Question

Question #4977c

Answer 1

How about this?

Explanation:

Starting materials

The name itself gives you a clue.

Ethyl phenylacetate is an ester of an alcohol and an acid.

The first word in the name tells you the alcohol is ethyl alcohol or ethanol.

The second word in the name tells you that the acid is phenylacetic acid.

So, the equation for the overall reaction is

`underbrace("C"_6"H"_5"CH"_2"CO-OH")_color(red)("phenylacetic acid") + underbrace("CH"_3"CH"_2"O-H")_color(red)("ethanol") stackrelcolor(blue)("H"^"+"color(white)(m))(→) underbrace("C"_6"H"_5"CH"_2"CO-OCH"_2"CH"_3)_color(red)("ethyl phenylacetate") + "H"_2"O"`

The mechanism

(Adapted from Diman Regional Vocational Technical High School)

Step 1. Protonation

Sulfuric acid protonates the oxygen atom of the carbonyl group to generate a resonance-stabilized carbocation with a more electrophilic carbon atom.

Step 2. Nucleophilic attack

The oxygen atom in ethanol attacks the carbocation.

Step 3 Deprotonation

The `"HSO"_4^"-"` ion removes a proton from the oxonium ion …

Step 4. Reprotonation

… and replaces it on one of the `"OH"` groups.

Step 5. Loss of water

A water molecule leaves, generating a protonated carbonyl group.

Step 6. Deprotonation

Finally, an `"HSO"_4^"-"` ion removes the proton and generates the ester.

Here's an expanded version of Step 6.