Electrophilic hydration is the addition of electrophilic hydrogen from a non-nucleophilic strong acid (a reusable catalyst, examples of which include sulfuric and phosphoric acid) and applying appropriate temperatures to break the alkene’s double bond. After a carbocation is formed, water bonds with the carbocation to form a 1º, 2º, or 3º alcohol on the alkane. Electrophilic hydration is the reverse dehydration of alcohols and has practical application in making alcohols for fuels and reagents for other reactions. The basic reaction under certain temperatures is as follows;

generic acid-catalyzed electrophilic hydration of an alkene reaction.svg

Electrophilic hydrogen is essentially a proton: a hydrogen atom stripped of its electrons. Electrophilic hydrogen is commonly used to help break double bonds or restore catalysts.

Mechanism for 3º Alcohol:

Hydration is the process where water is added to an alkene to yield an alcohol. Acid-catalyzed hydration is when a strong acid is used as a catalyst to begin the reaction, the mechanism:

mechanism for an acid-catalyzed electrophilic hydration of an alkene reaction.svg

Step 1: A hydrogen atom from the acid is attacked by the nucleophilic Pi-electrons in the double bond. A new C-H bond is formed to create the more stable carbocation.

Step 2: A nucleophilic water attacks or donates a lone pair to the positively charged carbon in the carbocation intermediate created in the first step. There is new C-O bond with the O having a formal charge of +1. The product is a protonated alcohol.

Step 3: The final step is to deprotonate the oxygen atom with the +1 formal charge using the acid regenerating the acid catalyst and yields the neutral alcohol product.

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