Concept explainers
(a)
Interpretation:
The product for the reaction between
Concept introduction:
The reaction in which one form of an ester is converted to another form by changing the carbon skeleton of the alkoxide part (OR) of the ester is called transesterification. The transesterification reaction is a nucleophilic addition-elimination reaction. In the first step, the nucleophile adds the electro-poor carbonyl carbon of the ester, which forces the bonding pair of carbonyl p bond onto the O atom. A negative charge is produced on that O, and a tetrahedral intermediate is formed. In the second step, tetrahedral intermediate undergoes nucleophilic elimination to form the transesterification product. The transesterification is a reversible reaction. The base hydrolysis of an ester to produce corresponding carboxylic acid and alcohol is called a saponification reaction. Saponification also involves a reversible nucleophilic addition-elimination reaction. The first step in saponification is the same as in the transesterification reaction in which the tetrahedral intermediate is formed. In the second step, nucleophilic elimination takes place to produce an alkoxide ion and the corresponding carboxylic acid. The alkoxide ion rapidly irreversibly deprotonates the carboxylic acid, leading to form the carboxylate ion and alcohol. Finally, on acid workup step, carboxylic acid is regenerated.
Answer to Problem 20.28P
The product for the reaction between
The complete detailed, mechanism for the given reaction is
Explanation of Solution
The given reaction is
So this is a saponification reaction of
In the second step, nucleophilic elimination takes place to produce an alkoxide ion and corresponding carboxylic acid. These steps are reversible.
In the third step, irreversible deprotonation of the carboxylic acid takes place and the carboxylate ion is formed. Finally, on acid workup step, protonation of the carboxylate ion takes place to form the carboxylic acid.
Thus, the products of the given reaction are
The product is predicted by using transesterification concept and the detailed mechanism is drawn.
(b)
Interpretation:
The product for the reaction between
Concept introduction:
The reaction in which one form of an ester is converted to another form by changing the carbon skeleton of the alkoxide part (OR) of the ester is called transesterification. The transesterification reaction is a nucleophilic addition-elimination reaction. In the first step, the nucleophile adds the electro-poor carbonyl carbon of the ester, which forces the bonding pair of carbonyl p bond onto the O atom. A negative charge is produced on that O, and a tetrahedral intermediate is formed. In the second step, tetrahedral intermediate undergoes nucleophilic elimination to form the transesterification product. The transesterification is a reversible reaction. The base hydrolysis of an ester to produce corresponding carboxylic acid and alcohol is called a saponification reaction.
Answer to Problem 20.28P
The product for the reaction between
The complete detailed, mechanism for the given reaction is
Explanation of Solution
The given reaction is
This is a transesterification reaction of
In the second step, the tetrahedral intermediate undergoes nucleophilic elimination to form the transesterification product.
Thus, the product of the given reaction is
The product is predicted by using transesterification concept and the detailed mechanism is drawn.
(c)
Interpretation:
The product for the reaction between
Concept introduction:
The reaction in which one form of an ester is converted to another form by changing the carbon skeleton of the alkoxide part (OR) of the ester is called transesterification. The transesterification reaction is a nucleophilic addition-elimination reaction. In the first step, the nucleophile adds the electro-poor carbonyl carbon of the ester, which forces the bonding pair of carbonyl p bond onto the O atom. A negative charge is produced on that O, and a tetrahedral intermediate is formed. In the second step, tetrahedral intermediate undergoes nucleophilic elimination to form the transesterification product. The transesterification is a reversible reaction. The base hydrolysis of an ester to produce corresponding carboxylic acid and alcohol is called a saponification reaction.
Answer to Problem 20.28P
The product for the reaction between
The complete detailed, mechanism for the given reaction is
Explanation of Solution
The given reaction is
This is a transesterification reaction of the
In the second step, tetrahedral intermediate undergoes nucleophilic elimination to form the transesterification product.
Since phenoxide ion (
Thus, the product of the given reaction is
The product is predicted by using transesterification concept and the detailed mechanism is drawn.
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Chapter 20 Solutions
ORGANIC CHEMISTRY:PRIN...(PB)-W/ACCESS
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- Organic Chemistry: A Guided InquiryChemistryISBN:9780618974122Author:Andrei StraumanisPublisher:Cengage Learning