Video Transcript
Consider the following reaction. What product, X, is formed in the reaction?
Let’s begin by examining the reactants of the provided reaction. The first reactant belongs to a class of organic molecules called phenols or phenolic compounds. The basic unit of a phenolic compound is a hydroxy group bonded directly to an aromatic ring. The phenolic compound shown here has a second substituent bonded to the aromatic ring. This substituent is known as a hydroxymethyl group. Therefore, one name that chemists use for this molecule is 4-(hydroxymethyl)phenol. The number four tells the carbon position of the hydroxymethyl group. And hydroxymethyl appears inside parentheses to indicate that this hydroxy group is associated with a methyl group and not bonded directly to the aromatic ring.
The second reactant is the hydrohalic acid known as hydrochloric acid. We know that phenol alone does not react with hydrochloric acid. However, primary alcohols, such as ethanol, do react with hydrochloric acid under certain conditions. A substitution reaction takes place, in which the hydroxy group of ethanol is removed and replaced with chlorine. The products of the reaction are a haloalkane called chloroethane and water. Similarly, when 4-(hydroxymethyl)phenol and hydrochloric acid are heated, a substitution reaction does take place. The hydroxy group that is not bonded directly to the aromatic ring is removed and replaced with chlorine.
The products of the substitution reaction are a new phenolic compound, compound X, and water. And we can see in the chemical structure of this new phenolic compound that the hydroxy group that was not directly bonded to the aromatic ring has been replaced with a chlorine atom. In conclusion, the product X of the provided reaction is the structure we’ve drawn here in blue.
