Intermediate Topic 779 of 1102 Organic Chemistry
Hydration of Alkenes
Acid-catalyzed addition of water to give alcohols.
In-depth explanation of Hydration of Alkenes
Hydration of alkenes is the addition of water across the carbon-carbon double bond to form an alcohol. Under acid catalysis, the alkene is protonated to form the more stable carbocation, which then reacts with water and loses a proton, so the reaction follows Markovnikov's rule. The process is reversible, and the equilibrium can be shifted by controlling the conditions. Industrially, ethanol is made from ethene by this route using phosphoric acid on a solid support at about 300 degrees Celsius and around 70 atmospheres.
Going deeper: Hydration of Alkenes
Key ideas: Acid-catalysed hydration (dilute H2SO4 or H3PO4) follows Markovnikov addition to give the more substituted alcohol; it is reversible and rearrangements are possible. Oxymercuration-demercuration (Hg(OAc)2, then NaBH4) gives the same regiochemistry without rearrangement. Hydroboration-oxidation gives the anti-Markovnikov alcohol with syn stereochemistry. Industrial ethanol: ethene at 300 C, 60 atm, phosphoric acid.
Common mistakes and connections: Students predict rearrangement-free products with strong acid, or the wrong regiochemistry from hydroboration. Ethene gives a primary alcohol only because of its symmetry. Links to Markovnikov rule, ethanol production and dehydration (the reverse reaction, by Le Chatelier).
Visualization of Hydration of Alkenes
Acid-catalysed hydration protonates the alkene, water attacks the carbocation, and loss of a proton gives the alcohol in line with Markovnikov orientation. The interactive lesson shows this as a live animation or chart.
Worked example and use case
Ethene reacts with water in the presence of an acid catalyst to give ethanol, CH2=CH2 plus H2O giving CH3CH2OH.
Frequently asked questions about Hydration of Alkenes
What is Hydration of Alkenes?
Acid-catalyzed addition of water to give alcohols.
Is Hydration of Alkenes a beginner, intermediate or advanced topic?
Hydration of Alkenes is a intermediate topic in Organic Chemistry. It builds on the vocabulary of beginner topics in this area.
What should I learn before Hydration of Alkenes?
Study these earlier topics in Organic Chemistry first: Markovnikov's Rule, Anti-Markovnikov Addition, Hydrogenation.
What comes after Hydration of Alkenes?
The next topics in Organic Chemistry are Ozonolysis and Polymerization of Alkenes.
Can I practise Hydration of Alkenes with quizzes?
Yes. The interactive lesson includes a self-check question on Hydration of Alkenes, and the Organic Chemistry quiz draws on every topic in this area.
Where Hydration of Alkenes fits in Organic Chemistry
Hydration of Alkenes is topic 51 of 148 in Organic Chemistry.