Organic Chemistry : Help with Carboxylic Acid Synthesis

Study concepts, example questions & explanations for Organic Chemistry

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Example Questions

Example Question #1 : Carboxylic Acid Chemistry

Which of the following reactions would NOT produce a carboxylic acid?

Possible Answers:

Correct answer:

Explanation:

PCC is considered a weak oxidizing agent. The reaction of a primary alcohol with PCC would only yield an aldehyde, while reaction with a secondary alcohol will yield a ketone. PCC will not be used to generate carboxylic acids.

A stronger oxidation, like or , is required to oxidize up to the carboxylic acid. Treatment of an ester with a base or treatment of carbon dioxide with a Grignard reagent are other ways of making carboxylic acids.

Example Question #2 : Carboxylic Acid Chemistry

Which one of the following compounds can produce a carboxylic acid only when reacted with sodium dichromate and sulfuric acid?

Possible Answers:

Pentanal

1-pentanol

2-pentanone

2-methylpentan-2-ol

2-pentanol

Correct answer:

1-pentanol

Explanation:

After recognizing the reagents given, we know we need to begin with an alcohol. The alcohol choices differ only by how substituted they are.

For a carboxylic acid to form from a reaction with sodium dichromate and sulfuric acid, a primary alcohol needs to be available. Therefore, 1-pentanol is the correct answer.

Example Question #1 : Carboxylic Acid Chemistry

When 3-chloroheptane undergoes malonic ester synthesis, the final product is __________.

Possible Answers:

malonic ester

None of the other answers

a ten-carbon ketone

nonanoic acid

3-ethylheptanoic acid

Correct answer:

3-ethylheptanoic acid

Explanation:

The malonic ester is deprotonated at the most acidic hydrogen, the one on the carbon between the two oxygens. The electrons from that bond to the hydrogen form a carbon-carbon double bond while electrons from the oxygen-carbon double bond go to the oxygen atom. This is the enolate form. The chlorine leaves the 3-chloroheptane and the electrons from the carbon-carbon double bond bond to the carbon that the chlorine left. At the same time, the carbonyl is reformed. After deesterfication, 3-ethylheptanoic acid is formed.

Example Question #1 : Help With Carboxylic Acid Synthesis

Which of the following is not a derivative of a carboxylic acid?

Possible Answers:

Ester

Amide

Aldehyde

All of these are carboxylic acid derivatives

Correct answer:

Aldehyde

Explanation:

Aldehyde is not a derivative of carboxylic acid. Esters can be derived from carboxylic acids by reacting them with  to form an acid chloride. From there, react it with an  to form an ester. Amides can be derived from carboxylic acids by reacting them with  to form an acid chloride. From there, react it with  to form an amide.

Example Question #1 : Help With Carboxylic Acid Synthesis

Which of the following reagents is needed to convert an amide into a carboxylic acid?

Possible Answers:

All of these

Correct answer:

Explanation:

As a general rule, any carboxylic acid derivative can be converted into al carboxylic acid when reacting with 

Example Question #2 : Help With Carboxylic Acid Synthesis

Noname01

What is the product of the given reaction?

Possible Answers:

Noname02

5

Noname01

3

Noname01

Correct answer:

Noname01

Explanation:

The hydrolyzation of a nitrile with hydronium leads to a carboxylic acid. Only one choice is a carboxylic acid.

Example Question #3 : Help With Carboxylic Acid Synthesis

Please choose the best answer for the following question.

Which of the following reagents is best for converting a primary alcohol to a carboxylic acid?

Possible Answers:

 and 

 (cold and dilute)

PCC

Correct answer:

Explanation:

 is the only strong oxidizing agent listed. It is strong enough to oxidize the primary alcohol even further to a carboxylic acid product. The rest of the compounds listed are weak oxidizing agents or reducing agents.

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