Organic Chemistry : Using PCC

Study concepts, example questions & explanations for Organic Chemistry

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Example Questions

Example Question #1 : Using Pcc

What is the product when 2-butanol is treated with PCC?

Possible Answers:

2-butanone

1-butanol

1-butanone

None of these

2-butanol

Correct answer:

2-butanone

Explanation:

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.

Example Question #2 : Using Pcc

What is the product of 1-pentanol when it is treated with PCC?

Possible Answers:

2-pentanol

Pentanal

None of these

1-pentanone

No reaction occurs

Correct answer:

Pentanal

Explanation:

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.

Example Question #3 : Using Pcc

Screen shot 2015 07 02 at 8.08.51 pm

Which reagent is best-suited to accomplish the given reaction?

Possible Answers:

PCC

Correct answer:

PCC

Explanation:

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.

Example Question #3 : Using Pcc

Img 0634

Which reagents are required to drive the given reaction?

Possible Answers:

Correct answer:

Explanation:

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.

Example Question #1 : Organic Oxidizing Agents

Which of the following is not true regarding the reagent ?

Possible Answers:

 can oxidize secondary alcohols into ketones

 can oxidize aldehydes into carboxylic acids

None of these

 can oxidize primary alcohols into aldehydes

Correct answer:

 can oxidize aldehydes into carboxylic acids

Explanation:

 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 .

Example Question #5 : Using Pcc

What is the product of the reaction shown?

Screen shot 2015 11 13 at 3.21.06 pm

Screen shot 2015 11 13 at 3.21.14 pm

Possible Answers:

IV

III

V

II

I

Correct answer:

III

Explanation:

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

Example Question #6 : Using Pcc

Which of the following compounds is not a reducing agent?

Possible Answers:

Correct answer:

Explanation:

 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.

Example Question #4 : Using Pcc

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What would be the product of the given reaction?

Possible Answers:

Screen shot 2015 12 29 at 6.56.32 am

Screen shot 2015 12 29 at 6.56.22 am

Screen shot 2015 12 29 at 6.56.28 am

Screen shot 2015 12 29 at 6.44.15 am

Correct answer:

Screen shot 2015 12 29 at 6.44.15 am

Explanation:

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:

Screen shot 2015 12 31 at 12.49.15 pm

Example Question #5 : Using Pcc

Screen shot 2015 12 31 at 10.30.13 am

What would be the product of the given reaction?

Possible Answers:

Screen shot 2015 12 31 at 10.27.21 am

Screen shot 2015 12 31 at 10.27.13 am

Screen shot 2015 12 31 at 10.27.26 am

Screen shot 2015 12 31 at 10.27.06 am

Correct answer:

Screen shot 2015 12 31 at 10.27.06 am

Explanation:

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:

Screen shot 2015 12 31 at 12.35.23 pm

Example Question #6 : Using Pcc

What is the product of the reaction shown?

Image6

Possible Answers:

Correct answer:

Explanation:

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).

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