Question

What is the structure of the acetal formed by reaction of ethanol with acetophenone?

Answer 1

The structure of the acetal is `"C"_6"H"_5"C"("CH"_3)("OCH"_2"CH"_3)_2`.

Explanation:

The structure of the acetal is `"C"_6"H"_5"C"("CH"_3)("OCH"_2"CH"_3)_2`.

Ketones react in the presence of acids to form hemiacetals, and the hemiacetals can react further to form acetals.

The general equation is

`"RCOR' + 2R''OH" stackrel("HCl")(→) "RR'C"("OR''")_2 + "H"_2"O"`

The mechanism is

(from en.wikipedia.org)

In the addition of ethanol to acetophenone, `"R" = "C"_6"H"_5`, `"R'" = "CH"_3`, and `"R''" = "CH"_2"CH"_3`.

So the structure of the acetal is given by the equation

`"C"_6"H"_5"COCH"_3 + "2CH"_3"CH"_2"OH" stackrel("HCl")(→) "C"_6"H"_5"C"("CH"_3)("OCH"_2"CH"_3)_2`