What products would you expect from acid-catalyzed hydration of the following alkenes?
a. propene
b. 2-methylpropene
To predict the products obtained from acid-catalyzed hydration of alkenes, we need to understand the mechanism of the reaction. Acid-catalyzed hydration involves the addition of water (H2O) across the carbon-carbon double bond (C=C) of an alkene, resulting in the formation of an alcohol.
a. Propene:
The acid-catalyzed hydration of propene proceeds as follows:
1. The acidic catalyst, usually sulfuric acid (H2SO4), donates a proton (H+) to the double bond, forming a carbocation intermediate.
2. Water molecules then attack the carbocation, with one water molecule acting as a nucleophile and attacking the carbon atom linked to the most number of hydrogen atoms. This leads to the formation of a protonated alcohol intermediate.
3. Finally, the protonated alcohol intermediate loses a proton (H+), resulting in the formation of the alcohol product.
In the case of propene, the addition of water across the double bond would result in the formation of propan-2-ol (isopropyl alcohol) as the product.
b. 2-methylpropene:
The acid-catalyzed hydration of 2-methylpropene proceeds similarly to propene:
1. The acidic catalyst donates a proton (H+) to the double bond, forming a carbocation intermediate.
2. Water molecules attack the carbocation, leading to the formation of a protonated alcohol intermediate.
3. Finally, the protonated alcohol intermediate loses a proton (H+), resulting in the formation of the alcohol product.
In the case of 2-methylpropene, the addition of water across the double bond would result in the formation of 2-methylpropan-2-ol (tert-butyl alcohol) as the product.
So, the expected products from acid-catalyzed hydration are propan-2-ol for propene and 2-methylpropan-2-ol for 2-methylpropene.