaction given by (sodium dichromate) in an aqueous solution of (acetic acid) solvent yields a ketone. However, if we performed the same reaction with a primary alcohol, a carboxylic acid would have formed.

The Jones reagent can convert primary alcohol to acids and secondary alcohols to ketones. The Tollen's test only converts aldehydes to carboxylic acids. PCC can only convert primary and secondary alcohol to aldehydes and ketones, respectively. and are reducing agents.

To form the aldehyde, the alcohol must be oxidized. However, potassium permanganate and chromic acid are too strong and would yield a carboxylic acid. Ozonolysis works with alkenes and oxygen over platinum would not react. PCC is correct because it will oxidize the alcohol to form an aldehyde but is too weak to continue on to form the carboxylic acid.

PCC is an oxidizing agent. It converts alcohols to ketones, but is not strong enough to convert primary alcohols to carboxylic acids. 2-butanol has a hydroxy group on its carbon 2. The addition of PCC will convert this hydroxy group into a carbonyl, producing 2-butanone.

PCC is an oxidizing agent. It converts alcohols to carbonyls, but is not strong enough to convert a primary alcohol into a carboxylic acid. It only converts primary alcohols to aldehydes, and secondary alcohols to ketones. 1-pentanol is a primary alcohol so it will be converted to the aldehyde pentanal.

PCC is an oxidizing agent that reacts with primary and secondary alcohols. However, it is less reactive than potassium permanganate and chromic acid. PCC differs from chromic acid by oxidizing primary alcohols to aldehydes, whereas chromic acid oxidizes primary alcohols and aldehydes to carboxylic acids. The desired product of the reaction given requires that the primary alcohol be oxidized to an aldehyde, so PCC is the best option. is a reducing agent and would have the opposite effect than what is desired, yielding an alkane.

This is a two step reaction. In the first step, an alcohol is substituted for the bromine via an reaction. Next, the alcohol is oxidized into a ketone with , a strong oxidizing agent used almost exclusively for converting alcohols into carbonyls.

has the capability of oxidizing primary alcohols into aldehydes and secondary alcohols into ketones. However, it cannot oxidize aldehydes into carboxylic acids. To do that, we would need a stronger oxidizing agent such as .

First step: PCC oxidizes the primary alcohol to acetaldehyde

Second step: Grignard reagent attacks carbonyl carbon

Third step: Neutralization of the anion forms isoproyl alcohol

is the only compound listed that is not a reducing agent. Pyridinium chlorochromate is a weak oxidizing agent and is often used to oxidize alcohols into carbony compounds. All of the other compounds are similar in that they function as reducing agents.

The reaction given would give an aldehyde. This type of reaction is called an oxidation reaction. Oxidation of a primary alcohol as in the reaction given by PCC (pyridinium chlorochromate) in (dichloromethane) solvent yields an aldehyde. Like chromic acid, PCC oxidizes alcohols. However, PCC only oxidizes primary alcohols one step up to aldehydes and secondary alcohols to ketones. Chromic acid is a harsher oxidant because it will oxidize aldehydes to carboxylic acids. Below is the mechanism for this reaction:

The reaction given would give an aldehyde. This type of reaction is called an oxidation reaction. Oxidation of a primary alcohol as in the reaction given by PCC (pyridinium chlorochromate) in (dichloromethane) solvent yields an aldehyde. Like chromic acid, PCC oxidizes alcohols. However, PCC only oxidizes primary alcohols one step up to aldehydes and secondary alcohols to ketones. Chromic acid is a harsher oxidant because it will oxidize aldehydes to carboxylic acids. Below is the mechanism for this reaction: Below is the mechanism:

PCC can be used to oxidize primary alcohols into aldehydes, or secondary alcohols into ketones. The starting material shown is a secondary alcohol, so the product will be a ketone (a carbonyl () group where the carbonyl carbon is also attached to two other carbons).

Potassium permanganate is a strong oxidizing agent. It can convert secondary alcohols to ketones. It can also convert primary alcohols to carboxylic acids. 1-propanol has a hydroxy group on carbon 1, so it is primary; thus it will be converted to propanoic acid.